posts: 36318

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id	title	slug	type	status	content	archieml	archieml_update_statistics	published_at	updated_at	gdocSuccessorId	authors	excerpt	created_at_in_wordpress	updated_at_in_wordpress	featured_image	formattingOptions	markdown	wpApiSnapshot
36318	Transport	transport	page	publish	<!-- wp:html --> <div class="blog-info">First published in September 2021.</div> <!-- /wp:html --> <!-- wp:html --> <!-- formatting-options subnavId:energy subnavCurrentId:transport --> <!-- /wp:html --> <!-- wp:heading --> <h2>Road travel</h2> <!-- /wp:heading --> <!-- wp:heading {"level":3} --> <h3>Passenger vehicle registrations by type</h3> <!-- /wp:heading --> <!-- wp:columns --> <div class="wp-block-columns"><!-- wp:column --> <div class="wp-block-column"><!-- wp:paragraph --> <p>These interactive charts show the breakdown of new passenger vehicle registrations by type.</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>This is broken down by: petroleum; diesel; full hybrid (excluding plug-in hybrids); plug-in electric hybrids; and fully electric battery vehicles.</p> <!-- /wp:paragraph --></div> <!-- /wp:column --> <!-- wp:column --> <div class="wp-block-column"><!-- wp:html --> <iframe src="https://ourworldindata.org/grapher/new-vehicles-type-area?tab=chart&stackMode=relative&country=~NOR" loading="lazy" style="width: 100%; height: 600px; border: 0px none;"></iframe> <!-- /wp:html --> <!-- wp:html --> <iframe src="https://ourworldindata.org/grapher/new-vehicles-type-share?tab=chart&country=~GBR" loading="lazy" style="width: 100%; height: 600px; border: 0px none;"></iframe> <!-- /wp:html --> <!-- wp:owid/prominent-link {"title":"Number of new passenger vehicle registrations by type","linkUrl":"https://ourworldindata.org/grapher/new-passenger-vehicles-type?country=~GBR","className":"is-style-thin"} /--></div> <!-- /wp:column --></div> <!-- /wp:columns --> <!-- wp:heading {"level":3} --> <h3>Electric vehicle registrations</h3> <!-- /wp:heading --> <!-- wp:columns --> <div class="wp-block-columns"><!-- wp:column --> <div class="wp-block-column"><!-- wp:paragraph --> <p>This interactive chart shows the share of new passenger vehicle registrations that are battery electric vehicles. This does not include plug-in hybrid vehicles.</p> <!-- /wp:paragraph --></div> <!-- /wp:column --> <!-- wp:column --> <div class="wp-block-column"><!-- wp:html --> <iframe src="https://ourworldindata.org/grapher/share-vehicle-electric?country=AUT~ITA~NOR~PRT~ESP~SWE~CHE~TUR~GBR~IRL~ISL~GRC~DEU~FRA~FIN~DNK~BEL~LUX~NLD" loading="lazy" style="width: 100%; height: 600px; border: 0px none;"></iframe> <!-- /wp:html --></div> <!-- /wp:column --></div> <!-- /wp:columns --> <!-- wp:columns --> <div class="wp-block-columns"><!-- wp:column --> <div class="wp-block-column"><!-- wp:paragraph --> <p>This interactive chart shows the share of new passenger vehicle registrations that are battery electric <em>plus</em> plug-in hybrid vehicles.</p> <!-- /wp:paragraph --></div> <!-- /wp:column --> <!-- wp:column --> <div class="wp-block-column"><!-- wp:html --> <iframe src="https://ourworldindata.org/grapher/battery-plugin-hybrid-vehicles?time=2019&country=~AUT~BEL~DNK~FIN~EU-27+%2B+UK~FRA~DEU~GRC~ISL~IRL~GBR~TUR~CHE~SWE~ESP~PRT~NOR~NLD~LUX~ITA" loading="lazy" style="width: 100%; height: 600px; border: 0px none;"></iframe> <!-- /wp:html --></div> <!-- /wp:column --></div> <!-- /wp:columns --> <!-- wp:heading {"level":3} --> <h3>Carbon intensity of new passenger vehicles</h3> <!-- /wp:heading --> <!-- wp:columns --> <div class="wp-block-columns"><!-- wp:column --> <div class="wp-block-column"><!-- wp:paragraph --> <p>This interactive chart shows the average carbon intensity of new passenger vehicles in each country.</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>This is measured as the average emissions of CO₂ (in grams) per kilometer travelled across all types of passenger vehicles.</p> <!-- /wp:paragraph --></div> <!-- /wp:column --> <!-- wp:column --> <div class="wp-block-column"><!-- wp:html --> <iframe src="https://ourworldindata.org/grapher/carbon-new-passenger-vehicles?country=AUT~ITA~LUX~NLD~NOR~PRT~ESP~SWE~CHE~TUR~GBR~IRL~ISL~GRC~DEU~FRA~FIN~DNK~BEL" loading="lazy" style="width: 100%; height: 600px; border: 0px none;"></iframe> <!-- /wp:html --></div> <!-- /wp:column --></div> <!-- /wp:columns --> <!-- wp:heading {"level":3} --> <h3>Fuel economy of new passenger vehicles</h3> <!-- /wp:heading --> <!-- wp:columns --> <div class="wp-block-columns"><!-- wp:column --> <div class="wp-block-column"><!-- wp:paragraph --> <p>This interacrive chart shows the average fuel economy of new passenger vehicles in each country.</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>This is measured as the average liters consumed per 100 kilometers travelled, across all types of passenger vehicles.</p> <!-- /wp:paragraph --></div> <!-- /wp:column --> <!-- wp:column --> <div class="wp-block-column"><!-- wp:html --> <iframe src="https://ourworldindata.org/grapher/fuel-efficiency-new-vehicles?country=AUT~BEL~ITA~LUX~NLD~NOR~PRT~ESP~SWE~CHE~TUR~GBR~IRL~ISL~GRC~DEU~FRA~FIN~DNK" loading="lazy" style="width: 100%; height: 600px; border: 0px none;"></iframe> <!-- /wp:html --></div> <!-- /wp:column --></div> <!-- /wp:columns --> <!-- wp:heading --> <h2>Aviation</h2> <!-- /wp:heading --> <!-- wp:heading {"level":3} --> <h3>What share of global CO<sub>2</sub> emissions come from aviation?</h3> <!-- /wp:heading --> <!-- wp-block-tombstone 45124 --> <!-- wp:paragraph --> <p>Flying is a highly controversial topic in climate debates. There are a few reasons for this. </p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>The first is the disconnect between its role in our personal and collective carbon emissions. Air travel dominates a frequent traveller's individual contribution to climate change. Yet aviation overall accounts for only 2.5% of global carbon dioxide (CO<sub>2</sub>) emissions. This is because there are large inequalities in how much people fly – many do not, or cannot afford to, fly at all.{ref}The best estimates put this figure at around 80% of the world population. We look at this in more detail in our article "<a href="https://ourworldindata.org/carbon-footprint-flying">Where in the world do people have the highest CO2 emissions from flying?</a>"{/ref}</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>The second is how aviation emissions are attributed to countries. CO<sub>2</sub> emissions from domestic flights <em>are</em> counted in a country’s emission accounts. International flights are not – instead they are counted as their own category: ‘bunker fuels’. The fact that they don’t count towards the emissions of any country means there are few incentives for countries to reduce them.</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>It’s also important to note that unlike the most common greenhouse gases – carbon dioxide, methane or nitrous oxide – non-CO<sub>2</sub> forcings from aviation <em>are not included</em> in the Paris Agreement. This means they could be easily overlooked – especially since international aviation is not counted within any country’s emissions inventories or targets.</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>How much of a role does aviation play in global emissions and climate change? In this article we take a look at the key numbers that are useful to know.</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>Global aviation (including domestic and international; passenger and freight) accounts for:</p> <!-- /wp:paragraph --> <!-- wp:list --> <ul><li><strong>1.9%</strong> of <a href="https://ourworldindata.org/ghg-emissions-by-sector">greenhouse gas emissions</a> (which includes all greenhouse gases, not only CO<sub>2</sub>)</li><li><strong>2.5%</strong> of CO<sub>2</sub> emissions</li><li><strong>3.5%</strong> of 'effective radiative forcing' – a closer measure of its impact on warming.</li></ul> <!-- /wp:list --> <!-- wp:paragraph --> <p>The latter two numbers refer to 2018, and the first to 2016, the latest year for which such data are available.</p> <!-- /wp:paragraph --> <!-- wp:separator --> <hr class="wp-block-separator"/> <!-- /wp:separator --> <!-- wp:heading {"level":4} --> <h4>Aviation accounts for 2.5% of global CO<sub>2</sub> emissions</h4> <!-- /wp:heading --> <!-- wp:paragraph --> <p>As we will see later in this article, there are a number of processes by which aviation contributes to climate change. But the one that gets the most attention is its contribution via CO<sub>2</sub> emissions. Most flights are powered by jet gasoline – although some partially run on biofuels – which is converted to CO<sub>2</sub> when burned.  </p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>In a recent paper, researchers – David Lee and colleagues – reconstructed annual CO<sub>2 </sub>emissions from global aviation dating back to 1940.{ref}Lee, D. S., Fahey, D. W., Skowron, A., Allen, M. R., Burkhardt, U., Chen, Q., ... & Gettelman, A. (2020). <a href="https://www.sciencedirect.com/science/article/pii/S1352231020305689">The contribution of global aviation to anthropogenic climate forcing for 2000 to 2018</a>. <em>Atmospheric Environment</em>, 117834.{/ref} This was calculated based on fuel consumption data from the International Energy Agency (IEA), and earlier estimates from Robert Sausen and Ulrich Schumann (2000).{ref}Sausen, R., & Schumann, U. (2000). <a href="https://link.springer.com/article/10.1023/A:1005579306109">Estimates of the climate response to aircraft CO2 and NOx emissions scenarios</a>. <em>Climatic Change</em>, <em>44</em>(1-2), 27-58.{/ref}</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>The time series of global emissions from aviation since 1940 is shown in the accompanying chart. In 2018, it’s estimated that global aviation – which includes both passenger and freight – emitted 1.04 billion tonnes of CO<sub>2</sub>.</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>This represented 2.5% of <a href="https://ourworldindata.org/co2-emissions#global-co2-emissions-from-fossil-fuels-global-co2-emissions-from-fossil-fuels" data-type="URL" data-id="https://ourworldindata.org/co2-emissions#global-co2-emissions-from-fossil-fuels-global-co2-emissions-from-fossil-fuels">total CO<sub>2</sub> emissions</a> in 2018.{ref}The Global Carbon Budget estimated total CO<sub>2</sub> emissions from all fossil fuels, cement production and land-use change to be 42.1 billion tonnes in 2018. This means aviation accounted for [1 / 42.1 * 100] = 2.5% of total emissions.{/ref}<sup>,</sup>{ref}Global Carbon Project. (2019). Supplemental data of Global Carbon Budget 2019 (Version 1.0) [Data set]. Global Carbon Project. <a href="https://doi.org/10.18160/gcp-2019">https://doi.org/10.18160/gcp-2019</a>.<br><br>If we were to exclude land use change emissions, aviation accounted for 2.8% of fossil fuel emissions. The Global Carbon Budget estimated total CO<sub>2</sub> emissions from fossil fuels and cement production to be 36.6 billion tonnes in 2018. This means aviation accounted for [1 / 36.6 * 100] = 2.8% of total emissions.{/ref}</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>Aviation emissions have doubled since the mid-1980s. But, they’ve been growing at a similar rate as total CO<sub>2</sub> emissions – this means its share of global emissions has been relatively stable: in the range of 2% to 2.5%.{ref}2.3% to 2.8% of emissions if land use is excluded.{/ref}</p> <!-- /wp:paragraph --> <!-- wp:image {"id":36836,"sizeSlug":"large"} --> <figure class="wp-block-image size-large"><img src="https://owid.cloud/app/uploads/2020/10/Global-CO2-emissions-from-aviation-693x550.png" alt="" class="wp-image-36836"/></figure> <!-- /wp:image --> <!-- wp:heading {"level":4} --> <h4>Non-CO<sub>2</sub> climate impacts mean aviation accounts for 3.5% of global warming</h4> <!-- /wp:heading --> <!-- wp:paragraph --> <p>Aviation accounts for around 2.5% of global CO<sub>2</sub> emissions, but it’s overall contribution to climate change is higher. This is because air travel does not only emit CO<sub>2</sub>: it affects the climate in a number of more complex ways.</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>As well as emitting CO<sub>2</sub> from burning fuel, planes affect the concentration of other gases and pollutants in the atmosphere. They result in a short-term increase, but long-term decrease in ozone (O<sub>3</sub>); a decrease in methane (CH<sub>4</sub>); emissions of water vapour; soot; sulfur aerosols; and water contrails. While some of these impacts result in warming, others induce a cooling effect. Overall, the warming effect is stronger.</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>David Lee et al. (2020) quantified the overall effect of aviation on global warming when all of these impacts were included.{ref}Lee, D. S., Fahey, D. W., Skowron, A., Allen, M. R., Burkhardt, U., Chen, Q., ... & Gettelman, A. (2020). <a href="https://www.sciencedirect.com/science/article/pii/S1352231020305689">The contribution of global aviation to anthropogenic climate forcing for 2000 to 2018</a>. <em>Atmospheric Environment</em>, 117834.{/ref} To do this they calculated the so-called ‘Radiative Forcing’. Radiative forcing measures the difference between incoming energy and the energy radiated back to space. If more energy is absorbed than radiated, the atmosphere becomes warmer. </p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>In their chart we see <a href="https://ars.els-cdn.com/content/image/1-s2.0-S1352231020305689-gr3_lrg.jpg" target="_blank" rel="noreferrer noopener">their estimates for the radiative forcing</a> of the different elements. When we combine them, aviation accounts for approximately 3.5% of effective radiative forcing: that is, 3.5% of warming.<br><br>Although CO<sub>2  </sub>gets most of the attention, it accounts for less than half of this warming. Two-thirds (66%) comes from non-CO<sub>2 </sub>forcings. Contrails – water vapor trails from aircraft exhausts – account for the largest share.</p> <!-- /wp:paragraph --> <!-- wp:heading {"level":4} --> <h4>We don’t yet have the technologies to decarbonize air travel</h4> <!-- /wp:heading --> <!-- wp:paragraph --> <p>Aviation’s contribution to climate change – 3.5% of warming, or 2.5% of CO<sub>2</sub> emissions – is often less than people think. It’s currently a relatively small chunk of emissions compared to other sectors. </p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>The key challenge is that it is particularly hard to decarbonize. We have solutions to reduce emissions for many of the <a href="https://ourworldindata.org/ghg-emissions-by-sector">largest emitters</a> – such as power or road transport – and it’s now a matter of scaling them. We can deploy renewable and nuclear energy technologies, and transition to electric cars. But we don’t have proven solutions to tackle aviation yet. </p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>There are some design concepts emerging – Airbus, for example, <a href="https://web.archive.org/web/20201031121346/https://www.airbus.com/innovation/zero-emission/hydrogen/zeroe.html" data-type="URL" data-id="https://web.archive.org/web/20201031121346/https://www.airbus.com/innovation/zero-emission/hydrogen/zeroe.html">have announced plans</a> to have the first zero-emission aircraft by 2035, using hydrogen fuel cells. Electric planes may be a viable concept, but are likely to be limited to very small aircraft due to the limitations of battery technologies and capacity. </p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>Innovative solutions may be on the horizon, but they’re likely to be far in the distance.</p> <!-- /wp:paragraph --> <!-- wp:owid/prominent-link {"title":"Towards zero-carbon transport: how can we expect the sector’s CO\u003csub\u003e2\u003c/sub\u003e emissions to change in the future?","linkUrl":"ourworldindata.org/co2-emissions-from-transport","mediaId":36827,"mediaUrl":"https://owid.cloud/app/uploads/2020/10/IEA-Transport-to-2070.png","mediaAlt":"","className":"is-style-thin"} --> <!-- wp:paragraph --> <p></p> <!-- /wp:paragraph --> <!-- /wp:owid/prominent-link --> <!-- wp:owid/additional-information {"defaultOpen":true} --> <!-- wp:heading {"level":3} --> <h3>Appendix: <strong>Efficiency improvements means air traffic has increased more rapidly than emissions</strong></h3> <!-- /wp:heading --> <!-- wp:columns {"className":"is-style-sticky-right"} --> <div class="wp-block-columns is-style-sticky-right"><!-- wp:column --> <div class="wp-block-column"><!-- wp:paragraph --> <p>Global emissions from aviation have increased a lot over the past half-century. However, air travel volumes increased even more rapidly. </p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>Since 1960, aviation emissions increased almost seven-fold; since 1970 they’ve tripled. Air traffic volume – here defined as revenue passenger kilometers (RPK) traveled – <a href="https://ourworldindata.org/grapher/airline-capacity-and-traffic">increased by orders of magnitude more</a>: almost 300-fold since 1950; and 75-fold since 1960.{ref}Airline traffic data comes from the International Civil Aviation Organization (ICAO) via <a href="https://www.airlines.org/dataset/world-airlines-traffic-and-capacity">Airlines for America</a>. Revenue passenger kilometers (RPK) measures the number of paying passengers multiplied by their distance traveled.{/ref} </p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>The much slower growth in emissions means aviation efficiency has seen massive improvements. In the chart we show both the increase in global airline traffic since 1950, and aviation efficiency, measured as the quantity of CO<sub>2</sub> emitted per revenue passenger kilometer traveled. In 2018, approximately 125 grams of CO<sub>2 </sub> were emitted per RPK. In 1960, this was eleven-fold higher; in 1950 it was twenty-fold higher. Aviation has seen massive efficiency improvements over the past 50 years.</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>These improvements have come from several sources: improvements in the design and technology of aircraft; larger aircraft sizes (allowing for more passengers per flight); and an increase in how ‘full’ passenger flights are. This last metric is termed the ‘passenger load factor’. The passenger load factor measures the actual number of kilometers traveled by paying customers (RPK) as a percentage of the available seat kilometers (ASK) – the kilometers traveled if every plane was full. If every plane was full the passenger load factor would be 100%. If only three-quarters of the seats were filled, it would be 75%.</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>The global passenger load factor <a href="https://ourworldindata.org/grapher/airline-passenger-load-factor">increased from 61% in 1950 to 82% in 2018</a>. </p> <!-- /wp:paragraph --></div> <!-- /wp:column --> <!-- wp:column --> <div class="wp-block-column"><!-- wp:image {"id":36837,"sizeSlug":"large"} --> <figure class="wp-block-image size-large"><img src="https://owid.cloud/app/uploads/2020/10/Aviation-traffic-and-efficiency-Lee-et-al.-2020-800x505.png" alt="" class="wp-image-36837"/></figure> <!-- /wp:image --></div> <!-- /wp:column --></div> <!-- /wp:columns --> <!-- /wp:owid/additional-information --> <!-- wp:heading {"level":3} --> <h3>Passenger vs. freight; domestic vs. international: where do aviation emissions come from?</h3> <!-- /wp:heading --> <!-- wp-block-tombstone 45128 --> <!-- wp:paragraph --> <p>Global aviation – both passenger flights and freight – emits around one billion tonnes of carbon dioxide (CO<sub>2</sub>) each year. This was equivalent to around 2.4% of CO<sub>2</sub> emissions in 2018.</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>How do global aviation emissions break down?</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>The chart gives the answer. This data is sourced from the 2019 <em>International Council on Clean Transportation</em> <em>(ICCT)</em> report on global aviation.{ref}Graver, B., Zhang, K., & Rutherford, D. (2019). <a href="https://theicct.org/sites/default/files/publications/ICCT_CO2-commercl-aviation-2018_20190918.pdf" target="_blank" rel="noreferrer noopener">CO2 emissions from commercial aviation, 2018</a>. <em>The International Council of Clean Transportation</em>.{/ref}</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>Most emissions come from passenger flights – in 2018, they accounted for 81% of aviation’s emissions; the remaining 19% came from freight, the transport of goods. </p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>Sixty percent of emissions from<em> passenger</em> flights come from international travel; the other 40% come from domestic (in-country) flights. </p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>When we break passenger flight emissions down by travel distance, we get a (surprisingly) equal three-way split in emissions between short-haul (less than 1,500 kilometers); medium-haul (1,500 to 4,000 km); and long-haul (greater than 4,000 km) journeys.</p> <!-- /wp:paragraph --> <!-- wp:image {"id":36848,"sizeSlug":"large"} --> <figure class="wp-block-image size-large"><img src="https://owid.cloud/app/uploads/2020/10/Global-breakdown-of-aviation-emissions-800x507.png" alt="" class="wp-image-36848"/></figure> <!-- /wp:image --> <!-- wp:heading {"level":4} --> <h4>The richest half are responsible for 90% of air travel CO<sub>2</sub> emissions</h4> <!-- /wp:heading --> <!-- wp:paragraph --> <p>The global inequalities in how much people fly become clear when we compare aviation emissions across countries of different income levels. The ICCT split these emissions based on World Bank's four <a href="https://ourworldindata.org/grapher/world-banks-income-groups?year=latest" target="_blank" rel="noreferrer noopener">income groups</a>.</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>A further study by Susanne Becek and Paresh Pant (2019) compared the contribution of each income group to global air travel emissions versus its share of world population.{ref}Becken, S. and P. Pant (2019). <a href="https://amadeus.com/en/insights/white-paper/airline-initiatives-to-reduce-climate-impact" target="_blank" rel="noreferrer noopener">Airline initiatives to reduce climate impact: ways to accelerate action</a> (White paper).{/ref} This comparison is shown in the visualization.</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>The ‘richest’ half of the world (high and upper-middle income countries) were responsible for 90% of air travel emissions.{ref}Note that this is based on categorisations from the average income level of countries, and does not take account of variation in income <em>within </em>countries. If we were to look at this distribution based on the income level of individuals rather than countries, the inequality in aviation emissions would be even larger.{/ref}</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>Looking at specific income groups:</p> <!-- /wp:paragraph --> <!-- wp:list --> <ul><li>Only 16% of the world population live in high-income countries yet the planes that take off in those countries account for almost two-thirds (62%) of passenger emissions;</li><li>Upper-middle income countries are home to 35% of the world population, and contribute 28% of emissions;</li><li>Lower-middle income countries are home to the largest share (40% of the world), yet emit the planes taking off there just account for 9%;</li><li>The poorest countries – which are home to 9% of the world population – emit just 1%.</li></ul> <!-- /wp:list --> <!-- wp:paragraph --> <p>In an upcoming article we will look in more detail at the contribution of each country to global aviation emissions.</p> <!-- /wp:paragraph --> <!-- wp:image {"id":36849,"sizeSlug":"large"} --> <figure class="wp-block-image size-large"><img src="https://owid.cloud/app/uploads/2020/10/Inequalities-in-CO2-emissions-from-air-travel-800x437.png" alt="" class="wp-image-36849"/></figure> <!-- /wp:image --> <!-- wp:heading {"level":3} --> <h3>Where in the world do people have the highest carbon footprint from flying?</h3> <!-- /wp:heading --> <!-- wp-block-tombstone 45131 --> <!-- wp:paragraph --> <p>Aviation accounts <a href="https://ourworldindata.org/co2-emissions-from-aviation" target="_blank" rel="noreferrer noopener">for around 2.5%</a> of global carbon dioxide (CO<sub>2</sub>) emissions. But if you are someone who does fly, air travel will make up a much larger share of your personal carbon footprint.</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>The fact that aviation is relatively small for global emissions as a whole, but of large importance for individuals that fly is due to large inequalities in the world. Most people in the  world do not take flights. There is no global reliable figure, but often cited estimates suggest that more than 80% of the global population have never flown.{ref}There is no global database available on <em>who</em> in the world flies each year. Passenger information is maintained by private airlines. Therefore, deriving estimates of this exact percentage is challenging. The most-cited estimate I’ve seen on this is that around 80% of the world population have never flown. This figure seems to circle back to a <a href="https://www.cnbc.com/2017/12/07/boeing-ceo-80-percent-of-people-never-flown-for-us-that-means-growth.html#:~:text=%E2%80%9CLess%20than%2020%20percent%20of,the%20entire%20economy%2C%20Muilenburg%20said.">quoted estimate</a> from the Boeing CEO.<br><br>Even in some of the world’s richest countries, a large share of the population do not fly frequently. Gallup <a href="https://news.gallup.com/poll/1579/airlines.aspx">survey data</a> from the United States suggests that in 2015, half of the population did not take a flight. Survey data from the UK <a href="http://publicapps.caa.co.uk/docs/33/CAA%20Aviation%20Consumer%20survey%20--%205th%20wave%20report%20FINAL%20(2).pdf">provides similar estimates</a>: 46% had not flown in the previous year.{/ref}</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>How do emissions from aviation vary across the world? Where do people have the highest footprint from flying?</p> <!-- /wp:paragraph --> <!-- wp:heading {"level":4} --> <h4>Per capita emissions from domestic flights</h4> <!-- /wp:heading --> <!-- wp:columns --> <div class="wp-block-columns"><!-- wp:column --> <div class="wp-block-column"><!-- wp:paragraph --> <p>The first and most straightforward comparison is to look at emissions from <em>domestic</em> aviation – that is, flights that depart and arrive in the same country. </p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>This is easiest to compare because domestic aviation is counted in each country’s inventory of greenhouse gas emissions. International flights, on the other hand, are not attributed to specific countries – partly because of contention as to who should take responsibility (should it be the country of departure or arrival? What about layover flights?).</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>In the chart here we see the average per capita emissions from domestic flights in 2018. This data is sourced from the <em>International Council on Clean Transportation</em> – we then used <a href="https://population.un.org/wpp/">UN population estimates</a> to calculate per capita figures.{ref}Graver, B., Zhang, K., & Rutherford, D. (2019). <a href="https://theicct.org/publications/co2-emissions-commercial-aviation-2018">CO2 emissions from commercial aviation, 2018</a>. <em>The International Council of Clean Transportation</em>.{/ref}<sup>,</sup>{ref}Note that this gives us <em>mean</em> per capita emissions, which  does not account for in-country inequalities in the amount of flights people take.{/ref}</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>We see large differences in emissions from domestic flights across the world. In the United States the average person emits around 386 kilograms of CO<sub>2</sub> each year from internal flights. This is followed by Australia (267 kg); Norway (209 kg); New Zealand (174 kg); and Canada (168 kg). Compare this with  countries at the bottom of the table – many across Africa, Asia, and Eastern Europe in particular emit less than one kilogram per person – just 0.8 kilograms; or 0.14 kilograms in Rwanda. For very small countries where there are no internal commercial flights, domestic emissions are of course, zero.</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>There are some obvious factors that explain some of these cross-country differences. Firstly, countries that are richer <a href="https://ourworldindata.org/grapher/per-capita-co2-domestic-aviation-vs-gdp">are more likely</a> to have higher emissions because people can afford to fly. Second, countries that have a larger land mass may have more internal flights – and indeed we see a <a href="https://ourworldindata.org/grapher/per-capita-co2-domestic-aviation-vs-land-area">correlation</a> between land area and domestic flight emissions; in small countries people are more likely to travel by other means such as car or train.  And third, countries that are more geographically-isolated – such as Australia and New Zealand – may have more internal travel.</p> <!-- /wp:paragraph --></div> <!-- /wp:column --> <!-- wp:column --> <div class="wp-block-column"><!-- wp:html --> <iframe src="https://ourworldindata.org/grapher/per-capita-co2-domestic-aviation" loading="lazy" style="width: 100%; height: 600px; border: 0px none;"></iframe> <!-- /wp:html --> <!-- wp:heading {"level":5} --> <h5>Related charts:</h5> <!-- /wp:heading --> <!-- wp:owid/prominent-link {"title":"Total CO₂ emissions from domestic aviation","linkUrl":"https://ourworldindata.org/grapher/co2-emissions-domestic-aviation","className":"is-style-thin"} /--> <!-- wp:owid/prominent-link {"title":"Share of global CO₂ emissions from domestic aviation","linkUrl":"https://ourworldindata.org/grapher/share-global-co2-domestic-aviation","className":"is-style-thin"} /--></div> <!-- /wp:column --></div> <!-- /wp:columns --> <!-- wp:heading {"level":4} --> <h4>Per capita emissions from international flights</h4> <!-- /wp:heading --> <!-- wp:columns --> <div class="wp-block-columns"><!-- wp:column --> <div class="wp-block-column"><!-- wp:paragraph --> <p>Allocating emissions from international flights is more complex. International databases report these emissions separately as a category termed ‘bunker fuels’. The term ‘bunker fuel’ is used to describe emissions which come from international transport – either aviation or shipping.</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>Because they are <a href="https://unfccc.int/topics/mitigation/workstreams/emissions-from-international-transport-bunker-fuels">not counted towards</a> any particular country these emissions are also not taken into account in the goals that are set by countries in international treaties like the Kyoto protocol or the Paris Agreement.{ref}Larsson, J., Kamb, A., Nässén, J., & Åkerman, J. (2018). <a href="https://www.sciencedirect.com/science/article/pii/S0195925517303116">Measuring greenhouse gas emissions from international air travel of a country’s residents methodological development and application for Sweden</a>. <em>Environmental Impact Assessment Review</em>, <em>72</em>, 137-144.{/ref}</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>But if we wanted to allocate them to a particular country, how would we do it? Who do emissions from international flights belong to: the country that owns the airline; the country of departure; the country of arrival?</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>Let’s first take a look at how emissions would compare if we allocated them to the country of <em>departure</em>. This means, for example, that emissions from any flight that departs from Spain are counted towards Spain’s total. In the chart here we see international aviation emissions in per capita terms.</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>Some of the largest emitters per person in 2018 were Iceland (3.5 tonnes of CO<sub>2</sub> per person); Qatar (2.5 tonnes); United Arab Emirates (2.2 tonnes); Singapore (1.7 tonnes); and Malta (992 kilograms). </p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>Again, we see large inequalities in emissions across the world – in many lower-income countries per capita emissions are only a few kilograms: 6 kilograms in India, 4 kilograms in Nigeria; and only 1.4 kilograms in the Democratic Republic of Congo.</p> <!-- /wp:paragraph --></div> <!-- /wp:column --> <!-- wp:column --> <div class="wp-block-column"><!-- wp:html --> <iframe src="https://ourworldindata.org/grapher/per-capita-co2-international-aviation?stackMode=absolute&time=latest&region=World" loading="lazy" style="width: 100%; height: 600px; border: 0px none;"></iframe> <!-- /wp:html --> <!-- wp:heading {"level":5} --> <h5>Related charts:</h5> <!-- /wp:heading --> <!-- wp:owid/prominent-link {"title":"Total CO₂ emissions from international aviation","linkUrl":"https://ourworldindata.org/grapher/co2-international-aviation","className":"is-style-thin"} /--> <!-- wp:owid/prominent-link {"title":"Share of global CO₂ emissions from international aviation","linkUrl":"https://ourworldindata.org/grapher/share-co2-international-aviation","className":"is-style-thin"} /--></div> <!-- /wp:column --></div> <!-- /wp:columns --> <!-- wp:heading {"level":4} --> <h4>Per capita emissions from international flights – adjusted for tourism</h4> <!-- /wp:heading --> <!-- wp:columns --> <div class="wp-block-columns"><!-- wp:column --> <div class="wp-block-column"><!-- wp:paragraph --> <p>The above allocation of international aviation emissions to the country of <em>departure</em> raises some issues. It is not an accurate reflection of the local population of countries that rely a lot on tourism, for example. Most of the departing flights from these countries are carrying visiting tourists rather than locals. </p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>One way to correct for this is to adjust these figures for the ratio of inbound to outbound travellers. This approach was applied <a href="https://theicct.org/blog/staff/not-every-tonne-of-aviation-CO2">in an analysis</a> by Sola Zheng for the <em>International Council on Clean Transportation</em>. This attempts to distinguish between locals traveling abroad and foreign visitors traveling to that country on the same flight.{ref}A country with a ratio greater than one will have more incoming travellers than outgoing locals i.e. they are more of a hotspot for tourism.{/ref} For example, if we calculated that Spain had 50% more incoming than outgoing travellers, we would reduce its per capita footprint from flying by 50%. If the UK had 75% more outgoing travellers than incoming, we’d increase its footprint by 75%.</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>We have replicated this approach and  applied this adjustment to these figures by calculating the <a href="https://ourworldindata.org/grapher/ratio-of-inbound-to-outbound-tourists">inbound:outbound tourist ratio</a> based on flight departures and arrival data from the <a href="https://datacatalog.worldbank.org/dataset/world-development-indicators">World Bank</a>. </p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>How does this affect per capita emissions from international flights? The adjusted figures are shown in the chart here.</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>As we would expect, countries which are tourist hotspots see the largest change. Portugal’s emissions, for example, fall from 388 to just 60 kilograms per person. Portuguese locals are responsible for much fewer travel emissions than outgoing tourists. Spanish emissions fall from 335 to 77 kilograms per person.</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>On the other hand, countries where the locals travel elsewhere see a large increase. In the UK, they almost double from 422 to 818 kilograms.</p> <!-- /wp:paragraph --></div> <!-- /wp:column --> <!-- wp:column --> <div class="wp-block-column"><!-- wp:html --> <iframe src="https://ourworldindata.org/grapher/per-capita-co2-international-flights-adjusted?stackMode=absolute&time=latest&region=World" loading="lazy" style="width: 100%; height: 600px; border: 0px none;"></iframe> <!-- /wp:html --></div> <!-- /wp:column --></div> <!-- /wp:columns --> <!-- wp:heading {"level":4} --> <h4>Per capita emissions from domestic <em>and </em>international flights</h4> <!-- /wp:heading --> <!-- wp:columns --> <div class="wp-block-columns"><!-- wp:column --> <div class="wp-block-column"><!-- wp:paragraph --> <p>Let’s combine per capita emissions from domestic and international travel to compare the total footprint from flying.</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>This is shown in the interactive map <em>[we’ve taken the adjusted international figures – you can find the  combined figures without tourism-adjustment </em><a href="https://ourworldindata.org/grapher/per-capita-co2-aviation"><strong><em>here</em></strong></a><em>]. </em></p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>The global average emissions from aviation were 103 kilograms. The inequality in emissions across the world becomes clear when this is broken down by country. </p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>At the top of the table lies the United Arab Emirates – each person emits close to two tonnes – 1950 kg – of CO<sub>2</sub> from flying each year. That’s 200 times the global average.  This was followed by Singapore (1173 kilograms); Iceland (1070 kg); Finland (1000 kg); and Australia (878 kilograms). </p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>To put this into perspective: a return flight (in economy class) from London to Dubai/United Arab Emirates would emit around one tonne of CO<sub>2</sub>.{ref}We can calculate this by taking the standard CO2 conversion factors for travel, used in the <a href="https://www.gov.uk/government/publications/greenhouse-gas-reporting-conversion-factors-2019">UK greenhouse gas accounting framework</a>. For a long-haul flight in economy class, around 0.079 kilograms of CO<sub>2</sub> <a href="https://ourworldindata.org/travel-carbon-footprint">are emitted</a> per passenger-kilometer. This means that you would travel around 12,600 kilometers to emit one tonne [1,000,000 / 0.079 kg = 12,626 kilometers]. Since we’re taking a return flight, the travel distance would be half of that figure: around 6300 kilometers. The direct distance from <a href="https://www.distance.to/London/Dubai,ARE">London to Dubai</a> is around 5,500 kilometers. Depending on the flight path, it’s likely to be slightly longer than this, and in the range of 5500 to 6500 kilometers.</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>Note that in this case we’re looking at CO<sub>2</sub> emissions <em>without</em> the extra warming effects of these emissions at high altitudes. This is to allow us to compare with the ICCT figures by country presented in this article. You find additional data on how the footprint of flying is impacted by non-CO<sub>2</sub> warming effects<a href="https://ourworldindata.org/grapher/carbon-footprint-travel-mode"> <strong>here</strong></a>.{/ref} So the two-tonne average for the UAE is equivalent to around two return trips to London.</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>In many countries, most people do not fly at all. The average Indian emits just 18 kilograms from aviation – this is much, much less than even a short-haul flight which confirms that most did not take a flight.</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>In fact, we can compare just the aviation emissions for the top countries to the <em>total</em> carbon footprint of citizens elsewhere. The average UAE citizen emits 1950 kilograms of CO<sub>2</sub> from flying. This is the same as the <em>total</em> <a href="https://ourworldindata.org/explorers/co2?tab=chart&xScale=linear&yScale=linear&stackMode=absolute&endpointsOnly=0&year=latest&time=1858..2018&country=~India&region=World&Gas%20=CO%E2%82%82&Accounting%20=Production-based&Fuel%20=Total&Count%20=Per%20capita&Relative%20to%20world%20total%20=">CO<sub>2</sub> footprint of the average Indian</a> (including everything from electricity to road transport, heating and industry). Or, to take a more extreme example, 200 times the total footprint of the average Nigerien, Ugandan or Ethiopian, which <a href="https://ourworldindata.org/explorers/co2?tab=chart&xScale=linear&yScale=linear&stackMode=absolute&endpointsOnly=0&year=latest&time=1958..2018&country=Niger~Uganda~Ethiopia&region=World&Gas%20=CO%E2%82%82&Accounting%20=Production-based&Fuel%20=Total&Count%20=Per%20capita&Relative%20to%20world%20total%20=">have per capita emissions</a> of around 100 kilograms. </p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>This again emphasises the large difference between the global average and the individual emissions of people who fly. Aviation contributes a few percent of total CO<sub>2</sub> emissions each year – this is not insignificant, but far from being the largest sector to tackle. Yet from the perspective of the individual, flying <em>is</em> often one of the largest chunks of our carbon footprint. The average rich person emits tonnes of CO<sub>2</sub> from flying each year – this is equivalent to the <em>total</em> carbon footprint of tens or hundreds of people in many countries of the world.</p> <!-- /wp:paragraph --></div> <!-- /wp:column --> <!-- wp:column --> <div class="wp-block-column"><!-- wp:html --> <iframe src="https://ourworldindata.org/grapher/per-capita-co2-aviation-adjusted?stackMode=absolute&region=World" loading="lazy" style="width: 100%; height: 600px; border: 0px none;"></iframe> <!-- /wp:html --> <!-- wp:heading {"level":5} --> <h5>Related charts:</h5> <!-- /wp:heading --> <!-- wp:owid/prominent-link {"title":"Per capita CO₂ emissions from aviation (without tourism adjustment)","linkUrl":"https://ourworldindata.org/grapher/per-capita-co2-aviation","className":"is-style-thin"} /--> <!-- wp:owid/prominent-link {"title":"Total CO₂ emissions from aviation","linkUrl":"https://ourworldindata.org/grapher/co2-emissions-aviation","className":"is-style-thin"} /--> <!-- wp:owid/prominent-link {"title":"Share of global CO₂ emissions from aviation","linkUrl":"https://ourworldindata.org/grapher/share-co2-emissions-aviation","className":"is-style-thin"} /--></div> <!-- /wp:column --></div> <!-- /wp:columns --> <!-- wp:heading {"level":3} --> <h3>Where in the world do people fly the most?</h3> <!-- /wp:heading --> <!-- wp:heading {"level":4} --> <h4>Domestic air travel</h4> <!-- /wp:heading --> <!-- wp:columns {"className":"is-style-sticky-right"} --> <div class="wp-block-columns is-style-sticky-right"><!-- wp:column --> <div class="wp-block-column"><!-- wp:paragraph --> <p>This interactive chart shows the average distance travelled per person through domestic air travel each year. This data is for passenger flights only and does not include freight.</p> <!-- /wp:paragraph --></div> <!-- /wp:column --> <!-- wp:column --> <div class="wp-block-column"><!-- wp:html --> <iframe src="https://ourworldindata.org/grapher/per-capita-domestic-aviation-km" loading="lazy" style="width: 100%; height: 600px; border: 0px none;"></iframe> <!-- /wp:html --> <!-- wp:heading {"level":5} --> <h5>Related charts:</h5> <!-- /wp:heading --> <!-- wp:owid/prominent-link {"title":"Share of global passenger kilometers from domestic air travel","linkUrl":"https://ourworldindata.org/grapher/share-global-domestic-aviation-km","className":"is-style-thin"} --> <!-- wp:paragraph --> <p>What share of global domestic air travel does each country account for?</p> <!-- /wp:paragraph --> <!-- /wp:owid/prominent-link --> <!-- wp:owid/prominent-link {"title":"Total passenger kilometers from domestic air travel","linkUrl":"https://ourworldindata.org/grapher/total-domestic-aviation-km","className":"is-style-thin"} --> <!-- wp:paragraph --> <p></p> <!-- /wp:paragraph --> <!-- /wp:owid/prominent-link --></div> <!-- /wp:column --></div> <!-- /wp:columns --> <!-- wp:heading {"level":4} --> <h4>International air travel</h4> <!-- /wp:heading --> <!-- wp:columns {"className":"is-style-sticky-right"} --> <div class="wp-block-columns is-style-sticky-right"><!-- wp:column --> <div class="wp-block-column"><!-- wp:paragraph --> <p>This interactive chart shows the average distance travelled per person through international air travel each year. This data is for passenger flights only and does not include freight.</p> <!-- /wp:paragraph --></div> <!-- /wp:column --> <!-- wp:column --> <div class="wp-block-column"><!-- wp:html --> <iframe src="https://ourworldindata.org/grapher/per-capita-international-aviation-km" loading="lazy" style="width: 100%; height: 600px; border: 0px none;"></iframe> <!-- /wp:html --> <!-- wp:heading {"level":5} --> <h5>Related charts:</h5> <!-- /wp:heading --> <!-- wp:owid/prominent-link {"title":"Share of global passenger kilometers from international air travel","linkUrl":"https://ourworldindata.org/grapher/share-international-aviation-km","className":"is-style-thin"} --> <!-- wp:paragraph --> <p>What share of global international air travel does each country account for?</p> <!-- /wp:paragraph --> <!-- /wp:owid/prominent-link --> <!-- wp:owid/prominent-link {"title":"Total passenger kilometers from international air travel","linkUrl":"https://ourworldindata.org/grapher/passenger-km-international-aviation","className":"is-style-thin"} --> <!-- wp:paragraph --> <p></p> <!-- /wp:paragraph --> <!-- /wp:owid/prominent-link --></div> <!-- /wp:column --></div> <!-- /wp:columns --> <!-- wp:heading {"level":4} --> <h4>Total air travel</h4> <!-- /wp:heading --> <!-- wp:columns {"className":"is-style-sticky-right"} --> <div class="wp-block-columns is-style-sticky-right"><!-- wp:column --> <div class="wp-block-column"><!-- wp:paragraph --> <p>This interactive chart shows the average distance travelled per person through domestic <em>and</em> international air travel each year. This data is for passenger flights only and does not include freight.</p> <!-- /wp:paragraph --></div> <!-- /wp:column --> <!-- wp:column --> <div class="wp-block-column"><!-- wp:html --> <iframe src="https://ourworldindata.org/grapher/per-capita-km-aviation" loading="lazy" style="width: 100%; height: 600px; border: 0px none;"></iframe> <!-- /wp:html --> <!-- wp:heading {"level":5} --> <h5>Related charts:</h5> <!-- /wp:heading --> <!-- wp:owid/prominent-link {"title":"Share of global passenger kilometers from air travel","linkUrl":"https://ourworldindata.org/grapher/share-km-aviation","className":"is-style-thin"} --> <!-- wp:paragraph --> <p>What share of global air travel does each country account for?</p> <!-- /wp:paragraph --> <!-- /wp:owid/prominent-link --> <!-- wp:owid/prominent-link {"title":"Total passenger kilometers from air travel","linkUrl":"https://ourworldindata.org/grapher/total-aviation-km","className":"is-style-thin"} --> <!-- wp:paragraph --> <p></p> <!-- /wp:paragraph --> <!-- /wp:owid/prominent-link --></div> <!-- /wp:column --></div> <!-- /wp:columns --> <!-- wp:heading --> <h2>Rail</h2> <!-- /wp:heading --> <!-- wp:columns {"className":"is-style-sticky-right"} --> <div class="wp-block-columns is-style-sticky-right"><!-- wp:column --> <div class="wp-block-column"><!-- wp:paragraph --> <p>This interactive chart shows the total rail travel in each country, measured in passenger-kilometers per year.</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>This includes passenger travel only and does not include freight.</p> <!-- /wp:paragraph --></div> <!-- /wp:column --> <!-- wp:column --> <div class="wp-block-column"><!-- wp:html --> <iframe src="https://ourworldindata.org/grapher/railways-passengers-carried-passenger-km" loading="lazy" style="width: 100%; height: 600px; border: 0px none;"></iframe> <!-- /wp:html --></div> <!-- /wp:column --></div> <!-- /wp:columns --> <!-- wp:heading --> <h2>Energy intensity of transport</h2> <!-- /wp:heading --> <!-- wp:paragraph --> <p>This chart shows the average energy intensity of transport across different modes of travel. It is measured as the average kilowatt-hours required per passenger-kilometer.</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>This data comes from the United States Department of Transportation's Bureau of Transportation Statistics (BTS). The energy intensity of public transport depends on the assumptions made about the capacity of transport modes i.e. how many passengers travel on a given train or bus journey. This data thererfore reflects average capacities in the United States, but will vary from country-to-country.</p> <!-- /wp:paragraph --> <!-- wp:html --> <iframe src="https://ourworldindata.org/grapher/energy-intensity-transport?country=Amtrak~Bus~Domestic+flight~International+flight~Motorcycle~~Transit+motor+bus~Truck+%28with+trailer%29~Truck~" loading="lazy" style="width: 100%; height: 600px; border: 0px none;"></iframe> <!-- /wp:html --> <!-- wp:heading --> <h2>CO<sub>2</sub> emissions from transport</h2> <!-- /wp:heading --> <!-- wp:heading {"level":3} --> <h3>Per capita transport emissions from transport</h3> <!-- /wp:heading --> <!-- wp:paragraph --> <p>This interactive shows the average per capita emissions of carbon dioxide from transport each year. This includes road, train, bus and domestic air travel but <em>does not </em>include international aviation and shipping.</p> <!-- /wp:paragraph --> <!-- wp:html --> <iframe src="https://ourworldindata.org/grapher/per-capita-co2-transport?stackMode=absolute&region=World" loading="lazy" style="width: 100%; height: 600px; border: 0px none;"></iframe> <!-- /wp:html --> <!-- wp:heading {"level":3} --> <h3>Total transport emissions</h3> <!-- /wp:heading --> <!-- wp:paragraph --> <p>This interactive shows the emissions of carbon dioxide from transport each year. This includes road, train, bus and domestic air travel but <em>does not </em>include international aviation and shipping.</p> <!-- /wp:paragraph --> <!-- wp:html --> <iframe src="https://ourworldindata.org/grapher/co2-emissions-transport?stackMode=absolute&time=earliest..latest&region=World" loading="lazy" style="width: 100%; height: 600px; border: 0px none;"></iframe> <!-- /wp:html --> <!-- wp:heading {"level":3} --> <h3>CO<sub>2</sub> emissions by mode of transport</h3> <!-- /wp:heading --> <!-- wp-block-tombstone 45118 --> <!-- wp:paragraph --> <p>Transport accounts for around one-fifth of global carbon dioxide (CO<sub>2</sub>) emissions <em>[24% if we only consider CO<sub>2</sub> emissions from energy]</em>.{ref}The <em>World Resource Institute</em>’s Climate Data Explorer <a href="https://www.climatewatchdata.org/data-explorer/historical-emissions?historical-emissions-data-sources=cait&historical-emissions-gases=co2&historical-emissions-regions=All%20Selected&historical-emissions-sectors=total-including-lucf%2Ctransportation&page=1&sort_col=country&sort_dir=ASC">provides data</a> from CAIT on the breakdown of emissions by sector. In 2016, global CO<sub>2</sub> emissions (including land use) were 36.7 billion tonnes CO<sub>2</sub>; emissions from transport were 7.9 billion tonnes CO<sub>2</sub>. Transport therefore accounted for 7.9 / 36.7 = 21% of global emissions. </p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>The IEA <a href="https://www.iea.org/data-and-statistics/?country=WORLD&fuel=CO2%20emissions&indicator=TotCO2">looks at CO<sub>2</sub> emissions</a> from energy production alone – in 2018 it reported 33.5 billion tonnes of energy-related CO<sub>2</sub> [hence, transport accounted for 8 billion / 33.5 billion = 24% of energy-related emissions.{/ref}</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>How do these emissions break down? Is it cars, trucks, planes or trains that dominate?</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>In the chart here we see global transport emissions in 2018. This data is <a href="https://www.iea.org/data-and-statistics/charts/transport-sector-co2-emissions-by-mode-in-the-sustainable-development-scenario-2000-2030">sourced from</a> the <em>International Energy Agency (IEA)</em>. </p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>Road travel accounts for three-quarters of transport emissions. Most of this comes from passenger vehicles – cars and buses – which contribute 45.1%. The other 29.4% comes from trucks carrying freight.</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>Since the entire transport sector accounts for 21% of total emissions, and road transport accounts for three-quarters of transport emissions, road transport accounts for 15% of total CO<sub>2</sub> emissions.</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>Aviation – while it often gets the most attention in discussions on action against climate change – accounts for only 11.6% of transport emissions. It emits just under one billion tonnes of CO<sub>2</sub> each year – around 2.5% of total global emissions <em>[we look at the role that air travel plays in climate change in more detail in an upcoming article]</em>. International shipping contributes a similar amount, at 10.6%. </p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>Rail travel and freight emits very little – only 1% of transport emissions. Other transport – which is mainly the movement of materials such as water, oil, and gas via pipelines – is responsible for 2.2%.</p> <!-- /wp:paragraph --> <!-- wp:image {"id":36825,"sizeSlug":"large"} --> <figure class="wp-block-image size-large"><img src="https://owid.cloud/app/uploads/2020/10/Transport-CO2-emissions-by-mode-bar-chart-800x315.png" alt="" class="wp-image-36825"/></figure> <!-- /wp:image --> <!-- wp:heading {"level":4} --> <h4>Towards zero-carbon transport: how can we expect the sector’s CO<sub>2</sub> emissions to change in the future?</h4> <!-- /wp:heading --> <!-- wp:columns --> <div class="wp-block-columns"><!-- wp:column --> <div class="wp-block-column"><!-- wp:paragraph --> <p>Transport demand is expected to grow across the world in the coming decades as the global population increases, incomes rise, and more people can afford cars, trains and flights. In its <em>Energy Technology Perspectives</em> report, the International Energy Agency (IEA) expects global transport (measured in passenger-kilometers) to double, car ownership rates to increase by 60%, and demand for passenger and freight aviation to triple by 2070.{ref}IEA (2020), <a href="https://www.iea.org/reports/energy-technology-perspectives-2020">Energy Technology Perspectives 2020</a>, IEA, Paris.{/ref} Combined, these factors would result in a large increase in transport emissions.</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>But major technological innovations can help offset this rise in demand. As the world shifts towards lower-carbon electricity sources, the rise of electric vehicles offers a viable option to reduce emissions from passenger vehicles.</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>This is reflected in the IEA’s <em>Energy Technology Perspective</em> report. There it outlines its “Sustainable Development Scenario” for reaching net-zero CO2 emissions from global energy by 2070. The pathways for the different elements of the transport sector in this optimistic scenario are shown in the visualization.</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>We see that with electrification- and hydrogen- technologies some of these sub-sectors could decarbonize within decades. The IEA scenario assumes the phase-out of emissions from motorcycles by 2040; rail by 2050; small trucks by 2060; and although emissions from cars and buses are not completely eliminated until 2070, it expects many regions, including the European Union; United States; China and Japan to have phased-out conventional vehicles as early as 2040.</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>Other transport sectors will be much more difficult to decarbonize.</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>In a paper published in <em>Science</em>, Steven Davis and colleagues looked at our options across sectors to reach a net-zero emissions energy system.{ref}Davis, S. J., Lewis, N. S., Shaner, M., Aggarwal, S., Arent, D., Azevedo, I. L., ... & Clack, C. T. (2018). <a href="https://science.sciencemag.org/content/360/6396/eaas9793.full">Net-zero emissions energy systems</a>. <em>Science</em>, 360(6396).{/ref} They highlighted long-distance road freight (large trucks), aviation and shipping as particularly difficult to eliminate. The potential for hydrogen as a fuel, or battery electricity to run planes, ships and large trucks is limited by the range and power required; the size and weight of batteries or hydrogen fuel tanks would be <em>much</em> larger and heavier than current combustion engines.{ref}Cecere, D., Giacomazzi, E., & Ingenito, A. (2014). <a href="https://www.sciencedirect.com/science/article/pii/S0360319914011847">A review on hydrogen industrial aerospace applications</a>. <em>International Journal of Hydrogen Energy</em>, <em>39</em>(20), 10731-10747.{/ref}<sup>,</sup>{ref}Fulton, L. M., Lynd, L. R., Körner, A., Greene, N., & Tonachel, L. R. (2015). <a href="https://onlinelibrary.wiley.com/doi/full/10.1002/bbb.1559">The need for biofuels as part of a low carbon energy future</a>. <em>Biofuels, Bioproducts and Biorefining</em>, 9(5), 476-483.{/ref}</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>So, despite falling by three-quarters in the visualized scenario, emissions from these sub-sectors would still make transport the largest contributor to energy-related emissions in 2070. To reach net-zero for the energy sector as a whole, these emissions would have to be offset by ‘negative emissions’ (e.g. the capture and storage of carbon from bioenergy or <a href="https://www.iea.org/reports/direct-air-capture">direct air capture</a>) from other parts of the energy system.</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>In the IEA’s net-zero scenario, nearly two-thirds of the emissions reductions come from technologies that are not yet commercially available. As the IEA states, “Reducing CO<sub>2</sub> emissions in the transport sector over the next half-century will be a formidable task.”{ref}IEA (2020), <a href="https://www.iea.org/reports/energy-technology-perspectives-2020">Energy Technology Perspectives 2020</a>, IEA, Paris.{/ref}</p> <!-- /wp:paragraph --></div> <!-- /wp:column --> <!-- wp:column --> <div class="wp-block-column"><!-- wp:heading {"level":6} --> <h6>Global CO2 emissions from transport in the IEA's Sustainable Development Scenario to 2070{ref}IEA (2020), <a href="https://www.iea.org/reports/energy-technology-perspectives-2020">Energy Technology Perspectives 2020</a>, IEA, Paris.{/ref}</h6> <!-- /wp:heading --> <!-- wp:image {"id":36827,"sizeSlug":"large"} --> <figure class="wp-block-image size-large"><img src="https://owid.cloud/app/uploads/2020/10/IEA-Transport-to-2070-800x505.png" alt="" class="wp-image-36827"/></figure> <!-- /wp:image --></div> <!-- /wp:column --></div> <!-- /wp:columns -->	{ "id": "wp-36318", "slug": "transport", "content": { "toc": [], "body": [ { "type": "text", "value": [ { "text": "First published in September 2021.", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "horizontal-rule", "parseErrors": [] }, { "text": [ { "text": "Road travel", "spanType": "span-simple-text" } ], "type": "heading", "level": 1, "parseErrors": [] }, { "type": "horizontal-rule", "parseErrors": [] }, { "text": [ { "text": "Passenger vehicle registrations by type", "spanType": "span-simple-text" } ], "type": "heading", "level": 2, "parseErrors": [] }, { "type": "text", "value": [ { "text": "These interactive charts show the breakdown of new passenger vehicle registrations by type.", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "This is broken down by: petroleum; diesel; full hybrid (excluding plug-in hybrids); plug-in electric hybrids; and fully electric battery vehicles.", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "url": "https://ourworldindata.org/grapher/new-vehicles-type-area?tab=chart&stackMode=relative&country=~NOR", "type": "chart", "parseErrors": [] }, { "url": "https://ourworldindata.org/grapher/new-vehicles-type-share?tab=chart&country=~GBR", "type": "chart", "parseErrors": [] }, { "url": "https://ourworldindata.org/grapher/new-passenger-vehicles-type?country=~GBR", "type": "prominent-link", "title": "Number of new passenger vehicle registrations by type", "description": "", "parseErrors": [] }, { "text": [ { "text": "Electric vehicle registrations", "spanType": "span-simple-text" } ], "type": "heading", "level": 2, "parseErrors": [] }, { "type": "text", "value": [ { "text": "This interactive chart shows the share of new passenger vehicle registrations that are battery electric vehicles. This does not include plug-in hybrid vehicles.", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "url": "https://ourworldindata.org/grapher/share-vehicle-electric?country=AUT~ITA~NOR~PRT~ESP~SWE~CHE~TUR~GBR~IRL~ISL~GRC~DEU~FRA~FIN~DNK~BEL~LUX~NLD", "type": "chart", "parseErrors": [] }, { "type": "text", "value": [ { "text": "This interactive chart shows the share of new passenger vehicle registrations that are battery electric ", "spanType": "span-simple-text" }, { "children": [ { "text": "plus", "spanType": "span-simple-text" } ], "spanType": "span-italic" }, { "text": " plug-in hybrid vehicles.", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "url": "https://ourworldindata.org/grapher/battery-plugin-hybrid-vehicles?time=2019&country=~AUT~BEL~DNK~FIN~EU-27+%2B+UK~FRA~DEU~GRC~ISL~IRL~GBR~TUR~CHE~SWE~ESP~PRT~NOR~NLD~LUX~ITA", "type": "chart", "parseErrors": [] }, { "text": [ { "text": "Carbon intensity of new passenger vehicles", "spanType": "span-simple-text" } ], "type": "heading", "level": 2, "parseErrors": [] }, { "type": "text", "value": [ { "text": "This interactive chart shows the average carbon intensity of new passenger vehicles in each country.", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "This is measured as the average emissions of CO\u2082 (in grams) per kilometer travelled across all types of passenger vehicles.", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "url": "https://ourworldindata.org/grapher/carbon-new-passenger-vehicles?country=AUT~ITA~LUX~NLD~NOR~PRT~ESP~SWE~CHE~TUR~GBR~IRL~ISL~GRC~DEU~FRA~FIN~DNK~BEL", "type": "chart", "parseErrors": [] }, { "text": [ { "text": "Fuel economy of new passenger vehicles", "spanType": "span-simple-text" } ], "type": "heading", "level": 2, "parseErrors": [] }, { "type": "text", "value": [ { "text": "This interacrive chart shows the average fuel economy of new passenger vehicles in each country.", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "This is measured as the average liters consumed per 100 kilometers travelled, across all types of passenger vehicles.", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "url": "https://ourworldindata.org/grapher/fuel-efficiency-new-vehicles?country=AUT~BEL~ITA~LUX~NLD~NOR~PRT~ESP~SWE~CHE~TUR~GBR~IRL~ISL~GRC~DEU~FRA~FIN~DNK", "type": "chart", "parseErrors": [] }, { "type": "horizontal-rule", "parseErrors": [] }, { "text": [ { "text": "Aviation", "spanType": "span-simple-text" } ], "type": "heading", "level": 1, "parseErrors": [] }, { "type": "horizontal-rule", "parseErrors": [] }, { "text": [ { "text": "What share of global CO", "spanType": "span-simple-text" }, { "children": [ { "text": "2", "spanType": "span-simple-text" } ], "spanType": "span-subscript" }, { "text": " emissions come from aviation?", "spanType": "span-simple-text" } ], "type": "heading", "level": 2, "parseErrors": [] }, { "type": "text", "value": [ { "text": "Flying is a highly controversial topic in climate debates. There are a few reasons for this.\u00a0", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "The first is the disconnect between its role in our personal and collective carbon emissions. Air travel dominates a frequent traveller's individual contribution to climate change. Yet aviation overall accounts for only 2.5% of global carbon dioxide (CO", "spanType": "span-simple-text" }, { "children": [ { "text": "2", "spanType": "span-simple-text" } ], "spanType": "span-subscript" }, { "text": ") emissions. This is because there are large inequalities in how much people fly \u2013 many do not, or cannot afford to, fly at all.{ref}The best estimates put this figure at around 80% of the world population. We look at this in more detail in our article \"", "spanType": "span-simple-text" }, { "url": "https://ourworldindata.org/carbon-footprint-flying", "children": [ { "text": "Where in the world do people have the highest CO2 emissions from flying?", "spanType": "span-simple-text" } ], "spanType": "span-link" }, { "text": "\"{/ref}", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "The second is how aviation emissions are attributed to countries. CO", "spanType": "span-simple-text" }, { "children": [ { "text": "2", "spanType": "span-simple-text" } ], "spanType": "span-subscript" }, { "text": " emissions from domestic flights ", "spanType": "span-simple-text" }, { "children": [ { "text": "are", "spanType": "span-simple-text" } ], "spanType": "span-italic" }, { "text": " counted in a country\u2019s emission accounts. International flights are not \u2013 instead they are counted as their own category: \u2018bunker fuels\u2019. The fact that they don\u2019t count towards the emissions of any country means there are few incentives for countries to reduce them.", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "It\u2019s also important to note that unlike the most common greenhouse gases \u2013 carbon dioxide, methane or nitrous oxide \u2013 non-CO", "spanType": "span-simple-text" }, { "children": [ { "text": "2", "spanType": "span-simple-text" } ], "spanType": "span-subscript" }, { "text": " forcings from aviation ", "spanType": "span-simple-text" }, { "children": [ { "text": "are not included", "spanType": "span-simple-text" } ], "spanType": "span-italic" }, { "text": " in the Paris Agreement. This means they could be easily overlooked \u2013 especially since international aviation is not counted within any country\u2019s emissions inventories or targets.", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "How much of a role does aviation play in global emissions and climate change? In this article we take a look at the key numbers that are useful to know.", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "Global aviation (including domestic and international; passenger and freight) accounts for:", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "list", "items": [ { "type": "text", "value": [ { "children": [ { "text": "1.9%", "spanType": "span-simple-text" } ], "spanType": "span-bold" }, { "text": " of ", "spanType": "span-simple-text" }, { "url": "https://ourworldindata.org/ghg-emissions-by-sector", "children": [ { "text": "greenhouse gas emissions", "spanType": "span-simple-text" } ], "spanType": "span-link" }, { "text": " (which includes all greenhouse gases, not only CO", "spanType": "span-simple-text" }, { "children": [ { "text": "2", "spanType": "span-simple-text" } ], "spanType": "span-subscript" }, { "text": ")", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "children": [ { "text": "2.5%", "spanType": "span-simple-text" } ], "spanType": "span-bold" }, { "text": " of CO", "spanType": "span-simple-text" }, { "children": [ { "text": "2", "spanType": "span-simple-text" } ], "spanType": "span-subscript" }, { "text": " emissions", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "children": [ { "text": "3.5%", "spanType": "span-simple-text" } ], "spanType": "span-bold" }, { "text": " of 'effective radiative forcing' \u2013 a closer measure of its impact on warming.", "spanType": "span-simple-text" } ], "parseErrors": [] } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "The latter two numbers refer to 2018, and the first to 2016, the latest year for which such data are available.", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "text": [ { "text": "Aviation accounts for 2.5% of global CO", "spanType": "span-simple-text" }, { "children": [ { "text": "2", "spanType": "span-simple-text" } ], "spanType": "span-subscript" }, { "text": " emissions", "spanType": "span-simple-text" } ], "type": "heading", "level": 3, "parseErrors": [] }, { "type": "text", "value": [ { "text": "As we will see later in this article, there are a number of processes by which aviation contributes to climate change. But the one that gets the most attention is its contribution via CO", "spanType": "span-simple-text" }, { "children": [ { "text": "2", "spanType": "span-simple-text" } ], "spanType": "span-subscript" }, { "text": " emissions. Most flights are powered by jet gasoline \u2013 although some partially run on biofuels \u2013 which is converted to CO", "spanType": "span-simple-text" }, { "children": [ { "text": "2", "spanType": "span-simple-text" } ], "spanType": "span-subscript" }, { "text": " when burned.\u00a0\u00a0", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "In a recent paper, researchers \u2013 David Lee and colleagues \u2013 reconstructed annual CO", "spanType": "span-simple-text" }, { "children": [ { "text": "2 ", "spanType": "span-simple-text" } ], "spanType": "span-subscript" }, { "text": "emissions from global aviation dating back to 1940.{ref}Lee, D. S., Fahey, D. W., Skowron, A., Allen, M. R., Burkhardt, U., Chen, Q., ... & Gettelman, A. (2020). ", "spanType": "span-simple-text" }, { "url": "https://www.sciencedirect.com/science/article/pii/S1352231020305689", "children": [ { "text": "The contribution of global aviation to anthropogenic climate forcing for 2000 to 2018", "spanType": "span-simple-text" } ], "spanType": "span-link" }, { "text": ". ", "spanType": "span-simple-text" }, { "children": [ { "text": "Atmospheric Environment", "spanType": "span-simple-text" } ], "spanType": "span-italic" }, { "text": ", 117834.{/ref} This was calculated based on fuel consumption data from the International Energy Agency (IEA), and earlier estimates from Robert Sausen and Ulrich Schumann (2000).{ref}Sausen, R., & Schumann, U. (2000). ", "spanType": "span-simple-text" }, { "url": "https://link.springer.com/article/10.1023/A:1005579306109", "children": [ { "text": "Estimates of the climate response to aircraft CO2 and NOx emissions scenarios", "spanType": "span-simple-text" } ], "spanType": "span-link" }, { "text": ". ", "spanType": "span-simple-text" }, { "children": [ { "text": "Climatic Change", "spanType": "span-simple-text" } ], "spanType": "span-italic" }, { "text": ", ", "spanType": "span-simple-text" }, { "children": [ { "text": "44", "spanType": "span-simple-text" } ], "spanType": "span-italic" }, { "text": "(1-2), 27-58.{/ref}", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "The time series of global emissions from aviation since 1940 is shown in the accompanying chart. In 2018, it\u2019s estimated that global aviation \u2013 which includes both passenger and freight \u2013 emitted 1.04 billion tonnes of CO", "spanType": "span-simple-text" }, { "children": [ { "text": "2", "spanType": "span-simple-text" } ], "spanType": "span-subscript" }, { "text": ".", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "This represented 2.5% of ", "spanType": "span-simple-text" }, { "url": "https://ourworldindata.org/co2-emissions#global-co2-emissions-from-fossil-fuels-global-co2-emissions-from-fossil-fuels", "children": [ { "text": "total CO", "spanType": "span-simple-text" }, { "children": [ { "text": "2", "spanType": "span-simple-text" } ], "spanType": "span-subscript" }, { "text": " emissions", "spanType": "span-simple-text" } ], "spanType": "span-link" }, { "text": " in 2018.{ref}The Global Carbon Budget estimated total CO", "spanType": "span-simple-text" }, { "children": [ { "text": "2", "spanType": "span-simple-text" } ], "spanType": "span-subscript" }, { "text": " emissions from all fossil fuels, cement production and land-use change to be 42.1 billion tonnes in 2018. This means aviation accounted for [1 / 42.1 * 100] = 2.5% of total emissions.{/ref}", "spanType": "span-simple-text" }, { "children": [ { "text": ",", "spanType": "span-simple-text" } ], "spanType": "span-superscript" }, { "text": "{ref}Global Carbon Project. (2019). Supplemental data of Global Carbon Budget 2019 (Version 1.0) [Data set]. Global Carbon Project. ", "spanType": "span-simple-text" }, { "url": "https://doi.org/10.18160/gcp-2019", "children": [ { "text": "https://doi.org/10.18160/gcp-2019", "spanType": "span-simple-text" } ], "spanType": "span-link" }, { "text": ".", "spanType": "span-simple-text" }, { "spanType": "span-newline" }, { "spanType": "span-newline" }, { "text": "If we were to exclude land use change emissions, aviation accounted for 2.8% of fossil fuel emissions. The Global Carbon Budget estimated total CO", "spanType": "span-simple-text" }, { "children": [ { "text": "2", "spanType": "span-simple-text" } ], "spanType": "span-subscript" }, { "text": " emissions from fossil fuels and cement production to be 36.6 billion tonnes in 2018. This means aviation accounted for [1 / 36.6 * 100] = 2.8% of total emissions.{/ref}", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "Aviation emissions have doubled since the mid-1980s. But, they\u2019ve been growing at a similar rate as total CO", "spanType": "span-simple-text" }, { "children": [ { "text": "2", "spanType": "span-simple-text" } ], "spanType": "span-subscript" }, { "text": " emissions \u2013 this means its share of global emissions has been relatively stable: in the range of 2% to 2.5%.{ref}2.3% to 2.8% of emissions if land use is excluded.{/ref}", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "alt": "", "size": "wide", "type": "image", "filename": "Global-CO2-emissions-from-aviation.png", "parseErrors": [] }, { "text": [ { "text": "Non-CO", "spanType": "span-simple-text" }, { "children": [ { "text": "2", "spanType": "span-simple-text" } ], "spanType": "span-subscript" }, { "text": " climate impacts mean aviation accounts for 3.5% of global warming", "spanType": "span-simple-text" } ], "type": "heading", "level": 3, "parseErrors": [] }, { "type": "text", "value": [ { "text": "Aviation accounts for around 2.5% of global CO", "spanType": "span-simple-text" }, { "children": [ { "text": "2", "spanType": "span-simple-text" } ], "spanType": "span-subscript" }, { "text": " emissions, but it\u2019s overall contribution to climate change is higher. This is because air travel does not only emit CO", "spanType": "span-simple-text" }, { "children": [ { "text": "2", "spanType": "span-simple-text" } ], "spanType": "span-subscript" }, { "text": ": it affects the climate in a number of more complex ways.", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "As well as emitting CO", "spanType": "span-simple-text" }, { "children": [ { "text": "2", "spanType": "span-simple-text" } ], "spanType": "span-subscript" }, { "text": " from burning fuel, planes affect the concentration of other gases and pollutants in the atmosphere. They result in a short-term increase, but long-term decrease in ozone (O", "spanType": "span-simple-text" }, { "children": [ { "text": "3", "spanType": "span-simple-text" } ], "spanType": "span-subscript" }, { "text": "); a decrease in methane (CH", "spanType": "span-simple-text" }, { "children": [ { "text": "4", "spanType": "span-simple-text" } ], "spanType": "span-subscript" }, { "text": "); emissions of water vapour; soot; sulfur aerosols; and water contrails. While some of these impacts result in warming, others induce a cooling effect. Overall, the warming effect is stronger.", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "David Lee et al. (2020) quantified the overall effect of aviation on global warming when all of these impacts were included.{ref}Lee, D. S., Fahey, D. W., Skowron, A., Allen, M. R., Burkhardt, U., Chen, Q., ... & Gettelman, A. (2020). ", "spanType": "span-simple-text" }, { "url": "https://www.sciencedirect.com/science/article/pii/S1352231020305689", "children": [ { "text": "The contribution of global aviation to anthropogenic climate forcing for 2000 to 2018", "spanType": "span-simple-text" } ], "spanType": "span-link" }, { "text": ". ", "spanType": "span-simple-text" }, { "children": [ { "text": "Atmospheric Environment", "spanType": "span-simple-text" } ], "spanType": "span-italic" }, { "text": ", 117834.{/ref} To do this they calculated the so-called \u2018Radiative Forcing\u2019. Radiative forcing measures the difference between incoming energy and the energy radiated back to space. If more energy is absorbed than radiated, the atmosphere becomes warmer.\u00a0", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "In their chart we see ", "spanType": "span-simple-text" }, { "url": "https://ars.els-cdn.com/content/image/1-s2.0-S1352231020305689-gr3_lrg.jpg", "children": [ { "text": "their estimates for the radiative forcing", "spanType": "span-simple-text" } ], "spanType": "span-link" }, { "text": " of the different elements. When we combine them, aviation accounts for approximately 3.5% of effective radiative forcing: that is, 3.5% of warming.", "spanType": "span-simple-text" }, { "spanType": "span-newline" }, { "spanType": "span-newline" }, { "text": "Although CO", "spanType": "span-simple-text" }, { "children": [ { "text": "2\u00a0 ", "spanType": "span-simple-text" } ], "spanType": "span-subscript" }, { "text": "gets most of the attention, it accounts for less than half of this warming. Two-thirds (66%) comes from non-CO", "spanType": "span-simple-text" }, { "children": [ { "text": "2 ", "spanType": "span-simple-text" } ], "spanType": "span-subscript" }, { "text": "forcings. Contrails \u2013 water vapor trails from aircraft exhausts \u2013 account for the largest share.", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "text": [ { "text": "We don\u2019t yet have the technologies to decarbonize air travel", "spanType": "span-simple-text" } ], "type": "heading", "level": 3, "parseErrors": [] }, { "type": "text", "value": [ { "text": "Aviation\u2019s contribution to climate change \u2013 3.5% of warming, or 2.5% of CO", "spanType": "span-simple-text" }, { "children": [ { "text": "2", "spanType": "span-simple-text" } ], "spanType": "span-subscript" }, { "text": " emissions \u2013 is often less than people think. It\u2019s currently a relatively small chunk of emissions compared to other sectors.\u00a0", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "The key challenge is that it is particularly hard to decarbonize. We have solutions to reduce emissions for many of the ", "spanType": "span-simple-text" }, { "url": "https://ourworldindata.org/ghg-emissions-by-sector", "children": [ { "text": "largest emitters", "spanType": "span-simple-text" } ], "spanType": "span-link" }, { "text": " \u2013 such as power or road transport \u2013 and it\u2019s now a matter of scaling them. We can deploy renewable and nuclear energy technologies, and transition to electric cars. But we don\u2019t have proven solutions to tackle aviation yet. ", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "There are some design concepts emerging \u2013 Airbus, for example, ", "spanType": "span-simple-text" }, { "url": "https://web.archive.org/web/20201031121346/https://www.airbus.com/innovation/zero-emission/hydrogen/zeroe.html", "children": [ { "text": "have announced plans", "spanType": "span-simple-text" } ], "spanType": "span-link" }, { "text": " to have the first zero-emission aircraft by 2035, using hydrogen fuel cells. Electric planes may be a viable concept, but are likely to be limited to very small aircraft due to the limitations of battery technologies and capacity.\u00a0", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "Innovative solutions may be on the horizon, but they\u2019re likely to be far in the distance.", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "url": "ourworldindata.org/co2-emissions-from-transport", "type": "prominent-link", "title": "Towards zero-carbon transport: how can we expect the sector\u2019s CO<sub>2</sub> emissions to change in the future?", "description": "", "parseErrors": [] }, { "type": "gray-section", "items": [ { "text": [ { "text": "Additional information", "spanType": "span-simple-text" } ], "type": "heading", "level": 2, "parseErrors": [] }, { "type": "expandable-paragraph", "items": [ { "type": "text", "value": [ { "text": "Global emissions from aviation have increased a lot over the past half-century. However, air travel volumes increased even more rapidly.\u00a0", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "Since 1960, aviation emissions increased almost seven-fold; since 1970 they\u2019ve tripled. Air traffic volume \u2013 here defined as revenue passenger kilometers (RPK) traveled \u2013 ", "spanType": "span-simple-text" }, { "url": "https://ourworldindata.org/grapher/airline-capacity-and-traffic", "children": [ { "text": "increased by orders of magnitude more", "spanType": "span-simple-text" } ], "spanType": "span-link" }, { "text": ": almost 300-fold since 1950; and 75-fold since 1960.{ref}Airline traffic data comes from the International Civil Aviation Organization (ICAO) via ", "spanType": "span-simple-text" }, { "url": "https://www.airlines.org/dataset/world-airlines-traffic-and-capacity", "children": [ { "text": "Airlines for America", "spanType": "span-simple-text" } ], "spanType": "span-link" }, { "text": ". Revenue passenger kilometers (RPK) measures the number of paying passengers multiplied by their distance traveled.{/ref}\u00a0", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "The much slower growth in emissions means aviation efficiency has seen massive improvements. In the chart we show both the increase in global airline traffic since 1950, and aviation efficiency, measured as the quantity of CO", "spanType": "span-simple-text" }, { "children": [ { "text": "2", "spanType": "span-simple-text" } ], "spanType": "span-subscript" }, { "text": " emitted per revenue passenger kilometer traveled. In 2018, approximately 125 grams of CO", "spanType": "span-simple-text" }, { "children": [ { "text": "2 ", "spanType": "span-simple-text" } ], "spanType": "span-subscript" }, { "text": "\u00a0were emitted per RPK. In 1960, this was eleven-fold higher; in 1950 it was twenty-fold higher. Aviation has seen massive efficiency improvements over the past 50 years.", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "These improvements have come from several sources: improvements in the design and technology of aircraft; larger aircraft sizes (allowing for more passengers per flight); and an increase in how \u2018full\u2019 passenger flights are. This last metric is termed the \u2018passenger load factor\u2019. The passenger load factor measures the actual number of kilometers traveled by paying customers (RPK) as a percentage of the available seat kilometers (ASK) \u2013 the kilometers traveled if every plane was full. If every plane was full the passenger load factor would be 100%. If only three-quarters of the seats were filled, it would be 75%.", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "The global passenger load factor ", "spanType": "span-simple-text" }, { "url": "https://ourworldindata.org/grapher/airline-passenger-load-factor", "children": [ { "text": "increased from 61% in 1950 to 82% in 2018", "spanType": "span-simple-text" } ], "spanType": "span-link" }, { "text": ".\u00a0\u00a0", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "alt": "", "size": "wide", "type": "image", "filename": "Aviation-traffic-and-efficiency-Lee-et-al.-2020.png", "parseErrors": [] } ], "parseErrors": [] } ], "parseErrors": [] }, { "text": [ { "text": "Passenger vs. freight; domestic vs. international: where do aviation emissions come from?", "spanType": "span-simple-text" } ], "type": "heading", "level": 2, "parseErrors": [] }, { "type": "text", "value": [ { "text": "Global aviation \u2013 both passenger flights and freight \u2013 emits around one billion tonnes of carbon dioxide (CO", "spanType": "span-simple-text" }, { "children": [ { "text": "2", "spanType": "span-simple-text" } ], "spanType": "span-subscript" }, { "text": ") each year. This was equivalent to around 2.4% of CO", "spanType": "span-simple-text" }, { "children": [ { "text": "2", "spanType": "span-simple-text" } ], "spanType": "span-subscript" }, { "text": " emissions in 2018.", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "How do global aviation emissions break down?", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "The chart gives the answer. This data is sourced from the 2019 ", "spanType": "span-simple-text" }, { "children": [ { "text": "International Council on Clean Transportation", "spanType": "span-simple-text" } ], "spanType": "span-italic" }, { "children": [ { "text": "(ICCT)", "spanType": "span-simple-text" } ], "spanType": "span-italic" }, { "text": " report on global aviation.{ref}Graver, B., Zhang, K., & Rutherford, D. (2019). ", "spanType": "span-simple-text" }, { "url": "https://theicct.org/sites/default/files/publications/ICCT_CO2-commercl-aviation-2018_20190918.pdf", "children": [ { "text": "CO2 emissions from commercial aviation, 2018", "spanType": "span-simple-text" } ], "spanType": "span-link" }, { "text": ". ", "spanType": "span-simple-text" }, { "children": [ { "text": "The International Council of Clean Transportation", "spanType": "span-simple-text" } ], "spanType": "span-italic" }, { "text": ".{/ref}", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "Most emissions come from passenger flights \u2013 in 2018, they accounted for 81% of aviation\u2019s emissions; the remaining 19% came from freight, the transport of goods.\u00a0", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "Sixty percent of emissions from", "spanType": "span-simple-text" }, { "children": [ { "text": " passenger", "spanType": "span-simple-text" } ], "spanType": "span-italic" }, { "text": " flights come from international travel; the other 40% come from domestic (in-country) flights.\u00a0", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "When we break passenger flight emissions down by travel distance, we get a (surprisingly) equal three-way split in emissions between short-haul (less than 1,500 kilometers); medium-haul (1,500 to 4,000 km); and long-haul (greater than 4,000 km) journeys.", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "alt": "", "size": "wide", "type": "image", "filename": "Global-breakdown-of-aviation-emissions.png", "parseErrors": [] }, { "text": [ { "text": "The richest half are responsible for 90% of air travel CO", "spanType": "span-simple-text" }, { "children": [ { "text": "2", "spanType": "span-simple-text" } ], "spanType": "span-subscript" }, { "text": " emissions", "spanType": "span-simple-text" } ], "type": "heading", "level": 3, "parseErrors": [] }, { "type": "text", "value": [ { "text": "The global inequalities in how much people fly become clear when we compare aviation emissions across countries of different income levels. The ICCT split these emissions based on World Bank's four ", "spanType": "span-simple-text" }, { "url": "https://ourworldindata.org/grapher/world-banks-income-groups?year=latest", "children": [ { "text": "income groups", "spanType": "span-simple-text" } ], "spanType": "span-link" }, { "text": ".", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "A further study by Susanne Becek and Paresh Pant (2019) compared the contribution of each income group to global air travel emissions versus its share of world population.{ref}Becken, S. and P. Pant (2019). ", "spanType": "span-simple-text" }, { "url": "https://amadeus.com/en/insights/white-paper/airline-initiatives-to-reduce-climate-impact", "children": [ { "text": "Airline initiatives to reduce climate impact: ways to accelerate action", "spanType": "span-simple-text" } ], "spanType": "span-link" }, { "text": " (White paper).{/ref} This comparison is shown in the visualization.", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "The \u2018richest\u2019 half of the world (high and upper-middle income countries) were responsible for 90% of air travel emissions.{ref}Note that this is based on categorisations from the average income level of countries, and does not take account of variation in income ", "spanType": "span-simple-text" }, { "children": [ { "text": "within ", "spanType": "span-simple-text" } ], "spanType": "span-italic" }, { "text": "countries. If we were to look at this distribution based on the income level of individuals rather than countries, the inequality in aviation emissions would be even larger.{/ref}", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "Looking at specific income groups:", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "list", "items": [ { "type": "text", "value": [ { "text": "Only 16% of the world population live in high-income countries yet the planes that take off in those countries account for almost two-thirds (62%) of passenger emissions;", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "Upper-middle income countries are home to 35% of the world population, and contribute 28% of emissions;", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "Lower-middle income countries are home to the largest share (40% of the world), yet emit the planes taking off there just account for 9%;", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "The poorest countries \u2013 which are home to 9% of the world population \u2013 emit just 1%.", "spanType": "span-simple-text" } ], "parseErrors": [] } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "In an upcoming article we will look in more detail at the contribution of each country to global aviation emissions.", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "alt": "", "size": "wide", "type": "image", "filename": "Inequalities-in-CO2-emissions-from-air-travel.png", "parseErrors": [] }, { "text": [ { "text": "Where in the world do people have the highest carbon footprint from flying?", "spanType": "span-simple-text" } ], "type": "heading", "level": 2, "parseErrors": [] }, { "type": "text", "value": [ { "text": "Aviation accounts ", "spanType": "span-simple-text" }, { "url": "https://ourworldindata.org/co2-emissions-from-aviation", "children": [ { "text": "for around 2.5%", "spanType": "span-simple-text" } ], "spanType": "span-link" }, { "text": " of global carbon dioxide (CO", "spanType": "span-simple-text" }, { "children": [ { "text": "2", "spanType": "span-simple-text" } ], "spanType": "span-subscript" }, { "text": ") emissions. But if you are someone who does fly, air travel will make up a much larger share of your personal carbon footprint.", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "The fact that aviation is relatively small for global emissions as a whole, but of large importance for individuals that fly is due to large inequalities in the world. Most people in the\u00a0 world do not take flights. There is no global reliable figure, but often cited estimates suggest that more than 80% of the global population have never flown.{ref}There is no global database available on ", "spanType": "span-simple-text" }, { "children": [ { "text": "who", "spanType": "span-simple-text" } ], "spanType": "span-italic" }, { "text": " in the world flies each year. Passenger information is maintained by private airlines. Therefore, deriving estimates of this exact percentage is challenging. The most-cited estimate I\u2019ve seen on this is that around 80% of the world population have never flown. This figure seems to circle back to a ", "spanType": "span-simple-text" }, { "url": "https://www.cnbc.com/2017/12/07/boeing-ceo-80-percent-of-people-never-flown-for-us-that-means-growth.html#:~:text=%E2%80%9CLess%20than%2020%20percent%20of,the%20entire%20economy%2C%20Muilenburg%20said.", "children": [ { "text": "quoted estimate", "spanType": "span-simple-text" } ], "spanType": "span-link" }, { "text": " from the Boeing CEO.", "spanType": "span-simple-text" }, { "spanType": "span-newline" }, { "spanType": "span-newline" }, { "text": "Even in some of the world\u2019s richest countries, a large share of the population do not fly frequently. Gallup ", "spanType": "span-simple-text" }, { "url": "https://news.gallup.com/poll/1579/airlines.aspx", "children": [ { "text": "survey data", "spanType": "span-simple-text" } ], "spanType": "span-link" }, { "text": " from the United States suggests that in 2015, half of the population did not take a flight. Survey data from the UK ", "spanType": "span-simple-text" }, { "url": "http://publicapps.caa.co.uk/docs/33/CAA%20Aviation%20Consumer%20survey%20--%205th%20wave%20report%20FINAL%20(2).pdf", "children": [ { "text": "provides similar estimates", "spanType": "span-simple-text" } ], "spanType": "span-link" }, { "text": ": 46% had not flown in the previous year.{/ref}", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "How do emissions from aviation vary across the world? Where do people have the highest footprint from flying?", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "text": [ { "text": "Per capita emissions from domestic flights", "spanType": "span-simple-text" } ], "type": "heading", "level": 3, "parseErrors": [] }, { "type": "text", "value": [ { "text": "The first and most straightforward comparison is to look at emissions from ", "spanType": "span-simple-text" }, { "children": [ { "text": "domestic", "spanType": "span-simple-text" } ], "spanType": "span-italic" }, { "text": " aviation \u2013 that is, flights that depart and arrive in the same country.\u00a0", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "This is easiest to compare because domestic aviation is counted in each country\u2019s inventory of greenhouse gas emissions. International flights, on the other hand, are not attributed to specific countries \u2013 partly because of contention as to who should take responsibility (should it be the country of departure or arrival? What about layover flights?).", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "In the chart here we see the average per capita emissions from domestic flights in 2018. This data is sourced from the ", "spanType": "span-simple-text" }, { "children": [ { "text": "International Council on Clean Transportation", "spanType": "span-simple-text" } ], "spanType": "span-italic" }, { "text": " \u2013 we then used ", "spanType": "span-simple-text" }, { "url": "https://population.un.org/wpp/", "children": [ { "text": "UN population estimates", "spanType": "span-simple-text" } ], "spanType": "span-link" }, { "text": " to calculate per capita figures.{ref}Graver, B., Zhang, K., & Rutherford, D. (2019). ", "spanType": "span-simple-text" }, { "url": "https://theicct.org/publications/co2-emissions-commercial-aviation-2018", "children": [ { "text": "CO2 emissions from commercial aviation, 2018", "spanType": "span-simple-text" } ], "spanType": "span-link" }, { "text": ". ", "spanType": "span-simple-text" }, { "children": [ { "text": "The International Council of Clean Transportation", "spanType": "span-simple-text" } ], "spanType": "span-italic" }, { "text": ".{/ref}", "spanType": "span-simple-text" }, { "children": [ { "text": ",", "spanType": "span-simple-text" } ], "spanType": "span-superscript" }, { "text": "{ref}Note that this gives us ", "spanType": "span-simple-text" }, { "children": [ { "text": "mean", "spanType": "span-simple-text" } ], "spanType": "span-italic" }, { "text": " per capita emissions, which\u00a0 does not account for in-country inequalities in the amount of flights people take.{/ref}", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "We see large differences in emissions from domestic flights across the world. In the United States the average person emits around 386 kilograms of CO", "spanType": "span-simple-text" }, { "children": [ { "text": "2", "spanType": "span-simple-text" } ], "spanType": "span-subscript" }, { "text": " each year from internal flights. This is followed by Australia (267 kg); Norway (209 kg); New Zealand (174 kg); and Canada (168 kg). Compare this with\u00a0 countries at the bottom of the table \u2013 many across Africa, Asia, and Eastern Europe in particular emit less than one kilogram per person \u2013 just 0.8 kilograms; or 0.14 kilograms in Rwanda. For very small countries where there are no internal commercial flights, domestic emissions are of course, zero.", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "There are some obvious factors that explain some of these cross-country differences. Firstly, countries that are richer ", "spanType": "span-simple-text" }, { "url": "https://ourworldindata.org/grapher/per-capita-co2-domestic-aviation-vs-gdp", "children": [ { "text": "are more likely", "spanType": "span-simple-text" } ], "spanType": "span-link" }, { "text": " to have higher emissions because people can afford to fly. Second, countries that have a larger land mass may have more internal flights \u2013\u00a0and indeed we see a ", "spanType": "span-simple-text" }, { "url": "https://ourworldindata.org/grapher/per-capita-co2-domestic-aviation-vs-land-area", "children": [ { "text": "correlation", "spanType": "span-simple-text" } ], "spanType": "span-link" }, { "text": " between land area and domestic flight emissions; in small countries people are more likely to travel by other means such as car or train.\u00a0 And third, countries that are more geographically-isolated \u2013 such as Australia and New Zealand \u2013 may have more internal travel.", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "url": "https://ourworldindata.org/grapher/per-capita-co2-domestic-aviation", "type": "chart", "parseErrors": [] }, { "text": [ { "text": "Related charts:", "spanType": "span-simple-text" } ], "type": "heading", "level": 4, "parseErrors": [] }, { "url": "https://ourworldindata.org/grapher/co2-emissions-domestic-aviation", "type": "prominent-link", "title": "Total CO\u2082 emissions from domestic aviation", "description": "", "parseErrors": [] }, { "url": "https://ourworldindata.org/grapher/share-global-co2-domestic-aviation", "type": "prominent-link", "title": "Share of global CO\u2082 emissions from domestic aviation", "description": "", "parseErrors": [] }, { "text": [ { "text": "Per capita emissions from international flights", "spanType": "span-simple-text" } ], "type": "heading", "level": 3, "parseErrors": [] }, { "type": "text", "value": [ { "text": "Allocating emissions from international flights is more complex. International databases report these emissions separately as a category termed \u2018bunker fuels\u2019. The term \u2018bunker fuel\u2019 is used to describe emissions which come from international transport \u2013 either aviation or shipping.", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "Because they are ", "spanType": "span-simple-text" }, { "url": "https://unfccc.int/topics/mitigation/workstreams/emissions-from-international-transport-bunker-fuels", "children": [ { "text": "not counted towards", "spanType": "span-simple-text" } ], "spanType": "span-link" }, { "text": " any particular country these emissions are also not taken into account in the goals that are set by countries in international treaties like the Kyoto protocol or the Paris Agreement.{ref}Larsson, J., Kamb, A., N\u00e4ss\u00e9n, J., & \u00c5kerman, J. (2018). ", "spanType": "span-simple-text" }, { "url": "https://www.sciencedirect.com/science/article/pii/S0195925517303116", "children": [ { "text": "Measuring greenhouse gas emissions from international air travel of a country\u2019s residents methodological development and application for Sweden", "spanType": "span-simple-text" } ], "spanType": "span-link" }, { "text": ". ", "spanType": "span-simple-text" }, { "children": [ { "text": "Environmental Impact Assessment Review", "spanType": "span-simple-text" } ], "spanType": "span-italic" }, { "text": ", ", "spanType": "span-simple-text" }, { "children": [ { "text": "72", "spanType": "span-simple-text" } ], "spanType": "span-italic" }, { "text": ", 137-144.{/ref}", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "But if we wanted to allocate them to a particular country, how would we do it? Who do emissions from international flights belong to: the country that owns the airline; the country of departure; the country of arrival?", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "Let\u2019s first take a look at how emissions would compare if we allocated them to the country of ", "spanType": "span-simple-text" }, { "children": [ { "text": "departure", "spanType": "span-simple-text" } ], "spanType": "span-italic" }, { "text": ". This means, for example, that emissions from any flight that departs from Spain are counted towards Spain\u2019s total. In the chart here we see international aviation emissions in per capita terms.", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "Some of the largest emitters per person in 2018 were Iceland (3.5 tonnes of CO", "spanType": "span-simple-text" }, { "children": [ { "text": "2", "spanType": "span-simple-text" } ], "spanType": "span-subscript" }, { "text": " per person); Qatar (2.5 tonnes); United Arab Emirates (2.2 tonnes); Singapore (1.7 tonnes); and Malta (992 kilograms).\u00a0", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "Again, we see large inequalities in emissions across the world \u2013 in many lower-income countries per capita emissions are only a few kilograms: 6 kilograms in India, 4 kilograms in Nigeria; and only 1.4 kilograms in the Democratic Republic of Congo.", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "url": "https://ourworldindata.org/grapher/per-capita-co2-international-aviation?stackMode=absolute&time=latest&region=World", "type": "chart", "parseErrors": [] }, { "text": [ { "text": "Related charts:", "spanType": "span-simple-text" } ], "type": "heading", "level": 4, "parseErrors": [] }, { "url": "https://ourworldindata.org/grapher/co2-international-aviation", "type": "prominent-link", "title": "Total CO\u2082 emissions from international aviation", "description": "", "parseErrors": [] }, { "url": "https://ourworldindata.org/grapher/share-co2-international-aviation", "type": "prominent-link", "title": "Share of global CO\u2082 emissions from international aviation", "description": "", "parseErrors": [] }, { "text": [ { "text": "Per capita emissions from international flights \u2013 adjusted for tourism", "spanType": "span-simple-text" } ], "type": "heading", "level": 3, "parseErrors": [] }, { "type": "text", "value": [ { "text": "The above allocation of international aviation emissions to the country of ", "spanType": "span-simple-text" }, { "children": [ { "text": "departure", "spanType": "span-simple-text" } ], "spanType": "span-italic" }, { "text": " raises some issues. It is not an accurate reflection of the local population of countries that rely a lot on tourism, for example. Most of the departing flights from these countries are carrying visiting tourists rather than locals.\u00a0", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "One way to correct for this is to adjust these figures for the ratio of inbound to outbound travellers. This approach was applied ", "spanType": "span-simple-text" }, { "url": "https://theicct.org/blog/staff/not-every-tonne-of-aviation-CO2", "children": [ { "text": "in an analysis", "spanType": "span-simple-text" } ], "spanType": "span-link" }, { "text": " by Sola Zheng for the ", "spanType": "span-simple-text" }, { "children": [ { "text": "International Council on Clean Transportation", "spanType": "span-simple-text" } ], "spanType": "span-italic" }, { "text": ". This attempts to distinguish between locals traveling abroad and foreign visitors traveling to that country on the same flight.{ref}A country with a ratio greater than one will have more incoming travellers than outgoing locals i.e. they are more of a hotspot for tourism.{/ref} For example, if we calculated that Spain had 50% more incoming than outgoing travellers, we would reduce its per capita footprint from flying by 50%. If the UK had 75% more outgoing travellers than incoming, we\u2019d increase its footprint by 75%.", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "We have replicated this approach and\u00a0 applied this adjustment to these figures by calculating the ", "spanType": "span-simple-text" }, { "url": "https://ourworldindata.org/grapher/ratio-of-inbound-to-outbound-tourists", "children": [ { "text": "inbound:outbound tourist ratio", "spanType": "span-simple-text" } ], "spanType": "span-link" }, { "text": " based on flight departures and arrival data from the ", "spanType": "span-simple-text" }, { "url": "https://datacatalog.worldbank.org/dataset/world-development-indicators", "children": [ { "text": "World Bank", "spanType": "span-simple-text" } ], "spanType": "span-link" }, { "text": ".\u00a0", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "How does this affect per capita emissions from international flights? The adjusted figures are shown in the chart here.", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "As we would expect, countries which are tourist hotspots see the largest change. Portugal\u2019s emissions, for example, fall from 388 to just 60 kilograms per person. Portuguese locals are responsible for much fewer travel emissions than outgoing tourists. Spanish emissions fall from 335 to 77 kilograms per person.", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "On the other hand, countries where the locals travel elsewhere see a large increase. In the UK, they almost double from 422 to 818 kilograms.", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "url": "https://ourworldindata.org/grapher/per-capita-co2-international-flights-adjusted?stackMode=absolute&time=latest&region=World", "type": "chart", "parseErrors": [] }, { "text": [ { "text": "Per capita emissions from domestic ", "spanType": "span-simple-text" }, { "children": [ { "text": "and ", "spanType": "span-simple-text" } ], "spanType": "span-italic" }, { "text": "international flights", "spanType": "span-simple-text" } ], "type": "heading", "level": 3, "parseErrors": [] }, { "type": "text", "value": [ { "text": "Let\u2019s combine per capita emissions from domestic and international travel to compare the total footprint from flying.", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "This is shown in the interactive map ", "spanType": "span-simple-text" }, { "children": [ { "text": "[we\u2019ve taken the adjusted international figures \u2013 you can find the\u00a0 combined figures without tourism-adjustment ", "spanType": "span-simple-text" } ], "spanType": "span-italic" }, { "url": "https://ourworldindata.org/grapher/per-capita-co2-aviation", "children": [ { "children": [ { "children": [ { "text": "here", "spanType": "span-simple-text" } ], "spanType": "span-italic" } ], "spanType": "span-bold" } ], "spanType": "span-link" }, { "children": [ { "text": "].\u00a0", "spanType": "span-simple-text" } ], "spanType": "span-italic" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "The global average emissions from aviation were 103 kilograms. The inequality in emissions across the world becomes clear when this is broken down by country.\u00a0", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "At the top of the table lies the United Arab Emirates \u2013 each person emits close to two tonnes \u2013 1950 kg \u2013 of CO", "spanType": "span-simple-text" }, { "children": [ { "text": "2", "spanType": "span-simple-text" } ], "spanType": "span-subscript" }, { "text": " from flying each year. That\u2019s 200 times the global average.\u00a0 This was followed by Singapore (1173 kilograms); Iceland (1070 kg); Finland (1000 kg); and Australia (878 kilograms).\u00a0", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "To put this into perspective: a return flight (in economy class) from London to Dubai/United Arab Emirates would emit around one tonne of CO", "spanType": "span-simple-text" }, { "children": [ { "text": "2", "spanType": "span-simple-text" } ], "spanType": "span-subscript" }, { "text": ".{ref}We can calculate this by taking the standard CO2 conversion factors for travel, used in the ", "spanType": "span-simple-text" }, { "url": "https://www.gov.uk/government/publications/greenhouse-gas-reporting-conversion-factors-2019", "children": [ { "text": "UK greenhouse gas accounting framework", "spanType": "span-simple-text" } ], "spanType": "span-link" }, { "text": ". For a long-haul flight in economy class, around 0.079 kilograms of CO", "spanType": "span-simple-text" }, { "children": [ { "text": "2", "spanType": "span-simple-text" } ], "spanType": "span-subscript" }, { "url": "https://ourworldindata.org/travel-carbon-footprint", "children": [ { "text": "are emitted", "spanType": "span-simple-text" } ], "spanType": "span-link" }, { "text": " per passenger-kilometer. This means that you would travel around 12,600 kilometers to emit one tonne [1,000,000 / 0.079 kg = 12,626 kilometers]. Since we\u2019re taking a return flight, the travel distance would be half of that figure: around 6300 kilometers. The direct distance from ", "spanType": "span-simple-text" }, { "url": "https://www.distance.to/London/Dubai,ARE", "children": [ { "text": "London to Dubai", "spanType": "span-simple-text" } ], "spanType": "span-link" }, { "text": " is around 5,500 kilometers. Depending on the flight path, it\u2019s likely to be slightly longer than this, and in the range of 5500 to 6500 kilometers.", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "Note that in this case we\u2019re looking at CO", "spanType": "span-simple-text" }, { "children": [ { "text": "2", "spanType": "span-simple-text" } ], "spanType": "span-subscript" }, { "text": " emissions ", "spanType": "span-simple-text" }, { "children": [ { "text": "without", "spanType": "span-simple-text" } ], "spanType": "span-italic" }, { "text": " the extra warming effects of these emissions at high altitudes. This is to allow us to compare with the ICCT figures by country presented in this article. You find additional data on how the footprint of flying is impacted by non-CO", "spanType": "span-simple-text" }, { "children": [ { "text": "2", "spanType": "span-simple-text" } ], "spanType": "span-subscript" }, { "text": " warming effects", "spanType": "span-simple-text" }, { "url": "https://ourworldindata.org/grapher/carbon-footprint-travel-mode", "children": [ { "text": " ", "spanType": "span-simple-text" }, { "children": [ { "text": "here", "spanType": "span-simple-text" } ], "spanType": "span-bold" } ], "spanType": "span-link" }, { "text": ".{/ref} So the two-tonne average for the UAE is equivalent to around two return trips to London.", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "In many countries, most people do not fly at all. The average Indian emits just 18 kilograms from aviation \u2013 this is much, much less than even a short-haul flight which confirms that most did not take a flight.", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "In fact, we can compare just the aviation emissions for the top countries to the ", "spanType": "span-simple-text" }, { "children": [ { "text": "total", "spanType": "span-simple-text" } ], "spanType": "span-italic" }, { "text": " carbon footprint of citizens elsewhere. The average UAE citizen emits 1950 kilograms of CO", "spanType": "span-simple-text" }, { "children": [ { "text": "2", "spanType": "span-simple-text" } ], "spanType": "span-subscript" }, { "text": " from flying. This is the same as the ", "spanType": "span-simple-text" }, { "children": [ { "text": "total", "spanType": "span-simple-text" } ], "spanType": "span-italic" }, { "url": "https://ourworldindata.org/explorers/co2?tab=chart&xScale=linear&yScale=linear&stackMode=absolute&endpointsOnly=0&year=latest&time=1858..2018&country=~India&region=World&Gas%20=CO%E2%82%82&Accounting%20=Production-based&Fuel%20=Total&Count%20=Per%20capita&Relative%20to%20world%20total%20=", "children": [ { "text": "CO", "spanType": "span-simple-text" }, { "children": [ { "text": "2", "spanType": "span-simple-text" } ], "spanType": "span-subscript" }, { "text": " footprint of the average Indian", "spanType": "span-simple-text" } ], "spanType": "span-link" }, { "text": " (including everything from electricity to road transport, heating and industry). Or, to take a more extreme example, 200 times the total footprint of the average Nigerien, Ugandan or Ethiopian, which ", "spanType": "span-simple-text" }, { "url": "https://ourworldindata.org/explorers/co2?tab=chart&xScale=linear&yScale=linear&stackMode=absolute&endpointsOnly=0&year=latest&time=1958..2018&country=Niger~Uganda~Ethiopia&region=World&Gas%20=CO%E2%82%82&Accounting%20=Production-based&Fuel%20=Total&Count%20=Per%20capita&Relative%20to%20world%20total%20=", "children": [ { "text": "have per capita emissions", "spanType": "span-simple-text" } ], "spanType": "span-link" }, { "text": " of around 100 kilograms.\u00a0", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "This again emphasises the large difference between the global average and the individual emissions of people who fly. Aviation contributes a few percent of total CO", "spanType": "span-simple-text" }, { "children": [ { "text": "2", "spanType": "span-simple-text" } ], "spanType": "span-subscript" }, { "text": " emissions each year \u2013 this is not insignificant, but far from being the largest sector to tackle. Yet from the perspective of the individual, flying ", "spanType": "span-simple-text" }, { "children": [ { "text": "is", "spanType": "span-simple-text" } ], "spanType": "span-italic" }, { "text": " often one of the largest chunks of our carbon footprint. The average rich person emits tonnes of CO", "spanType": "span-simple-text" }, { "children": [ { "text": "2", "spanType": "span-simple-text" } ], "spanType": "span-subscript" }, { "text": " from flying each year \u2013 this is equivalent to the ", "spanType": "span-simple-text" }, { "children": [ { "text": "total", "spanType": "span-simple-text" } ], "spanType": "span-italic" }, { "text": " carbon footprint of tens or hundreds of people in many countries of the world.", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "url": "https://ourworldindata.org/grapher/per-capita-co2-aviation-adjusted?stackMode=absolute&region=World", "type": "chart", "parseErrors": [] }, { "text": [ { "text": "Related charts:", "spanType": "span-simple-text" } ], "type": "heading", "level": 4, "parseErrors": [] }, { "url": "https://ourworldindata.org/grapher/per-capita-co2-aviation", "type": "prominent-link", "title": "Per capita CO\u2082 emissions from aviation (without tourism adjustment)", "description": "", "parseErrors": [] }, { "url": "https://ourworldindata.org/grapher/co2-emissions-aviation", "type": "prominent-link", "title": "Total CO\u2082 emissions from aviation", "description": "", "parseErrors": [] }, { "url": "https://ourworldindata.org/grapher/share-co2-emissions-aviation", "type": "prominent-link", "title": "Share of global CO\u2082 emissions from aviation", "description": "", "parseErrors": [] }, { "text": [ { "text": "Where in the world do people fly the most?", "spanType": "span-simple-text" } ], "type": "heading", "level": 2, "parseErrors": [] }, { "text": [ { "text": "Domestic air travel", "spanType": "span-simple-text" } ], "type": "heading", "level": 3, "parseErrors": [] }, { "type": "text", "value": [ { "text": "This interactive chart shows the average distance travelled per person through domestic air travel each year. This data is for passenger flights only and does not include freight.", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "url": "https://ourworldindata.org/grapher/per-capita-domestic-aviation-km", "type": "chart", "parseErrors": [] }, { "text": [ { "text": "Related charts:", "spanType": "span-simple-text" } ], "type": "heading", "level": 4, "parseErrors": [] }, { "url": "https://ourworldindata.org/grapher/share-global-domestic-aviation-km", "type": "prominent-link", "title": "Share of global passenger kilometers from domestic air travel", "description": "What share of global domestic air travel does each country account for?", "parseErrors": [] }, { "url": "https://ourworldindata.org/grapher/total-domestic-aviation-km", "type": "prominent-link", "title": "Total passenger kilometers from domestic air travel", "description": "", "parseErrors": [] }, { "text": [ { "text": "International air travel", "spanType": "span-simple-text" } ], "type": "heading", "level": 3, "parseErrors": [] }, { "type": "text", "value": [ { "text": "This interactive chart shows the average distance travelled per person through international air travel each year. This data is for passenger flights only and does not include freight.", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "url": "https://ourworldindata.org/grapher/per-capita-international-aviation-km", "type": "chart", "parseErrors": [] }, { "text": [ { "text": "Related charts:", "spanType": "span-simple-text" } ], "type": "heading", "level": 4, "parseErrors": [] }, { "url": "https://ourworldindata.org/grapher/share-international-aviation-km", "type": "prominent-link", "title": "Share of global passenger kilometers from international air travel", "description": "What share of global international air travel does each country account for?", "parseErrors": [] }, { "url": "https://ourworldindata.org/grapher/passenger-km-international-aviation", "type": "prominent-link", "title": "Total passenger kilometers from international air travel", "description": "", "parseErrors": [] }, { "text": [ { "text": "Total air travel", "spanType": "span-simple-text" } ], "type": "heading", "level": 3, "parseErrors": [] }, { "type": "text", "value": [ { "text": "This interactive chart shows the average distance travelled per person through domestic ", "spanType": "span-simple-text" }, { "children": [ { "text": "and", "spanType": "span-simple-text" } ], "spanType": "span-italic" }, { "text": " international air travel each year. This data is for passenger flights only and does not include freight.", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "url": "https://ourworldindata.org/grapher/per-capita-km-aviation", "type": "chart", "parseErrors": [] }, { "text": [ { "text": "Related charts:", "spanType": "span-simple-text" } ], "type": "heading", "level": 4, "parseErrors": [] }, { "url": "https://ourworldindata.org/grapher/share-km-aviation", "type": "prominent-link", "title": "Share of global passenger kilometers from air travel", "description": "What share of global air travel does each country account for?", "parseErrors": [] }, { "url": "https://ourworldindata.org/grapher/total-aviation-km", "type": "prominent-link", "title": "Total passenger kilometers from air travel", "description": "", "parseErrors": [] }, { "type": "horizontal-rule", "parseErrors": [] }, { "text": [ { "text": "Rail", "spanType": "span-simple-text" } ], "type": "heading", "level": 1, "parseErrors": [] }, { "type": "horizontal-rule", "parseErrors": [] }, { "type": "text", "value": [ { "text": "This interactive chart shows the total rail travel in each country, measured in passenger-kilometers per year.", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "This includes passenger travel only and does not include freight.", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "url": "https://ourworldindata.org/grapher/railways-passengers-carried-passenger-km", "type": "chart", "parseErrors": [] }, { "type": "horizontal-rule", "parseErrors": [] }, { "text": [ { "text": "Energy intensity of transport", "spanType": "span-simple-text" } ], "type": "heading", "level": 1, "parseErrors": [] }, { "type": "horizontal-rule", "parseErrors": [] }, { "type": "text", "value": [ { "text": "This chart shows the average energy intensity of transport across different modes of travel. It is measured as the average kilowatt-hours required per passenger-kilometer.", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "This data comes from the United States Department of Transportation's Bureau of Transportation Statistics (BTS). The energy intensity of public transport depends on the assumptions made about the capacity of transport modes i.e. how many passengers travel on a given train or bus journey. This data thererfore reflects average capacities in the United States, but will vary from country-to-country.", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "url": "https://ourworldindata.org/grapher/energy-intensity-transport?country=Amtrak~Bus~Domestic+flight~International+flight~Motorcycle~~Transit+motor+bus~Truck+%28with+trailer%29~Truck~", "type": "chart", "parseErrors": [] }, { "type": "horizontal-rule", "parseErrors": [] }, { "text": [ { "text": "CO", "spanType": "span-simple-text" }, { "children": [ { "text": "2", "spanType": "span-simple-text" } ], "spanType": "span-subscript" }, { "text": " emissions from transport", "spanType": "span-simple-text" } ], "type": "heading", "level": 1, "parseErrors": [] }, { "type": "horizontal-rule", "parseErrors": [] }, { "text": [ { "text": "Per capita transport emissions from transport", "spanType": "span-simple-text" } ], "type": "heading", "level": 2, "parseErrors": [] }, { "type": "text", "value": [ { "text": "This interactive shows the average per capita emissions of carbon dioxide from transport each year. This includes road, train, bus and domestic air travel but ", "spanType": "span-simple-text" }, { "children": [ { "text": "does not ", "spanType": "span-simple-text" } ], "spanType": "span-italic" }, { "text": "include international aviation and shipping.", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "url": "https://ourworldindata.org/grapher/per-capita-co2-transport?stackMode=absolute&region=World", "type": "chart", "parseErrors": [] }, { "text": [ { "text": "Total transport emissions", "spanType": "span-simple-text" } ], "type": "heading", "level": 2, "parseErrors": [] }, { "type": "text", "value": [ { "text": "This interactive shows the emissions of carbon dioxide from transport each year. This includes road, train, bus and domestic air travel but ", "spanType": "span-simple-text" }, { "children": [ { "text": "does not ", "spanType": "span-simple-text" } ], "spanType": "span-italic" }, { "text": "include international aviation and shipping.", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "url": "https://ourworldindata.org/grapher/co2-emissions-transport?stackMode=absolute&time=earliest..latest&region=World", "type": "chart", "parseErrors": [] }, { "text": [ { "text": "CO", "spanType": "span-simple-text" }, { "children": [ { "text": "2", "spanType": "span-simple-text" } ], "spanType": "span-subscript" }, { "text": " emissions by mode of transport", "spanType": "span-simple-text" } ], "type": "heading", "level": 2, "parseErrors": [] }, { "type": "text", "value": [ { "text": "Transport accounts for around one-fifth of global carbon dioxide (CO", "spanType": "span-simple-text" }, { "children": [ { "text": "2", "spanType": "span-simple-text" } ], "spanType": "span-subscript" }, { "text": ") emissions ", "spanType": "span-simple-text" }, { "children": [ { "text": "[24% if we only consider CO", "spanType": "span-simple-text" }, { "children": [ { "text": "2", "spanType": "span-simple-text" } ], "spanType": "span-subscript" }, { "text": " emissions from energy]", "spanType": "span-simple-text" } ], "spanType": "span-italic" }, { "text": ".{ref}The ", "spanType": "span-simple-text" }, { "children": [ { "text": "World Resource Institute", "spanType": "span-simple-text" } ], "spanType": "span-italic" }, { "text": "\u2019s Climate Data Explorer ", "spanType": "span-simple-text" }, { "url": "https://www.climatewatchdata.org/data-explorer/historical-emissions?historical-emissions-data-sources=cait&historical-emissions-gases=co2&historical-emissions-regions=All%20Selected&historical-emissions-sectors=total-including-lucf%2Ctransportation&page=1&sort_col=country&sort_dir=ASC", "children": [ { "text": "provides data", "spanType": "span-simple-text" } ], "spanType": "span-link" }, { "text": " from CAIT on the breakdown of emissions by sector. In 2016, global CO", "spanType": "span-simple-text" }, { "children": [ { "text": "2", "spanType": "span-simple-text" } ], "spanType": "span-subscript" }, { "text": " emissions (including land use) were 36.7 billion tonnes CO", "spanType": "span-simple-text" }, { "children": [ { "text": "2", "spanType": "span-simple-text" } ], "spanType": "span-subscript" }, { "text": "; emissions from transport were 7.9 billion tonnes CO", "spanType": "span-simple-text" }, { "children": [ { "text": "2", "spanType": "span-simple-text" } ], "spanType": "span-subscript" }, { "text": ". Transport therefore accounted for 7.9 / 36.7 = 21% of global emissions. ", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "The IEA ", "spanType": "span-simple-text" }, { "url": "https://www.iea.org/data-and-statistics/?country=WORLD&fuel=CO2%20emissions&indicator=TotCO2", "children": [ { "text": "looks at CO", "spanType": "span-simple-text" }, { "children": [ { "text": "2", "spanType": "span-simple-text" } ], "spanType": "span-subscript" }, { "text": " emissions", "spanType": "span-simple-text" } ], "spanType": "span-link" }, { "text": " from energy production alone \u2013 in 2018 it reported 33.5 billion tonnes of energy-related CO", "spanType": "span-simple-text" }, { "children": [ { "text": "2", "spanType": "span-simple-text" } ], "spanType": "span-subscript" }, { "text": " [hence, transport accounted for 8 billion / 33.5 billion = 24% of energy-related emissions.{/ref}", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "How do these emissions break down? Is it cars, trucks, planes or trains that dominate?", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "In the chart here we see global transport emissions in 2018. This data is ", "spanType": "span-simple-text" }, { "url": "https://www.iea.org/data-and-statistics/charts/transport-sector-co2-emissions-by-mode-in-the-sustainable-development-scenario-2000-2030", "children": [ { "text": "sourced from", "spanType": "span-simple-text" } ], "spanType": "span-link" }, { "text": " the ", "spanType": "span-simple-text" }, { "children": [ { "text": "International Energy Agency (IEA)", "spanType": "span-simple-text" } ], "spanType": "span-italic" }, { "text": ".\u00a0", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "Road travel accounts for three-quarters of transport emissions. Most of this comes from passenger vehicles \u2013 cars and buses \u2013 which contribute 45.1%. The other 29.4% comes from trucks carrying freight.", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "Since the entire transport sector accounts for 21% of total emissions, and road transport accounts for three-quarters of transport emissions, road transport accounts for 15% of total CO", "spanType": "span-simple-text" }, { "children": [ { "text": "2", "spanType": "span-simple-text" } ], "spanType": "span-subscript" }, { "text": " emissions.", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "Aviation \u2013 while it often gets the most attention in discussions on action against climate change \u2013 accounts for only 11.6% of transport emissions. It emits just under one billion tonnes of CO", "spanType": "span-simple-text" }, { "children": [ { "text": "2", "spanType": "span-simple-text" } ], "spanType": "span-subscript" }, { "text": " each year \u2013 around 2.5% of total global emissions ", "spanType": "span-simple-text" }, { "children": [ { "text": "[we look at the role that air travel plays in climate change in more detail in an upcoming article]", "spanType": "span-simple-text" } ], "spanType": "span-italic" }, { "text": ".\u00a0International shipping contributes a similar amount, at 10.6%.\u00a0", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "Rail travel and freight emits very little \u2013 only 1% of transport emissions. Other transport \u2013 which is mainly the movement of materials such as water, oil, and gas via pipelines \u2013 is responsible for 2.2%.", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "alt": "", "size": "wide", "type": "image", "filename": "Transport-CO2-emissions-by-mode-bar-chart.png", "parseErrors": [] }, { "text": [ { "text": "Towards zero-carbon transport: how can we expect the sector\u2019s CO", "spanType": "span-simple-text" }, { "children": [ { "text": "2", "spanType": "span-simple-text" } ], "spanType": "span-subscript" }, { "text": " emissions to change in the future?", "spanType": "span-simple-text" } ], "type": "heading", "level": 3, "parseErrors": [] }, { "type": "text", "value": [ { "text": "Transport demand is expected to grow across the world in the coming decades as the global population increases, incomes rise, and more people can afford cars, trains and flights. In its ", "spanType": "span-simple-text" }, { "children": [ { "text": "Energy Technology Perspectives", "spanType": "span-simple-text" } ], "spanType": "span-italic" }, { "text": " report, the International Energy Agency (IEA) expects global transport (measured in passenger-kilometers) to double, car ownership rates to increase by 60%, and demand for passenger and freight aviation to triple by 2070.{ref}IEA (2020), ", "spanType": "span-simple-text" }, { "url": "https://www.iea.org/reports/energy-technology-perspectives-2020", "children": [ { "text": "Energy Technology Perspectives 2020", "spanType": "span-simple-text" } ], "spanType": "span-link" }, { "text": ", IEA, Paris.{/ref} Combined, these factors would result in a large increase in transport emissions.", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "But major technological innovations can help offset this rise in demand. As the world shifts towards lower-carbon electricity sources, the rise of electric vehicles offers a viable option to reduce emissions from passenger vehicles.", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "This is reflected in the IEA\u2019s ", "spanType": "span-simple-text" }, { "children": [ { "text": "Energy Technology Perspective", "spanType": "span-simple-text" } ], "spanType": "span-italic" }, { "text": " report. There it outlines its \u201cSustainable Development Scenario\u201d for reaching net-zero CO2 emissions from global energy by 2070. The pathways for the different elements of the transport sector in this optimistic scenario are shown in the visualization.", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "We see that with electrification- and hydrogen- technologies some of these sub-sectors could decarbonize within decades. The IEA scenario assumes the phase-out of emissions from motorcycles by 2040; rail by 2050; small trucks by 2060; and although emissions from cars and buses are not completely eliminated until 2070, it expects many regions, including the European Union; United States; China and Japan to have phased-out conventional vehicles as early as 2040.", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "Other transport sectors will be much more difficult to decarbonize.", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "In a paper published in ", "spanType": "span-simple-text" }, { "children": [ { "text": "Science", "spanType": "span-simple-text" } ], "spanType": "span-italic" }, { "text": ", Steven Davis and colleagues looked at our options across sectors to reach a net-zero emissions energy system.{ref}Davis, S. J., Lewis, N. S., Shaner, M., Aggarwal, S., Arent, D., Azevedo, I. L., ... & Clack, C. T. (2018). ", "spanType": "span-simple-text" }, { "url": "https://science.sciencemag.org/content/360/6396/eaas9793.full", "children": [ { "text": "Net-zero emissions energy systems", "spanType": "span-simple-text" } ], "spanType": "span-link" }, { "text": ". ", "spanType": "span-simple-text" }, { "children": [ { "text": "Science", "spanType": "span-simple-text" } ], "spanType": "span-italic" }, { "text": ", 360(6396).{/ref} They highlighted long-distance road freight (large trucks), aviation and shipping as particularly difficult to eliminate. The potential for hydrogen as a fuel, or battery electricity to run planes, ships and large trucks is limited by the range and power required; the size and weight of batteries or hydrogen fuel tanks would be ", "spanType": "span-simple-text" }, { "children": [ { "text": "much", "spanType": "span-simple-text" } ], "spanType": "span-italic" }, { "text": " larger and heavier than current combustion engines.{ref}Cecere, D., Giacomazzi, E., & Ingenito, A. (2014). ", "spanType": "span-simple-text" }, { "url": "https://www.sciencedirect.com/science/article/pii/S0360319914011847", "children": [ { "text": "A review on hydrogen industrial aerospace applications", "spanType": "span-simple-text" } ], "spanType": "span-link" }, { "text": ". ", "spanType": "span-simple-text" }, { "children": [ { "text": "International Journal of Hydrogen Energy", "spanType": "span-simple-text" } ], "spanType": "span-italic" }, { "text": ", ", "spanType": "span-simple-text" }, { "children": [ { "text": "39", "spanType": "span-simple-text" } ], "spanType": "span-italic" }, { "text": "(20), 10731-10747.{/ref}", "spanType": "span-simple-text" }, { "children": [ { "text": ",", "spanType": "span-simple-text" } ], "spanType": "span-superscript" }, { "text": "{ref}Fulton, L. M., Lynd, L. R., K\u00f6rner, A., Greene, N., & Tonachel, L. R. (2015). ", "spanType": "span-simple-text" }, { "url": "https://onlinelibrary.wiley.com/doi/full/10.1002/bbb.1559", "children": [ { "text": "The need for biofuels as part of a low carbon energy future", "spanType": "span-simple-text" } ], "spanType": "span-link" }, { "text": ". ", "spanType": "span-simple-text" }, { "children": [ { "text": "Biofuels, Bioproducts and Biorefining", "spanType": "span-simple-text" } ], "spanType": "span-italic" }, { "text": ", 9(5), 476-483.{/ref}", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "So, despite falling by three-quarters in the visualized scenario, emissions from these sub-sectors would still make transport the largest contributor to energy-related emissions in 2070. To reach net-zero for the energy sector as a whole, these emissions would have to be offset by \u2018negative emissions\u2019 (e.g. the capture and storage of carbon from bioenergy or ", "spanType": "span-simple-text" }, { "url": "https://www.iea.org/reports/direct-air-capture", "children": [ { "text": "direct air capture", "spanType": "span-simple-text" } ], "spanType": "span-link" }, { "text": ") from other parts of the energy system.", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "In the IEA\u2019s net-zero scenario, nearly two-thirds of the emissions reductions come from technologies that are not yet commercially available. As the IEA states, \u201cReducing CO", "spanType": "span-simple-text" }, { "children": [ { "text": "2", "spanType": "span-simple-text" } ], "spanType": "span-subscript" }, { "text": " emissions in the transport sector over the next half-century will be a formidable task.\u201d{ref}IEA (2020), ", "spanType": "span-simple-text" }, { "url": "https://www.iea.org/reports/energy-technology-perspectives-2020", "children": [ { "text": "Energy Technology Perspectives 2020", "spanType": "span-simple-text" } ], "spanType": "span-link" }, { "text": ", IEA, Paris.{/ref}", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "text": [ { "text": "Global CO2 emissions from transport in the IEA's Sustainable Development Scenario to 2070{ref}IEA (2020), ", "spanType": "span-simple-text" }, { "url": "https://www.iea.org/reports/energy-technology-perspectives-2020", "children": [ { "text": "Energy Technology Perspectives 2020", "spanType": "span-simple-text" } ], "spanType": "span-link" }, { "text": ", IEA, Paris.{/ref}", "spanType": "span-simple-text" } ], "type": "heading", "level": 5, "parseErrors": [] }, { "alt": "", "size": "wide", "type": "image", "filename": "IEA-Transport-to-2070.png", "parseErrors": [] } ], "type": "linear-topic-page", "title": "Transport", "authors": [ "Hannah Ritchie", "Max Roser" ], "excerpt": "Explore trends in transport technologies and emissions across the world.", "dateline": "September 24, 2021", "subtitle": "Explore trends in transport technologies and emissions across the world.", "sticky-nav": [], "sidebar-toc": true, "featured-image": "transport-thumbnail.png" }, "createdAt": "2020-09-02T14:42:44.000Z", "published": false, "updatedAt": "2023-06-09T18:20:39.000Z", "revisionId": null, "publishedAt": "2021-09-24T13:42:00.000Z", "relatedCharts": [], "publicationContext": "listed" }	{ "errors": [ { "name": "unexpected wp component tag", "details": "Found unhandled wp:comment tag list" }, { "name": "unhandled html tag found", "details": "Encountered the unhandled tag hr" }, { "name": "unexpected wp component tag", "details": "Found unhandled wp:comment tag separator" }, { "name": "unexpected wp component tag", "details": "Found unhandled wp:comment tag image" }, { "name": "unexpected wp component tag", "details": "Found unhandled wp:comment tag image" }, { "name": "unexpected wp component tag", "details": "Found unhandled wp:comment tag list" }, { "name": "unexpected wp component tag", "details": "Found unhandled wp:comment tag image" }, { "name": "unexpected wp component tag", "details": "Found unhandled wp:comment tag image" }, { "name": "unexpected wp component tag", "details": "Found unhandled wp:comment tag image" } ], "numBlocks": 179, "numErrors": 9, "wpTagCounts": { "html": 19, "list": 2, "image": 6, "column": 30, "columns": 15, "heading": 36, "paragraph": 105, "separator": 1, "owid/prominent-link": 15, "owid/additional-information": 1 }, "htmlTagCounts": { "p": 105, "h2": 5, "h3": 12, "h4": 12, "h5": 6, "h6": 1, "hr": 1, "ul": 2, "div": 46, "figure": 6, "iframe": 17 } }	2021-09-24 13:42:00	2024-02-16 14:22:41		[ "Hannah Ritchie", "Max Roser" ]	Explore trends in transport technologies and emissions across the world.	2020-09-02 14:42:44	2023-06-09 18:20:39	https://ourworldindata.org/wp-content/uploads/2021/09/transport-thumbnail.png	{ "subnavId": "energy", "subnavCurrentId": "transport" }	First published in September 2021. --- # Road travel --- ## Passenger vehicle registrations by type These interactive charts show the breakdown of new passenger vehicle registrations by type. This is broken down by: petroleum; diesel; full hybrid (excluding plug-in hybrids); plug-in electric hybrids; and fully electric battery vehicles. <Chart url="https://ourworldindata.org/grapher/new-vehicles-type-area?tab=chart&stackMode=relative&country=~NOR"/> <Chart url="https://ourworldindata.org/grapher/new-vehicles-type-share?tab=chart&country=~GBR"/> ### Number of new passenger vehicle registrations by type https://ourworldindata.org/grapher/new-passenger-vehicles-type?country=~GBR ## Electric vehicle registrations This interactive chart shows the share of new passenger vehicle registrations that are battery electric vehicles. This does not include plug-in hybrid vehicles. <Chart url="https://ourworldindata.org/grapher/share-vehicle-electric?country=AUT~ITA~NOR~PRT~ESP~SWE~CHE~TUR~GBR~IRL~ISL~GRC~DEU~FRA~FIN~DNK~BEL~LUX~NLD"/> This interactive chart shows the share of new passenger vehicle registrations that are battery electric _plus_ plug-in hybrid vehicles. <Chart url="https://ourworldindata.org/grapher/battery-plugin-hybrid-vehicles?time=2019&country=~AUT~BEL~DNK~FIN~EU-27+%2B+UK~FRA~DEU~GRC~ISL~IRL~GBR~TUR~CHE~SWE~ESP~PRT~NOR~NLD~LUX~ITA"/> ## Carbon intensity of new passenger vehicles This interactive chart shows the average carbon intensity of new passenger vehicles in each country. This is measured as the average emissions of CO₂ (in grams) per kilometer travelled across all types of passenger vehicles. <Chart url="https://ourworldindata.org/grapher/carbon-new-passenger-vehicles?country=AUT~ITA~LUX~NLD~NOR~PRT~ESP~SWE~CHE~TUR~GBR~IRL~ISL~GRC~DEU~FRA~FIN~DNK~BEL"/> ## Fuel economy of new passenger vehicles This interacrive chart shows the average fuel economy of new passenger vehicles in each country. This is measured as the average liters consumed per 100 kilometers travelled, across all types of passenger vehicles. <Chart url="https://ourworldindata.org/grapher/fuel-efficiency-new-vehicles?country=AUT~BEL~ITA~LUX~NLD~NOR~PRT~ESP~SWE~CHE~TUR~GBR~IRL~ISL~GRC~DEU~FRA~FIN~DNK"/> --- # Aviation --- ## What share of global CO2 emissions come from aviation? Flying is a highly controversial topic in climate debates. There are a few reasons for this. The first is the disconnect between its role in our personal and collective carbon emissions. Air travel dominates a frequent traveller's individual contribution to climate change. Yet aviation overall accounts for only 2.5% of global carbon dioxide (CO2) emissions. This is because there are large inequalities in how much people fly – many do not, or cannot afford to, fly at all.{ref}The best estimates put this figure at around 80% of the world population. We look at this in more detail in our article "[Where in the world do people have the highest CO2 emissions from flying?](https://ourworldindata.org/carbon-footprint-flying)"{/ref} The second is how aviation emissions are attributed to countries. CO2 emissions from domestic flights _are_ counted in a country’s emission accounts. International flights are not – instead they are counted as their own category: ‘bunker fuels’. The fact that they don’t count towards the emissions of any country means there are few incentives for countries to reduce them. It’s also important to note that unlike the most common greenhouse gases – carbon dioxide, methane or nitrous oxide – non-CO2 forcings from aviation _are not included_ in the Paris Agreement. This means they could be easily overlooked – especially since international aviation is not counted within any country’s emissions inventories or targets. How much of a role does aviation play in global emissions and climate change? In this article we take a look at the key numbers that are useful to know. Global aviation (including domestic and international; passenger and freight) accounts for: * 1.9% of [greenhouse gas emissions](https://ourworldindata.org/ghg-emissions-by-sector) (which includes all greenhouse gases, not only CO2) * 2.5% of CO2 emissions * 3.5% of 'effective radiative forcing' – a closer measure of its impact on warming. The latter two numbers refer to 2018, and the first to 2016, the latest year for which such data are available. ### Aviation accounts for 2.5% of global CO2 emissions As we will see later in this article, there are a number of processes by which aviation contributes to climate change. But the one that gets the most attention is its contribution via CO2 emissions. Most flights are powered by jet gasoline – although some partially run on biofuels – which is converted to CO2 when burned. In a recent paper, researchers – David Lee and colleagues – reconstructed annual CO2 emissions from global aviation dating back to 1940.{ref}Lee, D. S., Fahey, D. W., Skowron, A., Allen, M. R., Burkhardt, U., Chen, Q., ... & Gettelman, A. (2020). [The contribution of global aviation to anthropogenic climate forcing for 2000 to 2018](https://www.sciencedirect.com/science/article/pii/S1352231020305689). _Atmospheric Environment_, 117834.{/ref} This was calculated based on fuel consumption data from the International Energy Agency (IEA), and earlier estimates from Robert Sausen and Ulrich Schumann (2000).{ref}Sausen, R., & Schumann, U. (2000). [Estimates of the climate response to aircraft CO2 and NOx emissions scenarios](https://link.springer.com/article/10.1023/A:1005579306109). _Climatic Change_, _44_(1-2), 27-58.{/ref} The time series of global emissions from aviation since 1940 is shown in the accompanying chart. In 2018, it’s estimated that global aviation – which includes both passenger and freight – emitted 1.04 billion tonnes of CO2. This represented 2.5% of [total CO2 emissions](https://ourworldindata.org/co2-emissions#global-co2-emissions-from-fossil-fuels-global-co2-emissions-from-fossil-fuels) in 2018.{ref}The Global Carbon Budget estimated total CO2 emissions from all fossil fuels, cement production and land-use change to be 42.1 billion tonnes in 2018. This means aviation accounted for [1 / 42.1 * 100] = 2.5% of total emissions.{/ref},{ref}Global Carbon Project. (2019). Supplemental data of Global Carbon Budget 2019 (Version 1.0) [Data set]. Global Carbon Project. [https://doi.org/10.18160/gcp-2019](https://doi.org/10.18160/gcp-2019). If we were to exclude land use change emissions, aviation accounted for 2.8% of fossil fuel emissions. The Global Carbon Budget estimated total CO2 emissions from fossil fuels and cement production to be 36.6 billion tonnes in 2018. This means aviation accounted for [1 / 36.6 * 100] = 2.8% of total emissions.{/ref} Aviation emissions have doubled since the mid-1980s. But, they’ve been growing at a similar rate as total CO2 emissions – this means its share of global emissions has been relatively stable: in the range of 2% to 2.5%.{ref}2.3% to 2.8% of emissions if land use is excluded.{/ref} <Image filename="Global-CO2-emissions-from-aviation.png" alt=""/> ### Non-CO2 climate impacts mean aviation accounts for 3.5% of global warming Aviation accounts for around 2.5% of global CO2 emissions, but it’s overall contribution to climate change is higher. This is because air travel does not only emit CO2: it affects the climate in a number of more complex ways. As well as emitting CO2 from burning fuel, planes affect the concentration of other gases and pollutants in the atmosphere. They result in a short-term increase, but long-term decrease in ozone (O3); a decrease in methane (CH4); emissions of water vapour; soot; sulfur aerosols; and water contrails. While some of these impacts result in warming, others induce a cooling effect. Overall, the warming effect is stronger. David Lee et al. (2020) quantified the overall effect of aviation on global warming when all of these impacts were included.{ref}Lee, D. S., Fahey, D. W., Skowron, A., Allen, M. R., Burkhardt, U., Chen, Q., ... & Gettelman, A. (2020). [The contribution of global aviation to anthropogenic climate forcing for 2000 to 2018](https://www.sciencedirect.com/science/article/pii/S1352231020305689). _Atmospheric Environment_, 117834.{/ref} To do this they calculated the so-called ‘Radiative Forcing’. Radiative forcing measures the difference between incoming energy and the energy radiated back to space. If more energy is absorbed than radiated, the atmosphere becomes warmer. In their chart we see [their estimates for the radiative forcing](https://ars.els-cdn.com/content/image/1-s2.0-S1352231020305689-gr3_lrg.jpg) of the different elements. When we combine them, aviation accounts for approximately 3.5% of effective radiative forcing: that is, 3.5% of warming. Although CO2 gets most of the attention, it accounts for less than half of this warming. Two-thirds (66%) comes from non-CO2 forcings. Contrails – water vapor trails from aircraft exhausts – account for the largest share. ### We don’t yet have the technologies to decarbonize air travel Aviation’s contribution to climate change – 3.5% of warming, or 2.5% of CO2 emissions – is often less than people think. It’s currently a relatively small chunk of emissions compared to other sectors. The key challenge is that it is particularly hard to decarbonize. We have solutions to reduce emissions for many of the [largest emitters](https://ourworldindata.org/ghg-emissions-by-sector) – such as power or road transport – and it’s now a matter of scaling them. We can deploy renewable and nuclear energy technologies, and transition to electric cars. But we don’t have proven solutions to tackle aviation yet. There are some design concepts emerging – Airbus, for example, [have announced plans](https://web.archive.org/web/20201031121346/https://www.airbus.com/innovation/zero-emission/hydrogen/zeroe.html) to have the first zero-emission aircraft by 2035, using hydrogen fuel cells. Electric planes may be a viable concept, but are likely to be limited to very small aircraft due to the limitations of battery technologies and capacity. Innovative solutions may be on the horizon, but they’re likely to be far in the distance. ### Towards zero-carbon transport: how can we expect the sector’s CO<sub>2</sub> emissions to change in the future? ourworldindata.org/co2-emissions-from-transport ## Additional information Global emissions from aviation have increased a lot over the past half-century. However, air travel volumes increased even more rapidly. Since 1960, aviation emissions increased almost seven-fold; since 1970 they’ve tripled. Air traffic volume – here defined as revenue passenger kilometers (RPK) traveled – [increased by orders of magnitude more](https://ourworldindata.org/grapher/airline-capacity-and-traffic): almost 300-fold since 1950; and 75-fold since 1960.{ref}Airline traffic data comes from the International Civil Aviation Organization (ICAO) via [Airlines for America](https://www.airlines.org/dataset/world-airlines-traffic-and-capacity). Revenue passenger kilometers (RPK) measures the number of paying passengers multiplied by their distance traveled.{/ref} The much slower growth in emissions means aviation efficiency has seen massive improvements. In the chart we show both the increase in global airline traffic since 1950, and aviation efficiency, measured as the quantity of CO2 emitted per revenue passenger kilometer traveled. In 2018, approximately 125 grams of CO2 were emitted per RPK. In 1960, this was eleven-fold higher; in 1950 it was twenty-fold higher. Aviation has seen massive efficiency improvements over the past 50 years. These improvements have come from several sources: improvements in the design and technology of aircraft; larger aircraft sizes (allowing for more passengers per flight); and an increase in how ‘full’ passenger flights are. This last metric is termed the ‘passenger load factor’. The passenger load factor measures the actual number of kilometers traveled by paying customers (RPK) as a percentage of the available seat kilometers (ASK) – the kilometers traveled if every plane was full. If every plane was full the passenger load factor would be 100%. If only three-quarters of the seats were filled, it would be 75%. The global passenger load factor [increased from 61% in 1950 to 82% in 2018](https://ourworldindata.org/grapher/airline-passenger-load-factor). <Image filename="Aviation-traffic-and-efficiency-Lee-et-al.-2020.png" alt=""/> ## Passenger vs. freight; domestic vs. international: where do aviation emissions come from? Global aviation – both passenger flights and freight – emits around one billion tonnes of carbon dioxide (CO2) each year. This was equivalent to around 2.4% of CO2 emissions in 2018. How do global aviation emissions break down? The chart gives the answer. This data is sourced from the 2019 _International Council on Clean Transportation__(ICCT)_ report on global aviation.{ref}Graver, B., Zhang, K., & Rutherford, D. (2019). [CO2 emissions from commercial aviation, 2018](https://theicct.org/sites/default/files/publications/ICCT_CO2-commercl-aviation-2018_20190918.pdf). _The International Council of Clean Transportation_.{/ref} Most emissions come from passenger flights – in 2018, they accounted for 81% of aviation’s emissions; the remaining 19% came from freight, the transport of goods. Sixty percent of emissions from_ passenger_ flights come from international travel; the other 40% come from domestic (in-country) flights. When we break passenger flight emissions down by travel distance, we get a (surprisingly) equal three-way split in emissions between short-haul (less than 1,500 kilometers); medium-haul (1,500 to 4,000 km); and long-haul (greater than 4,000 km) journeys. <Image filename="Global-breakdown-of-aviation-emissions.png" alt=""/> ### The richest half are responsible for 90% of air travel CO2 emissions The global inequalities in how much people fly become clear when we compare aviation emissions across countries of different income levels. The ICCT split these emissions based on World Bank's four [income groups](https://ourworldindata.org/grapher/world-banks-income-groups?year=latest). A further study by Susanne Becek and Paresh Pant (2019) compared the contribution of each income group to global air travel emissions versus its share of world population.{ref}Becken, S. and P. Pant (2019). [Airline initiatives to reduce climate impact: ways to accelerate action](https://amadeus.com/en/insights/white-paper/airline-initiatives-to-reduce-climate-impact) (White paper).{/ref} This comparison is shown in the visualization. The ‘richest’ half of the world (high and upper-middle income countries) were responsible for 90% of air travel emissions.{ref}Note that this is based on categorisations from the average income level of countries, and does not take account of variation in income _within _countries. If we were to look at this distribution based on the income level of individuals rather than countries, the inequality in aviation emissions would be even larger.{/ref} Looking at specific income groups: * Only 16% of the world population live in high-income countries yet the planes that take off in those countries account for almost two-thirds (62%) of passenger emissions; * Upper-middle income countries are home to 35% of the world population, and contribute 28% of emissions; * Lower-middle income countries are home to the largest share (40% of the world), yet emit the planes taking off there just account for 9%; * The poorest countries – which are home to 9% of the world population – emit just 1%. In an upcoming article we will look in more detail at the contribution of each country to global aviation emissions. <Image filename="Inequalities-in-CO2-emissions-from-air-travel.png" alt=""/> ## Where in the world do people have the highest carbon footprint from flying? Aviation accounts [for around 2.5%](https://ourworldindata.org/co2-emissions-from-aviation) of global carbon dioxide (CO2) emissions. But if you are someone who does fly, air travel will make up a much larger share of your personal carbon footprint. The fact that aviation is relatively small for global emissions as a whole, but of large importance for individuals that fly is due to large inequalities in the world. Most people in the world do not take flights. There is no global reliable figure, but often cited estimates suggest that more than 80% of the global population have never flown.{ref}There is no global database available on _who_ in the world flies each year. Passenger information is maintained by private airlines. Therefore, deriving estimates of this exact percentage is challenging. The most-cited estimate I’ve seen on this is that around 80% of the world population have never flown. This figure seems to circle back to a [quoted estimate](https://www.cnbc.com/2017/12/07/boeing-ceo-80-percent-of-people-never-flown-for-us-that-means-growth.html#:~:text=%E2%80%9CLess%20than%2020%20percent%20of,the%20entire%20economy%2C%20Muilenburg%20said.) from the Boeing CEO. Even in some of the world’s richest countries, a large share of the population do not fly frequently. Gallup [survey data](https://news.gallup.com/poll/1579/airlines.aspx) from the United States suggests that in 2015, half of the population did not take a flight. Survey data from the UK [provides similar estimates](http://publicapps.caa.co.uk/docs/33/CAA%20Aviation%20Consumer%20survey%20--%205th%20wave%20report%20FINAL%20(2).pdf): 46% had not flown in the previous year.{/ref} How do emissions from aviation vary across the world? Where do people have the highest footprint from flying? ### Per capita emissions from domestic flights The first and most straightforward comparison is to look at emissions from _domestic_ aviation – that is, flights that depart and arrive in the same country. This is easiest to compare because domestic aviation is counted in each country’s inventory of greenhouse gas emissions. International flights, on the other hand, are not attributed to specific countries – partly because of contention as to who should take responsibility (should it be the country of departure or arrival? What about layover flights?). In the chart here we see the average per capita emissions from domestic flights in 2018. This data is sourced from the _International Council on Clean Transportation_ – we then used [UN population estimates](https://population.un.org/wpp/) to calculate per capita figures.{ref}Graver, B., Zhang, K., & Rutherford, D. (2019). [CO2 emissions from commercial aviation, 2018](https://theicct.org/publications/co2-emissions-commercial-aviation-2018). _The International Council of Clean Transportation_.{/ref},{ref}Note that this gives us _mean_ per capita emissions, which does not account for in-country inequalities in the amount of flights people take.{/ref} We see large differences in emissions from domestic flights across the world. In the United States the average person emits around 386 kilograms of CO2 each year from internal flights. This is followed by Australia (267 kg); Norway (209 kg); New Zealand (174 kg); and Canada (168 kg). Compare this with countries at the bottom of the table – many across Africa, Asia, and Eastern Europe in particular emit less than one kilogram per person – just 0.8 kilograms; or 0.14 kilograms in Rwanda. For very small countries where there are no internal commercial flights, domestic emissions are of course, zero. There are some obvious factors that explain some of these cross-country differences. Firstly, countries that are richer [are more likely](https://ourworldindata.org/grapher/per-capita-co2-domestic-aviation-vs-gdp) to have higher emissions because people can afford to fly. Second, countries that have a larger land mass may have more internal flights – and indeed we see a [correlation](https://ourworldindata.org/grapher/per-capita-co2-domestic-aviation-vs-land-area) between land area and domestic flight emissions; in small countries people are more likely to travel by other means such as car or train. And third, countries that are more geographically-isolated – such as Australia and New Zealand – may have more internal travel. <Chart url="https://ourworldindata.org/grapher/per-capita-co2-domestic-aviation"/> #### Related charts: ### Total CO₂ emissions from domestic aviation https://ourworldindata.org/grapher/co2-emissions-domestic-aviation ### Share of global CO₂ emissions from domestic aviation https://ourworldindata.org/grapher/share-global-co2-domestic-aviation ### Per capita emissions from international flights Allocating emissions from international flights is more complex. International databases report these emissions separately as a category termed ‘bunker fuels’. The term ‘bunker fuel’ is used to describe emissions which come from international transport – either aviation or shipping. Because they are [not counted towards](https://unfccc.int/topics/mitigation/workstreams/emissions-from-international-transport-bunker-fuels) any particular country these emissions are also not taken into account in the goals that are set by countries in international treaties like the Kyoto protocol or the Paris Agreement.{ref}Larsson, J., Kamb, A., Nässén, J., & Åkerman, J. (2018). [Measuring greenhouse gas emissions from international air travel of a country’s residents methodological development and application for Sweden](https://www.sciencedirect.com/science/article/pii/S0195925517303116). _Environmental Impact Assessment Review_, _72_, 137-144.{/ref} But if we wanted to allocate them to a particular country, how would we do it? Who do emissions from international flights belong to: the country that owns the airline; the country of departure; the country of arrival? Let’s first take a look at how emissions would compare if we allocated them to the country of _departure_. This means, for example, that emissions from any flight that departs from Spain are counted towards Spain’s total. In the chart here we see international aviation emissions in per capita terms. Some of the largest emitters per person in 2018 were Iceland (3.5 tonnes of CO2 per person); Qatar (2.5 tonnes); United Arab Emirates (2.2 tonnes); Singapore (1.7 tonnes); and Malta (992 kilograms). Again, we see large inequalities in emissions across the world – in many lower-income countries per capita emissions are only a few kilograms: 6 kilograms in India, 4 kilograms in Nigeria; and only 1.4 kilograms in the Democratic Republic of Congo. <Chart url="https://ourworldindata.org/grapher/per-capita-co2-international-aviation?stackMode=absolute&time=latest&region=World"/> #### Related charts: ### Total CO₂ emissions from international aviation https://ourworldindata.org/grapher/co2-international-aviation ### Share of global CO₂ emissions from international aviation https://ourworldindata.org/grapher/share-co2-international-aviation ### Per capita emissions from international flights – adjusted for tourism The above allocation of international aviation emissions to the country of _departure_ raises some issues. It is not an accurate reflection of the local population of countries that rely a lot on tourism, for example. Most of the departing flights from these countries are carrying visiting tourists rather than locals. One way to correct for this is to adjust these figures for the ratio of inbound to outbound travellers. This approach was applied [in an analysis](https://theicct.org/blog/staff/not-every-tonne-of-aviation-CO2) by Sola Zheng for the _International Council on Clean Transportation_. This attempts to distinguish between locals traveling abroad and foreign visitors traveling to that country on the same flight.{ref}A country with a ratio greater than one will have more incoming travellers than outgoing locals i.e. they are more of a hotspot for tourism.{/ref} For example, if we calculated that Spain had 50% more incoming than outgoing travellers, we would reduce its per capita footprint from flying by 50%. If the UK had 75% more outgoing travellers than incoming, we’d increase its footprint by 75%. We have replicated this approach and applied this adjustment to these figures by calculating the [inbound:outbound tourist ratio](https://ourworldindata.org/grapher/ratio-of-inbound-to-outbound-tourists) based on flight departures and arrival data from the [World Bank](https://datacatalog.worldbank.org/dataset/world-development-indicators). How does this affect per capita emissions from international flights? The adjusted figures are shown in the chart here. As we would expect, countries which are tourist hotspots see the largest change. Portugal’s emissions, for example, fall from 388 to just 60 kilograms per person. Portuguese locals are responsible for much fewer travel emissions than outgoing tourists. Spanish emissions fall from 335 to 77 kilograms per person. On the other hand, countries where the locals travel elsewhere see a large increase. In the UK, they almost double from 422 to 818 kilograms. <Chart url="https://ourworldindata.org/grapher/per-capita-co2-international-flights-adjusted?stackMode=absolute&time=latest&region=World"/> ### Per capita emissions from domestic _and _international flights Let’s combine per capita emissions from domestic and international travel to compare the total footprint from flying. This is shown in the interactive map _[we’ve taken the adjusted international figures – you can find the combined figures without tourism-adjustment _[_here_](https://ourworldindata.org/grapher/per-capita-co2-aviation)_]. _ The global average emissions from aviation were 103 kilograms. The inequality in emissions across the world becomes clear when this is broken down by country. At the top of the table lies the United Arab Emirates – each person emits close to two tonnes – 1950 kg – of CO2 from flying each year. That’s 200 times the global average. This was followed by Singapore (1173 kilograms); Iceland (1070 kg); Finland (1000 kg); and Australia (878 kilograms). To put this into perspective: a return flight (in economy class) from London to Dubai/United Arab Emirates would emit around one tonne of CO2.{ref}We can calculate this by taking the standard CO2 conversion factors for travel, used in the [UK greenhouse gas accounting framework](https://www.gov.uk/government/publications/greenhouse-gas-reporting-conversion-factors-2019). For a long-haul flight in economy class, around 0.079 kilograms of CO2[are emitted](https://ourworldindata.org/travel-carbon-footprint) per passenger-kilometer. This means that you would travel around 12,600 kilometers to emit one tonne [1,000,000 / 0.079 kg = 12,626 kilometers]. Since we’re taking a return flight, the travel distance would be half of that figure: around 6300 kilometers. The direct distance from [London to Dubai](https://www.distance.to/London/Dubai,ARE) is around 5,500 kilometers. Depending on the flight path, it’s likely to be slightly longer than this, and in the range of 5500 to 6500 kilometers. Note that in this case we’re looking at CO2 emissions _without_ the extra warming effects of these emissions at high altitudes. This is to allow us to compare with the ICCT figures by country presented in this article. You find additional data on how the footprint of flying is impacted by non-CO2 warming effects[ here](https://ourworldindata.org/grapher/carbon-footprint-travel-mode).{/ref} So the two-tonne average for the UAE is equivalent to around two return trips to London. In many countries, most people do not fly at all. The average Indian emits just 18 kilograms from aviation – this is much, much less than even a short-haul flight which confirms that most did not take a flight. In fact, we can compare just the aviation emissions for the top countries to the _total_ carbon footprint of citizens elsewhere. The average UAE citizen emits 1950 kilograms of CO2 from flying. This is the same as the _total_[CO2 footprint of the average Indian](https://ourworldindata.org/explorers/co2?tab=chart&xScale=linear&yScale=linear&stackMode=absolute&endpointsOnly=0&year=latest&time=1858..2018&country=~India&region=World&Gas%20=CO%E2%82%82&Accounting%20=Production-based&Fuel%20=Total&Count%20=Per%20capita&Relative%20to%20world%20total%20=) (including everything from electricity to road transport, heating and industry). Or, to take a more extreme example, 200 times the total footprint of the average Nigerien, Ugandan or Ethiopian, which [have per capita emissions](https://ourworldindata.org/explorers/co2?tab=chart&xScale=linear&yScale=linear&stackMode=absolute&endpointsOnly=0&year=latest&time=1958..2018&country=Niger~Uganda~Ethiopia&region=World&Gas%20=CO%E2%82%82&Accounting%20=Production-based&Fuel%20=Total&Count%20=Per%20capita&Relative%20to%20world%20total%20=) of around 100 kilograms. This again emphasises the large difference between the global average and the individual emissions of people who fly. Aviation contributes a few percent of total CO2 emissions each year – this is not insignificant, but far from being the largest sector to tackle. Yet from the perspective of the individual, flying _is_ often one of the largest chunks of our carbon footprint. The average rich person emits tonnes of CO2 from flying each year – this is equivalent to the _total_ carbon footprint of tens or hundreds of people in many countries of the world. <Chart url="https://ourworldindata.org/grapher/per-capita-co2-aviation-adjusted?stackMode=absolute&region=World"/> #### Related charts: ### Per capita CO₂ emissions from aviation (without tourism adjustment) https://ourworldindata.org/grapher/per-capita-co2-aviation ### Total CO₂ emissions from aviation https://ourworldindata.org/grapher/co2-emissions-aviation ### Share of global CO₂ emissions from aviation https://ourworldindata.org/grapher/share-co2-emissions-aviation ## Where in the world do people fly the most? ### Domestic air travel This interactive chart shows the average distance travelled per person through domestic air travel each year. This data is for passenger flights only and does not include freight. <Chart url="https://ourworldindata.org/grapher/per-capita-domestic-aviation-km"/> #### Related charts: ### Share of global passenger kilometers from domestic air travel What share of global domestic air travel does each country account for? https://ourworldindata.org/grapher/share-global-domestic-aviation-km ### Total passenger kilometers from domestic air travel https://ourworldindata.org/grapher/total-domestic-aviation-km ### International air travel This interactive chart shows the average distance travelled per person through international air travel each year. This data is for passenger flights only and does not include freight. <Chart url="https://ourworldindata.org/grapher/per-capita-international-aviation-km"/> #### Related charts: ### Share of global passenger kilometers from international air travel What share of global international air travel does each country account for? https://ourworldindata.org/grapher/share-international-aviation-km ### Total passenger kilometers from international air travel https://ourworldindata.org/grapher/passenger-km-international-aviation ### Total air travel This interactive chart shows the average distance travelled per person through domestic _and_ international air travel each year. This data is for passenger flights only and does not include freight. <Chart url="https://ourworldindata.org/grapher/per-capita-km-aviation"/> #### Related charts: ### Share of global passenger kilometers from air travel What share of global air travel does each country account for? https://ourworldindata.org/grapher/share-km-aviation ### Total passenger kilometers from air travel https://ourworldindata.org/grapher/total-aviation-km --- # Rail --- This interactive chart shows the total rail travel in each country, measured in passenger-kilometers per year. This includes passenger travel only and does not include freight. <Chart url="https://ourworldindata.org/grapher/railways-passengers-carried-passenger-km"/> --- # Energy intensity of transport --- This chart shows the average energy intensity of transport across different modes of travel. It is measured as the average kilowatt-hours required per passenger-kilometer. This data comes from the United States Department of Transportation's Bureau of Transportation Statistics (BTS). The energy intensity of public transport depends on the assumptions made about the capacity of transport modes i.e. how many passengers travel on a given train or bus journey. This data thererfore reflects average capacities in the United States, but will vary from country-to-country. <Chart url="https://ourworldindata.org/grapher/energy-intensity-transport?country=Amtrak~Bus~Domestic+flight~International+flight~Motorcycle~~Transit+motor+bus~Truck+%28with+trailer%29~Truck~"/> --- # CO2 emissions from transport --- ## Per capita transport emissions from transport This interactive shows the average per capita emissions of carbon dioxide from transport each year. This includes road, train, bus and domestic air travel but _does not _include international aviation and shipping. <Chart url="https://ourworldindata.org/grapher/per-capita-co2-transport?stackMode=absolute&region=World"/> ## Total transport emissions This interactive shows the emissions of carbon dioxide from transport each year. This includes road, train, bus and domestic air travel but _does not _include international aviation and shipping. <Chart url="https://ourworldindata.org/grapher/co2-emissions-transport?stackMode=absolute&time=earliest..latest&region=World"/> ## CO2 emissions by mode of transport Transport accounts for around one-fifth of global carbon dioxide (CO2) emissions _[24% if we only consider CO2 emissions from energy]_.{ref}The _World Resource Institute_’s Climate Data Explorer [provides data](https://www.climatewatchdata.org/data-explorer/historical-emissions?historical-emissions-data-sources=cait&historical-emissions-gases=co2&historical-emissions-regions=All%20Selected&historical-emissions-sectors=total-including-lucf%2Ctransportation&page=1&sort_col=country&sort_dir=ASC) from CAIT on the breakdown of emissions by sector. In 2016, global CO2 emissions (including land use) were 36.7 billion tonnes CO2; emissions from transport were 7.9 billion tonnes CO2. Transport therefore accounted for 7.9 / 36.7 = 21% of global emissions. The IEA [looks at CO2 emissions](https://www.iea.org/data-and-statistics/?country=WORLD&fuel=CO2%20emissions&indicator=TotCO2) from energy production alone – in 2018 it reported 33.5 billion tonnes of energy-related CO2 [hence, transport accounted for 8 billion / 33.5 billion = 24% of energy-related emissions.{/ref} How do these emissions break down? Is it cars, trucks, planes or trains that dominate? In the chart here we see global transport emissions in 2018. This data is [sourced from](https://www.iea.org/data-and-statistics/charts/transport-sector-co2-emissions-by-mode-in-the-sustainable-development-scenario-2000-2030) the _International Energy Agency (IEA)_. Road travel accounts for three-quarters of transport emissions. Most of this comes from passenger vehicles – cars and buses – which contribute 45.1%. The other 29.4% comes from trucks carrying freight. Since the entire transport sector accounts for 21% of total emissions, and road transport accounts for three-quarters of transport emissions, road transport accounts for 15% of total CO2 emissions. Aviation – while it often gets the most attention in discussions on action against climate change – accounts for only 11.6% of transport emissions. It emits just under one billion tonnes of CO2 each year – around 2.5% of total global emissions _[we look at the role that air travel plays in climate change in more detail in an upcoming article]_. International shipping contributes a similar amount, at 10.6%. Rail travel and freight emits very little – only 1% of transport emissions. Other transport – which is mainly the movement of materials such as water, oil, and gas via pipelines – is responsible for 2.2%. <Image filename="Transport-CO2-emissions-by-mode-bar-chart.png" alt=""/> ### Towards zero-carbon transport: how can we expect the sector’s CO2 emissions to change in the future? Transport demand is expected to grow across the world in the coming decades as the global population increases, incomes rise, and more people can afford cars, trains and flights. In its _Energy Technology Perspectives_ report, the International Energy Agency (IEA) expects global transport (measured in passenger-kilometers) to double, car ownership rates to increase by 60%, and demand for passenger and freight aviation to triple by 2070.{ref}IEA (2020), [Energy Technology Perspectives 2020](https://www.iea.org/reports/energy-technology-perspectives-2020), IEA, Paris.{/ref} Combined, these factors would result in a large increase in transport emissions. But major technological innovations can help offset this rise in demand. As the world shifts towards lower-carbon electricity sources, the rise of electric vehicles offers a viable option to reduce emissions from passenger vehicles. This is reflected in the IEA’s _Energy Technology Perspective_ report. There it outlines its “Sustainable Development Scenario” for reaching net-zero CO2 emissions from global energy by 2070. The pathways for the different elements of the transport sector in this optimistic scenario are shown in the visualization. We see that with electrification- and hydrogen- technologies some of these sub-sectors could decarbonize within decades. The IEA scenario assumes the phase-out of emissions from motorcycles by 2040; rail by 2050; small trucks by 2060; and although emissions from cars and buses are not completely eliminated until 2070, it expects many regions, including the European Union; United States; China and Japan to have phased-out conventional vehicles as early as 2040. Other transport sectors will be much more difficult to decarbonize. In a paper published in _Science_, Steven Davis and colleagues looked at our options across sectors to reach a net-zero emissions energy system.{ref}Davis, S. J., Lewis, N. S., Shaner, M., Aggarwal, S., Arent, D., Azevedo, I. L., ... & Clack, C. T. (2018). [Net-zero emissions energy systems](https://science.sciencemag.org/content/360/6396/eaas9793.full). _Science_, 360(6396).{/ref} They highlighted long-distance road freight (large trucks), aviation and shipping as particularly difficult to eliminate. The potential for hydrogen as a fuel, or battery electricity to run planes, ships and large trucks is limited by the range and power required; the size and weight of batteries or hydrogen fuel tanks would be _much_ larger and heavier than current combustion engines.{ref}Cecere, D., Giacomazzi, E., & Ingenito, A. (2014). [A review on hydrogen industrial aerospace applications](https://www.sciencedirect.com/science/article/pii/S0360319914011847). _International Journal of Hydrogen Energy_, _39_(20), 10731-10747.{/ref},{ref}Fulton, L. M., Lynd, L. R., Körner, A., Greene, N., & Tonachel, L. R. (2015). [The need for biofuels as part of a low carbon energy future](https://onlinelibrary.wiley.com/doi/full/10.1002/bbb.1559). _Biofuels, Bioproducts and Biorefining_, 9(5), 476-483.{/ref} So, despite falling by three-quarters in the visualized scenario, emissions from these sub-sectors would still make transport the largest contributor to energy-related emissions in 2070. To reach net-zero for the energy sector as a whole, these emissions would have to be offset by ‘negative emissions’ (e.g. the capture and storage of carbon from bioenergy or [direct air capture](https://www.iea.org/reports/direct-air-capture)) from other parts of the energy system. In the IEA’s net-zero scenario, nearly two-thirds of the emissions reductions come from technologies that are not yet commercially available. As the IEA states, “Reducing CO2 emissions in the transport sector over the next half-century will be a formidable task.”{ref}IEA (2020), [Energy Technology Perspectives 2020](https://www.iea.org/reports/energy-technology-perspectives-2020), IEA, Paris.{/ref} ##### Global CO2 emissions from transport in the IEA's Sustainable Development Scenario to 2070{ref}IEA (2020), [Energy Technology Perspectives 2020](https://www.iea.org/reports/energy-technology-perspectives-2020), IEA, Paris.{/ref} <Image filename="IEA-Transport-to-2070.png" alt=""/>	{ "id": 36318, "date": "2021-09-24T14:42:00", "guid": { "rendered": "https://owid.cloud/?page_id=36318" }, "link": "https://owid.cloud/transport", "meta": { "owid_publication_context_meta_field": [], "owid_key_performance_indicators_meta_field": { "raw": "Transport is an important measure of technological progress", "rendered": "<p>Transport is an important measure of technological progress</p>\n" } }, "slug": "transport", "tags": [], "type": "page", "title": { "rendered": "Transport" }, "_links": { "self": [ { "href": "https://owid.cloud/wp-json/wp/v2/pages/36318" } ], "about": [ { "href": "https://owid.cloud/wp-json/wp/v2/types/page" } ], "author": [ { "href": "https://owid.cloud/wp-json/wp/v2/users/17", "embeddable": true } ], "curies": [ { "href": "https://api.w.org/{rel}", "name": "wp", "templated": true } ], "replies": [ { "href": "https://owid.cloud/wp-json/wp/v2/comments?post=36318", "embeddable": true } ], "wp:term": [ { "href": "https://owid.cloud/wp-json/wp/v2/categories?post=36318", "taxonomy": "category", "embeddable": true }, { "href": "https://owid.cloud/wp-json/wp/v2/tags?post=36318", "taxonomy": "post_tag", "embeddable": true } ], "collection": [ { "href": "https://owid.cloud/wp-json/wp/v2/pages" } ], "wp:attachment": [ { "href": "https://owid.cloud/wp-json/wp/v2/media?parent=36318" } ], "version-history": [ { "href": "https://owid.cloud/wp-json/wp/v2/pages/36318/revisions", "count": 22 } ], "wp:featuredmedia": [ { "href": "https://owid.cloud/wp-json/wp/v2/media/45158", "embeddable": true } ], "predecessor-version": [ { "id": 53390, "href": "https://owid.cloud/wp-json/wp/v2/pages/36318/revisions/53390" } ] }, "author": 17, "parent": 0, "status": "publish", "content": { "rendered": "\n<div class=\"blog-info\">First published in September 2021.</div>\n\n\n\n<!-- formatting-options subnavId:energy subnavCurrentId:transport -->\n\n\n\n<h2>Road travel</h2>\n\n\n\n<h3>Passenger vehicle registrations by type</h3>\n\n\n\n<div class=\"wp-block-columns\">\n<div class=\"wp-block-column\">\n<p>These interactive charts show the breakdown of new passenger vehicle registrations by type.</p>\n\n\n\n<p>This is broken down by: petroleum; diesel; full hybrid (excluding plug-in hybrids); plug-in electric hybrids; and fully electric battery vehicles.</p>\n</div>\n\n\n\n<div class=\"wp-block-column\">\n<iframe src=\"https://ourworldindata.org/grapher/new-vehicles-type-area?tab=chart&stackMode=relative&country=~NOR\" loading=\"lazy\" style=\"width: 100%; height: 600px; border: 0px none;\"></iframe>\n\n\n\n<iframe src=\"https://ourworldindata.org/grapher/new-vehicles-type-share?tab=chart&country=~GBR\" loading=\"lazy\" style=\"width: 100%; height: 600px; border: 0px none;\"></iframe>\n\n\n <block type=\"prominent-link\" style=\"is-style-thin\">\n <link-url>https://ourworldindata.org/grapher/new-passenger-vehicles-type?country=~GBR</link-url>\n <title>Number of new passenger vehicle registrations by type</title>\n <content></content>\n <figure></figure>\n </block></div>\n</div>\n\n\n\n<h3>Electric vehicle registrations</h3>\n\n\n\n<div class=\"wp-block-columns\">\n<div class=\"wp-block-column\">\n<p>This interactive chart shows the share of new passenger vehicle registrations that are battery electric vehicles. This does not include plug-in hybrid vehicles.</p>\n</div>\n\n\n\n<div class=\"wp-block-column\">\n<iframe src=\"https://ourworldindata.org/grapher/share-vehicle-electric?country=AUT~ITA~NOR~PRT~ESP~SWE~CHE~TUR~GBR~IRL~ISL~GRC~DEU~FRA~FIN~DNK~BEL~LUX~NLD\" loading=\"lazy\" style=\"width: 100%; height: 600px; border: 0px none;\"></iframe>\n</div>\n</div>\n\n\n\n<div class=\"wp-block-columns\">\n<div class=\"wp-block-column\">\n<p>This interactive chart shows the share of new passenger vehicle registrations that are battery electric <em>plus</em> plug-in hybrid vehicles.</p>\n</div>\n\n\n\n<div class=\"wp-block-column\">\n<iframe src=\"https://ourworldindata.org/grapher/battery-plugin-hybrid-vehicles?time=2019&country=~AUT~BEL~DNK~FIN~EU-27+%2B+UK~FRA~DEU~GRC~ISL~IRL~GBR~TUR~CHE~SWE~ESP~PRT~NOR~NLD~LUX~ITA\" loading=\"lazy\" style=\"width: 100%; height: 600px; border: 0px none;\"></iframe>\n</div>\n</div>\n\n\n\n<h3>Carbon intensity of new passenger vehicles</h3>\n\n\n\n<div class=\"wp-block-columns\">\n<div class=\"wp-block-column\">\n<p>This interactive chart shows the average carbon intensity of new passenger vehicles in each country.</p>\n\n\n\n<p>This is measured as the average emissions of CO\u2082 (in grams) per kilometer travelled across all types of passenger vehicles.</p>\n</div>\n\n\n\n<div class=\"wp-block-column\">\n<iframe src=\"https://ourworldindata.org/grapher/carbon-new-passenger-vehicles?country=AUT~ITA~LUX~NLD~NOR~PRT~ESP~SWE~CHE~TUR~GBR~IRL~ISL~GRC~DEU~FRA~FIN~DNK~BEL\" loading=\"lazy\" style=\"width: 100%; height: 600px; border: 0px none;\"></iframe>\n</div>\n</div>\n\n\n\n<h3>Fuel economy of new passenger vehicles</h3>\n\n\n\n<div class=\"wp-block-columns\">\n<div class=\"wp-block-column\">\n<p>This interacrive chart shows the average fuel economy of new passenger vehicles in each country.</p>\n\n\n\n<p>This is measured as the average liters consumed per 100 kilometers travelled, across all types of passenger vehicles.</p>\n</div>\n\n\n\n<div class=\"wp-block-column\">\n<iframe src=\"https://ourworldindata.org/grapher/fuel-efficiency-new-vehicles?country=AUT~BEL~ITA~LUX~NLD~NOR~PRT~ESP~SWE~CHE~TUR~GBR~IRL~ISL~GRC~DEU~FRA~FIN~DNK\" loading=\"lazy\" style=\"width: 100%; height: 600px; border: 0px none;\"></iframe>\n</div>\n</div>\n\n\n\n<h2>Aviation</h2>\n\n\n\n<h3>What share of global CO<sub>2</sub> emissions come from aviation?</h3>\n\n\n\n<p>Flying is a highly controversial topic in climate debates. There are a few reasons for this. </p>\n\n\n\n<p>The first is the disconnect between its role in our personal and collective carbon emissions. Air travel dominates a frequent traveller’s individual contribution to climate change. Yet aviation overall accounts for only 2.5% of global carbon dioxide (CO<sub>2</sub>) emissions. This is because there are large inequalities in how much people fly \u2013 many do not, or cannot afford to, fly at all.{ref}The best estimates put this figure at around 80% of the world population. We look at this in more detail in our article “<a href=\"https://ourworldindata.org/carbon-footprint-flying\">Where in the world do people have the highest CO2 emissions from flying?</a>“{/ref}</p>\n\n\n\n<p>The second is how aviation emissions are attributed to countries. CO<sub>2</sub> emissions from domestic flights <em>are</em> counted in a country\u2019s emission accounts. International flights are not \u2013 instead they are counted as their own category: \u2018bunker fuels\u2019. The fact that they don\u2019t count towards the emissions of any country means there are few incentives for countries to reduce them.</p>\n\n\n\n<p>It\u2019s also important to note that unlike the most common greenhouse gases \u2013 carbon dioxide, methane or nitrous oxide \u2013 non-CO<sub>2</sub> forcings from aviation <em>are not included</em> in the Paris Agreement. This means they could be easily overlooked \u2013 especially since international aviation is not counted within any country\u2019s emissions inventories or targets.</p>\n\n\n\n<p>How much of a role does aviation play in global emissions and climate change? In this article we take a look at the key numbers that are useful to know.</p>\n\n\n\n<p>Global aviation (including domestic and international; passenger and freight) accounts for:</p>\n\n\n\n<ul><li><strong>1.9%</strong> of <a href=\"https://ourworldindata.org/ghg-emissions-by-sector\">greenhouse gas emissions</a> (which includes all greenhouse gases, not only CO<sub>2</sub>)</li><li><strong>2.5%</strong> of CO<sub>2</sub> emissions</li><li><strong>3.5%</strong> of ‘effective radiative forcing’ \u2013 a closer measure of its impact on warming.</li></ul>\n\n\n\n<p>The latter two numbers refer to 2018, and the first to 2016, the latest year for which such data are available.</p>\n\n\n\n<hr class=\"wp-block-separator\"/>\n\n\n\n<h4>Aviation accounts for 2.5% of global CO<sub>2</sub> emissions</h4>\n\n\n\n<p>As we will see later in this article, there are a number of processes by which aviation contributes to climate change. But the one that gets the most attention is its contribution via CO<sub>2</sub> emissions. Most flights are powered by jet gasoline \u2013 although some partially run on biofuels \u2013 which is converted to CO<sub>2</sub> when burned.  </p>\n\n\n\n<p>In a recent paper, researchers \u2013 David Lee and colleagues \u2013 reconstructed annual CO<sub>2 </sub>emissions from global aviation dating back to 1940.{ref}Lee, D. S., Fahey, D. W., Skowron, A., Allen, M. R., Burkhardt, U., Chen, Q., … & Gettelman, A. (2020). <a href=\"https://www.sciencedirect.com/science/article/pii/S1352231020305689\">The contribution of global aviation to anthropogenic climate forcing for 2000 to 2018</a>. <em>Atmospheric Environment</em>, 117834.{/ref} This was calculated based on fuel consumption data from the International Energy Agency (IEA), and earlier estimates from Robert Sausen and Ulrich Schumann (2000).{ref}Sausen, R., & Schumann, U. (2000). <a href=\"https://link.springer.com/article/10.1023/A:1005579306109\">Estimates of the climate response to aircraft CO2 and NOx emissions scenarios</a>. <em>Climatic Change</em>, <em>44</em>(1-2), 27-58.{/ref}</p>\n\n\n\n<p>The time series of global emissions from aviation since 1940 is shown in the accompanying chart. In 2018, it\u2019s estimated that global aviation \u2013 which includes both passenger and freight \u2013 emitted 1.04 billion tonnes of CO<sub>2</sub>.</p>\n\n\n\n<p>This represented 2.5% of <a href=\"https://ourworldindata.org/co2-emissions#global-co2-emissions-from-fossil-fuels-global-co2-emissions-from-fossil-fuels\" data-type=\"URL\" data-id=\"https://ourworldindata.org/co2-emissions#global-co2-emissions-from-fossil-fuels-global-co2-emissions-from-fossil-fuels\">total CO<sub>2</sub> emissions</a> in 2018.{ref}The Global Carbon Budget estimated total CO<sub>2</sub> emissions from all fossil fuels, cement production and land-use change to be 42.1 billion tonnes in 2018. This means aviation accounted for [1 / 42.1 * 100] = 2.5% of total emissions.{/ref}<sup>,</sup>{ref}Global Carbon Project. (2019). Supplemental data of Global Carbon Budget 2019 (Version 1.0) [Data set]. Global Carbon Project. <a href=\"https://doi.org/10.18160/gcp-2019\">https://doi.org/10.18160/gcp-2019</a>.<br><br>If we were to exclude land use change emissions, aviation accounted for 2.8% of fossil fuel emissions. The Global Carbon Budget estimated total CO<sub>2</sub> emissions from fossil fuels and cement production to be 36.6 billion tonnes in 2018. This means aviation accounted for [1 / 36.6 * 100] = 2.8% of total emissions.{/ref}</p>\n\n\n\n<p>Aviation emissions have doubled since the mid-1980s. But, they\u2019ve been growing at a similar rate as total CO<sub>2</sub> emissions \u2013 this means its share of global emissions has been relatively stable: in the range of 2% to 2.5%.{ref}2.3% to 2.8% of emissions if land use is excluded.{/ref}</p>\n\n\n\n<figure class=\"wp-block-image size-large\"><img loading=\"lazy\" width=\"693\" height=\"550\" src=\"https://owid.cloud/app/uploads/2020/10/Global-CO2-emissions-from-aviation-693x550.png\" alt=\"\" class=\"wp-image-36836\" srcset=\"https://owid.cloud/app/uploads/2020/10/Global-CO2-emissions-from-aviation-693x550.png 693w, https://owid.cloud/app/uploads/2020/10/Global-CO2-emissions-from-aviation-400x318.png 400w, https://owid.cloud/app/uploads/2020/10/Global-CO2-emissions-from-aviation-150x119.png 150w, https://owid.cloud/app/uploads/2020/10/Global-CO2-emissions-from-aviation-768x610.png 768w, https://owid.cloud/app/uploads/2020/10/Global-CO2-emissions-from-aviation.png 1505w\" sizes=\"(max-width: 693px) 100vw, 693px\" /></figure>\n\n\n\n<h4>Non-CO<sub>2</sub> climate impacts mean aviation accounts for 3.5% of global warming</h4>\n\n\n\n<p>Aviation accounts for around 2.5% of global CO<sub>2</sub> emissions, but it\u2019s overall contribution to climate change is higher. This is because air travel does not only emit CO<sub>2</sub>: it affects the climate in a number of more complex ways.</p>\n\n\n\n<p>As well as emitting CO<sub>2</sub> from burning fuel, planes affect the concentration of other gases and pollutants in the atmosphere. They result in a short-term increase, but long-term decrease in ozone (O<sub>3</sub>); a decrease in methane (CH<sub>4</sub>); emissions of water vapour; soot; sulfur aerosols; and water contrails. While some of these impacts result in warming, others induce a cooling effect. Overall, the warming effect is stronger.</p>\n\n\n\n<p>David Lee et al. (2020) quantified the overall effect of aviation on global warming when all of these impacts were included.{ref}Lee, D. S., Fahey, D. W., Skowron, A., Allen, M. R., Burkhardt, U., Chen, Q., … & Gettelman, A. (2020). <a href=\"https://www.sciencedirect.com/science/article/pii/S1352231020305689\">The contribution of global aviation to anthropogenic climate forcing for 2000 to 2018</a>. <em>Atmospheric Environment</em>, 117834.{/ref} To do this they calculated the so-called \u2018Radiative Forcing\u2019. Radiative forcing measures the difference between incoming energy and the energy radiated back to space. If more energy is absorbed than radiated, the atmosphere becomes warmer. </p>\n\n\n\n<p>In their chart we see <a href=\"https://ars.els-cdn.com/content/image/1-s2.0-S1352231020305689-gr3_lrg.jpg\" target=\"_blank\" rel=\"noreferrer noopener\">their estimates for the radiative forcing</a> of the different elements. When we combine them, aviation accounts for approximately 3.5% of effective radiative forcing: that is, 3.5% of warming.<br><br>Although CO<sub>2  </sub>gets most of the attention, it accounts for less than half of this warming. Two-thirds (66%) comes from non-CO<sub>2 </sub>forcings. Contrails \u2013 water vapor trails from aircraft exhausts \u2013 account for the largest share.</p>\n\n\n\n<h4>We don\u2019t yet have the technologies to decarbonize air travel</h4>\n\n\n\n<p>Aviation\u2019s contribution to climate change \u2013 3.5% of warming, or 2.5% of CO<sub>2</sub> emissions \u2013 is often less than people think. It\u2019s currently a relatively small chunk of emissions compared to other sectors. </p>\n\n\n\n<p>The key challenge is that it is particularly hard to decarbonize. We have solutions to reduce emissions for many of the <a href=\"https://ourworldindata.org/ghg-emissions-by-sector\">largest emitters</a> \u2013 such as power or road transport \u2013 and it\u2019s now a matter of scaling them. We can deploy renewable and nuclear energy technologies, and transition to electric cars. But we don\u2019t have proven solutions to tackle aviation yet. </p>\n\n\n\n<p>There are some design concepts emerging \u2013 Airbus, for example, <a href=\"https://web.archive.org/web/20201031121346/https://www.airbus.com/innovation/zero-emission/hydrogen/zeroe.html\" data-type=\"URL\" data-id=\"https://web.archive.org/web/20201031121346/https://www.airbus.com/innovation/zero-emission/hydrogen/zeroe.html\">have announced plans</a> to have the first zero-emission aircraft by 2035, using hydrogen fuel cells. Electric planes may be a viable concept, but are likely to be limited to very small aircraft due to the limitations of battery technologies and capacity. </p>\n\n\n\n<p>Innovative solutions may be on the horizon, but they\u2019re likely to be far in the distance.</p>\n\n\n <block type=\"prominent-link\" style=\"is-style-thin\">\n <link-url>http://ourworldindata.org/co2-emissions-from-transport</link-url>\n <title>Towards zero-carbon transport: how can we expect the sector\u2019s CO<sub>2</sub> emissions to change in the future?</title>\n <content>\n\n<p></p>\n\n</content>\n <figure><img width=\"768\" height=\"485\" src=\"https://owid.cloud/app/uploads/2020/10/IEA-Transport-to-2070-768x485.png\" class=\"attachment-medium_large size-medium_large\" alt=\"\" loading=\"lazy\" srcset=\"https://owid.cloud/app/uploads/2020/10/IEA-Transport-to-2070-768x485.png 768w, https://owid.cloud/app/uploads/2020/10/IEA-Transport-to-2070-400x253.png 400w, https://owid.cloud/app/uploads/2020/10/IEA-Transport-to-2070-800x505.png 800w, https://owid.cloud/app/uploads/2020/10/IEA-Transport-to-2070-150x95.png 150w, https://owid.cloud/app/uploads/2020/10/IEA-Transport-to-2070-1536x970.png 1536w, https://owid.cloud/app/uploads/2020/10/IEA-Transport-to-2070.png 1732w\" sizes=\"(max-width: 768px) 100vw, 768px\" /></figure>\n </block>\n\n\t<block type=\"additional-information\" default-open=\"true\">\n\t\t<content>\n\n<h3>Appendix: <strong>Efficiency improvements means air traffic has increased more rapidly than emissions</strong></h3>\n\n\n\n<div class=\"wp-block-columns is-style-sticky-right\">\n<div class=\"wp-block-column\">\n<p>Global emissions from aviation have increased a lot over the past half-century. However, air travel volumes increased even more rapidly. </p>\n\n\n\n<p>Since 1960, aviation emissions increased almost seven-fold; since 1970 they\u2019ve tripled. Air traffic volume \u2013 here defined as revenue passenger kilometers (RPK) traveled \u2013 <a href=\"https://ourworldindata.org/grapher/airline-capacity-and-traffic\">increased by orders of magnitude more</a>: almost 300-fold since 1950; and 75-fold since 1960.{ref}Airline traffic data comes from the International Civil Aviation Organization (ICAO) via <a href=\"https://www.airlines.org/dataset/world-airlines-traffic-and-capacity\">Airlines for America</a>. Revenue passenger kilometers (RPK) measures the number of paying passengers multiplied by their distance traveled.{/ref}\u00a0</p>\n\n\n\n<p>The much slower growth in emissions means aviation efficiency has seen massive improvements. In the chart we show both the increase in global airline traffic since 1950, and aviation efficiency, measured as the quantity of CO<sub>2</sub> emitted per revenue passenger kilometer traveled. In 2018, approximately 125 grams of CO<sub>2 </sub> were emitted per RPK. In 1960, this was eleven-fold higher; in 1950 it was twenty-fold higher. Aviation has seen massive efficiency improvements over the past 50 years.</p>\n\n\n\n<p>These improvements have come from several sources: improvements in the design and technology of aircraft; larger aircraft sizes (allowing for more passengers per flight); and an increase in how \u2018full\u2019 passenger flights are. This last metric is termed the \u2018passenger load factor\u2019. The passenger load factor measures the actual number of kilometers traveled by paying customers (RPK) as a percentage of the available seat kilometers (ASK) \u2013 the kilometers traveled if every plane was full. If every plane was full the passenger load factor would be 100%. If only three-quarters of the seats were filled, it would be 75%.</p>\n\n\n\n<p>The global passenger load factor <a href=\"https://ourworldindata.org/grapher/airline-passenger-load-factor\">increased from 61% in 1950 to 82% in 2018</a>.\u00a0\u00a0</p>\n</div>\n\n\n\n<div class=\"wp-block-column\">\n<figure class=\"wp-block-image size-large\"><img loading=\"lazy\" width=\"800\" height=\"505\" src=\"https://owid.cloud/app/uploads/2020/10/Aviation-traffic-and-efficiency-Lee-et-al.-2020-800x505.png\" alt=\"\" class=\"wp-image-36837\" srcset=\"https://owid.cloud/app/uploads/2020/10/Aviation-traffic-and-efficiency-Lee-et-al.-2020-800x505.png 800w, https://owid.cloud/app/uploads/2020/10/Aviation-traffic-and-efficiency-Lee-et-al.-2020-400x253.png 400w, https://owid.cloud/app/uploads/2020/10/Aviation-traffic-and-efficiency-Lee-et-al.-2020-150x95.png 150w, https://owid.cloud/app/uploads/2020/10/Aviation-traffic-and-efficiency-Lee-et-al.-2020-768x485.png 768w, https://owid.cloud/app/uploads/2020/10/Aviation-traffic-and-efficiency-Lee-et-al.-2020-1536x970.png 1536w, https://owid.cloud/app/uploads/2020/10/Aviation-traffic-and-efficiency-Lee-et-al.-2020.png 1832w\" sizes=\"(max-width: 800px) 100vw, 800px\" /></figure>\n</div>\n</div>\n\n</content>\n\t</block>\n\n\n<h3>Passenger vs. freight; domestic vs. international: where do aviation emissions come from?</h3>\n\n\n\n<p>Global aviation \u2013 both passenger flights and freight \u2013 emits around one billion tonnes of carbon dioxide (CO<sub>2</sub>) each year. This was equivalent to around 2.4% of CO<sub>2</sub> emissions in 2018.</p>\n\n\n\n<p>How do global aviation emissions break down?</p>\n\n\n\n<p>The chart gives the answer. This data is sourced from the 2019 <em>International Council on Clean Transportation</em> <em>(ICCT)</em> report on global aviation.{ref}Graver, B., Zhang, K., & Rutherford, D. (2019). <a href=\"https://theicct.org/sites/default/files/publications/ICCT_CO2-commercl-aviation-2018_20190918.pdf\" target=\"_blank\" rel=\"noreferrer noopener\">CO2 emissions from commercial aviation, 2018</a>. <em>The International Council of Clean Transportation</em>.{/ref}</p>\n\n\n\n<p>Most emissions come from passenger flights \u2013 in 2018, they accounted for 81% of aviation\u2019s emissions; the remaining 19% came from freight, the transport of goods. </p>\n\n\n\n<p>Sixty percent of emissions from<em> passenger</em> flights come from international travel; the other 40% come from domestic (in-country) flights. </p>\n\n\n\n<p>When we break passenger flight emissions down by travel distance, we get a (surprisingly) equal three-way split in emissions between short-haul (less than 1,500 kilometers); medium-haul (1,500 to 4,000 km); and long-haul (greater than 4,000 km) journeys.</p>\n\n\n\n<figure class=\"wp-block-image size-large\"><img loading=\"lazy\" width=\"800\" height=\"507\" src=\"https://owid.cloud/app/uploads/2020/10/Global-breakdown-of-aviation-emissions-800x507.png\" alt=\"\" class=\"wp-image-36848\" srcset=\"https://owid.cloud/app/uploads/2020/10/Global-breakdown-of-aviation-emissions-800x507.png 800w, https://owid.cloud/app/uploads/2020/10/Global-breakdown-of-aviation-emissions-400x253.png 400w, https://owid.cloud/app/uploads/2020/10/Global-breakdown-of-aviation-emissions-150x95.png 150w, https://owid.cloud/app/uploads/2020/10/Global-breakdown-of-aviation-emissions-768x486.png 768w, https://owid.cloud/app/uploads/2020/10/Global-breakdown-of-aviation-emissions-1536x973.png 1536w, https://owid.cloud/app/uploads/2020/10/Global-breakdown-of-aviation-emissions.png 1650w\" sizes=\"(max-width: 800px) 100vw, 800px\" /></figure>\n\n\n\n<h4>The richest half are responsible for 90% of air travel CO<sub>2</sub> emissions</h4>\n\n\n\n<p>The global inequalities in how much people fly become clear when we compare aviation emissions across countries of different income levels. The ICCT split these emissions based on World Bank’s four <a href=\"https://ourworldindata.org/grapher/world-banks-income-groups?year=latest\" target=\"_blank\" rel=\"noreferrer noopener\">income groups</a>.</p>\n\n\n\n<p>A further study by Susanne Becek and Paresh Pant (2019) compared the contribution of each income group to global air travel emissions versus its share of world population.{ref}Becken, S. and P. Pant (2019). <a href=\"https://amadeus.com/en/insights/white-paper/airline-initiatives-to-reduce-climate-impact\" target=\"_blank\" rel=\"noreferrer noopener\">Airline initiatives to reduce climate impact: ways to accelerate action</a> (White paper).{/ref} This comparison is shown in the visualization.</p>\n\n\n\n<p>The \u2018richest\u2019 half of the world (high and upper-middle income countries) were responsible for 90% of air travel emissions.{ref}Note that this is based on categorisations from the average income level of countries, and does not take account of variation in income <em>within </em>countries. If we were to look at this distribution based on the income level of individuals rather than countries, the inequality in aviation emissions would be even larger.{/ref}</p>\n\n\n\n<p>Looking at specific income groups:</p>\n\n\n\n<ul><li>Only 16% of the world population live in high-income countries yet the planes that take off in those countries account for almost two-thirds (62%) of passenger emissions;</li><li>Upper-middle income countries are home to 35% of the world population, and contribute 28% of emissions;</li><li>Lower-middle income countries are home to the largest share (40% of the world), yet emit the planes taking off there just account for 9%;</li><li>The poorest countries \u2013 which are home to 9% of the world population \u2013 emit just 1%.</li></ul>\n\n\n\n<p>In an upcoming article we will look in more detail at the contribution of each country to global aviation emissions.</p>\n\n\n\n<figure class=\"wp-block-image size-large\"><img loading=\"lazy\" width=\"800\" height=\"437\" src=\"https://owid.cloud/app/uploads/2020/10/Inequalities-in-CO2-emissions-from-air-travel-800x437.png\" alt=\"\" class=\"wp-image-36849\" srcset=\"https://owid.cloud/app/uploads/2020/10/Inequalities-in-CO2-emissions-from-air-travel-800x437.png 800w, https://owid.cloud/app/uploads/2020/10/Inequalities-in-CO2-emissions-from-air-travel-400x219.png 400w, https://owid.cloud/app/uploads/2020/10/Inequalities-in-CO2-emissions-from-air-travel-150x82.png 150w, https://owid.cloud/app/uploads/2020/10/Inequalities-in-CO2-emissions-from-air-travel-768x420.png 768w, https://owid.cloud/app/uploads/2020/10/Inequalities-in-CO2-emissions-from-air-travel-1536x840.png 1536w, https://owid.cloud/app/uploads/2020/10/Inequalities-in-CO2-emissions-from-air-travel.png 1655w\" sizes=\"(max-width: 800px) 100vw, 800px\" /></figure>\n\n\n\n<h3>Where in the world do people have the highest carbon footprint from flying?</h3>\n\n\n\n<p>Aviation accounts <a href=\"https://ourworldindata.org/co2-emissions-from-aviation\" target=\"_blank\" rel=\"noreferrer noopener\">for around 2.5%</a> of global carbon dioxide (CO<sub>2</sub>) emissions. But if you are someone who does fly, air travel will make up a much larger share of your personal carbon footprint.</p>\n\n\n\n<p>The fact that aviation is relatively small for global emissions as a whole, but of large importance for individuals that fly is due to large inequalities in the world. Most people in the  world do not take flights. There is no global reliable figure, but often cited estimates suggest that more than 80% of the global population have never flown.{ref}There is no global database available on <em>who</em> in the world flies each year. Passenger information is maintained by private airlines. Therefore, deriving estimates of this exact percentage is challenging. The most-cited estimate I\u2019ve seen on this is that around 80% of the world population have never flown. This figure seems to circle back to a <a href=\"https://www.cnbc.com/2017/12/07/boeing-ceo-80-percent-of-people-never-flown-for-us-that-means-growth.html#:~:text=%E2%80%9CLess%20than%2020%20percent%20of,the%20entire%20economy%2C%20Muilenburg%20said.\">quoted estimate</a> from the Boeing CEO.<br><br>Even in some of the world\u2019s richest countries, a large share of the population do not fly frequently. Gallup <a href=\"https://news.gallup.com/poll/1579/airlines.aspx\">survey data</a> from the United States suggests that in 2015, half of the population did not take a flight. Survey data from the UK <a href=\"http://publicapps.caa.co.uk/docs/33/CAA%20Aviation%20Consumer%20survey%20--%205th%20wave%20report%20FINAL%20(2).pdf\">provides similar estimates</a>: 46% had not flown in the previous year.{/ref}</p>\n\n\n\n<p>How do emissions from aviation vary across the world? Where do people have the highest footprint from flying?</p>\n\n\n\n<h4>Per capita emissions from domestic flights</h4>\n\n\n\n<div class=\"wp-block-columns\">\n<div class=\"wp-block-column\">\n<p>The first and most straightforward comparison is to look at emissions from <em>domestic</em> aviation \u2013 that is, flights that depart and arrive in the same country. </p>\n\n\n\n<p>This is easiest to compare because domestic aviation is counted in each country\u2019s inventory of greenhouse gas emissions. International flights, on the other hand, are not attributed to specific countries \u2013 partly because of contention as to who should take responsibility (should it be the country of departure or arrival? What about layover flights?).</p>\n\n\n\n<p>In the chart here we see the average per capita emissions from domestic flights in 2018. This data is sourced from the <em>International Council on Clean Transportation</em> \u2013 we then used <a href=\"https://population.un.org/wpp/\">UN population estimates</a> to calculate per capita figures.{ref}Graver, B., Zhang, K., & Rutherford, D. (2019). <a href=\"https://theicct.org/publications/co2-emissions-commercial-aviation-2018\">CO2 emissions from commercial aviation, 2018</a>. <em>The International Council of Clean Transportation</em>.{/ref}<sup>,</sup>{ref}Note that this gives us <em>mean</em> per capita emissions, which  does not account for in-country inequalities in the amount of flights people take.{/ref}</p>\n\n\n\n<p>We see large differences in emissions from domestic flights across the world. In the United States the average person emits around 386 kilograms of CO<sub>2</sub> each year from internal flights. This is followed by Australia (267 kg); Norway (209 kg); New Zealand (174 kg); and Canada (168 kg). Compare this with  countries at the bottom of the table \u2013 many across Africa, Asia, and Eastern Europe in particular emit less than one kilogram per person \u2013 just 0.8 kilograms; or 0.14 kilograms in Rwanda. For very small countries where there are no internal commercial flights, domestic emissions are of course, zero.</p>\n\n\n\n<p>There are some obvious factors that explain some of these cross-country differences. Firstly, countries that are richer <a href=\"https://ourworldindata.org/grapher/per-capita-co2-domestic-aviation-vs-gdp\">are more likely</a> to have higher emissions because people can afford to fly. Second, countries that have a larger land mass may have more internal flights \u2013 and indeed we see a <a href=\"https://ourworldindata.org/grapher/per-capita-co2-domestic-aviation-vs-land-area\">correlation</a> between land area and domestic flight emissions; in small countries people are more likely to travel by other means such as car or train.  And third, countries that are more geographically-isolated \u2013 such as Australia and New Zealand \u2013 may have more internal travel.</p>\n</div>\n\n\n\n<div class=\"wp-block-column\">\n<iframe src=\"https://ourworldindata.org/grapher/per-capita-co2-domestic-aviation\" loading=\"lazy\" style=\"width: 100%; height: 600px; border: 0px none;\"></iframe>\n\n\n\n<h5>Related charts:</h5>\n\n\n <block type=\"prominent-link\" style=\"is-style-thin\">\n <link-url>https://ourworldindata.org/grapher/co2-emissions-domestic-aviation</link-url>\n <title>Total CO\u2082 emissions from domestic aviation</title>\n <content></content>\n <figure></figure>\n </block>\n\n <block type=\"prominent-link\" style=\"is-style-thin\">\n <link-url>https://ourworldindata.org/grapher/share-global-co2-domestic-aviation</link-url>\n <title>Share of global CO\u2082 emissions from domestic aviation</title>\n <content></content>\n <figure></figure>\n </block></div>\n</div>\n\n\n\n<h4>Per capita emissions from international flights</h4>\n\n\n\n<div class=\"wp-block-columns\">\n<div class=\"wp-block-column\">\n<p>Allocating emissions from international flights is more complex. International databases report these emissions separately as a category termed \u2018bunker fuels\u2019. The term \u2018bunker fuel\u2019 is used to describe emissions which come from international transport \u2013 either aviation or shipping.</p>\n\n\n\n<p>Because they are <a href=\"https://unfccc.int/topics/mitigation/workstreams/emissions-from-international-transport-bunker-fuels\">not counted towards</a> any particular country these emissions are also not taken into account in the goals that are set by countries in international treaties like the Kyoto protocol or the Paris Agreement.{ref}Larsson, J., Kamb, A., N\u00e4ss\u00e9n, J., & \u00c5kerman, J. (2018). <a href=\"https://www.sciencedirect.com/science/article/pii/S0195925517303116\">Measuring greenhouse gas emissions from international air travel of a country\u2019s residents methodological development and application for Sweden</a>. <em>Environmental Impact Assessment Review</em>, <em>72</em>, 137-144.{/ref}</p>\n\n\n\n<p>But if we wanted to allocate them to a particular country, how would we do it? Who do emissions from international flights belong to: the country that owns the airline; the country of departure; the country of arrival?</p>\n\n\n\n<p>Let\u2019s first take a look at how emissions would compare if we allocated them to the country of <em>departure</em>. This means, for example, that emissions from any flight that departs from Spain are counted towards Spain\u2019s total. In the chart here we see international aviation emissions in per capita terms.</p>\n\n\n\n<p>Some of the largest emitters per person in 2018 were Iceland (3.5 tonnes of CO<sub>2</sub> per person); Qatar (2.5 tonnes); United Arab Emirates (2.2 tonnes); Singapore (1.7 tonnes); and Malta (992 kilograms). </p>\n\n\n\n<p>Again, we see large inequalities in emissions across the world \u2013 in many lower-income countries per capita emissions are only a few kilograms: 6 kilograms in India, 4 kilograms in Nigeria; and only 1.4 kilograms in the Democratic Republic of Congo.</p>\n</div>\n\n\n\n<div class=\"wp-block-column\">\n<iframe src=\"https://ourworldindata.org/grapher/per-capita-co2-international-aviation?stackMode=absolute&time=latest&region=World\" loading=\"lazy\" style=\"width: 100%; height: 600px; border: 0px none;\"></iframe>\n\n\n\n<h5>Related charts:</h5>\n\n\n <block type=\"prominent-link\" style=\"is-style-thin\">\n <link-url>https://ourworldindata.org/grapher/co2-international-aviation</link-url>\n <title>Total CO\u2082 emissions from international aviation</title>\n <content></content>\n <figure></figure>\n </block>\n\n <block type=\"prominent-link\" style=\"is-style-thin\">\n <link-url>https://ourworldindata.org/grapher/share-co2-international-aviation</link-url>\n <title>Share of global CO\u2082 emissions from international aviation</title>\n <content></content>\n <figure></figure>\n </block></div>\n</div>\n\n\n\n<h4>Per capita emissions from international flights \u2013 adjusted for tourism</h4>\n\n\n\n<div class=\"wp-block-columns\">\n<div class=\"wp-block-column\">\n<p>The above allocation of international aviation emissions to the country of <em>departure</em> raises some issues. It is not an accurate reflection of the local population of countries that rely a lot on tourism, for example. Most of the departing flights from these countries are carrying visiting tourists rather than locals. </p>\n\n\n\n<p>One way to correct for this is to adjust these figures for the ratio of inbound to outbound travellers. This approach was applied <a href=\"https://theicct.org/blog/staff/not-every-tonne-of-aviation-CO2\">in an analysis</a> by Sola Zheng for the <em>International Council on Clean Transportation</em>. This attempts to distinguish between locals traveling abroad and foreign visitors traveling to that country on the same flight.{ref}A country with a ratio greater than one will have more incoming travellers than outgoing locals i.e. they are more of a hotspot for tourism.{/ref} For example, if we calculated that Spain had 50% more incoming than outgoing travellers, we would reduce its per capita footprint from flying by 50%. If the UK had 75% more outgoing travellers than incoming, we\u2019d increase its footprint by 75%.</p>\n\n\n\n<p>We have replicated this approach and  applied this adjustment to these figures by calculating the <a href=\"https://ourworldindata.org/grapher/ratio-of-inbound-to-outbound-tourists\">inbound:outbound tourist ratio</a> based on flight departures and arrival data from the <a href=\"https://datacatalog.worldbank.org/dataset/world-development-indicators\">World Bank</a>. </p>\n\n\n\n<p>How does this affect per capita emissions from international flights? The adjusted figures are shown in the chart here.</p>\n\n\n\n<p>As we would expect, countries which are tourist hotspots see the largest change. Portugal\u2019s emissions, for example, fall from 388 to just 60 kilograms per person. Portuguese locals are responsible for much fewer travel emissions than outgoing tourists. Spanish emissions fall from 335 to 77 kilograms per person.</p>\n\n\n\n<p>On the other hand, countries where the locals travel elsewhere see a large increase. In the UK, they almost double from 422 to 818 kilograms.</p>\n</div>\n\n\n\n<div class=\"wp-block-column\">\n<iframe src=\"https://ourworldindata.org/grapher/per-capita-co2-international-flights-adjusted?stackMode=absolute&time=latest&region=World\" loading=\"lazy\" style=\"width: 100%; height: 600px; border: 0px none;\"></iframe>\n</div>\n</div>\n\n\n\n<h4>Per capita emissions from domestic <em>and </em>international flights</h4>\n\n\n\n<div class=\"wp-block-columns\">\n<div class=\"wp-block-column\">\n<p>Let\u2019s combine per capita emissions from domestic and international travel to compare the total footprint from flying.</p>\n\n\n\n<p>This is shown in the interactive map <em>[we\u2019ve taken the adjusted international figures \u2013 you can find the  combined figures without tourism-adjustment </em><a href=\"https://ourworldindata.org/grapher/per-capita-co2-aviation\"><strong><em>here</em></strong></a><em>]. </em></p>\n\n\n\n<p>The global average emissions from aviation were 103 kilograms. The inequality in emissions across the world becomes clear when this is broken down by country. </p>\n\n\n\n<p>At the top of the table lies the United Arab Emirates \u2013 each person emits close to two tonnes \u2013 1950 kg \u2013 of CO<sub>2</sub> from flying each year. That\u2019s 200 times the global average.  This was followed by Singapore (1173 kilograms); Iceland (1070 kg); Finland (1000 kg); and Australia (878 kilograms). </p>\n\n\n\n<p>To put this into perspective: a return flight (in economy class) from London to Dubai/United Arab Emirates would emit around one tonne of CO<sub>2</sub>.{ref}We can calculate this by taking the standard CO2 conversion factors for travel, used in the <a href=\"https://www.gov.uk/government/publications/greenhouse-gas-reporting-conversion-factors-2019\">UK greenhouse gas accounting framework</a>. For a long-haul flight in economy class, around 0.079 kilograms of CO<sub>2</sub> <a href=\"https://ourworldindata.org/travel-carbon-footprint\">are emitted</a> per passenger-kilometer. This means that you would travel around 12,600 kilometers to emit one tonne [1,000,000 / 0.079 kg = 12,626 kilometers]. Since we\u2019re taking a return flight, the travel distance would be half of that figure: around 6300 kilometers. The direct distance from <a href=\"https://www.distance.to/London/Dubai,ARE\">London to Dubai</a> is around 5,500 kilometers. Depending on the flight path, it\u2019s likely to be slightly longer than this, and in the range of 5500 to 6500 kilometers.</p>\n\n\n\n<p>Note that in this case we\u2019re looking at CO<sub>2</sub> emissions <em>without</em> the extra warming effects of these emissions at high altitudes. This is to allow us to compare with the ICCT figures by country presented in this article. You find additional data on how the footprint of flying is impacted by non-CO<sub>2</sub> warming effects<a href=\"https://ourworldindata.org/grapher/carbon-footprint-travel-mode\"> <strong>here</strong></a>.{/ref} So the two-tonne average for the UAE is equivalent to around two return trips to London.</p>\n\n\n\n<p>In many countries, most people do not fly at all. The average Indian emits just 18 kilograms from aviation \u2013 this is much, much less than even a short-haul flight which confirms that most did not take a flight.</p>\n\n\n\n<p>In fact, we can compare just the aviation emissions for the top countries to the <em>total</em> carbon footprint of citizens elsewhere. The average UAE citizen emits 1950 kilograms of CO<sub>2</sub> from flying. This is the same as the <em>total</em> <a href=\"https://ourworldindata.org/explorers/co2?tab=chart&xScale=linear&yScale=linear&stackMode=absolute&endpointsOnly=0&year=latest&time=1858..2018&country=~India&region=World&Gas%20=CO%E2%82%82&Accounting%20=Production-based&Fuel%20=Total&Count%20=Per%20capita&Relative%20to%20world%20total%20=\">CO<sub>2</sub> footprint of the average Indian</a> (including everything from electricity to road transport, heating and industry). Or, to take a more extreme example, 200 times the total footprint of the average Nigerien, Ugandan or Ethiopian, which <a href=\"https://ourworldindata.org/explorers/co2?tab=chart&xScale=linear&yScale=linear&stackMode=absolute&endpointsOnly=0&year=latest&time=1958..2018&country=Niger~Uganda~Ethiopia&region=World&Gas%20=CO%E2%82%82&Accounting%20=Production-based&Fuel%20=Total&Count%20=Per%20capita&Relative%20to%20world%20total%20=\">have per capita emissions</a> of around 100 kilograms. </p>\n\n\n\n<p>This again emphasises the large difference between the global average and the individual emissions of people who fly. Aviation contributes a few percent of total CO<sub>2</sub> emissions each year \u2013 this is not insignificant, but far from being the largest sector to tackle. Yet from the perspective of the individual, flying <em>is</em> often one of the largest chunks of our carbon footprint. The average rich person emits tonnes of CO<sub>2</sub> from flying each year \u2013 this is equivalent to the <em>total</em> carbon footprint of tens or hundreds of people in many countries of the world.</p>\n</div>\n\n\n\n<div class=\"wp-block-column\">\n<iframe src=\"https://ourworldindata.org/grapher/per-capita-co2-aviation-adjusted?stackMode=absolute&region=World\" loading=\"lazy\" style=\"width: 100%; height: 600px; border: 0px none;\"></iframe>\n\n\n\n<h5>Related charts:</h5>\n\n\n <block type=\"prominent-link\" style=\"is-style-thin\">\n <link-url>https://ourworldindata.org/grapher/per-capita-co2-aviation</link-url>\n <title>Per capita CO\u2082 emissions from aviation (without tourism adjustment)</title>\n <content></content>\n <figure></figure>\n </block>\n\n <block type=\"prominent-link\" style=\"is-style-thin\">\n <link-url>https://ourworldindata.org/grapher/co2-emissions-aviation</link-url>\n <title>Total CO\u2082 emissions from aviation</title>\n <content></content>\n <figure></figure>\n </block>\n\n <block type=\"prominent-link\" style=\"is-style-thin\">\n <link-url>https://ourworldindata.org/grapher/share-co2-emissions-aviation</link-url>\n <title>Share of global CO\u2082 emissions from aviation</title>\n <content></content>\n <figure></figure>\n </block></div>\n</div>\n\n\n\n<h3>Where in the world do people fly the most?</h3>\n\n\n\n<h4>Domestic air travel</h4>\n\n\n\n<div class=\"wp-block-columns is-style-sticky-right\">\n<div class=\"wp-block-column\">\n<p>This interactive chart shows the average distance travelled per person through domestic air travel each year. This data is for passenger flights only and does not include freight.</p>\n</div>\n\n\n\n<div class=\"wp-block-column\">\n<iframe src=\"https://ourworldindata.org/grapher/per-capita-domestic-aviation-km\" loading=\"lazy\" style=\"width: 100%; height: 600px; border: 0px none;\"></iframe>\n\n\n\n<h5>Related charts:</h5>\n\n\n <block type=\"prominent-link\" style=\"is-style-thin\">\n <link-url>https://ourworldindata.org/grapher/share-global-domestic-aviation-km</link-url>\n <title>Share of global passenger kilometers from domestic air travel</title>\n <content>\n\n<p>What share of global domestic air travel does each country account for?</p>\n\n</content>\n <figure></figure>\n </block>\n\n <block type=\"prominent-link\" style=\"is-style-thin\">\n <link-url>https://ourworldindata.org/grapher/total-domestic-aviation-km</link-url>\n <title>Total passenger kilometers from domestic air travel</title>\n <content>\n\n<p></p>\n\n</content>\n <figure></figure>\n </block></div>\n</div>\n\n\n\n<h4>International air travel</h4>\n\n\n\n<div class=\"wp-block-columns is-style-sticky-right\">\n<div class=\"wp-block-column\">\n<p>This interactive chart shows the average distance travelled per person through international air travel each year. This data is for passenger flights only and does not include freight.</p>\n</div>\n\n\n\n<div class=\"wp-block-column\">\n<iframe src=\"https://ourworldindata.org/grapher/per-capita-international-aviation-km\" loading=\"lazy\" style=\"width: 100%; height: 600px; border: 0px none;\"></iframe>\n\n\n\n<h5>Related charts:</h5>\n\n\n <block type=\"prominent-link\" style=\"is-style-thin\">\n <link-url>https://ourworldindata.org/grapher/share-international-aviation-km</link-url>\n <title>Share of global passenger kilometers from international air travel</title>\n <content>\n\n<p>What share of global international air travel does each country account for?</p>\n\n</content>\n <figure></figure>\n </block>\n\n <block type=\"prominent-link\" style=\"is-style-thin\">\n <link-url>https://ourworldindata.org/grapher/passenger-km-international-aviation</link-url>\n <title>Total passenger kilometers from international air travel</title>\n <content>\n\n<p></p>\n\n</content>\n <figure></figure>\n </block></div>\n</div>\n\n\n\n<h4>Total air travel</h4>\n\n\n\n<div class=\"wp-block-columns is-style-sticky-right\">\n<div class=\"wp-block-column\">\n<p>This interactive chart shows the average distance travelled per person through domestic <em>and</em> international air travel each year. This data is for passenger flights only and does not include freight.</p>\n</div>\n\n\n\n<div class=\"wp-block-column\">\n<iframe src=\"https://ourworldindata.org/grapher/per-capita-km-aviation\" loading=\"lazy\" style=\"width: 100%; height: 600px; border: 0px none;\"></iframe>\n\n\n\n<h5>Related charts:</h5>\n\n\n <block type=\"prominent-link\" style=\"is-style-thin\">\n <link-url>https://ourworldindata.org/grapher/share-km-aviation</link-url>\n <title>Share of global passenger kilometers from air travel</title>\n <content>\n\n<p>What share of global air travel does each country account for?</p>\n\n</content>\n <figure></figure>\n </block>\n\n <block type=\"prominent-link\" style=\"is-style-thin\">\n <link-url>https://ourworldindata.org/grapher/total-aviation-km</link-url>\n <title>Total passenger kilometers from air travel</title>\n <content>\n\n<p></p>\n\n</content>\n <figure></figure>\n </block></div>\n</div>\n\n\n\n<h2>Rail</h2>\n\n\n\n<div class=\"wp-block-columns is-style-sticky-right\">\n<div class=\"wp-block-column\">\n<p>This interactive chart shows the total rail travel in each country, measured in passenger-kilometers per year.</p>\n\n\n\n<p>This includes passenger travel only and does not include freight.</p>\n</div>\n\n\n\n<div class=\"wp-block-column\">\n<iframe src=\"https://ourworldindata.org/grapher/railways-passengers-carried-passenger-km\" loading=\"lazy\" style=\"width: 100%; height: 600px; border: 0px none;\"></iframe>\n</div>\n</div>\n\n\n\n<h2>Energy intensity of transport</h2>\n\n\n\n<p>This chart shows the average energy intensity of transport across different modes of travel. It is measured as the average kilowatt-hours required per passenger-kilometer.</p>\n\n\n\n<p>This data comes from the United States Department of Transportation’s Bureau of Transportation Statistics (BTS). The energy intensity of public transport depends on the assumptions made about the capacity of transport modes i.e. how many passengers travel on a given train or bus journey. This data thererfore reflects average capacities in the United States, but will vary from country-to-country.</p>\n\n\n\n<iframe src=\"https://ourworldindata.org/grapher/energy-intensity-transport?country=Amtrak~Bus~Domestic+flight~International+flight~Motorcycle~~Transit+motor+bus~Truck+%28with+trailer%29~Truck~\" loading=\"lazy\" style=\"width: 100%; height: 600px; border: 0px none;\"></iframe>\n\n\n\n<h2>CO<sub>2</sub> emissions from transport</h2>\n\n\n\n<h3>Per capita transport emissions from transport</h3>\n\n\n\n<p>This interactive shows the average per capita emissions of carbon dioxide from transport each year. This includes road, train, bus and domestic air travel but <em>does not </em>include international aviation and shipping.</p>\n\n\n\n<iframe src=\"https://ourworldindata.org/grapher/per-capita-co2-transport?stackMode=absolute&region=World\" loading=\"lazy\" style=\"width: 100%; height: 600px; border: 0px none;\"></iframe>\n\n\n\n<h3>Total transport emissions</h3>\n\n\n\n<p>This interactive shows the emissions of carbon dioxide from transport each year. This includes road, train, bus and domestic air travel but <em>does not </em>include international aviation and shipping.</p>\n\n\n\n<iframe src=\"https://ourworldindata.org/grapher/co2-emissions-transport?stackMode=absolute&time=earliest..latest&region=World\" loading=\"lazy\" style=\"width: 100%; height: 600px; border: 0px none;\"></iframe>\n\n\n\n<h3>CO<sub>2</sub> emissions by mode of transport</h3>\n\n\n\n<p>Transport accounts for around one-fifth of global carbon dioxide (CO<sub>2</sub>) emissions <em>[24% if we only consider CO<sub>2</sub> emissions from energy]</em>.{ref}The <em>World Resource Institute</em>\u2019s Climate Data Explorer <a href=\"https://www.climatewatchdata.org/data-explorer/historical-emissions?historical-emissions-data-sources=cait&historical-emissions-gases=co2&historical-emissions-regions=All%20Selected&historical-emissions-sectors=total-including-lucf%2Ctransportation&page=1&sort_col=country&sort_dir=ASC\">provides data</a> from CAIT on the breakdown of emissions by sector. In 2016, global CO<sub>2</sub> emissions (including land use) were 36.7 billion tonnes CO<sub>2</sub>; emissions from transport were 7.9 billion tonnes CO<sub>2</sub>. Transport therefore accounted for 7.9 / 36.7 = 21% of global emissions. </p>\n\n\n\n<p>The IEA <a href=\"https://www.iea.org/data-and-statistics/?country=WORLD&fuel=CO2%20emissions&indicator=TotCO2\">looks at CO<sub>2</sub> emissions</a> from energy production alone \u2013 in 2018 it reported 33.5 billion tonnes of energy-related CO<sub>2</sub> [hence, transport accounted for 8 billion / 33.5 billion = 24% of energy-related emissions.{/ref}</p>\n\n\n\n<p>How do these emissions break down? Is it cars, trucks, planes or trains that dominate?</p>\n\n\n\n<p>In the chart here we see global transport emissions in 2018. This data is <a href=\"https://www.iea.org/data-and-statistics/charts/transport-sector-co2-emissions-by-mode-in-the-sustainable-development-scenario-2000-2030\">sourced from</a> the <em>International Energy Agency (IEA)</em>. </p>\n\n\n\n<p>Road travel accounts for three-quarters of transport emissions. Most of this comes from passenger vehicles \u2013 cars and buses \u2013 which contribute 45.1%. The other 29.4% comes from trucks carrying freight.</p>\n\n\n\n<p>Since the entire transport sector accounts for 21% of total emissions, and road transport accounts for three-quarters of transport emissions, road transport accounts for 15% of total CO<sub>2</sub> emissions.</p>\n\n\n\n<p>Aviation \u2013 while it often gets the most attention in discussions on action against climate change \u2013 accounts for only 11.6% of transport emissions. It emits just under one billion tonnes of CO<sub>2</sub> each year \u2013 around 2.5% of total global emissions <em>[we look at the role that air travel plays in climate change in more detail in an upcoming article]</em>. International shipping contributes a similar amount, at 10.6%. </p>\n\n\n\n<p>Rail travel and freight emits very little \u2013 only 1% of transport emissions. Other transport \u2013 which is mainly the movement of materials such as water, oil, and gas via pipelines \u2013 is responsible for 2.2%.</p>\n\n\n\n<figure class=\"wp-block-image size-large\"><img loading=\"lazy\" width=\"800\" height=\"315\" src=\"https://owid.cloud/app/uploads/2020/10/Transport-CO2-emissions-by-mode-bar-chart-800x315.png\" alt=\"\" class=\"wp-image-36825\" srcset=\"https://owid.cloud/app/uploads/2020/10/Transport-CO2-emissions-by-mode-bar-chart-800x315.png 800w, https://owid.cloud/app/uploads/2020/10/Transport-CO2-emissions-by-mode-bar-chart-400x158.png 400w, https://owid.cloud/app/uploads/2020/10/Transport-CO2-emissions-by-mode-bar-chart-150x59.png 150w, https://owid.cloud/app/uploads/2020/10/Transport-CO2-emissions-by-mode-bar-chart-768x303.png 768w, https://owid.cloud/app/uploads/2020/10/Transport-CO2-emissions-by-mode-bar-chart-1536x606.png 1536w, https://owid.cloud/app/uploads/2020/10/Transport-CO2-emissions-by-mode-bar-chart.png 1674w\" sizes=\"(max-width: 800px) 100vw, 800px\" /></figure>\n\n\n\n<h4>Towards zero-carbon transport: how can we expect the sector\u2019s CO<sub>2</sub> emissions to change in the future?</h4>\n\n\n\n<div class=\"wp-block-columns\">\n<div class=\"wp-block-column\">\n<p>Transport demand is expected to grow across the world in the coming decades as the global population increases, incomes rise, and more people can afford cars, trains and flights. In its <em>Energy Technology Perspectives</em> report, the International Energy Agency (IEA) expects global transport (measured in passenger-kilometers) to double, car ownership rates to increase by 60%, and demand for passenger and freight aviation to triple by 2070.{ref}IEA (2020), <a href=\"https://www.iea.org/reports/energy-technology-perspectives-2020\">Energy Technology Perspectives 2020</a>, IEA, Paris.{/ref} Combined, these factors would result in a large increase in transport emissions.</p>\n\n\n\n<p>But major technological innovations can help offset this rise in demand. As the world shifts towards lower-carbon electricity sources, the rise of electric vehicles offers a viable option to reduce emissions from passenger vehicles.</p>\n\n\n\n<p>This is reflected in the IEA\u2019s <em>Energy Technology Perspective</em> report. There it outlines its \u201cSustainable Development Scenario\u201d for reaching net-zero CO2 emissions from global energy by 2070. The pathways for the different elements of the transport sector in this optimistic scenario are shown in the visualization.</p>\n\n\n\n<p>We see that with electrification- and hydrogen- technologies some of these sub-sectors could decarbonize within decades. The IEA scenario assumes the phase-out of emissions from motorcycles by 2040; rail by 2050; small trucks by 2060; and although emissions from cars and buses are not completely eliminated until 2070, it expects many regions, including the European Union; United States; China and Japan to have phased-out conventional vehicles as early as 2040.</p>\n\n\n\n<p>Other transport sectors will be much more difficult to decarbonize.</p>\n\n\n\n<p>In a paper published in <em>Science</em>, Steven Davis and colleagues looked at our options across sectors to reach a net-zero emissions energy system.{ref}Davis, S. J., Lewis, N. S., Shaner, M., Aggarwal, S., Arent, D., Azevedo, I. L., … & Clack, C. T. (2018). <a href=\"https://science.sciencemag.org/content/360/6396/eaas9793.full\">Net-zero emissions energy systems</a>. <em>Science</em>, 360(6396).{/ref} They highlighted long-distance road freight (large trucks), aviation and shipping as particularly difficult to eliminate. The potential for hydrogen as a fuel, or battery electricity to run planes, ships and large trucks is limited by the range and power required; the size and weight of batteries or hydrogen fuel tanks would be <em>much</em> larger and heavier than current combustion engines.{ref}Cecere, D., Giacomazzi, E., & Ingenito, A. (2014). <a href=\"https://www.sciencedirect.com/science/article/pii/S0360319914011847\">A review on hydrogen industrial aerospace applications</a>. <em>International Journal of Hydrogen Energy</em>, <em>39</em>(20), 10731-10747.{/ref}<sup>,</sup>{ref}Fulton, L. M., Lynd, L. R., K\u00f6rner, A., Greene, N., & Tonachel, L. R. (2015). <a href=\"https://onlinelibrary.wiley.com/doi/full/10.1002/bbb.1559\">The need for biofuels as part of a low carbon energy future</a>. <em>Biofuels, Bioproducts and Biorefining</em>, 9(5), 476-483.{/ref}</p>\n\n\n\n<p>So, despite falling by three-quarters in the visualized scenario, emissions from these sub-sectors would still make transport the largest contributor to energy-related emissions in 2070. To reach net-zero for the energy sector as a whole, these emissions would have to be offset by \u2018negative emissions\u2019 (e.g. the capture and storage of carbon from bioenergy or <a href=\"https://www.iea.org/reports/direct-air-capture\">direct air capture</a>) from other parts of the energy system.</p>\n\n\n\n<p>In the IEA\u2019s net-zero scenario, nearly two-thirds of the emissions reductions come from technologies that are not yet commercially available. As the IEA states, \u201cReducing CO<sub>2</sub> emissions in the transport sector over the next half-century will be a formidable task.\u201d{ref}IEA (2020), <a href=\"https://www.iea.org/reports/energy-technology-perspectives-2020\">Energy Technology Perspectives 2020</a>, IEA, Paris.{/ref}</p>\n</div>\n\n\n\n<div class=\"wp-block-column\">\n<h6>Global CO2 emissions from transport in the IEA’s Sustainable Development Scenario to 2070{ref}IEA (2020), <a href=\"https://www.iea.org/reports/energy-technology-perspectives-2020\">Energy Technology Perspectives 2020</a>, IEA, Paris.{/ref}</h6>\n\n\n\n<figure class=\"wp-block-image size-large\"><img loading=\"lazy\" width=\"800\" height=\"505\" src=\"https://owid.cloud/app/uploads/2020/10/IEA-Transport-to-2070-800x505.png\" alt=\"\" class=\"wp-image-36827\" srcset=\"https://owid.cloud/app/uploads/2020/10/IEA-Transport-to-2070-800x505.png 800w, https://owid.cloud/app/uploads/2020/10/IEA-Transport-to-2070-400x253.png 400w, https://owid.cloud/app/uploads/2020/10/IEA-Transport-to-2070-150x95.png 150w, https://owid.cloud/app/uploads/2020/10/IEA-Transport-to-2070-768x485.png 768w, https://owid.cloud/app/uploads/2020/10/IEA-Transport-to-2070-1536x970.png 1536w, https://owid.cloud/app/uploads/2020/10/IEA-Transport-to-2070.png 1732w\" sizes=\"(max-width: 800px) 100vw, 800px\" /></figure>\n</div>\n</div>\n", "protected": false }, "excerpt": { "rendered": "Explore trends in transport technologies and emissions across the world.", "protected": false }, "date_gmt": "2021-09-24T13:42:00", "modified": "2023-06-09T19:20:39", "template": "", "categories": [ 50, 234 ], "menu_order": 116, "ping_status": "closed", "authors_name": [ "Hannah Ritchie", "Max Roser" ], "modified_gmt": "2023-06-09T18:20:39", "comment_status": "closed", "featured_media": 45158, "featured_media_paths": { "thumbnail": "/app/uploads/2021/09/transport-thumbnail-150x79.png", "medium_large": "/app/uploads/2021/09/transport-thumbnail-768x404.png" } }

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<div class="blog-info">First published in September 2021.</div>      <h2>Road travel</h2>   <h3>Passenger vehicle registrations by type</h3>   <div class="wp-block-columns"> <div class="wp-block-column"> <p>These interactive charts show the breakdown of new passenger vehicle registrations by type.</p>   <p>This is broken down by: petroleum; diesel; full hybrid (excluding plug-in hybrids); plug-in electric hybrids; and fully electric battery vehicles.</p> </div>   <div class="wp-block-column"> <iframe src="https://ourworldindata.org/grapher/new-vehicles-type-area?tab=chart&stackMode=relative&country=~NOR" loading="lazy" style="width: 100%; height: 600px; border: 0px none;"></iframe>   <iframe src="https://ourworldindata.org/grapher/new-vehicles-type-share?tab=chart&country=~GBR" loading="lazy" style="width: 100%; height: 600px; border: 0px none;"></iframe>  </div> </div>   <h3>Electric vehicle registrations</h3>   <div class="wp-block-columns"> <div class="wp-block-column"> <p>This interactive chart shows the share of new passenger vehicle registrations that are battery electric vehicles. This does not include plug-in hybrid vehicles.</p> </div>   <div class="wp-block-column"> <iframe src="https://ourworldindata.org/grapher/share-vehicle-electric?country=AUT~ITA~NOR~PRT~ESP~SWE~CHE~TUR~GBR~IRL~ISL~GRC~DEU~FRA~FIN~DNK~BEL~LUX~NLD" loading="lazy" style="width: 100%; height: 600px; border: 0px none;"></iframe> </div> </div>   <div class="wp-block-columns"> <div class="wp-block-column"> <p>This interactive chart shows the share of new passenger vehicle registrations that are battery electric <em>plus</em> plug-in hybrid vehicles.</p> </div>   <div class="wp-block-column"> <iframe src="https://ourworldindata.org/grapher/battery-plugin-hybrid-vehicles?time=2019&country=~AUT~BEL~DNK~FIN~EU-27+%2B+UK~FRA~DEU~GRC~ISL~IRL~GBR~TUR~CHE~SWE~ESP~PRT~NOR~NLD~LUX~ITA" loading="lazy" style="width: 100%; height: 600px; border: 0px none;"></iframe> </div> </div>   <h3>Carbon intensity of new passenger vehicles</h3>   <div class="wp-block-columns"> <div class="wp-block-column"> <p>This interactive chart shows the average carbon intensity of new passenger vehicles in each country.</p>   <p>This is measured as the average emissions of CO₂ (in grams) per kilometer travelled across all types of passenger vehicles.</p> </div>   <div class="wp-block-column"> <iframe src="https://ourworldindata.org/grapher/carbon-new-passenger-vehicles?country=AUT~ITA~LUX~NLD~NOR~PRT~ESP~SWE~CHE~TUR~GBR~IRL~ISL~GRC~DEU~FRA~FIN~DNK~BEL" loading="lazy" style="width: 100%; height: 600px; border: 0px none;"></iframe> </div> </div>   <h3>Fuel economy of new passenger vehicles</h3>   <div class="wp-block-columns"> <div class="wp-block-column"> <p>This interacrive chart shows the average fuel economy of new passenger vehicles in each country.</p>   <p>This is measured as the average liters consumed per 100 kilometers travelled, across all types of passenger vehicles.</p> </div>   <div class="wp-block-column"> <iframe src="https://ourworldindata.org/grapher/fuel-efficiency-new-vehicles?country=AUT~BEL~ITA~LUX~NLD~NOR~PRT~ESP~SWE~CHE~TUR~GBR~IRL~ISL~GRC~DEU~FRA~FIN~DNK" loading="lazy" style="width: 100%; height: 600px; border: 0px none;"></iframe> </div> </div>   <h2>Aviation</h2>   <h3>What share of global CO<sub>2</sub> emissions come from aviation?</h3>    <p>Flying is a highly controversial topic in climate debates. There are a few reasons for this. </p>   <p>The first is the disconnect between its role in our personal and collective carbon emissions. Air travel dominates a frequent traveller's individual contribution to climate change. Yet aviation overall accounts for only 2.5% of global carbon dioxide (CO<sub>2</sub>) emissions. This is because there are large inequalities in how much people fly – many do not, or cannot afford to, fly at all.{ref}The best estimates put this figure at around 80% of the world population. We look at this in more detail in our article "<a href="https://ourworldindata.org/carbon-footprint-flying">Where in the world do people have the highest CO2 emissions from flying?</a>"{/ref}</p>   <p>The second is how aviation emissions are attributed to countries. CO<sub>2</sub> emissions from domestic flights <em>are</em> counted in a country’s emission accounts. International flights are not – instead they are counted as their own category: ‘bunker fuels’. The fact that they don’t count towards the emissions of any country means there are few incentives for countries to reduce them.</p>   <p>It’s also important to note that unlike the most common greenhouse gases – carbon dioxide, methane or nitrous oxide – non-CO<sub>2</sub> forcings from aviation <em>are not included</em> in the Paris Agreement. This means they could be easily overlooked – especially since international aviation is not counted within any country’s emissions inventories or targets.</p>   <p>How much of a role does aviation play in global emissions and climate change? In this article we take a look at the key numbers that are useful to know.</p>   <p>Global aviation (including domestic and international; passenger and freight) accounts for:</p>   <ul><li><strong>1.9%</strong> of <a href="https://ourworldindata.org/ghg-emissions-by-sector">greenhouse gas emissions</a> (which includes all greenhouse gases, not only CO<sub>2</sub>)</li><li><strong>2.5%</strong> of CO<sub>2</sub> emissions</li><li><strong>3.5%</strong> of 'effective radiative forcing' – a closer measure of its impact on warming.</li></ul>   <p>The latter two numbers refer to 2018, and the first to 2016, the latest year for which such data are available.</p>   <hr class="wp-block-separator"/>   <h4>Aviation accounts for 2.5% of global CO<sub>2</sub> emissions</h4>   <p>As we will see later in this article, there are a number of processes by which aviation contributes to climate change. But the one that gets the most attention is its contribution via CO<sub>2</sub> emissions. Most flights are powered by jet gasoline – although some partially run on biofuels – which is converted to CO<sub>2</sub> when burned.  </p>   <p>In a recent paper, researchers – David Lee and colleagues – reconstructed annual CO<sub>2 </sub>emissions from global aviation dating back to 1940.{ref}Lee, D. S., Fahey, D. W., Skowron, A., Allen, M. R., Burkhardt, U., Chen, Q., ... & Gettelman, A. (2020). <a href="https://www.sciencedirect.com/science/article/pii/S1352231020305689">The contribution of global aviation to anthropogenic climate forcing for 2000 to 2018</a>. <em>Atmospheric Environment</em>, 117834.{/ref} This was calculated based on fuel consumption data from the International Energy Agency (IEA), and earlier estimates from Robert Sausen and Ulrich Schumann (2000).{ref}Sausen, R., & Schumann, U. (2000). <a href="https://link.springer.com/article/10.1023/A:1005579306109">Estimates of the climate response to aircraft CO2 and NOx emissions scenarios</a>. <em>Climatic Change</em>, <em>44</em>(1-2), 27-58.{/ref}</p>   <p>The time series of global emissions from aviation since 1940 is shown in the accompanying chart. In 2018, it’s estimated that global aviation – which includes both passenger and freight – emitted 1.04 billion tonnes of CO<sub>2</sub>.</p>   <p>This represented 2.5% of <a href="https://ourworldindata.org/co2-emissions#global-co2-emissions-from-fossil-fuels-global-co2-emissions-from-fossil-fuels" data-type="URL" data-id="https://ourworldindata.org/co2-emissions#global-co2-emissions-from-fossil-fuels-global-co2-emissions-from-fossil-fuels">total CO<sub>2</sub> emissions</a> in 2018.{ref}The Global Carbon Budget estimated total CO<sub>2</sub> emissions from all fossil fuels, cement production and land-use change to be 42.1 billion tonnes in 2018. This means aviation accounted for [1 / 42.1 * 100] = 2.5% of total emissions.{/ref}<sup>,</sup>{ref}Global Carbon Project. (2019). Supplemental data of Global Carbon Budget 2019 (Version 1.0) [Data set]. Global Carbon Project. <a href="https://doi.org/10.18160/gcp-2019">https://doi.org/10.18160/gcp-2019</a>.<br><br>If we were to exclude land use change emissions, aviation accounted for 2.8% of fossil fuel emissions. The Global Carbon Budget estimated total CO<sub>2</sub> emissions from fossil fuels and cement production to be 36.6 billion tonnes in 2018. This means aviation accounted for [1 / 36.6 * 100] = 2.8% of total emissions.{/ref}</p>   <p>Aviation emissions have doubled since the mid-1980s. But, they’ve been growing at a similar rate as total CO<sub>2</sub> emissions – this means its share of global emissions has been relatively stable: in the range of 2% to 2.5%.{ref}2.3% to 2.8% of emissions if land use is excluded.{/ref}</p>   <figure class="wp-block-image size-large"><img src="https://owid.cloud/app/uploads/2020/10/Global-CO2-emissions-from-aviation-693x550.png" alt="" class="wp-image-36836"/></figure>   <h4>Non-CO<sub>2</sub> climate impacts mean aviation accounts for 3.5% of global warming</h4>   <p>Aviation accounts for around 2.5% of global CO<sub>2</sub> emissions, but it’s overall contribution to climate change is higher. This is because air travel does not only emit CO<sub>2</sub>: it affects the climate in a number of more complex ways.</p>   <p>As well as emitting CO<sub>2</sub> from burning fuel, planes affect the concentration of other gases and pollutants in the atmosphere. They result in a short-term increase, but long-term decrease in ozone (O<sub>3</sub>); a decrease in methane (CH<sub>4</sub>); emissions of water vapour; soot; sulfur aerosols; and water contrails. While some of these impacts result in warming, others induce a cooling effect. Overall, the warming effect is stronger.</p>   <p>David Lee et al. (2020) quantified the overall effect of aviation on global warming when all of these impacts were included.{ref}Lee, D. S., Fahey, D. W., Skowron, A., Allen, M. R., Burkhardt, U., Chen, Q., ... & Gettelman, A. (2020). <a href="https://www.sciencedirect.com/science/article/pii/S1352231020305689">The contribution of global aviation to anthropogenic climate forcing for 2000 to 2018</a>. <em>Atmospheric Environment</em>, 117834.{/ref} To do this they calculated the so-called ‘Radiative Forcing’. Radiative forcing measures the difference between incoming energy and the energy radiated back to space. If more energy is absorbed than radiated, the atmosphere becomes warmer. </p>   <p>In their chart we see <a href="https://ars.els-cdn.com/content/image/1-s2.0-S1352231020305689-gr3_lrg.jpg" target="_blank" rel="noreferrer noopener">their estimates for the radiative forcing</a> of the different elements. When we combine them, aviation accounts for approximately 3.5% of effective radiative forcing: that is, 3.5% of warming.<br><br>Although CO<sub>2  </sub>gets most of the attention, it accounts for less than half of this warming. Two-thirds (66%) comes from non-CO<sub>2 </sub>forcings. Contrails – water vapor trails from aircraft exhausts – account for the largest share.</p>   <h4>We don’t yet have the technologies to decarbonize air travel</h4>   <p>Aviation’s contribution to climate change – 3.5% of warming, or 2.5% of CO<sub>2</sub> emissions – is often less than people think. It’s currently a relatively small chunk of emissions compared to other sectors. </p>   <p>The key challenge is that it is particularly hard to decarbonize. We have solutions to reduce emissions for many of the <a href="https://ourworldindata.org/ghg-emissions-by-sector">largest emitters</a> – such as power or road transport – and it’s now a matter of scaling them. We can deploy renewable and nuclear energy technologies, and transition to electric cars. But we don’t have proven solutions to tackle aviation yet. </p>   <p>There are some design concepts emerging – Airbus, for example, <a href="https://web.archive.org/web/20201031121346/https://www.airbus.com/innovation/zero-emission/hydrogen/zeroe.html" data-type="URL" data-id="https://web.archive.org/web/20201031121346/https://www.airbus.com/innovation/zero-emission/hydrogen/zeroe.html">have announced plans</a> to have the first zero-emission aircraft by 2035, using hydrogen fuel cells. Electric planes may be a viable concept, but are likely to be limited to very small aircraft due to the limitations of battery technologies and capacity. </p>   <p>Innovative solutions may be on the horizon, but they’re likely to be far in the distance.</p>    <p></p>     <h3>Appendix: <strong>Efficiency improvements means air traffic has increased more rapidly than emissions</strong></h3>   <div class="wp-block-columns is-style-sticky-right"> <div class="wp-block-column"> <p>Global emissions from aviation have increased a lot over the past half-century. However, air travel volumes increased even more rapidly. </p>   <p>Since 1960, aviation emissions increased almost seven-fold; since 1970 they’ve tripled. Air traffic volume – here defined as revenue passenger kilometers (RPK) traveled – <a href="https://ourworldindata.org/grapher/airline-capacity-and-traffic">increased by orders of magnitude more</a>: almost 300-fold since 1950; and 75-fold since 1960.{ref}Airline traffic data comes from the International Civil Aviation Organization (ICAO) via <a href="https://www.airlines.org/dataset/world-airlines-traffic-and-capacity">Airlines for America</a>. Revenue passenger kilometers (RPK) measures the number of paying passengers multiplied by their distance traveled.{/ref} </p>   <p>The much slower growth in emissions means aviation efficiency has seen massive improvements. In the chart we show both the increase in global airline traffic since 1950, and aviation efficiency, measured as the quantity of CO<sub>2</sub> emitted per revenue passenger kilometer traveled. In 2018, approximately 125 grams of CO<sub>2 </sub> were emitted per RPK. In 1960, this was eleven-fold higher; in 1950 it was twenty-fold higher. Aviation has seen massive efficiency improvements over the past 50 years.</p>   <p>These improvements have come from several sources: improvements in the design and technology of aircraft; larger aircraft sizes (allowing for more passengers per flight); and an increase in how ‘full’ passenger flights are. This last metric is termed the ‘passenger load factor’. The passenger load factor measures the actual number of kilometers traveled by paying customers (RPK) as a percentage of the available seat kilometers (ASK) – the kilometers traveled if every plane was full. If every plane was full the passenger load factor would be 100%. If only three-quarters of the seats were filled, it would be 75%.</p>   <p>The global passenger load factor <a href="https://ourworldindata.org/grapher/airline-passenger-load-factor">increased from 61% in 1950 to 82% in 2018</a>. </p> </div>   <div class="wp-block-column"> <figure class="wp-block-image size-large"><img src="https://owid.cloud/app/uploads/2020/10/Aviation-traffic-and-efficiency-Lee-et-al.-2020-800x505.png" alt="" class="wp-image-36837"/></figure> </div> </div>    <h3>Passenger vs. freight; domestic vs. international: where do aviation emissions come from?</h3>    <p>Global aviation – both passenger flights and freight – emits around one billion tonnes of carbon dioxide (CO<sub>2</sub>) each year. This was equivalent to around 2.4% of CO<sub>2</sub> emissions in 2018.</p>   <p>How do global aviation emissions break down?</p>   <p>The chart gives the answer. This data is sourced from the 2019 <em>International Council on Clean Transportation</em> <em>(ICCT)</em> report on global aviation.{ref}Graver, B., Zhang, K., & Rutherford, D. (2019). <a href="https://theicct.org/sites/default/files/publications/ICCT_CO2-commercl-aviation-2018_20190918.pdf" target="_blank" rel="noreferrer noopener">CO2 emissions from commercial aviation, 2018</a>. <em>The International Council of Clean Transportation</em>.{/ref}</p>   <p>Most emissions come from passenger flights – in 2018, they accounted for 81% of aviation’s emissions; the remaining 19% came from freight, the transport of goods. </p>   <p>Sixty percent of emissions from<em> passenger</em> flights come from international travel; the other 40% come from domestic (in-country) flights. </p>   <p>When we break passenger flight emissions down by travel distance, we get a (surprisingly) equal three-way split in emissions between short-haul (less than 1,500 kilometers); medium-haul (1,500 to 4,000 km); and long-haul (greater than 4,000 km) journeys.</p>   <figure class="wp-block-image size-large"><img src="https://owid.cloud/app/uploads/2020/10/Global-breakdown-of-aviation-emissions-800x507.png" alt="" class="wp-image-36848"/></figure>   <h4>The richest half are responsible for 90% of air travel CO<sub>2</sub> emissions</h4>   <p>The global inequalities in how much people fly become clear when we compare aviation emissions across countries of different income levels. The ICCT split these emissions based on World Bank's four <a href="https://ourworldindata.org/grapher/world-banks-income-groups?year=latest" target="_blank" rel="noreferrer noopener">income groups</a>.</p>   <p>A further study by Susanne Becek and Paresh Pant (2019) compared the contribution of each income group to global air travel emissions versus its share of world population.{ref}Becken, S. and P. Pant (2019). <a href="https://amadeus.com/en/insights/white-paper/airline-initiatives-to-reduce-climate-impact" target="_blank" rel="noreferrer noopener">Airline initiatives to reduce climate impact: ways to accelerate action</a> (White paper).{/ref} This comparison is shown in the visualization.</p>   <p>The ‘richest’ half of the world (high and upper-middle income countries) were responsible for 90% of air travel emissions.{ref}Note that this is based on categorisations from the average income level of countries, and does not take account of variation in income <em>within </em>countries. If we were to look at this distribution based on the income level of individuals rather than countries, the inequality in aviation emissions would be even larger.{/ref}</p>   <p>Looking at specific income groups:</p>   <ul><li>Only 16% of the world population live in high-income countries yet the planes that take off in those countries account for almost two-thirds (62%) of passenger emissions;</li><li>Upper-middle income countries are home to 35% of the world population, and contribute 28% of emissions;</li><li>Lower-middle income countries are home to the largest share (40% of the world), yet emit the planes taking off there just account for 9%;</li><li>The poorest countries – which are home to 9% of the world population – emit just 1%.</li></ul>   <p>In an upcoming article we will look in more detail at the contribution of each country to global aviation emissions.</p>   <figure class="wp-block-image size-large"><img src="https://owid.cloud/app/uploads/2020/10/Inequalities-in-CO2-emissions-from-air-travel-800x437.png" alt="" class="wp-image-36849"/></figure>   <h3>Where in the world do people have the highest carbon footprint from flying?</h3>    <p>Aviation accounts <a href="https://ourworldindata.org/co2-emissions-from-aviation" target="_blank" rel="noreferrer noopener">for around 2.5%</a> of global carbon dioxide (CO<sub>2</sub>) emissions. But if you are someone who does fly, air travel will make up a much larger share of your personal carbon footprint.</p>   <p>The fact that aviation is relatively small for global emissions as a whole, but of large importance for individuals that fly is due to large inequalities in the world. Most people in the  world do not take flights. There is no global reliable figure, but often cited estimates suggest that more than 80% of the global population have never flown.{ref}There is no global database available on <em>who</em> in the world flies each year. Passenger information is maintained by private airlines. Therefore, deriving estimates of this exact percentage is challenging. The most-cited estimate I’ve seen on this is that around 80% of the world population have never flown. This figure seems to circle back to a <a href="https://www.cnbc.com/2017/12/07/boeing-ceo-80-percent-of-people-never-flown-for-us-that-means-growth.html#:~:text=%E2%80%9CLess%20than%2020%20percent%20of,the%20entire%20economy%2C%20Muilenburg%20said.">quoted estimate</a> from the Boeing CEO.<br><br>Even in some of the world’s richest countries, a large share of the population do not fly frequently. Gallup <a href="https://news.gallup.com/poll/1579/airlines.aspx">survey data</a> from the United States suggests that in 2015, half of the population did not take a flight. Survey data from the UK <a href="http://publicapps.caa.co.uk/docs/33/CAA%20Aviation%20Consumer%20survey%20--%205th%20wave%20report%20FINAL%20(2).pdf">provides similar estimates</a>: 46% had not flown in the previous year.{/ref}</p>   <p>How do emissions from aviation vary across the world? Where do people have the highest footprint from flying?</p>   <h4>Per capita emissions from domestic flights</h4>   <div class="wp-block-columns"> <div class="wp-block-column"> <p>The first and most straightforward comparison is to look at emissions from <em>domestic</em> aviation – that is, flights that depart and arrive in the same country. </p>   <p>This is easiest to compare because domestic aviation is counted in each country’s inventory of greenhouse gas emissions. International flights, on the other hand, are not attributed to specific countries – partly because of contention as to who should take responsibility (should it be the country of departure or arrival? What about layover flights?).</p>   <p>In the chart here we see the average per capita emissions from domestic flights in 2018. This data is sourced from the <em>International Council on Clean Transportation</em> – we then used <a href="https://population.un.org/wpp/">UN population estimates</a> to calculate per capita figures.{ref}Graver, B., Zhang, K., & Rutherford, D. (2019). <a href="https://theicct.org/publications/co2-emissions-commercial-aviation-2018">CO2 emissions from commercial aviation, 2018</a>. <em>The International Council of Clean Transportation</em>.{/ref}<sup>,</sup>{ref}Note that this gives us <em>mean</em> per capita emissions, which  does not account for in-country inequalities in the amount of flights people take.{/ref}</p>   <p>We see large differences in emissions from domestic flights across the world. In the United States the average person emits around 386 kilograms of CO<sub>2</sub> each year from internal flights. This is followed by Australia (267 kg); Norway (209 kg); New Zealand (174 kg); and Canada (168 kg). Compare this with  countries at the bottom of the table – many across Africa, Asia, and Eastern Europe in particular emit less than one kilogram per person – just 0.8 kilograms; or 0.14 kilograms in Rwanda. For very small countries where there are no internal commercial flights, domestic emissions are of course, zero.</p>   <p>There are some obvious factors that explain some of these cross-country differences. Firstly, countries that are richer <a href="https://ourworldindata.org/grapher/per-capita-co2-domestic-aviation-vs-gdp">are more likely</a> to have higher emissions because people can afford to fly. Second, countries that have a larger land mass may have more internal flights – and indeed we see a <a href="https://ourworldindata.org/grapher/per-capita-co2-domestic-aviation-vs-land-area">correlation</a> between land area and domestic flight emissions; in small countries people are more likely to travel by other means such as car or train.  And third, countries that are more geographically-isolated – such as Australia and New Zealand – may have more internal travel.</p> </div>   <div class="wp-block-column"> <iframe src="https://ourworldindata.org/grapher/per-capita-co2-domestic-aviation" loading="lazy" style="width: 100%; height: 600px; border: 0px none;"></iframe>   <h5>Related charts:</h5>   </div> </div>   <h4>Per capita emissions from international flights</h4>   <div class="wp-block-columns"> <div class="wp-block-column"> <p>Allocating emissions from international flights is more complex. International databases report these emissions separately as a category termed ‘bunker fuels’. The term ‘bunker fuel’ is used to describe emissions which come from international transport – either aviation or shipping.</p>   <p>Because they are <a href="https://unfccc.int/topics/mitigation/workstreams/emissions-from-international-transport-bunker-fuels">not counted towards</a> any particular country these emissions are also not taken into account in the goals that are set by countries in international treaties like the Kyoto protocol or the Paris Agreement.{ref}Larsson, J., Kamb, A., Nässén, J., & Åkerman, J. (2018). <a href="https://www.sciencedirect.com/science/article/pii/S0195925517303116">Measuring greenhouse gas emissions from international air travel of a country’s residents methodological development and application for Sweden</a>. <em>Environmental Impact Assessment Review</em>, <em>72</em>, 137-144.{/ref}</p>   <p>But if we wanted to allocate them to a particular country, how would we do it? Who do emissions from international flights belong to: the country that owns the airline; the country of departure; the country of arrival?</p>   <p>Let’s first take a look at how emissions would compare if we allocated them to the country of <em>departure</em>. This means, for example, that emissions from any flight that departs from Spain are counted towards Spain’s total. In the chart here we see international aviation emissions in per capita terms.</p>   <p>Some of the largest emitters per person in 2018 were Iceland (3.5 tonnes of CO<sub>2</sub> per person); Qatar (2.5 tonnes); United Arab Emirates (2.2 tonnes); Singapore (1.7 tonnes); and Malta (992 kilograms). </p>   <p>Again, we see large inequalities in emissions across the world – in many lower-income countries per capita emissions are only a few kilograms: 6 kilograms in India, 4 kilograms in Nigeria; and only 1.4 kilograms in the Democratic Republic of Congo.</p> </div>   <div class="wp-block-column"> <iframe src="https://ourworldindata.org/grapher/per-capita-co2-international-aviation?stackMode=absolute&time=latest&region=World" loading="lazy" style="width: 100%; height: 600px; border: 0px none;"></iframe>   <h5>Related charts:</h5>   </div> </div>   <h4>Per capita emissions from international flights – adjusted for tourism</h4>   <div class="wp-block-columns"> <div class="wp-block-column"> <p>The above allocation of international aviation emissions to the country of <em>departure</em> raises some issues. It is not an accurate reflection of the local population of countries that rely a lot on tourism, for example. Most of the departing flights from these countries are carrying visiting tourists rather than locals. </p>   <p>One way to correct for this is to adjust these figures for the ratio of inbound to outbound travellers. This approach was applied <a href="https://theicct.org/blog/staff/not-every-tonne-of-aviation-CO2">in an analysis</a> by Sola Zheng for the <em>International Council on Clean Transportation</em>. This attempts to distinguish between locals traveling abroad and foreign visitors traveling to that country on the same flight.{ref}A country with a ratio greater than one will have more incoming travellers than outgoing locals i.e. they are more of a hotspot for tourism.{/ref} For example, if we calculated that Spain had 50% more incoming than outgoing travellers, we would reduce its per capita footprint from flying by 50%. If the UK had 75% more outgoing travellers than incoming, we’d increase its footprint by 75%.</p>   <p>We have replicated this approach and  applied this adjustment to these figures by calculating the <a href="https://ourworldindata.org/grapher/ratio-of-inbound-to-outbound-tourists">inbound:outbound tourist ratio</a> based on flight departures and arrival data from the <a href="https://datacatalog.worldbank.org/dataset/world-development-indicators">World Bank</a>. </p>   <p>How does this affect per capita emissions from international flights? The adjusted figures are shown in the chart here.</p>   <p>As we would expect, countries which are tourist hotspots see the largest change. Portugal’s emissions, for example, fall from 388 to just 60 kilograms per person. Portuguese locals are responsible for much fewer travel emissions than outgoing tourists. Spanish emissions fall from 335 to 77 kilograms per person.</p>   <p>On the other hand, countries where the locals travel elsewhere see a large increase. In the UK, they almost double from 422 to 818 kilograms.</p> </div>   <div class="wp-block-column"> <iframe src="https://ourworldindata.org/grapher/per-capita-co2-international-flights-adjusted?stackMode=absolute&time=latest&region=World" loading="lazy" style="width: 100%; height: 600px; border: 0px none;"></iframe> </div> </div>   <h4>Per capita emissions from domestic <em>and </em>international flights</h4>   <div class="wp-block-columns"> <div class="wp-block-column"> <p>Let’s combine per capita emissions from domestic and international travel to compare the total footprint from flying.</p>   <p>This is shown in the interactive map <em>[we’ve taken the adjusted international figures – you can find the  combined figures without tourism-adjustment </em><a href="https://ourworldindata.org/grapher/per-capita-co2-aviation"><strong><em>here</em></strong></a><em>]. </em></p>   <p>The global average emissions from aviation were 103 kilograms. The inequality in emissions across the world becomes clear when this is broken down by country. </p>   <p>At the top of the table lies the United Arab Emirates – each person emits close to two tonnes – 1950 kg – of CO<sub>2</sub> from flying each year. That’s 200 times the global average.  This was followed by Singapore (1173 kilograms); Iceland (1070 kg); Finland (1000 kg); and Australia (878 kilograms). </p>   <p>To put this into perspective: a return flight (in economy class) from London to Dubai/United Arab Emirates would emit around one tonne of CO<sub>2</sub>.{ref}We can calculate this by taking the standard CO2 conversion factors for travel, used in the <a href="https://www.gov.uk/government/publications/greenhouse-gas-reporting-conversion-factors-2019">UK greenhouse gas accounting framework</a>. For a long-haul flight in economy class, around 0.079 kilograms of CO<sub>2</sub> <a href="https://ourworldindata.org/travel-carbon-footprint">are emitted</a> per passenger-kilometer. This means that you would travel around 12,600 kilometers to emit one tonne [1,000,000 / 0.079 kg = 12,626 kilometers]. Since we’re taking a return flight, the travel distance would be half of that figure: around 6300 kilometers. The direct distance from <a href="https://www.distance.to/London/Dubai,ARE">London to Dubai</a> is around 5,500 kilometers. Depending on the flight path, it’s likely to be slightly longer than this, and in the range of 5500 to 6500 kilometers.</p>   <p>Note that in this case we’re looking at CO<sub>2</sub> emissions <em>without</em> the extra warming effects of these emissions at high altitudes. This is to allow us to compare with the ICCT figures by country presented in this article. You find additional data on how the footprint of flying is impacted by non-CO<sub>2</sub> warming effects<a href="https://ourworldindata.org/grapher/carbon-footprint-travel-mode"> <strong>here</strong></a>.{/ref} So the two-tonne average for the UAE is equivalent to around two return trips to London.</p>   <p>In many countries, most people do not fly at all. The average Indian emits just 18 kilograms from aviation – this is much, much less than even a short-haul flight which confirms that most did not take a flight.</p>   <p>In fact, we can compare just the aviation emissions for the top countries to the <em>total</em> carbon footprint of citizens elsewhere. The average UAE citizen emits 1950 kilograms of CO<sub>2</sub> from flying. This is the same as the <em>total</em> <a href="https://ourworldindata.org/explorers/co2?tab=chart&xScale=linear&yScale=linear&stackMode=absolute&endpointsOnly=0&year=latest&time=1858..2018&country=~India&region=World&Gas%20=CO%E2%82%82&Accounting%20=Production-based&Fuel%20=Total&Count%20=Per%20capita&Relative%20to%20world%20total%20=">CO<sub>2</sub> footprint of the average Indian</a> (including everything from electricity to road transport, heating and industry). Or, to take a more extreme example, 200 times the total footprint of the average Nigerien, Ugandan or Ethiopian, which <a href="https://ourworldindata.org/explorers/co2?tab=chart&xScale=linear&yScale=linear&stackMode=absolute&endpointsOnly=0&year=latest&time=1958..2018&country=Niger~Uganda~Ethiopia&region=World&Gas%20=CO%E2%82%82&Accounting%20=Production-based&Fuel%20=Total&Count%20=Per%20capita&Relative%20to%20world%20total%20=">have per capita emissions</a> of around 100 kilograms. </p>   <p>This again emphasises the large difference between the global average and the individual emissions of people who fly. Aviation contributes a few percent of total CO<sub>2</sub> emissions each year – this is not insignificant, but far from being the largest sector to tackle. Yet from the perspective of the individual, flying <em>is</em> often one of the largest chunks of our carbon footprint. The average rich person emits tonnes of CO<sub>2</sub> from flying each year – this is equivalent to the <em>total</em> carbon footprint of tens or hundreds of people in many countries of the world.</p> </div>   <div class="wp-block-column"> <iframe src="https://ourworldindata.org/grapher/per-capita-co2-aviation-adjusted?stackMode=absolute&region=World" loading="lazy" style="width: 100%; height: 600px; border: 0px none;"></iframe>   <h5>Related charts:</h5>    </div> </div>   <h3>Where in the world do people fly the most?</h3>   <h4>Domestic air travel</h4>   <div class="wp-block-columns is-style-sticky-right"> <div class="wp-block-column"> <p>This interactive chart shows the average distance travelled per person through domestic air travel each year. This data is for passenger flights only and does not include freight.</p> </div>   <div class="wp-block-column"> <iframe src="https://ourworldindata.org/grapher/per-capita-domestic-aviation-km" loading="lazy" style="width: 100%; height: 600px; border: 0px none;"></iframe>   <h5>Related charts:</h5>    <p>What share of global domestic air travel does each country account for?</p>     <p></p>  </div> </div>   <h4>International air travel</h4>   <div class="wp-block-columns is-style-sticky-right"> <div class="wp-block-column"> <p>This interactive chart shows the average distance travelled per person through international air travel each year. This data is for passenger flights only and does not include freight.</p> </div>   <div class="wp-block-column"> <iframe src="https://ourworldindata.org/grapher/per-capita-international-aviation-km" loading="lazy" style="width: 100%; height: 600px; border: 0px none;"></iframe>   <h5>Related charts:</h5>    <p>What share of global international air travel does each country account for?</p>     <p></p>  </div> </div>   <h4>Total air travel</h4>   <div class="wp-block-columns is-style-sticky-right"> <div class="wp-block-column"> <p>This interactive chart shows the average distance travelled per person through domestic <em>and</em> international air travel each year. This data is for passenger flights only and does not include freight.</p> </div>   <div class="wp-block-column"> <iframe src="https://ourworldindata.org/grapher/per-capita-km-aviation" loading="lazy" style="width: 100%; height: 600px; border: 0px none;"></iframe>   <h5>Related charts:</h5>    <p>What share of global air travel does each country account for?</p>     <p></p>  </div> </div>   <h2>Rail</h2>   <div class="wp-block-columns is-style-sticky-right"> <div class="wp-block-column"> <p>This interactive chart shows the total rail travel in each country, measured in passenger-kilometers per year.</p>   <p>This includes passenger travel only and does not include freight.</p> </div>   <div class="wp-block-column"> <iframe src="https://ourworldindata.org/grapher/railways-passengers-carried-passenger-km" loading="lazy" style="width: 100%; height: 600px; border: 0px none;"></iframe> </div> </div>   <h2>Energy intensity of transport</h2>   <p>This chart shows the average energy intensity of transport across different modes of travel. It is measured as the average kilowatt-hours required per passenger-kilometer.</p>   <p>This data comes from the United States Department of Transportation's Bureau of Transportation Statistics (BTS). The energy intensity of public transport depends on the assumptions made about the capacity of transport modes i.e. how many passengers travel on a given train or bus journey. This data thererfore reflects average capacities in the United States, but will vary from country-to-country.</p>   <iframe src="https://ourworldindata.org/grapher/energy-intensity-transport?country=Amtrak~Bus~Domestic+flight~International+flight~Motorcycle~~Transit+motor+bus~Truck+%28with+trailer%29~Truck~" loading="lazy" style="width: 100%; height: 600px; border: 0px none;"></iframe>   <h2>CO<sub>2</sub> emissions from transport</h2>   <h3>Per capita transport emissions from transport</h3>   <p>This interactive shows the average per capita emissions of carbon dioxide from transport each year. This includes road, train, bus and domestic air travel but <em>does not </em>include international aviation and shipping.</p>   <iframe src="https://ourworldindata.org/grapher/per-capita-co2-transport?stackMode=absolute&region=World" loading="lazy" style="width: 100%; height: 600px; border: 0px none;"></iframe>   <h3>Total transport emissions</h3>   <p>This interactive shows the emissions of carbon dioxide from transport each year. This includes road, train, bus and domestic air travel but <em>does not </em>include international aviation and shipping.</p>   <iframe src="https://ourworldindata.org/grapher/co2-emissions-transport?stackMode=absolute&time=earliest..latest&region=World" loading="lazy" style="width: 100%; height: 600px; border: 0px none;"></iframe>   <h3>CO<sub>2</sub> emissions by mode of transport</h3>    <p>Transport accounts for around one-fifth of global carbon dioxide (CO<sub>2</sub>) emissions <em>[24% if we only consider CO<sub>2</sub> emissions from energy]</em>.{ref}The <em>World Resource Institute</em>’s Climate Data Explorer <a href="https://www.climatewatchdata.org/data-explorer/historical-emissions?historical-emissions-data-sources=cait&historical-emissions-gases=co2&historical-emissions-regions=All%20Selected&historical-emissions-sectors=total-including-lucf%2Ctransportation&page=1&sort_col=country&sort_dir=ASC">provides data</a> from CAIT on the breakdown of emissions by sector. In 2016, global CO<sub>2</sub> emissions (including land use) were 36.7 billion tonnes CO<sub>2</sub>; emissions from transport were 7.9 billion tonnes CO<sub>2</sub>. Transport therefore accounted for 7.9 / 36.7 = 21% of global emissions. </p>   <p>The IEA <a href="https://www.iea.org/data-and-statistics/?country=WORLD&fuel=CO2%20emissions&indicator=TotCO2">looks at CO<sub>2</sub> emissions</a> from energy production alone – in 2018 it reported 33.5 billion tonnes of energy-related CO<sub>2</sub> [hence, transport accounted for 8 billion / 33.5 billion = 24% of energy-related emissions.{/ref}</p>   <p>How do these emissions break down? Is it cars, trucks, planes or trains that dominate?</p>   <p>In the chart here we see global transport emissions in 2018. This data is <a href="https://www.iea.org/data-and-statistics/charts/transport-sector-co2-emissions-by-mode-in-the-sustainable-development-scenario-2000-2030">sourced from</a> the <em>International Energy Agency (IEA)</em>. </p>   <p>Road travel accounts for three-quarters of transport emissions. Most of this comes from passenger vehicles – cars and buses – which contribute 45.1%. The other 29.4% comes from trucks carrying freight.</p>   <p>Since the entire transport sector accounts for 21% of total emissions, and road transport accounts for three-quarters of transport emissions, road transport accounts for 15% of total CO<sub>2</sub> emissions.</p>   <p>Aviation – while it often gets the most attention in discussions on action against climate change – accounts for only 11.6% of transport emissions. It emits just under one billion tonnes of CO<sub>2</sub> each year – around 2.5% of total global emissions <em>[we look at the role that air travel plays in climate change in more detail in an upcoming article]</em>. International shipping contributes a similar amount, at 10.6%. </p>   <p>Rail travel and freight emits very little – only 1% of transport emissions. Other transport – which is mainly the movement of materials such as water, oil, and gas via pipelines – is responsible for 2.2%.</p>   <figure class="wp-block-image size-large"><img src="https://owid.cloud/app/uploads/2020/10/Transport-CO2-emissions-by-mode-bar-chart-800x315.png" alt="" class="wp-image-36825"/></figure>   <h4>Towards zero-carbon transport: how can we expect the sector’s CO<sub>2</sub> emissions to change in the future?</h4>   <div class="wp-block-columns"> <div class="wp-block-column"> <p>Transport demand is expected to grow across the world in the coming decades as the global population increases, incomes rise, and more people can afford cars, trains and flights. In its <em>Energy Technology Perspectives</em> report, the International Energy Agency (IEA) expects global transport (measured in passenger-kilometers) to double, car ownership rates to increase by 60%, and demand for passenger and freight aviation to triple by 2070.{ref}IEA (2020), <a href="https://www.iea.org/reports/energy-technology-perspectives-2020">Energy Technology Perspectives 2020</a>, IEA, Paris.{/ref} Combined, these factors would result in a large increase in transport emissions.</p>   <p>But major technological innovations can help offset this rise in demand. As the world shifts towards lower-carbon electricity sources, the rise of electric vehicles offers a viable option to reduce emissions from passenger vehicles.</p>   <p>This is reflected in the IEA’s <em>Energy Technology Perspective</em> report. There it outlines its “Sustainable Development Scenario” for reaching net-zero CO2 emissions from global energy by 2070. The pathways for the different elements of the transport sector in this optimistic scenario are shown in the visualization.</p>   <p>We see that with electrification- and hydrogen- technologies some of these sub-sectors could decarbonize within decades. The IEA scenario assumes the phase-out of emissions from motorcycles by 2040; rail by 2050; small trucks by 2060; and although emissions from cars and buses are not completely eliminated until 2070, it expects many regions, including the European Union; United States; China and Japan to have phased-out conventional vehicles as early as 2040.</p>   <p>Other transport sectors will be much more difficult to decarbonize.</p>   <p>In a paper published in <em>Science</em>, Steven Davis and colleagues looked at our options across sectors to reach a net-zero emissions energy system.{ref}Davis, S. J., Lewis, N. S., Shaner, M., Aggarwal, S., Arent, D., Azevedo, I. L., ... & Clack, C. T. (2018). <a href="https://science.sciencemag.org/content/360/6396/eaas9793.full">Net-zero emissions energy systems</a>. <em>Science</em>, 360(6396).{/ref} They highlighted long-distance road freight (large trucks), aviation and shipping as particularly difficult to eliminate. The potential for hydrogen as a fuel, or battery electricity to run planes, ships and large trucks is limited by the range and power required; the size and weight of batteries or hydrogen fuel tanks would be <em>much</em> larger and heavier than current combustion engines.{ref}Cecere, D., Giacomazzi, E., & Ingenito, A. (2014). <a href="https://www.sciencedirect.com/science/article/pii/S0360319914011847">A review on hydrogen industrial aerospace applications</a>. <em>International Journal of Hydrogen Energy</em>, <em>39</em>(20), 10731-10747.{/ref}<sup>,</sup>{ref}Fulton, L. M., Lynd, L. R., Körner, A., Greene, N., & Tonachel, L. R. (2015). <a href="https://onlinelibrary.wiley.com/doi/full/10.1002/bbb.1559">The need for biofuels as part of a low carbon energy future</a>. <em>Biofuels, Bioproducts and Biorefining</em>, 9(5), 476-483.{/ref}</p>   <p>So, despite falling by three-quarters in the visualized scenario, emissions from these sub-sectors would still make transport the largest contributor to energy-related emissions in 2070. To reach net-zero for the energy sector as a whole, these emissions would have to be offset by ‘negative emissions’ (e.g. the capture and storage of carbon from bioenergy or <a href="https://www.iea.org/reports/direct-air-capture">direct air capture</a>) from other parts of the energy system.</p>   <p>In the IEA’s net-zero scenario, nearly two-thirds of the emissions reductions come from technologies that are not yet commercially available. As the IEA states, “Reducing CO<sub>2</sub> emissions in the transport sector over the next half-century will be a formidable task.”{ref}IEA (2020), <a href="https://www.iea.org/reports/energy-technology-perspectives-2020">Energy Technology Perspectives 2020</a>, IEA, Paris.{/ref}</p> </div>   <div class="wp-block-column"> <h6>Global CO2 emissions from transport in the IEA's Sustainable Development Scenario to 2070{ref}IEA (2020), <a href="https://www.iea.org/reports/energy-technology-perspectives-2020">Energy Technology Perspectives 2020</a>, IEA, Paris.{/ref}</h6>   <figure class="wp-block-image size-large"><img src="https://owid.cloud/app/uploads/2020/10/IEA-Transport-to-2070-800x505.png" alt="" class="wp-image-36827"/></figure> </div> </div>

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                        "text": "First published in September 2021.",
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                        "text": "Road travel",
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                        "text": "Passenger vehicle registrations by type",
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                        "text": "These interactive charts show the breakdown of new passenger vehicle registrations by type.",
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                        "text": "This is broken down by: petroleum; diesel; full hybrid (excluding plug-in hybrids); plug-in electric hybrids; and fully electric battery vehicles.",
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                "url": "https://ourworldindata.org/grapher/new-passenger-vehicles-type?country=~GBR",
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                "title": "Number of new passenger vehicle registrations by type",
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                        "text": "Electric vehicle registrations",
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                        "text": "This interactive chart shows the share of new passenger vehicle registrations that are battery electric vehicles. This does not include plug-in hybrid vehicles.",
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                "url": "https://ourworldindata.org/grapher/share-vehicle-electric?country=AUT~ITA~NOR~PRT~ESP~SWE~CHE~TUR~GBR~IRL~ISL~GRC~DEU~FRA~FIN~DNK~BEL~LUX~NLD",
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                        "text": "This interactive chart shows the share of new passenger vehicle registrations that are battery electric ",
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                                "text": "plus",
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                        "text": " plug-in hybrid vehicles.",
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                "url": "https://ourworldindata.org/grapher/battery-plugin-hybrid-vehicles?time=2019&country=~AUT~BEL~DNK~FIN~EU-27+%2B+UK~FRA~DEU~GRC~ISL~IRL~GBR~TUR~CHE~SWE~ESP~PRT~NOR~NLD~LUX~ITA",
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                        "text": "Carbon intensity of new passenger vehicles",
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                        "text": "This interactive chart shows the average carbon intensity of new passenger vehicles in each country.",
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                "value": [
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                        "text": "This is measured as the average emissions of CO\u2082 (in grams) per kilometer travelled across all types of passenger vehicles.",
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                "url": "https://ourworldindata.org/grapher/carbon-new-passenger-vehicles?country=AUT~ITA~LUX~NLD~NOR~PRT~ESP~SWE~CHE~TUR~GBR~IRL~ISL~GRC~DEU~FRA~FIN~DNK~BEL",
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                        "text": "Fuel economy of new passenger vehicles",
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                        "text": "This interacrive chart shows the average fuel economy of new passenger vehicles in each country.",
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                        "text": "This is measured as the average liters consumed per 100 kilometers travelled, across all types of passenger vehicles.",
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                        "text": "Aviation",
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                "text": [
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                        "text": "What share of global CO",
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                                "text": "2",
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                        "text": " emissions come from aviation?",
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                "value": [
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                        "text": "Flying is a highly controversial topic in climate debates. There are a few reasons for this.\u00a0",
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                        "text": "The first is the disconnect between its role in our personal and collective carbon emissions. Air travel dominates a frequent traveller's individual contribution to climate change. Yet aviation overall accounts for only 2.5% of global carbon dioxide (CO",
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                                "text": "2",
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                        "text": ") emissions. This is because there are large inequalities in how much people fly \u2013 many do not, or cannot afford to, fly at all.{ref}The best estimates put this figure at around 80% of the world population. We look at this in more detail in our article \"",
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                        "url": "https://ourworldindata.org/carbon-footprint-flying",
                        "children": [
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                                "text": "Where in the world do people have the highest CO2 emissions from flying?",
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                        "text": "\"{/ref}",
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                        "text": "The second is how aviation emissions are attributed to countries. CO",
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                                "text": "2",
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                        "text": " emissions from domestic flights ",
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                                "text": "are",
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                        "text": " counted in a country\u2019s emission accounts. International flights are not \u2013 instead they are counted as their own category: \u2018bunker fuels\u2019. The fact that they don\u2019t count towards the emissions of any country means there are few incentives for countries to reduce them.",
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                        "text": "It\u2019s also important to note that unlike the most common greenhouse gases \u2013 carbon dioxide, methane or nitrous oxide \u2013 non-CO",
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                                "text": "2",
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                        "text": " forcings from aviation ",
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                        "children": [
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                                "text": "are not included",
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                        "text": " in the Paris Agreement. This means they could be easily overlooked \u2013 especially since international aviation is not counted within any country\u2019s emissions inventories or targets.",
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                        "text": "How much of a role does aviation play in global emissions and climate change? In this article we take a look at the key numbers that are useful to know.",
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                        "text": "Global aviation (including domestic and international; passenger and freight) accounts for:",
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                                        "text": "1.9%",
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                            },
                            {
                                "text": " of ",
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                            {
                                "url": "https://ourworldindata.org/ghg-emissions-by-sector",
                                "children": [
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                                        "text": "greenhouse gas emissions",
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                                ],
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                            {
                                "text": " (which includes all greenhouse gases, not only CO",
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                                        "text": "2",
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                                "text": ")",
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                                        "text": "2.5%",
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                                "text": " of CO",
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                                        "text": "2",
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                                "text": " emissions",
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                                        "text": "3.5%",
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                            {
                                "text": " of 'effective radiative forcing' \u2013 a closer measure of its impact on warming.",
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                        "text": "The latter two numbers refer to 2018, and the first to 2016, the latest year for which such data are available.",
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                "text": [
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                        "text": "Aviation accounts for 2.5% of global CO",
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                                "text": "2",
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                        "text": " emissions",
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                        "text": "As we will see later in this article, there are a number of processes by which aviation contributes to climate change. But the one that gets the most attention is its contribution via CO",
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                                "text": "2",
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                        "text": " emissions. Most flights are powered by jet gasoline \u2013 although some partially run on biofuels \u2013 which is converted to CO",
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                                "text": "2",
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                        "text": " when burned.\u00a0\u00a0",
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                        "text": "In a recent paper, researchers \u2013 David Lee and colleagues \u2013 reconstructed annual CO",
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                                "text": "2 ",
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                        "text": "emissions from global aviation dating back to 1940.{ref}Lee, D. S., Fahey, D. W., Skowron, A., Allen, M. R., Burkhardt, U., Chen, Q., ... & Gettelman, A. (2020). ",
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                        "url": "https://www.sciencedirect.com/science/article/pii/S1352231020305689",
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                                "text": "The contribution of global aviation to anthropogenic climate forcing for 2000 to 2018",
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                        "text": ". ",
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                                "text": "Atmospheric Environment",
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                        "text": ", 117834.{/ref} This was calculated based on fuel consumption data from the International Energy Agency (IEA), and earlier estimates from Robert Sausen and Ulrich Schumann (2000).{ref}Sausen, R., & Schumann, U. (2000). ",
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                    },
                    {
                        "url": "https://link.springer.com/article/10.1023/A:1005579306109",
                        "children": [
                            {
                                "text": "Estimates of the climate response to aircraft CO2 and NOx emissions scenarios",
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                        "text": ". ",
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                                "text": "Climatic Change",
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                        "text": ", ",
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                        "children": [
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                                "text": "44",
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                        "text": "(1-2), 27-58.{/ref}",
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                        "text": "The time series of global emissions from aviation since 1940 is shown in the accompanying chart. In 2018, it\u2019s estimated that global aviation \u2013 which includes both passenger and freight \u2013 emitted 1.04 billion tonnes of CO",
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                        "children": [
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                                "text": "2",
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                        "text": ".",
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                "value": [
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                        "text": "This represented 2.5% of ",
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                        "url": "https://ourworldindata.org/co2-emissions#global-co2-emissions-from-fossil-fuels-global-co2-emissions-from-fossil-fuels",
                        "children": [
                            {
                                "text": "total CO",
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                            {
                                "children": [
                                    {
                                        "text": "2",
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                            {
                                "text": " emissions",
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                        "text": " in 2018.{ref}The Global Carbon Budget estimated total CO",
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                        "children": [
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                                "text": "2",
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                        "text": " emissions from all fossil fuels, cement production and land-use change to be 42.1 billion tonnes in 2018. This means aviation accounted for [1 / 42.1 * 100] = 2.5% of total emissions.{/ref}",
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                        "children": [
                            {
                                "text": ",",
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                        "text": "{ref}Global Carbon Project. (2019). Supplemental data of Global Carbon Budget 2019 (Version 1.0) [Data set]. Global Carbon Project. ",
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                        "url": "https://doi.org/10.18160/gcp-2019",
                        "children": [
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                                "text": "https://doi.org/10.18160/gcp-2019",
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                        "text": ".",
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                        "text": "If we were to exclude land use change emissions, aviation accounted for 2.8% of fossil fuel emissions. The Global Carbon Budget estimated total CO",
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                        "children": [
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                                "text": "2",
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                        "text": " emissions from fossil fuels and cement production to be 36.6 billion tonnes in 2018. This means aviation accounted for [1 / 36.6 * 100] = 2.8% of total emissions.{/ref}",
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                        "text": "Aviation emissions have doubled since the mid-1980s. But, they\u2019ve been growing at a similar rate as total CO",
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                        "text": " emissions \u2013 this means its share of global emissions has been relatively stable: in the range of 2% to 2.5%.{ref}2.3% to 2.8% of emissions if land use is excluded.{/ref}",
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                        "text": "Non-CO",
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                        "text": " climate impacts mean aviation accounts for 3.5% of global warming",
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                        "text": "Aviation accounts for around 2.5% of global CO",
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                        "text": " emissions, but it\u2019s overall contribution to climate change is higher. This is because air travel does not only emit CO",
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                                "text": "2",
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                        "text": ": it affects the climate in a number of more complex ways.",
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                        "text": "As well as emitting CO",
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                        "text": " from burning fuel, planes affect the concentration of other gases and pollutants in the atmosphere. They result in a short-term increase, but long-term decrease in ozone (O",
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                        "text": "); a decrease in methane (CH",
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                                "text": "4",
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                        "text": "); emissions of water vapour; soot; sulfur aerosols; and water contrails. While some of these impacts result in warming, others induce a cooling effect. Overall, the warming effect is stronger.",
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                        "text": "David Lee et al. (2020) quantified the overall effect of aviation on global warming when all of these impacts were included.{ref}Lee, D. S., Fahey, D. W., Skowron, A., Allen, M. R., Burkhardt, U., Chen, Q., ... & Gettelman, A. (2020). ",
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                    {
                        "url": "https://www.sciencedirect.com/science/article/pii/S1352231020305689",
                        "children": [
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                                "text": "The contribution of global aviation to anthropogenic climate forcing for 2000 to 2018",
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                        "text": ". ",
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                                "text": "Atmospheric Environment",
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                        "text": ", 117834.{/ref} To do this they calculated the so-called \u2018Radiative Forcing\u2019. Radiative forcing measures the difference between incoming energy and the energy radiated back to space. If more energy is absorbed than radiated, the atmosphere becomes warmer.\u00a0",
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                        "text": "In their chart we see ",
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                                "text": "their estimates for the radiative forcing",
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                        "text": " of the different elements. When we combine them, aviation accounts for approximately 3.5% of effective radiative forcing: that is, 3.5% of warming.",
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                        "text": "Although CO",
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                                "text": "2\u00a0 ",
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                        "text": "gets most of the attention, it accounts for less than half of this warming. Two-thirds (66%) comes from non-CO",
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                                "text": "2 ",
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                        "text": "forcings. Contrails \u2013 water vapor trails from aircraft exhausts \u2013 account for the largest share.",
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                        "text": "We don\u2019t yet have the technologies to decarbonize air travel",
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                        "text": "Aviation\u2019s contribution to climate change \u2013 3.5% of warming, or 2.5% of CO",
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                        "text": " emissions \u2013 is often less than people think. It\u2019s currently a relatively small chunk of emissions compared to other sectors.\u00a0",
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                        "text": "The key challenge is that it is particularly hard to decarbonize. We have solutions to reduce emissions for many of the ",
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                                "text": "largest emitters",
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                        "text": " \u2013 such as power or road transport \u2013 and it\u2019s now a matter of scaling them. We can deploy renewable and nuclear energy technologies, and transition to electric cars. But we don\u2019t have proven solutions to tackle aviation yet. ",
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                        "text": "There are some design concepts emerging \u2013 Airbus, for example, ",
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                                "text": "have announced plans",
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                        "text": " to have the first zero-emission aircraft by 2035, using hydrogen fuel cells. Electric planes may be a viable concept, but are likely to be limited to very small aircraft due to the limitations of battery technologies and capacity.\u00a0",
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                        "text": "Innovative solutions may be on the horizon, but they\u2019re likely to be far in the distance.",
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                                "text": "Additional information",
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                                        "text": "Global emissions from aviation have increased a lot over the past half-century. However, air travel volumes increased even more rapidly.\u00a0",
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                                        "text": "Since 1960, aviation emissions increased almost seven-fold; since 1970 they\u2019ve tripled. Air traffic volume \u2013 here defined as revenue passenger kilometers (RPK) traveled \u2013 ",
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                                        "url": "https://ourworldindata.org/grapher/airline-capacity-and-traffic",
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                                                "text": "increased by orders of magnitude more",
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                                        "text": ": almost 300-fold since 1950; and 75-fold since 1960.{ref}Airline traffic data comes from the International Civil Aviation Organization (ICAO) via ",
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                                    {
                                        "url": "https://www.airlines.org/dataset/world-airlines-traffic-and-capacity",
                                        "children": [
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                                                "text": "Airlines for America",
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                                    {
                                        "text": ". Revenue passenger kilometers (RPK) measures the number of paying passengers multiplied by their distance traveled.{/ref}\u00a0",
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                                        "text": "The much slower growth in emissions means aviation efficiency has seen massive improvements. In the chart we show both the increase in global airline traffic since 1950, and aviation efficiency, measured as the quantity of CO",
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                                        "text": " emitted per revenue passenger kilometer traveled. In 2018, approximately 125 grams of CO",
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                                                "text": "2 ",
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                                        "text": "\u00a0were emitted per RPK. In 1960, this was eleven-fold higher; in 1950 it was twenty-fold higher. Aviation has seen massive efficiency improvements over the past 50 years.",
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                                        "text": "These improvements have come from several sources: improvements in the design and technology of aircraft; larger aircraft sizes (allowing for more passengers per flight); and an increase in how \u2018full\u2019 passenger flights are. This last metric is termed the \u2018passenger load factor\u2019. The passenger load factor measures the actual number of kilometers traveled by paying customers (RPK) as a percentage of the available seat kilometers (ASK) \u2013 the kilometers traveled if every plane was full. If every plane was full the passenger load factor would be 100%. If only three-quarters of the seats were filled, it would be 75%.",
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                                        "text": "The global passenger load factor ",
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                                                "text": "increased from 61% in 1950 to 82% in 2018",
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                                        "text": ".\u00a0\u00a0",
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                        "text": "Passenger vs. freight; domestic vs. international: where do aviation emissions come from?",
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                        "text": "Global aviation \u2013 both passenger flights and freight \u2013 emits around one billion tonnes of carbon dioxide (CO",
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                        "text": ") each year. This was equivalent to around 2.4% of CO",
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                                "text": "2",
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                        "text": " emissions in 2018.",
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                        "text": "How do global aviation emissions break down?",
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                        "text": "The chart gives the answer. This data is sourced from the 2019 ",
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                                "text": "International Council on Clean Transportation",
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                                "text": "(ICCT)",
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                        "text": " report on global aviation.{ref}Graver, B., Zhang, K., & Rutherford, D. (2019). ",
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                        "url": "https://theicct.org/sites/default/files/publications/ICCT_CO2-commercl-aviation-2018_20190918.pdf",
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                                "text": "CO2 emissions from commercial aviation, 2018",
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                        "text": ". ",
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                                "text": "The International Council of Clean Transportation",
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                        "text": ".{/ref}",
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                        "text": "Most emissions come from passenger flights \u2013 in 2018, they accounted for 81% of aviation\u2019s emissions; the remaining 19% came from freight, the transport of goods.\u00a0",
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                        "text": "Sixty percent of emissions from",
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                        "text": " flights come from international travel; the other 40% come from domestic (in-country) flights.\u00a0",
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                        "text": "When we break passenger flight emissions down by travel distance, we get a (surprisingly) equal three-way split in emissions between short-haul (less than 1,500 kilometers); medium-haul (1,500 to 4,000 km); and long-haul (greater than 4,000 km) journeys.",
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                        "text": "The richest half are responsible for 90% of air travel CO",
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                        "text": "The global inequalities in how much people fly become clear when we compare aviation emissions across countries of different income levels. The ICCT split these emissions based on World Bank's four ",
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                        "url": "https://ourworldindata.org/grapher/world-banks-income-groups?year=latest",
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                                "text": "income groups",
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                        "text": "A further study by Susanne Becek and Paresh Pant (2019) compared the contribution of each income group to global air travel emissions versus its share of world population.{ref}Becken, S. and P. Pant (2019). ",
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                    {
                        "url": "https://amadeus.com/en/insights/white-paper/airline-initiatives-to-reduce-climate-impact",
                        "children": [
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                                "text": "Airline initiatives to reduce climate impact: ways to accelerate action",
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                        "text": " (White paper).{/ref} This comparison is shown in the visualization.",
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                        "text": "The \u2018richest\u2019 half of the world (high and upper-middle income countries) were responsible for 90% of air travel emissions.{ref}Note that this is based on categorisations from the average income level of countries, and does not take account of variation in income ",
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                        "text": "countries. If we were to look at this distribution based on the income level of individuals rather than countries, the inequality in aviation emissions would be even larger.{/ref}",
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                        "text": "Looking at specific income groups:",
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                                "text": "Only 16% of the world population live in high-income countries yet the planes that take off in those countries account for almost two-thirds (62%) of passenger emissions;",
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                                "text": "Upper-middle income countries are home to 35% of the world population, and contribute 28% of emissions;",
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                                "text": "Lower-middle income countries are home to the largest share (40% of the world), yet emit the planes taking off there just account for 9%;",
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                                "text": "The poorest countries \u2013 which are home to 9% of the world population \u2013 emit just 1%.",
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                        "text": "In an upcoming article we will look in more detail at the contribution of each country to global aviation emissions.",
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                        "text": "Where in the world do people have the highest carbon footprint from flying?",
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                "type": "text",
                "value": [
                    {
                        "text": "Aviation accounts ",
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                    },
                    {
                        "url": "https://ourworldindata.org/co2-emissions-from-aviation",
                        "children": [
                            {
                                "text": "for around 2.5%",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-link"
                    },
                    {
                        "text": " of global carbon dioxide (CO",
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                    {
                        "children": [
                            {
                                "text": "2",
                                "spanType": "span-simple-text"
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                    {
                        "text": ") emissions. But if you are someone who does fly, air travel will make up a much larger share of your personal carbon footprint.",
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                "type": "text",
                "value": [
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                        "text": "The fact that aviation is relatively small for global emissions as a whole, but of large importance for individuals that fly is due to large inequalities in the world. Most people in the\u00a0 world do not take flights. There is no global reliable figure, but often cited estimates suggest that more than 80% of the global population have never flown.{ref}There is no global database available on ",
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                    },
                    {
                        "children": [
                            {
                                "text": "who",
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                        ],
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                    {
                        "text": " in the world flies each year. Passenger information is maintained by private airlines. Therefore, deriving estimates of this exact percentage is challenging. The most-cited estimate I\u2019ve seen on this is that around 80% of the world population have never flown. This figure seems to circle back to a ",
                        "spanType": "span-simple-text"
                    },
                    {
                        "url": "https://www.cnbc.com/2017/12/07/boeing-ceo-80-percent-of-people-never-flown-for-us-that-means-growth.html#:~:text=%E2%80%9CLess%20than%2020%20percent%20of,the%20entire%20economy%2C%20Muilenburg%20said.",
                        "children": [
                            {
                                "text": "quoted estimate",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-link"
                    },
                    {
                        "text": " from the Boeing CEO.",
                        "spanType": "span-simple-text"
                    },
                    {
                        "spanType": "span-newline"
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                    {
                        "spanType": "span-newline"
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                    {
                        "text": "Even in some of the world\u2019s richest countries, a large share of the population do not fly frequently. Gallup ",
                        "spanType": "span-simple-text"
                    },
                    {
                        "url": "https://news.gallup.com/poll/1579/airlines.aspx",
                        "children": [
                            {
                                "text": "survey data",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-link"
                    },
                    {
                        "text": " from the United States suggests that in 2015, half of the population did not take a flight. Survey data from the UK ",
                        "spanType": "span-simple-text"
                    },
                    {
                        "url": "http://publicapps.caa.co.uk/docs/33/CAA%20Aviation%20Consumer%20survey%20--%205th%20wave%20report%20FINAL%20(2).pdf",
                        "children": [
                            {
                                "text": "provides similar estimates",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-link"
                    },
                    {
                        "text": ": 46% had not flown in the previous year.{/ref}",
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                    }
                ],
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            {
                "type": "text",
                "value": [
                    {
                        "text": "How do emissions from aviation vary across the world? Where do people have the highest footprint from flying?",
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                ],
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            {
                "text": [
                    {
                        "text": "Per capita emissions from domestic flights",
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                ],
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                        "text": "The first and most straightforward comparison is to look at emissions from ",
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                        "children": [
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                                "text": "domestic",
                                "spanType": "span-simple-text"
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                        ],
                        "spanType": "span-italic"
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                    {
                        "text": " aviation \u2013 that is, flights that depart and arrive in the same country.\u00a0",
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            {
                "type": "text",
                "value": [
                    {
                        "text": "This is easiest to compare because domestic aviation is counted in each country\u2019s inventory of greenhouse gas emissions. International flights, on the other hand, are not attributed to specific countries \u2013 partly because of contention as to who should take responsibility (should it be the country of departure or arrival? What about layover flights?).",
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                ],
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            {
                "type": "text",
                "value": [
                    {
                        "text": "In the chart here we see the average per capita emissions from domestic flights in 2018. This data is sourced from the ",
                        "spanType": "span-simple-text"
                    },
                    {
                        "children": [
                            {
                                "text": "International Council on Clean Transportation",
                                "spanType": "span-simple-text"
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                        ],
                        "spanType": "span-italic"
                    },
                    {
                        "text": " \u2013 we then used ",
                        "spanType": "span-simple-text"
                    },
                    {
                        "url": "https://population.un.org/wpp/",
                        "children": [
                            {
                                "text": "UN population estimates",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-link"
                    },
                    {
                        "text": " to calculate per capita figures.{ref}Graver, B., Zhang, K., & Rutherford, D. (2019). ",
                        "spanType": "span-simple-text"
                    },
                    {
                        "url": "https://theicct.org/publications/co2-emissions-commercial-aviation-2018",
                        "children": [
                            {
                                "text": "CO2 emissions from commercial aviation, 2018",
                                "spanType": "span-simple-text"
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                        ],
                        "spanType": "span-link"
                    },
                    {
                        "text": ". ",
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                    {
                        "children": [
                            {
                                "text": "The International Council of Clean Transportation",
                                "spanType": "span-simple-text"
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                        ],
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                    {
                        "text": ".{/ref}",
                        "spanType": "span-simple-text"
                    },
                    {
                        "children": [
                            {
                                "text": ",",
                                "spanType": "span-simple-text"
                            }
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                    {
                        "text": "{ref}Note that this gives us ",
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                    {
                        "children": [
                            {
                                "text": "mean",
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                    {
                        "text": " per capita emissions, which\u00a0 does not account for in-country inequalities in the amount of flights people take.{/ref}",
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                ],
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                "value": [
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                        "text": "We see large differences in emissions from domestic flights across the world. In the United States the average person emits around 386 kilograms of CO",
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                    {
                        "children": [
                            {
                                "text": "2",
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                    {
                        "text": " each year from internal flights. This is followed by Australia (267 kg); Norway (209 kg); New Zealand (174 kg); and Canada (168 kg). Compare this with\u00a0 countries at the bottom of the table \u2013 many across Africa, Asia, and Eastern Europe in particular emit less than one kilogram per person \u2013 just 0.8 kilograms; or 0.14 kilograms in Rwanda. For very small countries where there are no internal commercial flights, domestic emissions are of course, zero.",
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                        "text": "There are some obvious factors that explain some of these cross-country differences. Firstly, countries that are richer ",
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                    {
                        "url": "https://ourworldindata.org/grapher/per-capita-co2-domestic-aviation-vs-gdp",
                        "children": [
                            {
                                "text": "are more likely",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-link"
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                    {
                        "text": " to have higher emissions because people can afford to fly. Second, countries that have a larger land mass may have more internal flights \u2013\u00a0and indeed we see a ",
                        "spanType": "span-simple-text"
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                    {
                        "url": "https://ourworldindata.org/grapher/per-capita-co2-domestic-aviation-vs-land-area",
                        "children": [
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                                "text": "correlation",
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                        ],
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                        "text": " between land area and domestic flight emissions; in small countries people are more likely to travel by other means such as car or train.\u00a0 And third, countries that are more geographically-isolated \u2013 such as Australia and New Zealand \u2013 may have more internal travel.",
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                "url": "https://ourworldindata.org/grapher/per-capita-co2-domestic-aviation",
                "type": "chart",
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            {
                "text": [
                    {
                        "text": "Related charts:",
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                "type": "heading",
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            {
                "url": "https://ourworldindata.org/grapher/co2-emissions-domestic-aviation",
                "type": "prominent-link",
                "title": "Total CO\u2082 emissions from domestic aviation",
                "description": "",
                "parseErrors": []
            },
            {
                "url": "https://ourworldindata.org/grapher/share-global-co2-domestic-aviation",
                "type": "prominent-link",
                "title": "Share of global CO\u2082 emissions from domestic aviation",
                "description": "",
                "parseErrors": []
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            {
                "text": [
                    {
                        "text": "Per capita emissions from international flights",
                        "spanType": "span-simple-text"
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                "value": [
                    {
                        "text": "Allocating emissions from international flights is more complex. International databases report these emissions separately as a category termed \u2018bunker fuels\u2019. The term \u2018bunker fuel\u2019 is used to describe emissions which come from international transport \u2013 either aviation or shipping.",
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                ],
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            {
                "type": "text",
                "value": [
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                        "text": "Because they are ",
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                    {
                        "url": "https://unfccc.int/topics/mitigation/workstreams/emissions-from-international-transport-bunker-fuels",
                        "children": [
                            {
                                "text": "not counted towards",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-link"
                    },
                    {
                        "text": " any particular country these emissions are also not taken into account in the goals that are set by countries in international treaties like the Kyoto protocol or the Paris Agreement.{ref}Larsson, J., Kamb, A., N\u00e4ss\u00e9n, J., & \u00c5kerman, J. (2018). ",
                        "spanType": "span-simple-text"
                    },
                    {
                        "url": "https://www.sciencedirect.com/science/article/pii/S0195925517303116",
                        "children": [
                            {
                                "text": "Measuring greenhouse gas emissions from international air travel of a country\u2019s residents methodological development and application for Sweden",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-link"
                    },
                    {
                        "text": ". ",
                        "spanType": "span-simple-text"
                    },
                    {
                        "children": [
                            {
                                "text": "Environmental Impact Assessment Review",
                                "spanType": "span-simple-text"
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                    {
                        "text": ", ",
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                        "children": [
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                                "text": "72",
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                    {
                        "text": ", 137-144.{/ref}",
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            {
                "type": "text",
                "value": [
                    {
                        "text": "But if we wanted to allocate them to a particular country, how would we do it? Who do emissions from international flights belong to: the country that owns the airline; the country of departure; the country of arrival?",
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                ],
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                "value": [
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                        "text": "Let\u2019s first take a look at how emissions would compare if we allocated them to the country of ",
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                    },
                    {
                        "children": [
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                                "text": "departure",
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                        "text": ". This means, for example, that emissions from any flight that departs from Spain are counted towards Spain\u2019s total. In the chart here we see international aviation emissions in per capita terms.",
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                ],
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                "value": [
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                        "text": "Some of the largest emitters per person in 2018 were Iceland (3.5 tonnes of CO",
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                        "children": [
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                                "text": "2",
                                "spanType": "span-simple-text"
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                    {
                        "text": " per person); Qatar (2.5 tonnes); United Arab Emirates (2.2 tonnes); Singapore (1.7 tonnes); and Malta (992 kilograms).\u00a0",
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                ],
                "parseErrors": []
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                "value": [
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                        "text": "Again, we see large inequalities in emissions across the world \u2013 in many lower-income countries per capita emissions are only a few kilograms: 6 kilograms in India, 4 kilograms in Nigeria; and only 1.4 kilograms in the Democratic Republic of Congo.",
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                ],
                "parseErrors": []
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            {
                "url": "https://ourworldindata.org/grapher/per-capita-co2-international-aviation?stackMode=absolute&time=latest&region=World",
                "type": "chart",
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            {
                "text": [
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                        "text": "Related charts:",
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                "type": "heading",
                "level": 4,
                "parseErrors": []
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                "url": "https://ourworldindata.org/grapher/co2-international-aviation",
                "type": "prominent-link",
                "title": "Total CO\u2082 emissions from international aviation",
                "description": "",
                "parseErrors": []
            },
            {
                "url": "https://ourworldindata.org/grapher/share-co2-international-aviation",
                "type": "prominent-link",
                "title": "Share of global CO\u2082 emissions from international aviation",
                "description": "",
                "parseErrors": []
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            {
                "text": [
                    {
                        "text": "Per capita emissions from international flights \u2013 adjusted for tourism",
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                "type": "heading",
                "level": 3,
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                        "text": "The above allocation of international aviation emissions to the country of ",
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                    {
                        "children": [
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                                "text": "departure",
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                        "text": " raises some issues. It is not an accurate reflection of the local population of countries that rely a lot on tourism, for example. Most of the departing flights from these countries are carrying visiting tourists rather than locals.\u00a0",
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                ],
                "parseErrors": []
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                "value": [
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                        "text": "One way to correct for this is to adjust these figures for the ratio of inbound to outbound travellers. This approach was applied ",
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                    },
                    {
                        "url": "https://theicct.org/blog/staff/not-every-tonne-of-aviation-CO2",
                        "children": [
                            {
                                "text": "in an analysis",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "spanType": "span-link"
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                    {
                        "text": " by Sola Zheng for the ",
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                        "children": [
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                                "text": "International Council on Clean Transportation",
                                "spanType": "span-simple-text"
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                        "text": ". This attempts to distinguish between locals traveling abroad and foreign visitors traveling to that country on the same flight.{ref}A country with a ratio greater than one will have more incoming travellers than outgoing locals i.e. they are more of a hotspot for tourism.{/ref} For example, if we calculated that Spain had 50% more incoming than outgoing travellers, we would reduce its per capita footprint from flying by 50%. If the UK had 75% more outgoing travellers than incoming, we\u2019d increase its footprint by 75%.",
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                "value": [
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                        "text": "We have replicated this approach and\u00a0 applied this adjustment to these figures by calculating the ",
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                    {
                        "url": "https://ourworldindata.org/grapher/ratio-of-inbound-to-outbound-tourists",
                        "children": [
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                                "text": "inbound:outbound tourist ratio",
                                "spanType": "span-simple-text"
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                    {
                        "text": " based on flight departures and arrival data from the ",
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                    {
                        "url": "https://datacatalog.worldbank.org/dataset/world-development-indicators",
                        "children": [
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                                "text": "World Bank",
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                        "text": ".\u00a0",
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                "value": [
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                        "text": "How does this affect per capita emissions from international flights? The adjusted figures are shown in the chart here.",
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                        "text": "As we would expect, countries which are tourist hotspots see the largest change. Portugal\u2019s emissions, for example, fall from 388 to just 60 kilograms per person. Portuguese locals are responsible for much fewer travel emissions than outgoing tourists. Spanish emissions fall from 335 to 77 kilograms per person.",
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                        "text": "On the other hand, countries where the locals travel elsewhere see a large increase. In the UK, they almost double from 422 to 818 kilograms.",
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                "url": "https://ourworldindata.org/grapher/per-capita-co2-international-flights-adjusted?stackMode=absolute&time=latest&region=World",
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            {
                "text": [
                    {
                        "text": "Per capita emissions from domestic ",
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                    {
                        "children": [
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                                "text": "and ",
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                        "text": "international flights",
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                "value": [
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                        "text": "Let\u2019s combine per capita emissions from domestic and international travel to compare the total footprint from flying.",
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            {
                "type": "text",
                "value": [
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                        "text": "This is shown in the interactive map ",
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                    {
                        "children": [
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                                "text": "[we\u2019ve taken the adjusted international figures \u2013 you can find the\u00a0 combined figures without tourism-adjustment ",
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                        ],
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                        "url": "https://ourworldindata.org/grapher/per-capita-co2-aviation",
                        "children": [
                            {
                                "children": [
                                    {
                                        "children": [
                                            {
                                                "text": "here",
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                        "children": [
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                                "text": "].\u00a0",
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                "value": [
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                        "text": "The global average emissions from aviation were 103 kilograms. The inequality in emissions across the world becomes clear when this is broken down by country.\u00a0",
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                ],
                "parseErrors": []
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            {
                "type": "text",
                "value": [
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                        "text": "At the top of the table lies the United Arab Emirates \u2013 each person emits close to two tonnes \u2013 1950 kg \u2013 of CO",
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                    {
                        "children": [
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                                "text": "2",
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                        "spanType": "span-subscript"
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                    {
                        "text": " from flying each year. That\u2019s 200 times the global average.\u00a0 This was followed by Singapore (1173 kilograms); Iceland (1070 kg); Finland (1000 kg); and Australia (878 kilograms).\u00a0",
                        "spanType": "span-simple-text"
                    }
                ],
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            {
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                "value": [
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                        "text": "To put this into perspective: a return flight (in economy class) from London to Dubai/United Arab Emirates would emit around one tonne of CO",
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                    },
                    {
                        "children": [
                            {
                                "text": "2",
                                "spanType": "span-simple-text"
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                        ],
                        "spanType": "span-subscript"
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                    {
                        "text": ".{ref}We can calculate this by taking the standard CO2 conversion factors for travel, used in the ",
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                    },
                    {
                        "url": "https://www.gov.uk/government/publications/greenhouse-gas-reporting-conversion-factors-2019",
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                                "text": "UK greenhouse gas accounting framework",
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                        "text": ". For a long-haul flight in economy class, around 0.079 kilograms of CO",
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                                "text": "2",
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                                "text": "are emitted",
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                        "text": " per passenger-kilometer. This means that you would travel around 12,600 kilometers to emit one tonne [1,000,000 / 0.079 kg = 12,626 kilometers]. Since we\u2019re taking a return flight, the travel distance would be half of that figure: around 6300 kilometers. The direct distance from ",
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                        "text": " is around 5,500 kilometers. Depending on the flight path, it\u2019s likely to be slightly longer than this, and in the range of 5500 to 6500 kilometers.",
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                        "text": "Note that in this case we\u2019re looking at CO",
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                        "text": " emissions ",
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                        "text": " the extra warming effects of these emissions at high altitudes. This is to allow us to compare with the ICCT figures by country presented in this article. You find additional data on how the footprint of flying is impacted by non-CO",
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                        "text": " warming effects",
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                                "text": " ",
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                                        "text": "here",
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                        "text": ".{/ref} So the two-tonne average for the UAE is equivalent to around two return trips to London.",
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                        "text": "In many countries, most people do not fly at all. The average Indian emits just 18 kilograms from aviation \u2013 this is much, much less than even a short-haul flight which confirms that most did not take a flight.",
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                        "text": "In fact, we can compare just the aviation emissions for the top countries to the ",
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                        "text": " carbon footprint of citizens elsewhere. The average UAE citizen emits 1950 kilograms of CO",
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                        "text": " from flying. This is the same as the ",
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                        "text": " (including everything from electricity to road transport, heating and industry). Or, to take a more extreme example, 200 times the total footprint of the average Nigerien, Ugandan or Ethiopian, which ",
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                        "text": " of around 100 kilograms.\u00a0",
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                        "text": "This again emphasises the large difference between the global average and the individual emissions of people who fly. Aviation contributes a few percent of total CO",
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                        "text": " emissions each year \u2013 this is not insignificant, but far from being the largest sector to tackle. Yet from the perspective of the individual, flying ",
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                        "text": "CO",
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                        "text": "Transport accounts for around one-fifth of global carbon dioxide (CO",
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                        "text": ".{ref}The ",
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                        "text": " from CAIT on the breakdown of emissions by sector. In 2016, global CO",
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                        "text": " emissions (including land use) were 36.7 billion tonnes CO",
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                        "text": "; emissions from transport were 7.9 billion tonnes CO",
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                        "text": ". Transport therefore accounted for 7.9 / 36.7 = 21% of global emissions. ",
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                        "text": "The IEA ",
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                        "text": " from energy production alone \u2013 in 2018 it reported 33.5 billion tonnes of energy-related CO",
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                        "text": " [hence, transport accounted for 8 billion / 33.5 billion = 24% of energy-related emissions.{/ref}",
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                        "text": "Road travel accounts for three-quarters of transport emissions. Most of this comes from passenger vehicles \u2013 cars and buses \u2013 which contribute 45.1%. The other 29.4% comes from trucks carrying freight.",
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                        "text": "Aviation \u2013 while it often gets the most attention in discussions on action against climate change \u2013 accounts for only 11.6% of transport emissions. It emits just under one billion tonnes of CO",
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                        "text": " each year \u2013 around 2.5% of total global emissions ",
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                                "text": "[we look at the role that air travel plays in climate change in more detail in an upcoming article]",
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                        "text": ".\u00a0International shipping contributes a similar amount, at 10.6%.\u00a0",
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                        "text": "Rail travel and freight emits very little \u2013 only 1% of transport emissions. Other transport \u2013 which is mainly the movement of materials such as water, oil, and gas via pipelines \u2013 is responsible for 2.2%.",
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                        "text": "Transport demand is expected to grow across the world in the coming decades as the global population increases, incomes rise, and more people can afford cars, trains and flights. In its ",
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                        "text": " report, the International Energy Agency (IEA) expects global transport (measured in passenger-kilometers) to double, car ownership rates to increase by 60%, and demand for passenger and freight aviation to triple by 2070.{ref}IEA (2020), ",
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                        "text": ", IEA, Paris.{/ref} Combined, these factors would result in a large increase in transport emissions.",
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                        "text": "But major technological innovations can help offset this rise in demand. As the world shifts towards lower-carbon electricity sources, the rise of electric vehicles offers a viable option to reduce emissions from passenger vehicles.",
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                        "text": " report. There it outlines its \u201cSustainable Development Scenario\u201d for reaching net-zero CO2 emissions from global energy by 2070. The pathways for the different elements of the transport sector in this optimistic scenario are shown in the visualization.",
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                        "text": "We see that with electrification- and hydrogen- technologies some of these sub-sectors could decarbonize within decades. The IEA scenario assumes the phase-out of emissions from motorcycles by 2040; rail by 2050; small trucks by 2060; and although emissions from cars and buses are not completely eliminated until 2070, it expects many regions, including the European Union; United States; China and Japan to have phased-out conventional vehicles as early as 2040.",
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                        "text": ", Steven Davis and colleagues looked at our options across sectors to reach a net-zero emissions energy system.{ref}Davis, S. J., Lewis, N. S., Shaner, M., Aggarwal, S., Arent, D., Azevedo, I. L., ... & Clack, C. T. (2018). ",
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2021-09-24 13:42:00

2024-02-16 14:22:41

[
    "Hannah Ritchie",
    "Max Roser"
]

Explore trends in transport technologies and emissions across the world.

2020-09-02 14:42:44

2023-06-09 18:20:39

https://ourworldindata.org/wp-content/uploads/2021/09/transport-thumbnail.png

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First published in September 2021. --- # Road travel --- ## Passenger vehicle registrations by type These interactive charts show the breakdown of new passenger vehicle registrations by type. This is broken down by: petroleum; diesel; full hybrid (excluding plug-in hybrids); plug-in electric hybrids; and fully electric battery vehicles. <Chart url="https://ourworldindata.org/grapher/new-vehicles-type-area?tab=chart&stackMode=relative&country=~NOR"/> <Chart url="https://ourworldindata.org/grapher/new-vehicles-type-share?tab=chart&country=~GBR"/> ### Number of new passenger vehicle registrations by type https://ourworldindata.org/grapher/new-passenger-vehicles-type?country=~GBR ## Electric vehicle registrations This interactive chart shows the share of new passenger vehicle registrations that are battery electric vehicles. This does not include plug-in hybrid vehicles. <Chart url="https://ourworldindata.org/grapher/share-vehicle-electric?country=AUT~ITA~NOR~PRT~ESP~SWE~CHE~TUR~GBR~IRL~ISL~GRC~DEU~FRA~FIN~DNK~BEL~LUX~NLD"/> This interactive chart shows the share of new passenger vehicle registrations that are battery electric _plus_ plug-in hybrid vehicles. <Chart url="https://ourworldindata.org/grapher/battery-plugin-hybrid-vehicles?time=2019&country=~AUT~BEL~DNK~FIN~EU-27+%2B+UK~FRA~DEU~GRC~ISL~IRL~GBR~TUR~CHE~SWE~ESP~PRT~NOR~NLD~LUX~ITA"/> ## Carbon intensity of new passenger vehicles This interactive chart shows the average carbon intensity of new passenger vehicles in each country. This is measured as the average emissions of CO₂ (in grams) per kilometer travelled across all types of passenger vehicles. <Chart url="https://ourworldindata.org/grapher/carbon-new-passenger-vehicles?country=AUT~ITA~LUX~NLD~NOR~PRT~ESP~SWE~CHE~TUR~GBR~IRL~ISL~GRC~DEU~FRA~FIN~DNK~BEL"/> ## Fuel economy of new passenger vehicles This interacrive chart shows the average fuel economy of new passenger vehicles in each country. This is measured as the average liters consumed per 100 kilometers travelled, across all types of passenger vehicles. <Chart url="https://ourworldindata.org/grapher/fuel-efficiency-new-vehicles?country=AUT~BEL~ITA~LUX~NLD~NOR~PRT~ESP~SWE~CHE~TUR~GBR~IRL~ISL~GRC~DEU~FRA~FIN~DNK"/> --- # Aviation --- ## What share of global CO2 emissions come from aviation? Flying is a highly controversial topic in climate debates. There are a few reasons for this. The first is the disconnect between its role in our personal and collective carbon emissions. Air travel dominates a frequent traveller's individual contribution to climate change. Yet aviation overall accounts for only 2.5% of global carbon dioxide (CO2) emissions. This is because there are large inequalities in how much people fly – many do not, or cannot afford to, fly at all.{ref}The best estimates put this figure at around 80% of the world population. We look at this in more detail in our article "[Where in the world do people have the highest CO2 emissions from flying?](https://ourworldindata.org/carbon-footprint-flying)"{/ref} The second is how aviation emissions are attributed to countries. CO2 emissions from domestic flights _are_ counted in a country’s emission accounts. International flights are not – instead they are counted as their own category: ‘bunker fuels’. The fact that they don’t count towards the emissions of any country means there are few incentives for countries to reduce them. It’s also important to note that unlike the most common greenhouse gases – carbon dioxide, methane or nitrous oxide – non-CO2 forcings from aviation _are not included_ in the Paris Agreement. This means they could be easily overlooked – especially since international aviation is not counted within any country’s emissions inventories or targets. How much of a role does aviation play in global emissions and climate change? In this article we take a look at the key numbers that are useful to know. Global aviation (including domestic and international; passenger and freight) accounts for: * **1.9%** of [greenhouse gas emissions](https://ourworldindata.org/ghg-emissions-by-sector) (which includes all greenhouse gases, not only CO2) * **2.5%** of CO2 emissions * **3.5%** of 'effective radiative forcing' – a closer measure of its impact on warming. The latter two numbers refer to 2018, and the first to 2016, the latest year for which such data are available. ### Aviation accounts for 2.5% of global CO2 emissions As we will see later in this article, there are a number of processes by which aviation contributes to climate change. But the one that gets the most attention is its contribution via CO2 emissions. Most flights are powered by jet gasoline – although some partially run on biofuels – which is converted to CO2 when burned. In a recent paper, researchers – David Lee and colleagues – reconstructed annual CO2 emissions from global aviation dating back to 1940.{ref}Lee, D. S., Fahey, D. W., Skowron, A., Allen, M. R., Burkhardt, U., Chen, Q., ... & Gettelman, A. (2020). [The contribution of global aviation to anthropogenic climate forcing for 2000 to 2018](https://www.sciencedirect.com/science/article/pii/S1352231020305689). _Atmospheric Environment_, 117834.{/ref} This was calculated based on fuel consumption data from the International Energy Agency (IEA), and earlier estimates from Robert Sausen and Ulrich Schumann (2000).{ref}Sausen, R., & Schumann, U. (2000). [Estimates of the climate response to aircraft CO2 and NOx emissions scenarios](https://link.springer.com/article/10.1023/A:1005579306109). _Climatic Change_, _44_(1-2), 27-58.{/ref} The time series of global emissions from aviation since 1940 is shown in the accompanying chart. In 2018, it’s estimated that global aviation – which includes both passenger and freight – emitted 1.04 billion tonnes of CO2. This represented 2.5% of [total CO2 emissions](https://ourworldindata.org/co2-emissions#global-co2-emissions-from-fossil-fuels-global-co2-emissions-from-fossil-fuels) in 2018.{ref}The Global Carbon Budget estimated total CO2 emissions from all fossil fuels, cement production and land-use change to be 42.1 billion tonnes in 2018. This means aviation accounted for [1 / 42.1 * 100] = 2.5% of total emissions.{/ref},{ref}Global Carbon Project. (2019). Supplemental data of Global Carbon Budget 2019 (Version 1.0) [Data set]. Global Carbon Project. [https://doi.org/10.18160/gcp-2019](https://doi.org/10.18160/gcp-2019). If we were to exclude land use change emissions, aviation accounted for 2.8% of fossil fuel emissions. The Global Carbon Budget estimated total CO2 emissions from fossil fuels and cement production to be 36.6 billion tonnes in 2018. This means aviation accounted for [1 / 36.6 * 100] = 2.8% of total emissions.{/ref} Aviation emissions have doubled since the mid-1980s. But, they’ve been growing at a similar rate as total CO2 emissions – this means its share of global emissions has been relatively stable: in the range of 2% to 2.5%.{ref}2.3% to 2.8% of emissions if land use is excluded.{/ref} <Image filename="Global-CO2-emissions-from-aviation.png" alt=""/> ### Non-CO2 climate impacts mean aviation accounts for 3.5% of global warming Aviation accounts for around 2.5% of global CO2 emissions, but it’s overall contribution to climate change is higher. This is because air travel does not only emit CO2: it affects the climate in a number of more complex ways. As well as emitting CO2 from burning fuel, planes affect the concentration of other gases and pollutants in the atmosphere. They result in a short-term increase, but long-term decrease in ozone (O3); a decrease in methane (CH4); emissions of water vapour; soot; sulfur aerosols; and water contrails. While some of these impacts result in warming, others induce a cooling effect. Overall, the warming effect is stronger. David Lee et al. (2020) quantified the overall effect of aviation on global warming when all of these impacts were included.{ref}Lee, D. S., Fahey, D. W., Skowron, A., Allen, M. R., Burkhardt, U., Chen, Q., ... & Gettelman, A. (2020). [The contribution of global aviation to anthropogenic climate forcing for 2000 to 2018](https://www.sciencedirect.com/science/article/pii/S1352231020305689). _Atmospheric Environment_, 117834.{/ref} To do this they calculated the so-called ‘Radiative Forcing’. Radiative forcing measures the difference between incoming energy and the energy radiated back to space. If more energy is absorbed than radiated, the atmosphere becomes warmer. In their chart we see [their estimates for the radiative forcing](https://ars.els-cdn.com/content/image/1-s2.0-S1352231020305689-gr3_lrg.jpg) of the different elements. When we combine them, aviation accounts for approximately 3.5% of effective radiative forcing: that is, 3.5% of warming. Although CO2 gets most of the attention, it accounts for less than half of this warming. Two-thirds (66%) comes from non-CO2 forcings. Contrails – water vapor trails from aircraft exhausts – account for the largest share. ### We don’t yet have the technologies to decarbonize air travel Aviation’s contribution to climate change – 3.5% of warming, or 2.5% of CO2 emissions – is often less than people think. It’s currently a relatively small chunk of emissions compared to other sectors. The key challenge is that it is particularly hard to decarbonize. We have solutions to reduce emissions for many of the [largest emitters](https://ourworldindata.org/ghg-emissions-by-sector) – such as power or road transport – and it’s now a matter of scaling them. We can deploy renewable and nuclear energy technologies, and transition to electric cars. But we don’t have proven solutions to tackle aviation yet. There are some design concepts emerging – Airbus, for example, [have announced plans](https://web.archive.org/web/20201031121346/https://www.airbus.com/innovation/zero-emission/hydrogen/zeroe.html) to have the first zero-emission aircraft by 2035, using hydrogen fuel cells. Electric planes may be a viable concept, but are likely to be limited to very small aircraft due to the limitations of battery technologies and capacity. Innovative solutions may be on the horizon, but they’re likely to be far in the distance. ### Towards zero-carbon transport: how can we expect the sector’s CO<sub>2</sub> emissions to change in the future? ourworldindata.org/co2-emissions-from-transport ## Additional information Global emissions from aviation have increased a lot over the past half-century. However, air travel volumes increased even more rapidly. Since 1960, aviation emissions increased almost seven-fold; since 1970 they’ve tripled. Air traffic volume – here defined as revenue passenger kilometers (RPK) traveled – [increased by orders of magnitude more](https://ourworldindata.org/grapher/airline-capacity-and-traffic): almost 300-fold since 1950; and 75-fold since 1960.{ref}Airline traffic data comes from the International Civil Aviation Organization (ICAO) via [Airlines for America](https://www.airlines.org/dataset/world-airlines-traffic-and-capacity). Revenue passenger kilometers (RPK) measures the number of paying passengers multiplied by their distance traveled.{/ref} The much slower growth in emissions means aviation efficiency has seen massive improvements. In the chart we show both the increase in global airline traffic since 1950, and aviation efficiency, measured as the quantity of CO2 emitted per revenue passenger kilometer traveled. In 2018, approximately 125 grams of CO2 were emitted per RPK. In 1960, this was eleven-fold higher; in 1950 it was twenty-fold higher. Aviation has seen massive efficiency improvements over the past 50 years. These improvements have come from several sources: improvements in the design and technology of aircraft; larger aircraft sizes (allowing for more passengers per flight); and an increase in how ‘full’ passenger flights are. This last metric is termed the ‘passenger load factor’. The passenger load factor measures the actual number of kilometers traveled by paying customers (RPK) as a percentage of the available seat kilometers (ASK) – the kilometers traveled if every plane was full. If every plane was full the passenger load factor would be 100%. If only three-quarters of the seats were filled, it would be 75%. The global passenger load factor [increased from 61% in 1950 to 82% in 2018](https://ourworldindata.org/grapher/airline-passenger-load-factor). <Image filename="Aviation-traffic-and-efficiency-Lee-et-al.-2020.png" alt=""/> ## Passenger vs. freight; domestic vs. international: where do aviation emissions come from? Global aviation – both passenger flights and freight – emits around one billion tonnes of carbon dioxide (CO2) each year. This was equivalent to around 2.4% of CO2 emissions in 2018. How do global aviation emissions break down? The chart gives the answer. This data is sourced from the 2019 _International Council on Clean Transportation__(ICCT)_ report on global aviation.{ref}Graver, B., Zhang, K., & Rutherford, D. (2019). [CO2 emissions from commercial aviation, 2018](https://theicct.org/sites/default/files/publications/ICCT_CO2-commercl-aviation-2018_20190918.pdf). _The International Council of Clean Transportation_.{/ref} Most emissions come from passenger flights – in 2018, they accounted for 81% of aviation’s emissions; the remaining 19% came from freight, the transport of goods. Sixty percent of emissions from_ passenger_ flights come from international travel; the other 40% come from domestic (in-country) flights. When we break passenger flight emissions down by travel distance, we get a (surprisingly) equal three-way split in emissions between short-haul (less than 1,500 kilometers); medium-haul (1,500 to 4,000 km); and long-haul (greater than 4,000 km) journeys. <Image filename="Global-breakdown-of-aviation-emissions.png" alt=""/> ### The richest half are responsible for 90% of air travel CO2 emissions The global inequalities in how much people fly become clear when we compare aviation emissions across countries of different income levels. The ICCT split these emissions based on World Bank's four [income groups](https://ourworldindata.org/grapher/world-banks-income-groups?year=latest). A further study by Susanne Becek and Paresh Pant (2019) compared the contribution of each income group to global air travel emissions versus its share of world population.{ref}Becken, S. and P. Pant (2019). [Airline initiatives to reduce climate impact: ways to accelerate action](https://amadeus.com/en/insights/white-paper/airline-initiatives-to-reduce-climate-impact) (White paper).{/ref} This comparison is shown in the visualization. The ‘richest’ half of the world (high and upper-middle income countries) were responsible for 90% of air travel emissions.{ref}Note that this is based on categorisations from the average income level of countries, and does not take account of variation in income _within _countries. If we were to look at this distribution based on the income level of individuals rather than countries, the inequality in aviation emissions would be even larger.{/ref} Looking at specific income groups: * Only 16% of the world population live in high-income countries yet the planes that take off in those countries account for almost two-thirds (62%) of passenger emissions; * Upper-middle income countries are home to 35% of the world population, and contribute 28% of emissions; * Lower-middle income countries are home to the largest share (40% of the world), yet emit the planes taking off there just account for 9%; * The poorest countries – which are home to 9% of the world population – emit just 1%. In an upcoming article we will look in more detail at the contribution of each country to global aviation emissions. <Image filename="Inequalities-in-CO2-emissions-from-air-travel.png" alt=""/> ## Where in the world do people have the highest carbon footprint from flying? Aviation accounts [for around 2.5%](https://ourworldindata.org/co2-emissions-from-aviation) of global carbon dioxide (CO2) emissions. But if you are someone who does fly, air travel will make up a much larger share of your personal carbon footprint. The fact that aviation is relatively small for global emissions as a whole, but of large importance for individuals that fly is due to large inequalities in the world. Most people in the world do not take flights. There is no global reliable figure, but often cited estimates suggest that more than 80% of the global population have never flown.{ref}There is no global database available on _who_ in the world flies each year. Passenger information is maintained by private airlines. Therefore, deriving estimates of this exact percentage is challenging. The most-cited estimate I’ve seen on this is that around 80% of the world population have never flown. This figure seems to circle back to a [quoted estimate](https://www.cnbc.com/2017/12/07/boeing-ceo-80-percent-of-people-never-flown-for-us-that-means-growth.html#:~:text=%E2%80%9CLess%20than%2020%20percent%20of,the%20entire%20economy%2C%20Muilenburg%20said.) from the Boeing CEO. Even in some of the world’s richest countries, a large share of the population do not fly frequently. Gallup [survey data](https://news.gallup.com/poll/1579/airlines.aspx) from the United States suggests that in 2015, half of the population did not take a flight. Survey data from the UK [provides similar estimates](http://publicapps.caa.co.uk/docs/33/CAA%20Aviation%20Consumer%20survey%20--%205th%20wave%20report%20FINAL%20(2).pdf): 46% had not flown in the previous year.{/ref} How do emissions from aviation vary across the world? Where do people have the highest footprint from flying? ### Per capita emissions from domestic flights The first and most straightforward comparison is to look at emissions from _domestic_ aviation – that is, flights that depart and arrive in the same country. This is easiest to compare because domestic aviation is counted in each country’s inventory of greenhouse gas emissions. International flights, on the other hand, are not attributed to specific countries – partly because of contention as to who should take responsibility (should it be the country of departure or arrival? What about layover flights?). In the chart here we see the average per capita emissions from domestic flights in 2018. This data is sourced from the _International Council on Clean Transportation_ – we then used [UN population estimates](https://population.un.org/wpp/) to calculate per capita figures.{ref}Graver, B., Zhang, K., & Rutherford, D. (2019). [CO2 emissions from commercial aviation, 2018](https://theicct.org/publications/co2-emissions-commercial-aviation-2018). _The International Council of Clean Transportation_.{/ref},{ref}Note that this gives us _mean_ per capita emissions, which does not account for in-country inequalities in the amount of flights people take.{/ref} We see large differences in emissions from domestic flights across the world. In the United States the average person emits around 386 kilograms of CO2 each year from internal flights. This is followed by Australia (267 kg); Norway (209 kg); New Zealand (174 kg); and Canada (168 kg). Compare this with countries at the bottom of the table – many across Africa, Asia, and Eastern Europe in particular emit less than one kilogram per person – just 0.8 kilograms; or 0.14 kilograms in Rwanda. For very small countries where there are no internal commercial flights, domestic emissions are of course, zero. There are some obvious factors that explain some of these cross-country differences. Firstly, countries that are richer [are more likely](https://ourworldindata.org/grapher/per-capita-co2-domestic-aviation-vs-gdp) to have higher emissions because people can afford to fly. Second, countries that have a larger land mass may have more internal flights – and indeed we see a [correlation](https://ourworldindata.org/grapher/per-capita-co2-domestic-aviation-vs-land-area) between land area and domestic flight emissions; in small countries people are more likely to travel by other means such as car or train. And third, countries that are more geographically-isolated – such as Australia and New Zealand – may have more internal travel. <Chart url="https://ourworldindata.org/grapher/per-capita-co2-domestic-aviation"/> #### Related charts: ### Total CO₂ emissions from domestic aviation https://ourworldindata.org/grapher/co2-emissions-domestic-aviation ### Share of global CO₂ emissions from domestic aviation https://ourworldindata.org/grapher/share-global-co2-domestic-aviation ### Per capita emissions from international flights Allocating emissions from international flights is more complex. International databases report these emissions separately as a category termed ‘bunker fuels’. The term ‘bunker fuel’ is used to describe emissions which come from international transport – either aviation or shipping. Because they are [not counted towards](https://unfccc.int/topics/mitigation/workstreams/emissions-from-international-transport-bunker-fuels) any particular country these emissions are also not taken into account in the goals that are set by countries in international treaties like the Kyoto protocol or the Paris Agreement.{ref}Larsson, J., Kamb, A., Nässén, J., & Åkerman, J. (2018). [Measuring greenhouse gas emissions from international air travel of a country’s residents methodological development and application for Sweden](https://www.sciencedirect.com/science/article/pii/S0195925517303116). _Environmental Impact Assessment Review_, _72_, 137-144.{/ref} But if we wanted to allocate them to a particular country, how would we do it? Who do emissions from international flights belong to: the country that owns the airline; the country of departure; the country of arrival? Let’s first take a look at how emissions would compare if we allocated them to the country of _departure_. This means, for example, that emissions from any flight that departs from Spain are counted towards Spain’s total. In the chart here we see international aviation emissions in per capita terms. Some of the largest emitters per person in 2018 were Iceland (3.5 tonnes of CO2 per person); Qatar (2.5 tonnes); United Arab Emirates (2.2 tonnes); Singapore (1.7 tonnes); and Malta (992 kilograms). Again, we see large inequalities in emissions across the world – in many lower-income countries per capita emissions are only a few kilograms: 6 kilograms in India, 4 kilograms in Nigeria; and only 1.4 kilograms in the Democratic Republic of Congo. <Chart url="https://ourworldindata.org/grapher/per-capita-co2-international-aviation?stackMode=absolute&time=latest&region=World"/> #### Related charts: ### Total CO₂ emissions from international aviation https://ourworldindata.org/grapher/co2-international-aviation ### Share of global CO₂ emissions from international aviation https://ourworldindata.org/grapher/share-co2-international-aviation ### Per capita emissions from international flights – adjusted for tourism The above allocation of international aviation emissions to the country of _departure_ raises some issues. It is not an accurate reflection of the local population of countries that rely a lot on tourism, for example. Most of the departing flights from these countries are carrying visiting tourists rather than locals. One way to correct for this is to adjust these figures for the ratio of inbound to outbound travellers. This approach was applied [in an analysis](https://theicct.org/blog/staff/not-every-tonne-of-aviation-CO2) by Sola Zheng for the _International Council on Clean Transportation_. This attempts to distinguish between locals traveling abroad and foreign visitors traveling to that country on the same flight.{ref}A country with a ratio greater than one will have more incoming travellers than outgoing locals i.e. they are more of a hotspot for tourism.{/ref} For example, if we calculated that Spain had 50% more incoming than outgoing travellers, we would reduce its per capita footprint from flying by 50%. If the UK had 75% more outgoing travellers than incoming, we’d increase its footprint by 75%. We have replicated this approach and applied this adjustment to these figures by calculating the [inbound:outbound tourist ratio](https://ourworldindata.org/grapher/ratio-of-inbound-to-outbound-tourists) based on flight departures and arrival data from the [World Bank](https://datacatalog.worldbank.org/dataset/world-development-indicators). How does this affect per capita emissions from international flights? The adjusted figures are shown in the chart here. As we would expect, countries which are tourist hotspots see the largest change. Portugal’s emissions, for example, fall from 388 to just 60 kilograms per person. Portuguese locals are responsible for much fewer travel emissions than outgoing tourists. Spanish emissions fall from 335 to 77 kilograms per person. On the other hand, countries where the locals travel elsewhere see a large increase. In the UK, they almost double from 422 to 818 kilograms. <Chart url="https://ourworldindata.org/grapher/per-capita-co2-international-flights-adjusted?stackMode=absolute&time=latest&region=World"/> ### Per capita emissions from domestic _and _international flights Let’s combine per capita emissions from domestic and international travel to compare the total footprint from flying. This is shown in the interactive map _[we’ve taken the adjusted international figures – you can find the combined figures without tourism-adjustment _[**_here_**](https://ourworldindata.org/grapher/per-capita-co2-aviation)_]. _ The global average emissions from aviation were 103 kilograms. The inequality in emissions across the world becomes clear when this is broken down by country. At the top of the table lies the United Arab Emirates – each person emits close to two tonnes – 1950 kg – of CO2 from flying each year. That’s 200 times the global average. This was followed by Singapore (1173 kilograms); Iceland (1070 kg); Finland (1000 kg); and Australia (878 kilograms). To put this into perspective: a return flight (in economy class) from London to Dubai/United Arab Emirates would emit around one tonne of CO2.{ref}We can calculate this by taking the standard CO2 conversion factors for travel, used in the [UK greenhouse gas accounting framework](https://www.gov.uk/government/publications/greenhouse-gas-reporting-conversion-factors-2019). For a long-haul flight in economy class, around 0.079 kilograms of CO2[are emitted](https://ourworldindata.org/travel-carbon-footprint) per passenger-kilometer. This means that you would travel around 12,600 kilometers to emit one tonne [1,000,000 / 0.079 kg = 12,626 kilometers]. Since we’re taking a return flight, the travel distance would be half of that figure: around 6300 kilometers. The direct distance from [London to Dubai](https://www.distance.to/London/Dubai,ARE) is around 5,500 kilometers. Depending on the flight path, it’s likely to be slightly longer than this, and in the range of 5500 to 6500 kilometers. Note that in this case we’re looking at CO2 emissions _without_ the extra warming effects of these emissions at high altitudes. This is to allow us to compare with the ICCT figures by country presented in this article. You find additional data on how the footprint of flying is impacted by non-CO2 warming effects[ **here**](https://ourworldindata.org/grapher/carbon-footprint-travel-mode).{/ref} So the two-tonne average for the UAE is equivalent to around two return trips to London. In many countries, most people do not fly at all. The average Indian emits just 18 kilograms from aviation – this is much, much less than even a short-haul flight which confirms that most did not take a flight. In fact, we can compare just the aviation emissions for the top countries to the _total_ carbon footprint of citizens elsewhere. The average UAE citizen emits 1950 kilograms of CO2 from flying. This is the same as the _total_[CO2 footprint of the average Indian](https://ourworldindata.org/explorers/co2?tab=chart&xScale=linear&yScale=linear&stackMode=absolute&endpointsOnly=0&year=latest&time=1858..2018&country=~India&region=World&Gas%20=CO%E2%82%82&Accounting%20=Production-based&Fuel%20=Total&Count%20=Per%20capita&Relative%20to%20world%20total%20=) (including everything from electricity to road transport, heating and industry). Or, to take a more extreme example, 200 times the total footprint of the average Nigerien, Ugandan or Ethiopian, which [have per capita emissions](https://ourworldindata.org/explorers/co2?tab=chart&xScale=linear&yScale=linear&stackMode=absolute&endpointsOnly=0&year=latest&time=1958..2018&country=Niger~Uganda~Ethiopia&region=World&Gas%20=CO%E2%82%82&Accounting%20=Production-based&Fuel%20=Total&Count%20=Per%20capita&Relative%20to%20world%20total%20=) of around 100 kilograms. This again emphasises the large difference between the global average and the individual emissions of people who fly. Aviation contributes a few percent of total CO2 emissions each year – this is not insignificant, but far from being the largest sector to tackle. Yet from the perspective of the individual, flying _is_ often one of the largest chunks of our carbon footprint. The average rich person emits tonnes of CO2 from flying each year – this is equivalent to the _total_ carbon footprint of tens or hundreds of people in many countries of the world. <Chart url="https://ourworldindata.org/grapher/per-capita-co2-aviation-adjusted?stackMode=absolute&region=World"/> #### Related charts: ### Per capita CO₂ emissions from aviation (without tourism adjustment) https://ourworldindata.org/grapher/per-capita-co2-aviation ### Total CO₂ emissions from aviation https://ourworldindata.org/grapher/co2-emissions-aviation ### Share of global CO₂ emissions from aviation https://ourworldindata.org/grapher/share-co2-emissions-aviation ## Where in the world do people fly the most? ### Domestic air travel This interactive chart shows the average distance travelled per person through domestic air travel each year. This data is for passenger flights only and does not include freight. <Chart url="https://ourworldindata.org/grapher/per-capita-domestic-aviation-km"/> #### Related charts: ### Share of global passenger kilometers from domestic air travel What share of global domestic air travel does each country account for? https://ourworldindata.org/grapher/share-global-domestic-aviation-km ### Total passenger kilometers from domestic air travel https://ourworldindata.org/grapher/total-domestic-aviation-km ### International air travel This interactive chart shows the average distance travelled per person through international air travel each year. This data is for passenger flights only and does not include freight. <Chart url="https://ourworldindata.org/grapher/per-capita-international-aviation-km"/> #### Related charts: ### Share of global passenger kilometers from international air travel What share of global international air travel does each country account for? https://ourworldindata.org/grapher/share-international-aviation-km ### Total passenger kilometers from international air travel https://ourworldindata.org/grapher/passenger-km-international-aviation ### Total air travel This interactive chart shows the average distance travelled per person through domestic _and_ international air travel each year. This data is for passenger flights only and does not include freight. <Chart url="https://ourworldindata.org/grapher/per-capita-km-aviation"/> #### Related charts: ### Share of global passenger kilometers from air travel What share of global air travel does each country account for? https://ourworldindata.org/grapher/share-km-aviation ### Total passenger kilometers from air travel https://ourworldindata.org/grapher/total-aviation-km --- # Rail --- This interactive chart shows the total rail travel in each country, measured in passenger-kilometers per year. This includes passenger travel only and does not include freight. <Chart url="https://ourworldindata.org/grapher/railways-passengers-carried-passenger-km"/> --- # Energy intensity of transport --- This chart shows the average energy intensity of transport across different modes of travel. It is measured as the average kilowatt-hours required per passenger-kilometer. This data comes from the United States Department of Transportation's Bureau of Transportation Statistics (BTS). The energy intensity of public transport depends on the assumptions made about the capacity of transport modes i.e. how many passengers travel on a given train or bus journey. This data thererfore reflects average capacities in the United States, but will vary from country-to-country. <Chart url="https://ourworldindata.org/grapher/energy-intensity-transport?country=Amtrak~Bus~Domestic+flight~International+flight~Motorcycle~~Transit+motor+bus~Truck+%28with+trailer%29~Truck~"/> --- # CO2 emissions from transport --- ## Per capita transport emissions from transport This interactive shows the average per capita emissions of carbon dioxide from transport each year. This includes road, train, bus and domestic air travel but _does not _include international aviation and shipping. <Chart url="https://ourworldindata.org/grapher/per-capita-co2-transport?stackMode=absolute&region=World"/> ## Total transport emissions This interactive shows the emissions of carbon dioxide from transport each year. This includes road, train, bus and domestic air travel but _does not _include international aviation and shipping. <Chart url="https://ourworldindata.org/grapher/co2-emissions-transport?stackMode=absolute&time=earliest..latest&region=World"/> ## CO2 emissions by mode of transport Transport accounts for around one-fifth of global carbon dioxide (CO2) emissions _[24% if we only consider CO2 emissions from energy]_.{ref}The _World Resource Institute_’s Climate Data Explorer [provides data](https://www.climatewatchdata.org/data-explorer/historical-emissions?historical-emissions-data-sources=cait&historical-emissions-gases=co2&historical-emissions-regions=All%20Selected&historical-emissions-sectors=total-including-lucf%2Ctransportation&page=1&sort_col=country&sort_dir=ASC) from CAIT on the breakdown of emissions by sector. In 2016, global CO2 emissions (including land use) were 36.7 billion tonnes CO2; emissions from transport were 7.9 billion tonnes CO2. Transport therefore accounted for 7.9 / 36.7 = 21% of global emissions. The IEA [looks at CO2 emissions](https://www.iea.org/data-and-statistics/?country=WORLD&fuel=CO2%20emissions&indicator=TotCO2) from energy production alone – in 2018 it reported 33.5 billion tonnes of energy-related CO2 [hence, transport accounted for 8 billion / 33.5 billion = 24% of energy-related emissions.{/ref} How do these emissions break down? Is it cars, trucks, planes or trains that dominate? In the chart here we see global transport emissions in 2018. This data is [sourced from](https://www.iea.org/data-and-statistics/charts/transport-sector-co2-emissions-by-mode-in-the-sustainable-development-scenario-2000-2030) the _International Energy Agency (IEA)_. Road travel accounts for three-quarters of transport emissions. Most of this comes from passenger vehicles – cars and buses – which contribute 45.1%. The other 29.4% comes from trucks carrying freight. Since the entire transport sector accounts for 21% of total emissions, and road transport accounts for three-quarters of transport emissions, road transport accounts for 15% of total CO2 emissions. Aviation – while it often gets the most attention in discussions on action against climate change – accounts for only 11.6% of transport emissions. It emits just under one billion tonnes of CO2 each year – around 2.5% of total global emissions _[we look at the role that air travel plays in climate change in more detail in an upcoming article]_. International shipping contributes a similar amount, at 10.6%. Rail travel and freight emits very little – only 1% of transport emissions. Other transport – which is mainly the movement of materials such as water, oil, and gas via pipelines – is responsible for 2.2%. <Image filename="Transport-CO2-emissions-by-mode-bar-chart.png" alt=""/> ### Towards zero-carbon transport: how can we expect the sector’s CO2 emissions to change in the future? Transport demand is expected to grow across the world in the coming decades as the global population increases, incomes rise, and more people can afford cars, trains and flights. In its _Energy Technology Perspectives_ report, the International Energy Agency (IEA) expects global transport (measured in passenger-kilometers) to double, car ownership rates to increase by 60%, and demand for passenger and freight aviation to triple by 2070.{ref}IEA (2020), [Energy Technology Perspectives 2020](https://www.iea.org/reports/energy-technology-perspectives-2020), IEA, Paris.{/ref} Combined, these factors would result in a large increase in transport emissions. But major technological innovations can help offset this rise in demand. As the world shifts towards lower-carbon electricity sources, the rise of electric vehicles offers a viable option to reduce emissions from passenger vehicles. This is reflected in the IEA’s _Energy Technology Perspective_ report. There it outlines its “Sustainable Development Scenario” for reaching net-zero CO2 emissions from global energy by 2070. The pathways for the different elements of the transport sector in this optimistic scenario are shown in the visualization. We see that with electrification- and hydrogen- technologies some of these sub-sectors could decarbonize within decades. The IEA scenario assumes the phase-out of emissions from motorcycles by 2040; rail by 2050; small trucks by 2060; and although emissions from cars and buses are not completely eliminated until 2070, it expects many regions, including the European Union; United States; China and Japan to have phased-out conventional vehicles as early as 2040. Other transport sectors will be much more difficult to decarbonize. In a paper published in _Science_, Steven Davis and colleagues looked at our options across sectors to reach a net-zero emissions energy system.{ref}Davis, S. J., Lewis, N. S., Shaner, M., Aggarwal, S., Arent, D., Azevedo, I. L., ... & Clack, C. T. (2018). [Net-zero emissions energy systems](https://science.sciencemag.org/content/360/6396/eaas9793.full). _Science_, 360(6396).{/ref} They highlighted long-distance road freight (large trucks), aviation and shipping as particularly difficult to eliminate. The potential for hydrogen as a fuel, or battery electricity to run planes, ships and large trucks is limited by the range and power required; the size and weight of batteries or hydrogen fuel tanks would be _much_ larger and heavier than current combustion engines.{ref}Cecere, D., Giacomazzi, E., & Ingenito, A. (2014). [A review on hydrogen industrial aerospace applications](https://www.sciencedirect.com/science/article/pii/S0360319914011847). _International Journal of Hydrogen Energy_, _39_(20), 10731-10747.{/ref},{ref}Fulton, L. M., Lynd, L. R., Körner, A., Greene, N., & Tonachel, L. R. (2015). [The need for biofuels as part of a low carbon energy future](https://onlinelibrary.wiley.com/doi/full/10.1002/bbb.1559). _Biofuels, Bioproducts and Biorefining_, 9(5), 476-483.{/ref} So, despite falling by three-quarters in the visualized scenario, emissions from these sub-sectors would still make transport the largest contributor to energy-related emissions in 2070. To reach net-zero for the energy sector as a whole, these emissions would have to be offset by ‘negative emissions’ (e.g. the capture and storage of carbon from bioenergy or [direct air capture](https://www.iea.org/reports/direct-air-capture)) from other parts of the energy system. In the IEA’s net-zero scenario, nearly two-thirds of the emissions reductions come from technologies that are not yet commercially available. As the IEA states, “Reducing CO2 emissions in the transport sector over the next half-century will be a formidable task.”{ref}IEA (2020), [Energy Technology Perspectives 2020](https://www.iea.org/reports/energy-technology-perspectives-2020), IEA, Paris.{/ref} ##### Global CO2 emissions from transport in the IEA's Sustainable Development Scenario to 2070{ref}IEA (2020), [Energy Technology Perspectives 2020](https://www.iea.org/reports/energy-technology-perspectives-2020), IEA, Paris.{/ref} <Image filename="IEA-Transport-to-2070.png" alt=""/>

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        "rendered": "\n<div class=\"blog-info\">First published in September 2021.</div>\n\n\n\n<!-- formatting-options subnavId:energy subnavCurrentId:transport -->\n\n\n\n<h2>Road travel</h2>\n\n\n\n<h3>Passenger vehicle registrations by type</h3>\n\n\n\n<div class=\"wp-block-columns\">\n<div class=\"wp-block-column\">\n<p>These interactive charts show the breakdown of new passenger vehicle registrations by type.</p>\n\n\n\n<p>This is broken down by: petroleum; diesel; full hybrid (excluding plug-in hybrids); plug-in electric hybrids; and fully electric battery vehicles.</p>\n</div>\n\n\n\n<div class=\"wp-block-column\">\n<iframe src=\"https://ourworldindata.org/grapher/new-vehicles-type-area?tab=chart&amp;stackMode=relative&amp;country=~NOR\" loading=\"lazy\" style=\"width: 100%; height: 600px; border: 0px none;\"></iframe>\n\n\n\n<iframe src=\"https://ourworldindata.org/grapher/new-vehicles-type-share?tab=chart&amp;country=~GBR\" loading=\"lazy\" style=\"width: 100%; height: 600px; border: 0px none;\"></iframe>\n\n\n    <block type=\"prominent-link\" style=\"is-style-thin\">\n        <link-url>https://ourworldindata.org/grapher/new-passenger-vehicles-type?country=~GBR</link-url>\n        <title>Number of new passenger vehicle registrations by type</title>\n        <content></content>\n        <figure></figure>\n    </block></div>\n</div>\n\n\n\n<h3>Electric vehicle registrations</h3>\n\n\n\n<div class=\"wp-block-columns\">\n<div class=\"wp-block-column\">\n<p>This interactive chart shows the share of new passenger vehicle registrations that are battery electric vehicles. This does not include plug-in hybrid vehicles.</p>\n</div>\n\n\n\n<div class=\"wp-block-column\">\n<iframe src=\"https://ourworldindata.org/grapher/share-vehicle-electric?country=AUT~ITA~NOR~PRT~ESP~SWE~CHE~TUR~GBR~IRL~ISL~GRC~DEU~FRA~FIN~DNK~BEL~LUX~NLD\" loading=\"lazy\" style=\"width: 100%; height: 600px; border: 0px none;\"></iframe>\n</div>\n</div>\n\n\n\n<div class=\"wp-block-columns\">\n<div class=\"wp-block-column\">\n<p>This interactive chart shows the share of new passenger vehicle registrations that are battery electric <em>plus</em> plug-in hybrid vehicles.</p>\n</div>\n\n\n\n<div class=\"wp-block-column\">\n<iframe src=\"https://ourworldindata.org/grapher/battery-plugin-hybrid-vehicles?time=2019&amp;country=~AUT~BEL~DNK~FIN~EU-27+%2B+UK~FRA~DEU~GRC~ISL~IRL~GBR~TUR~CHE~SWE~ESP~PRT~NOR~NLD~LUX~ITA\" loading=\"lazy\" style=\"width: 100%; height: 600px; border: 0px none;\"></iframe>\n</div>\n</div>\n\n\n\n<h3>Carbon intensity of new passenger vehicles</h3>\n\n\n\n<div class=\"wp-block-columns\">\n<div class=\"wp-block-column\">\n<p>This interactive chart shows the average carbon intensity of new passenger vehicles in each country.</p>\n\n\n\n<p>This is measured as the average emissions of CO\u2082 (in grams) per kilometer travelled across all types of passenger vehicles.</p>\n</div>\n\n\n\n<div class=\"wp-block-column\">\n<iframe src=\"https://ourworldindata.org/grapher/carbon-new-passenger-vehicles?country=AUT~ITA~LUX~NLD~NOR~PRT~ESP~SWE~CHE~TUR~GBR~IRL~ISL~GRC~DEU~FRA~FIN~DNK~BEL\" loading=\"lazy\" style=\"width: 100%; height: 600px; border: 0px none;\"></iframe>\n</div>\n</div>\n\n\n\n<h3>Fuel economy of new passenger vehicles</h3>\n\n\n\n<div class=\"wp-block-columns\">\n<div class=\"wp-block-column\">\n<p>This interacrive chart shows the average fuel economy of new passenger vehicles in each country.</p>\n\n\n\n<p>This is measured as the average liters consumed per 100 kilometers travelled, across all types of passenger vehicles.</p>\n</div>\n\n\n\n<div class=\"wp-block-column\">\n<iframe src=\"https://ourworldindata.org/grapher/fuel-efficiency-new-vehicles?country=AUT~BEL~ITA~LUX~NLD~NOR~PRT~ESP~SWE~CHE~TUR~GBR~IRL~ISL~GRC~DEU~FRA~FIN~DNK\" loading=\"lazy\" style=\"width: 100%; height: 600px; border: 0px none;\"></iframe>\n</div>\n</div>\n\n\n\n<h2>Aviation</h2>\n\n\n\n<h3>What share of global CO<sub>2</sub> emissions come from aviation?</h3>\n\n\n\n<p>Flying is a highly controversial topic in climate debates. There are a few reasons for this.&nbsp;</p>\n\n\n\n<p>The first is the disconnect between its role in our personal and collective carbon emissions. Air travel dominates a frequent traveller&#8217;s individual contribution to climate change. Yet aviation overall accounts for only 2.5% of global carbon dioxide (CO<sub>2</sub>) emissions. This is because there are large inequalities in how much people fly \u2013 many do not, or cannot afford to, fly at all.{ref}The best estimates put this figure at around 80% of the world population. We look at this in more detail in our article &#8220;<a href=\"https://ourworldindata.org/carbon-footprint-flying\">Where in the world do people have the highest CO2 emissions from flying?</a>&#8220;{/ref}</p>\n\n\n\n<p>The second is how aviation emissions are attributed to countries. CO<sub>2</sub> emissions from domestic flights <em>are</em> counted in a country\u2019s emission accounts. International flights are not \u2013 instead they are counted as their own category: \u2018bunker fuels\u2019. The fact that they don\u2019t count towards the emissions of any country means there are few incentives for countries to reduce them.</p>\n\n\n\n<p>It\u2019s also important to note that unlike the most common greenhouse gases \u2013 carbon dioxide, methane or nitrous oxide \u2013 non-CO<sub>2</sub> forcings from aviation <em>are not included</em> in the Paris Agreement. This means they could be easily overlooked \u2013 especially since international aviation is not counted within any country\u2019s emissions inventories or targets.</p>\n\n\n\n<p>How much of a role does aviation play in global emissions and climate change? In this article we take a look at the key numbers that are useful to know.</p>\n\n\n\n<p>Global aviation (including domestic and international; passenger and freight) accounts for:</p>\n\n\n\n<ul><li><strong>1.9%</strong> of <a href=\"https://ourworldindata.org/ghg-emissions-by-sector\">greenhouse gas emissions</a> (which includes all greenhouse gases, not only CO<sub>2</sub>)</li><li><strong>2.5%</strong> of CO<sub>2</sub> emissions</li><li><strong>3.5%</strong> of &#8216;effective radiative forcing&#8217; \u2013 a closer measure of its impact on warming.</li></ul>\n\n\n\n<p>The latter two numbers refer to 2018, and the first to 2016, the latest year for which such data are available.</p>\n\n\n\n<hr class=\"wp-block-separator\"/>\n\n\n\n<h4>Aviation accounts for 2.5% of global CO<sub>2</sub> emissions</h4>\n\n\n\n<p>As we will see later in this article, there are a number of processes by which aviation contributes to climate change. But the one that gets the most attention is its contribution via CO<sub>2</sub> emissions. Most flights are powered by jet gasoline \u2013 although some partially run on biofuels \u2013 which is converted to CO<sub>2</sub> when burned.&nbsp;&nbsp;</p>\n\n\n\n<p>In a recent paper, researchers \u2013 David Lee and colleagues \u2013 reconstructed annual CO<sub>2 </sub>emissions from global aviation dating back to 1940.{ref}Lee, D. S., Fahey, D. W., Skowron, A., Allen, M. R., Burkhardt, U., Chen, Q., &#8230; &amp; Gettelman, A. (2020). <a href=\"https://www.sciencedirect.com/science/article/pii/S1352231020305689\">The contribution of global aviation to anthropogenic climate forcing for 2000 to 2018</a>. <em>Atmospheric Environment</em>, 117834.{/ref} This was calculated based on fuel consumption data from the International Energy Agency (IEA), and earlier estimates from Robert Sausen and Ulrich Schumann (2000).{ref}Sausen, R., &amp; Schumann, U. (2000). <a href=\"https://link.springer.com/article/10.1023/A:1005579306109\">Estimates of the climate response to aircraft CO2 and NOx emissions scenarios</a>. <em>Climatic Change</em>, <em>44</em>(1-2), 27-58.{/ref}</p>\n\n\n\n<p>The time series of global emissions from aviation since 1940 is shown in the accompanying chart. In 2018, it\u2019s estimated that global aviation \u2013 which includes both passenger and freight \u2013 emitted 1.04 billion tonnes of CO<sub>2</sub>.</p>\n\n\n\n<p>This represented 2.5% of <a href=\"https://ourworldindata.org/co2-emissions#global-co2-emissions-from-fossil-fuels-global-co2-emissions-from-fossil-fuels\" data-type=\"URL\" data-id=\"https://ourworldindata.org/co2-emissions#global-co2-emissions-from-fossil-fuels-global-co2-emissions-from-fossil-fuels\">total CO<sub>2</sub> emissions</a> in 2018.{ref}The Global Carbon Budget estimated total CO<sub>2</sub> emissions from all fossil fuels, cement production and land-use change to be 42.1 billion tonnes in 2018. This means aviation accounted for [1 / 42.1 * 100] = 2.5% of total emissions.{/ref}<sup>,</sup>{ref}Global Carbon Project. (2019). Supplemental data of Global Carbon Budget 2019 (Version 1.0) [Data set]. Global Carbon Project. <a href=\"https://doi.org/10.18160/gcp-2019\">https://doi.org/10.18160/gcp-2019</a>.<br><br>If we were to exclude land use change emissions, aviation accounted for 2.8% of fossil fuel emissions. The Global Carbon Budget estimated total CO<sub>2</sub> emissions from fossil fuels and cement production to be 36.6 billion tonnes in 2018. This means aviation accounted for [1 / 36.6 * 100] = 2.8% of total emissions.{/ref}</p>\n\n\n\n<p>Aviation emissions have doubled since the mid-1980s. But, they\u2019ve been growing at a similar rate as total CO<sub>2</sub> emissions \u2013 this means its share of global emissions has been relatively stable: in the range of 2% to 2.5%.{ref}2.3% to 2.8% of emissions if land use is excluded.{/ref}</p>\n\n\n\n<figure class=\"wp-block-image size-large\"><img loading=\"lazy\" width=\"693\" height=\"550\" src=\"https://owid.cloud/app/uploads/2020/10/Global-CO2-emissions-from-aviation-693x550.png\" alt=\"\" class=\"wp-image-36836\" srcset=\"https://owid.cloud/app/uploads/2020/10/Global-CO2-emissions-from-aviation-693x550.png 693w, https://owid.cloud/app/uploads/2020/10/Global-CO2-emissions-from-aviation-400x318.png 400w, https://owid.cloud/app/uploads/2020/10/Global-CO2-emissions-from-aviation-150x119.png 150w, https://owid.cloud/app/uploads/2020/10/Global-CO2-emissions-from-aviation-768x610.png 768w, https://owid.cloud/app/uploads/2020/10/Global-CO2-emissions-from-aviation.png 1505w\" sizes=\"(max-width: 693px) 100vw, 693px\" /></figure>\n\n\n\n<h4>Non-CO<sub>2</sub> climate impacts mean aviation accounts for 3.5% of global warming</h4>\n\n\n\n<p>Aviation accounts for around 2.5% of global CO<sub>2</sub> emissions, but it\u2019s overall contribution to climate change is higher. This is because air travel does not only emit CO<sub>2</sub>: it affects the climate in a number of more complex ways.</p>\n\n\n\n<p>As well as emitting CO<sub>2</sub> from burning fuel, planes affect the concentration of other gases and pollutants in the atmosphere. They result in a short-term increase, but long-term decrease in ozone (O<sub>3</sub>); a decrease in methane (CH<sub>4</sub>); emissions of water vapour; soot; sulfur aerosols; and water contrails. While some of these impacts result in warming, others induce a cooling effect. Overall, the warming effect is stronger.</p>\n\n\n\n<p>David Lee et al. (2020) quantified the overall effect of aviation on global warming when all of these impacts were included.{ref}Lee, D. S., Fahey, D. W., Skowron, A., Allen, M. R., Burkhardt, U., Chen, Q., &#8230; &amp; Gettelman, A. (2020). <a href=\"https://www.sciencedirect.com/science/article/pii/S1352231020305689\">The contribution of global aviation to anthropogenic climate forcing for 2000 to 2018</a>. <em>Atmospheric Environment</em>, 117834.{/ref} To do this they calculated the so-called \u2018Radiative Forcing\u2019. Radiative forcing measures the difference between incoming energy and the energy radiated back to space. If more energy is absorbed than radiated, the atmosphere becomes warmer.&nbsp;</p>\n\n\n\n<p>In their chart we see <a href=\"https://ars.els-cdn.com/content/image/1-s2.0-S1352231020305689-gr3_lrg.jpg\" target=\"_blank\" rel=\"noreferrer noopener\">their estimates for the radiative forcing</a> of the different elements. When we combine them, aviation accounts for approximately 3.5% of effective radiative forcing: that is, 3.5% of warming.<br><br>Although CO<sub>2&nbsp; </sub>gets most of the attention, it accounts for less than half of this warming. Two-thirds (66%) comes from non-CO<sub>2 </sub>forcings. Contrails \u2013 water vapor trails from aircraft exhausts \u2013 account for the largest share.</p>\n\n\n\n<h4>We don\u2019t yet have the technologies to decarbonize air travel</h4>\n\n\n\n<p>Aviation\u2019s contribution to climate change \u2013 3.5% of warming, or 2.5% of CO<sub>2</sub> emissions \u2013 is often less than people think. It\u2019s currently a relatively small chunk of emissions compared to other sectors.&nbsp;</p>\n\n\n\n<p>The key challenge is that it is particularly hard to decarbonize. We have solutions to reduce emissions for many of the <a href=\"https://ourworldindata.org/ghg-emissions-by-sector\">largest emitters</a> \u2013 such as power or road transport \u2013 and it\u2019s now a matter of scaling them. We can deploy renewable and nuclear energy technologies, and transition to electric cars. But we don\u2019t have proven solutions to tackle aviation yet. </p>\n\n\n\n<p>There are some design concepts emerging \u2013 Airbus, for example, <a href=\"https://web.archive.org/web/20201031121346/https://www.airbus.com/innovation/zero-emission/hydrogen/zeroe.html\" data-type=\"URL\" data-id=\"https://web.archive.org/web/20201031121346/https://www.airbus.com/innovation/zero-emission/hydrogen/zeroe.html\">have announced plans</a> to have the first zero-emission aircraft by 2035, using hydrogen fuel cells. Electric planes may be a viable concept, but are likely to be limited to very small aircraft due to the limitations of battery technologies and capacity.&nbsp;</p>\n\n\n\n<p>Innovative solutions may be on the horizon, but they\u2019re likely to be far in the distance.</p>\n\n\n    <block type=\"prominent-link\" style=\"is-style-thin\">\n        <link-url>http://ourworldindata.org/co2-emissions-from-transport</link-url>\n        <title>Towards zero-carbon transport: how can we expect the sector\u2019s CO<sub>2</sub> emissions to change in the future?</title>\n        <content>\n\n<p></p>\n\n</content>\n        <figure><img width=\"768\" height=\"485\" src=\"https://owid.cloud/app/uploads/2020/10/IEA-Transport-to-2070-768x485.png\" class=\"attachment-medium_large size-medium_large\" alt=\"\" loading=\"lazy\" srcset=\"https://owid.cloud/app/uploads/2020/10/IEA-Transport-to-2070-768x485.png 768w, https://owid.cloud/app/uploads/2020/10/IEA-Transport-to-2070-400x253.png 400w, https://owid.cloud/app/uploads/2020/10/IEA-Transport-to-2070-800x505.png 800w, https://owid.cloud/app/uploads/2020/10/IEA-Transport-to-2070-150x95.png 150w, https://owid.cloud/app/uploads/2020/10/IEA-Transport-to-2070-1536x970.png 1536w, https://owid.cloud/app/uploads/2020/10/IEA-Transport-to-2070.png 1732w\" sizes=\"(max-width: 768px) 100vw, 768px\" /></figure>\n    </block>\n\n\t<block type=\"additional-information\" default-open=\"true\">\n\t\t<content>\n\n<h3>Appendix: <strong>Efficiency improvements means air traffic has increased more rapidly than emissions</strong></h3>\n\n\n\n<div class=\"wp-block-columns is-style-sticky-right\">\n<div class=\"wp-block-column\">\n<p>Global emissions from aviation have increased a lot over the past half-century. However, air travel volumes increased even more rapidly.&nbsp;</p>\n\n\n\n<p>Since 1960, aviation emissions increased almost seven-fold; since 1970 they\u2019ve tripled. Air traffic volume \u2013 here defined as revenue passenger kilometers (RPK) traveled \u2013 <a href=\"https://ourworldindata.org/grapher/airline-capacity-and-traffic\">increased by orders of magnitude more</a>: almost 300-fold since 1950; and 75-fold since 1960.{ref}Airline traffic data comes from the International Civil Aviation Organization (ICAO) via <a href=\"https://www.airlines.org/dataset/world-airlines-traffic-and-capacity\">Airlines for America</a>. Revenue passenger kilometers (RPK) measures the number of paying passengers multiplied by their distance traveled.{/ref}\u00a0</p>\n\n\n\n<p>The much slower growth in emissions means aviation efficiency has seen massive improvements. In the chart we show both the increase in global airline traffic since 1950, and aviation efficiency, measured as the quantity of CO<sub>2</sub> emitted per revenue passenger kilometer traveled. In 2018, approximately 125 grams of CO<sub>2 </sub>&nbsp;were emitted per RPK. In 1960, this was eleven-fold higher; in 1950 it was twenty-fold higher. Aviation has seen massive efficiency improvements over the past 50 years.</p>\n\n\n\n<p>These improvements have come from several sources: improvements in the design and technology of aircraft; larger aircraft sizes (allowing for more passengers per flight); and an increase in how \u2018full\u2019 passenger flights are. This last metric is termed the \u2018passenger load factor\u2019. The passenger load factor measures the actual number of kilometers traveled by paying customers (RPK) as a percentage of the available seat kilometers (ASK) \u2013 the kilometers traveled if every plane was full. If every plane was full the passenger load factor would be 100%. If only three-quarters of the seats were filled, it would be 75%.</p>\n\n\n\n<p>The global passenger load factor <a href=\"https://ourworldindata.org/grapher/airline-passenger-load-factor\">increased from 61% in 1950 to 82% in 2018</a>.\u00a0\u00a0</p>\n</div>\n\n\n\n<div class=\"wp-block-column\">\n<figure class=\"wp-block-image size-large\"><img loading=\"lazy\" width=\"800\" height=\"505\" src=\"https://owid.cloud/app/uploads/2020/10/Aviation-traffic-and-efficiency-Lee-et-al.-2020-800x505.png\" alt=\"\" class=\"wp-image-36837\" srcset=\"https://owid.cloud/app/uploads/2020/10/Aviation-traffic-and-efficiency-Lee-et-al.-2020-800x505.png 800w, https://owid.cloud/app/uploads/2020/10/Aviation-traffic-and-efficiency-Lee-et-al.-2020-400x253.png 400w, https://owid.cloud/app/uploads/2020/10/Aviation-traffic-and-efficiency-Lee-et-al.-2020-150x95.png 150w, https://owid.cloud/app/uploads/2020/10/Aviation-traffic-and-efficiency-Lee-et-al.-2020-768x485.png 768w, https://owid.cloud/app/uploads/2020/10/Aviation-traffic-and-efficiency-Lee-et-al.-2020-1536x970.png 1536w, https://owid.cloud/app/uploads/2020/10/Aviation-traffic-and-efficiency-Lee-et-al.-2020.png 1832w\" sizes=\"(max-width: 800px) 100vw, 800px\" /></figure>\n</div>\n</div>\n\n</content>\n\t</block>\n\n\n<h3>Passenger vs. freight; domestic vs. international: where do aviation emissions come from?</h3>\n\n\n\n<p>Global aviation \u2013 both passenger flights and freight \u2013 emits around one billion tonnes of carbon dioxide (CO<sub>2</sub>) each year. This was equivalent to around 2.4% of CO<sub>2</sub> emissions in 2018.</p>\n\n\n\n<p>How do global aviation emissions break down?</p>\n\n\n\n<p>The chart gives the answer. This data is sourced from the 2019 <em>International Council on Clean Transportation</em> <em>(ICCT)</em> report on global aviation.{ref}Graver, B., Zhang, K., &amp; Rutherford, D. (2019). <a href=\"https://theicct.org/sites/default/files/publications/ICCT_CO2-commercl-aviation-2018_20190918.pdf\" target=\"_blank\" rel=\"noreferrer noopener\">CO2 emissions from commercial aviation, 2018</a>. <em>The International Council of Clean Transportation</em>.{/ref}</p>\n\n\n\n<p>Most emissions come from passenger flights \u2013 in 2018, they accounted for 81% of aviation\u2019s emissions; the remaining 19% came from freight, the transport of goods.&nbsp;</p>\n\n\n\n<p>Sixty percent of emissions from<em> passenger</em> flights come from international travel; the other 40% come from domestic (in-country) flights.&nbsp;</p>\n\n\n\n<p>When we break passenger flight emissions down by travel distance, we get a (surprisingly) equal three-way split in emissions between short-haul (less than 1,500 kilometers); medium-haul (1,500 to 4,000 km); and long-haul (greater than 4,000 km) journeys.</p>\n\n\n\n<figure class=\"wp-block-image size-large\"><img loading=\"lazy\" width=\"800\" height=\"507\" src=\"https://owid.cloud/app/uploads/2020/10/Global-breakdown-of-aviation-emissions-800x507.png\" alt=\"\" class=\"wp-image-36848\" srcset=\"https://owid.cloud/app/uploads/2020/10/Global-breakdown-of-aviation-emissions-800x507.png 800w, https://owid.cloud/app/uploads/2020/10/Global-breakdown-of-aviation-emissions-400x253.png 400w, https://owid.cloud/app/uploads/2020/10/Global-breakdown-of-aviation-emissions-150x95.png 150w, https://owid.cloud/app/uploads/2020/10/Global-breakdown-of-aviation-emissions-768x486.png 768w, https://owid.cloud/app/uploads/2020/10/Global-breakdown-of-aviation-emissions-1536x973.png 1536w, https://owid.cloud/app/uploads/2020/10/Global-breakdown-of-aviation-emissions.png 1650w\" sizes=\"(max-width: 800px) 100vw, 800px\" /></figure>\n\n\n\n<h4>The richest half are responsible for 90% of air travel CO<sub>2</sub> emissions</h4>\n\n\n\n<p>The global inequalities in how much people fly become clear when we compare aviation emissions across countries of different income levels. The ICCT split these emissions based on World Bank&#8217;s four <a href=\"https://ourworldindata.org/grapher/world-banks-income-groups?year=latest\" target=\"_blank\" rel=\"noreferrer noopener\">income groups</a>.</p>\n\n\n\n<p>A further study by Susanne Becek and Paresh Pant (2019) compared the contribution of each income group to global air travel emissions versus its share of world population.{ref}Becken, S. and P. Pant (2019). <a href=\"https://amadeus.com/en/insights/white-paper/airline-initiatives-to-reduce-climate-impact\" target=\"_blank\" rel=\"noreferrer noopener\">Airline initiatives to reduce climate impact: ways to accelerate action</a> (White paper).{/ref} This comparison is shown in the visualization.</p>\n\n\n\n<p>The \u2018richest\u2019 half of the world (high and upper-middle income countries) were responsible for 90% of air travel emissions.{ref}Note that this is based on categorisations from the average income level of countries, and does not take account of variation in income <em>within </em>countries. If we were to look at this distribution based on the income level of individuals rather than countries, the inequality in aviation emissions would be even larger.{/ref}</p>\n\n\n\n<p>Looking at specific income groups:</p>\n\n\n\n<ul><li>Only 16% of the world population live in high-income countries yet the planes that take off in those countries account for almost two-thirds (62%) of passenger emissions;</li><li>Upper-middle income countries are home to 35% of the world population, and contribute 28% of emissions;</li><li>Lower-middle income countries are home to the largest share (40% of the world), yet emit the planes taking off there just account for 9%;</li><li>The poorest countries \u2013 which are home to 9% of the world population \u2013 emit just 1%.</li></ul>\n\n\n\n<p>In an upcoming article we will look in more detail at the contribution of each country to global aviation emissions.</p>\n\n\n\n<figure class=\"wp-block-image size-large\"><img loading=\"lazy\" width=\"800\" height=\"437\" src=\"https://owid.cloud/app/uploads/2020/10/Inequalities-in-CO2-emissions-from-air-travel-800x437.png\" alt=\"\" class=\"wp-image-36849\" srcset=\"https://owid.cloud/app/uploads/2020/10/Inequalities-in-CO2-emissions-from-air-travel-800x437.png 800w, https://owid.cloud/app/uploads/2020/10/Inequalities-in-CO2-emissions-from-air-travel-400x219.png 400w, https://owid.cloud/app/uploads/2020/10/Inequalities-in-CO2-emissions-from-air-travel-150x82.png 150w, https://owid.cloud/app/uploads/2020/10/Inequalities-in-CO2-emissions-from-air-travel-768x420.png 768w, https://owid.cloud/app/uploads/2020/10/Inequalities-in-CO2-emissions-from-air-travel-1536x840.png 1536w, https://owid.cloud/app/uploads/2020/10/Inequalities-in-CO2-emissions-from-air-travel.png 1655w\" sizes=\"(max-width: 800px) 100vw, 800px\" /></figure>\n\n\n\n<h3>Where in the world do people have the highest carbon footprint from flying?</h3>\n\n\n\n<p>Aviation accounts <a href=\"https://ourworldindata.org/co2-emissions-from-aviation\" target=\"_blank\" rel=\"noreferrer noopener\">for around 2.5%</a> of global carbon dioxide (CO<sub>2</sub>) emissions. But if you are someone who does fly, air travel will make up a much larger share of your personal carbon footprint.</p>\n\n\n\n<p>The fact that aviation is relatively small for global emissions as a whole, but of large importance for individuals that fly is due to large inequalities in the world. Most people in the&nbsp; world do not take flights. There is no global reliable figure, but often cited estimates suggest that more than 80% of the global population have never flown.{ref}There is no global database available on <em>who</em> in the world flies each year. Passenger information is maintained by private airlines. Therefore, deriving estimates of this exact percentage is challenging. The most-cited estimate I\u2019ve seen on this is that around 80% of the world population have never flown. This figure seems to circle back to a <a href=\"https://www.cnbc.com/2017/12/07/boeing-ceo-80-percent-of-people-never-flown-for-us-that-means-growth.html#:~:text=%E2%80%9CLess%20than%2020%20percent%20of,the%20entire%20economy%2C%20Muilenburg%20said.\">quoted estimate</a> from the Boeing CEO.<br><br>Even in some of the world\u2019s richest countries, a large share of the population do not fly frequently. Gallup <a href=\"https://news.gallup.com/poll/1579/airlines.aspx\">survey data</a> from the United States suggests that in 2015, half of the population did not take a flight. Survey data from the UK <a href=\"http://publicapps.caa.co.uk/docs/33/CAA%20Aviation%20Consumer%20survey%20--%205th%20wave%20report%20FINAL%20(2).pdf\">provides similar estimates</a>: 46% had not flown in the previous year.{/ref}</p>\n\n\n\n<p>How do emissions from aviation vary across the world? Where do people have the highest footprint from flying?</p>\n\n\n\n<h4>Per capita emissions from domestic flights</h4>\n\n\n\n<div class=\"wp-block-columns\">\n<div class=\"wp-block-column\">\n<p>The first and most straightforward comparison is to look at emissions from <em>domestic</em> aviation \u2013 that is, flights that depart and arrive in the same country.&nbsp;</p>\n\n\n\n<p>This is easiest to compare because domestic aviation is counted in each country\u2019s inventory of greenhouse gas emissions. International flights, on the other hand, are not attributed to specific countries \u2013 partly because of contention as to who should take responsibility (should it be the country of departure or arrival? What about layover flights?).</p>\n\n\n\n<p>In the chart here we see the average per capita emissions from domestic flights in 2018. This data is sourced from the <em>International Council on Clean Transportation</em> \u2013 we then used <a href=\"https://population.un.org/wpp/\">UN population estimates</a> to calculate per capita figures.{ref}Graver, B., Zhang, K., &amp; Rutherford, D. (2019). <a href=\"https://theicct.org/publications/co2-emissions-commercial-aviation-2018\">CO2 emissions from commercial aviation, 2018</a>. <em>The International Council of Clean Transportation</em>.{/ref}<sup>,</sup>{ref}Note that this gives us <em>mean</em> per capita emissions, which&nbsp; does not account for in-country inequalities in the amount of flights people take.{/ref}</p>\n\n\n\n<p>We see large differences in emissions from domestic flights across the world. In the United States the average person emits around 386 kilograms of CO<sub>2</sub> each year from internal flights. This is followed by Australia (267 kg); Norway (209 kg); New Zealand (174 kg); and Canada (168 kg). Compare this with&nbsp; countries at the bottom of the table \u2013 many across Africa, Asia, and Eastern Europe in particular emit less than one kilogram per person \u2013 just 0.8 kilograms; or 0.14 kilograms in Rwanda. For very small countries where there are no internal commercial flights, domestic emissions are of course, zero.</p>\n\n\n\n<p>There are some obvious factors that explain some of these cross-country differences. Firstly, countries that are richer <a href=\"https://ourworldindata.org/grapher/per-capita-co2-domestic-aviation-vs-gdp\">are more likely</a> to have higher emissions because people can afford to fly. Second, countries that have a larger land mass may have more internal flights \u2013&nbsp;and indeed we see a <a href=\"https://ourworldindata.org/grapher/per-capita-co2-domestic-aviation-vs-land-area\">correlation</a> between land area and domestic flight emissions; in small countries people are more likely to travel by other means such as car or train.&nbsp; And third, countries that are more geographically-isolated \u2013 such as Australia and New Zealand \u2013 may have more internal travel.</p>\n</div>\n\n\n\n<div class=\"wp-block-column\">\n<iframe src=\"https://ourworldindata.org/grapher/per-capita-co2-domestic-aviation\" loading=\"lazy\" style=\"width: 100%; height: 600px; border: 0px none;\"></iframe>\n\n\n\n<h5>Related charts:</h5>\n\n\n    <block type=\"prominent-link\" style=\"is-style-thin\">\n        <link-url>https://ourworldindata.org/grapher/co2-emissions-domestic-aviation</link-url>\n        <title>Total CO\u2082 emissions from domestic aviation</title>\n        <content></content>\n        <figure></figure>\n    </block>\n\n    <block type=\"prominent-link\" style=\"is-style-thin\">\n        <link-url>https://ourworldindata.org/grapher/share-global-co2-domestic-aviation</link-url>\n        <title>Share of global CO\u2082 emissions from domestic aviation</title>\n        <content></content>\n        <figure></figure>\n    </block></div>\n</div>\n\n\n\n<h4>Per capita emissions from international flights</h4>\n\n\n\n<div class=\"wp-block-columns\">\n<div class=\"wp-block-column\">\n<p>Allocating emissions from international flights is more complex. International databases report these emissions separately as a category termed \u2018bunker fuels\u2019. The term \u2018bunker fuel\u2019 is used to describe emissions which come from international transport \u2013 either aviation or shipping.</p>\n\n\n\n<p>Because they are <a href=\"https://unfccc.int/topics/mitigation/workstreams/emissions-from-international-transport-bunker-fuels\">not counted towards</a> any particular country these emissions are also not taken into account in the goals that are set by countries in international treaties like the Kyoto protocol or the Paris Agreement.{ref}Larsson, J., Kamb, A., N\u00e4ss\u00e9n, J., &amp; \u00c5kerman, J. (2018). <a href=\"https://www.sciencedirect.com/science/article/pii/S0195925517303116\">Measuring greenhouse gas emissions from international air travel of a country\u2019s residents methodological development and application for Sweden</a>. <em>Environmental Impact Assessment Review</em>, <em>72</em>, 137-144.{/ref}</p>\n\n\n\n<p>But if we wanted to allocate them to a particular country, how would we do it? Who do emissions from international flights belong to: the country that owns the airline; the country of departure; the country of arrival?</p>\n\n\n\n<p>Let\u2019s first take a look at how emissions would compare if we allocated them to the country of <em>departure</em>. This means, for example, that emissions from any flight that departs from Spain are counted towards Spain\u2019s total. In the chart here we see international aviation emissions in per capita terms.</p>\n\n\n\n<p>Some of the largest emitters per person in 2018 were Iceland (3.5 tonnes of CO<sub>2</sub> per person); Qatar (2.5 tonnes); United Arab Emirates (2.2 tonnes); Singapore (1.7 tonnes); and Malta (992 kilograms).&nbsp;</p>\n\n\n\n<p>Again, we see large inequalities in emissions across the world \u2013 in many lower-income countries per capita emissions are only a few kilograms: 6 kilograms in India, 4 kilograms in Nigeria; and only 1.4 kilograms in the Democratic Republic of Congo.</p>\n</div>\n\n\n\n<div class=\"wp-block-column\">\n<iframe src=\"https://ourworldindata.org/grapher/per-capita-co2-international-aviation?stackMode=absolute&amp;time=latest&amp;region=World\" loading=\"lazy\" style=\"width: 100%; height: 600px; border: 0px none;\"></iframe>\n\n\n\n<h5>Related charts:</h5>\n\n\n    <block type=\"prominent-link\" style=\"is-style-thin\">\n        <link-url>https://ourworldindata.org/grapher/co2-international-aviation</link-url>\n        <title>Total CO\u2082 emissions from international aviation</title>\n        <content></content>\n        <figure></figure>\n    </block>\n\n    <block type=\"prominent-link\" style=\"is-style-thin\">\n        <link-url>https://ourworldindata.org/grapher/share-co2-international-aviation</link-url>\n        <title>Share of global CO\u2082 emissions from international aviation</title>\n        <content></content>\n        <figure></figure>\n    </block></div>\n</div>\n\n\n\n<h4>Per capita emissions from international flights \u2013 adjusted for tourism</h4>\n\n\n\n<div class=\"wp-block-columns\">\n<div class=\"wp-block-column\">\n<p>The above allocation of international aviation emissions to the country of <em>departure</em> raises some issues. It is not an accurate reflection of the local population of countries that rely a lot on tourism, for example. Most of the departing flights from these countries are carrying visiting tourists rather than locals.&nbsp;</p>\n\n\n\n<p>One way to correct for this is to adjust these figures for the ratio of inbound to outbound travellers. This approach was applied <a href=\"https://theicct.org/blog/staff/not-every-tonne-of-aviation-CO2\">in an analysis</a> by Sola Zheng for the <em>International Council on Clean Transportation</em>. This attempts to distinguish between locals traveling abroad and foreign visitors traveling to that country on the same flight.{ref}A country with a ratio greater than one will have more incoming travellers than outgoing locals i.e. they are more of a hotspot for tourism.{/ref} For example, if we calculated that Spain had 50% more incoming than outgoing travellers, we would reduce its per capita footprint from flying by 50%. If the UK had 75% more outgoing travellers than incoming, we\u2019d increase its footprint by 75%.</p>\n\n\n\n<p>We have replicated this approach and&nbsp; applied this adjustment to these figures by calculating the <a href=\"https://ourworldindata.org/grapher/ratio-of-inbound-to-outbound-tourists\">inbound:outbound tourist ratio</a> based on flight departures and arrival data from the <a href=\"https://datacatalog.worldbank.org/dataset/world-development-indicators\">World Bank</a>.&nbsp;</p>\n\n\n\n<p>How does this affect per capita emissions from international flights? The adjusted figures are shown in the chart here.</p>\n\n\n\n<p>As we would expect, countries which are tourist hotspots see the largest change. Portugal\u2019s emissions, for example, fall from 388 to just 60 kilograms per person. Portuguese locals are responsible for much fewer travel emissions than outgoing tourists. Spanish emissions fall from 335 to 77 kilograms per person.</p>\n\n\n\n<p>On the other hand, countries where the locals travel elsewhere see a large increase. In the UK, they almost double from 422 to 818 kilograms.</p>\n</div>\n\n\n\n<div class=\"wp-block-column\">\n<iframe src=\"https://ourworldindata.org/grapher/per-capita-co2-international-flights-adjusted?stackMode=absolute&amp;time=latest&amp;region=World\" loading=\"lazy\" style=\"width: 100%; height: 600px; border: 0px none;\"></iframe>\n</div>\n</div>\n\n\n\n<h4>Per capita emissions from domestic <em>and </em>international flights</h4>\n\n\n\n<div class=\"wp-block-columns\">\n<div class=\"wp-block-column\">\n<p>Let\u2019s combine per capita emissions from domestic and international travel to compare the total footprint from flying.</p>\n\n\n\n<p>This is shown in the interactive map <em>[we\u2019ve taken the adjusted international figures \u2013 you can find the&nbsp; combined figures without tourism-adjustment </em><a href=\"https://ourworldindata.org/grapher/per-capita-co2-aviation\"><strong><em>here</em></strong></a><em>].&nbsp;</em></p>\n\n\n\n<p>The global average emissions from aviation were 103 kilograms. The inequality in emissions across the world becomes clear when this is broken down by country.&nbsp;</p>\n\n\n\n<p>At the top of the table lies the United Arab Emirates \u2013 each person emits close to two tonnes \u2013 1950 kg \u2013 of CO<sub>2</sub> from flying each year. That\u2019s 200 times the global average.&nbsp; This was followed by Singapore (1173 kilograms); Iceland (1070 kg); Finland (1000 kg); and Australia (878 kilograms).&nbsp;</p>\n\n\n\n<p>To put this into perspective: a return flight (in economy class) from London to Dubai/United Arab Emirates would emit around one tonne of CO<sub>2</sub>.{ref}We can calculate this by taking the standard CO2 conversion factors for travel, used in the <a href=\"https://www.gov.uk/government/publications/greenhouse-gas-reporting-conversion-factors-2019\">UK greenhouse gas accounting framework</a>. For a long-haul flight in economy class, around 0.079 kilograms of CO<sub>2</sub> <a href=\"https://ourworldindata.org/travel-carbon-footprint\">are emitted</a> per passenger-kilometer. This means that you would travel around 12,600 kilometers to emit one tonne [1,000,000 / 0.079 kg = 12,626 kilometers]. Since we\u2019re taking a return flight, the travel distance would be half of that figure: around 6300 kilometers. The direct distance from <a href=\"https://www.distance.to/London/Dubai,ARE\">London to Dubai</a> is around 5,500 kilometers. Depending on the flight path, it\u2019s likely to be slightly longer than this, and in the range of 5500 to 6500 kilometers.</p>\n\n\n\n<p>Note that in this case we\u2019re looking at CO<sub>2</sub> emissions <em>without</em> the extra warming effects of these emissions at high altitudes. This is to allow us to compare with the ICCT figures by country presented in this article. You find additional data on how the footprint of flying is impacted by non-CO<sub>2</sub> warming effects<a href=\"https://ourworldindata.org/grapher/carbon-footprint-travel-mode\"> <strong>here</strong></a>.{/ref} So the two-tonne average for the UAE is equivalent to around two return trips to London.</p>\n\n\n\n<p>In many countries, most people do not fly at all. The average Indian emits just 18 kilograms from aviation \u2013 this is much, much less than even a short-haul flight which confirms that most did not take a flight.</p>\n\n\n\n<p>In fact, we can compare just the aviation emissions for the top countries to the <em>total</em> carbon footprint of citizens elsewhere. The average UAE citizen emits 1950 kilograms of CO<sub>2</sub> from flying. This is the same as the <em>total</em> <a href=\"https://ourworldindata.org/explorers/co2?tab=chart&amp;xScale=linear&amp;yScale=linear&amp;stackMode=absolute&amp;endpointsOnly=0&amp;year=latest&amp;time=1858..2018&amp;country=~India&amp;region=World&amp;Gas%20=CO%E2%82%82&amp;Accounting%20=Production-based&amp;Fuel%20=Total&amp;Count%20=Per%20capita&amp;Relative%20to%20world%20total%20=\">CO<sub>2</sub> footprint of the average Indian</a> (including everything from electricity to road transport, heating and industry). Or, to take a more extreme example, 200 times the total footprint of the average Nigerien, Ugandan or Ethiopian, which <a href=\"https://ourworldindata.org/explorers/co2?tab=chart&amp;xScale=linear&amp;yScale=linear&amp;stackMode=absolute&amp;endpointsOnly=0&amp;year=latest&amp;time=1958..2018&amp;country=Niger~Uganda~Ethiopia&amp;region=World&amp;Gas%20=CO%E2%82%82&amp;Accounting%20=Production-based&amp;Fuel%20=Total&amp;Count%20=Per%20capita&amp;Relative%20to%20world%20total%20=\">have per capita emissions</a> of around 100 kilograms.&nbsp;</p>\n\n\n\n<p>This again emphasises the large difference between the global average and the individual emissions of people who fly. Aviation contributes a few percent of total CO<sub>2</sub> emissions each year \u2013 this is not insignificant, but far from being the largest sector to tackle. Yet from the perspective of the individual, flying <em>is</em> often one of the largest chunks of our carbon footprint. The average rich person emits tonnes of CO<sub>2</sub> from flying each year \u2013 this is equivalent to the <em>total</em> carbon footprint of tens or hundreds of people in many countries of the world.</p>\n</div>\n\n\n\n<div class=\"wp-block-column\">\n<iframe src=\"https://ourworldindata.org/grapher/per-capita-co2-aviation-adjusted?stackMode=absolute&amp;region=World\" loading=\"lazy\" style=\"width: 100%; height: 600px; border: 0px none;\"></iframe>\n\n\n\n<h5>Related charts:</h5>\n\n\n    <block type=\"prominent-link\" style=\"is-style-thin\">\n        <link-url>https://ourworldindata.org/grapher/per-capita-co2-aviation</link-url>\n        <title>Per capita CO\u2082 emissions from aviation (without tourism adjustment)</title>\n        <content></content>\n        <figure></figure>\n    </block>\n\n    <block type=\"prominent-link\" style=\"is-style-thin\">\n        <link-url>https://ourworldindata.org/grapher/co2-emissions-aviation</link-url>\n        <title>Total CO\u2082 emissions from aviation</title>\n        <content></content>\n        <figure></figure>\n    </block>\n\n    <block type=\"prominent-link\" style=\"is-style-thin\">\n        <link-url>https://ourworldindata.org/grapher/share-co2-emissions-aviation</link-url>\n        <title>Share of global CO\u2082 emissions from aviation</title>\n        <content></content>\n        <figure></figure>\n    </block></div>\n</div>\n\n\n\n<h3>Where in the world do people fly the most?</h3>\n\n\n\n<h4>Domestic air travel</h4>\n\n\n\n<div class=\"wp-block-columns is-style-sticky-right\">\n<div class=\"wp-block-column\">\n<p>This interactive chart shows the average distance travelled per person through domestic air travel each year. This data is for passenger flights only and does not include freight.</p>\n</div>\n\n\n\n<div class=\"wp-block-column\">\n<iframe src=\"https://ourworldindata.org/grapher/per-capita-domestic-aviation-km\" loading=\"lazy\" style=\"width: 100%; height: 600px; border: 0px none;\"></iframe>\n\n\n\n<h5>Related charts:</h5>\n\n\n    <block type=\"prominent-link\" style=\"is-style-thin\">\n        <link-url>https://ourworldindata.org/grapher/share-global-domestic-aviation-km</link-url>\n        <title>Share of global passenger kilometers from domestic air travel</title>\n        <content>\n\n<p>What share of global domestic air travel does each country account for?</p>\n\n</content>\n        <figure></figure>\n    </block>\n\n    <block type=\"prominent-link\" style=\"is-style-thin\">\n        <link-url>https://ourworldindata.org/grapher/total-domestic-aviation-km</link-url>\n        <title>Total passenger kilometers from domestic air travel</title>\n        <content>\n\n<p></p>\n\n</content>\n        <figure></figure>\n    </block></div>\n</div>\n\n\n\n<h4>International air travel</h4>\n\n\n\n<div class=\"wp-block-columns is-style-sticky-right\">\n<div class=\"wp-block-column\">\n<p>This interactive chart shows the average distance travelled per person through international air travel each year. This data is for passenger flights only and does not include freight.</p>\n</div>\n\n\n\n<div class=\"wp-block-column\">\n<iframe src=\"https://ourworldindata.org/grapher/per-capita-international-aviation-km\" loading=\"lazy\" style=\"width: 100%; height: 600px; border: 0px none;\"></iframe>\n\n\n\n<h5>Related charts:</h5>\n\n\n    <block type=\"prominent-link\" style=\"is-style-thin\">\n        <link-url>https://ourworldindata.org/grapher/share-international-aviation-km</link-url>\n        <title>Share of global passenger kilometers from international air travel</title>\n        <content>\n\n<p>What share of global international air travel does each country account for?</p>\n\n</content>\n        <figure></figure>\n    </block>\n\n    <block type=\"prominent-link\" style=\"is-style-thin\">\n        <link-url>https://ourworldindata.org/grapher/passenger-km-international-aviation</link-url>\n        <title>Total passenger kilometers from international air travel</title>\n        <content>\n\n<p></p>\n\n</content>\n        <figure></figure>\n    </block></div>\n</div>\n\n\n\n<h4>Total air travel</h4>\n\n\n\n<div class=\"wp-block-columns is-style-sticky-right\">\n<div class=\"wp-block-column\">\n<p>This interactive chart shows the average distance travelled per person through domestic <em>and</em> international air travel each year. This data is for passenger flights only and does not include freight.</p>\n</div>\n\n\n\n<div class=\"wp-block-column\">\n<iframe src=\"https://ourworldindata.org/grapher/per-capita-km-aviation\" loading=\"lazy\" style=\"width: 100%; height: 600px; border: 0px none;\"></iframe>\n\n\n\n<h5>Related charts:</h5>\n\n\n    <block type=\"prominent-link\" style=\"is-style-thin\">\n        <link-url>https://ourworldindata.org/grapher/share-km-aviation</link-url>\n        <title>Share of global passenger kilometers from air travel</title>\n        <content>\n\n<p>What share of global air travel does each country account for?</p>\n\n</content>\n        <figure></figure>\n    </block>\n\n    <block type=\"prominent-link\" style=\"is-style-thin\">\n        <link-url>https://ourworldindata.org/grapher/total-aviation-km</link-url>\n        <title>Total passenger kilometers from air travel</title>\n        <content>\n\n<p></p>\n\n</content>\n        <figure></figure>\n    </block></div>\n</div>\n\n\n\n<h2>Rail</h2>\n\n\n\n<div class=\"wp-block-columns is-style-sticky-right\">\n<div class=\"wp-block-column\">\n<p>This interactive chart shows the total rail travel in each country, measured in passenger-kilometers per year.</p>\n\n\n\n<p>This includes passenger travel only and does not include freight.</p>\n</div>\n\n\n\n<div class=\"wp-block-column\">\n<iframe src=\"https://ourworldindata.org/grapher/railways-passengers-carried-passenger-km\" loading=\"lazy\" style=\"width: 100%; height: 600px; border: 0px none;\"></iframe>\n</div>\n</div>\n\n\n\n<h2>Energy intensity of transport</h2>\n\n\n\n<p>This chart shows the average energy intensity of transport across different modes of travel. It is measured as the average kilowatt-hours required per passenger-kilometer.</p>\n\n\n\n<p>This data comes from the United States Department of Transportation&#8217;s Bureau of Transportation Statistics (BTS). The energy intensity of public transport depends on the assumptions made about the capacity of transport modes i.e. how many passengers travel on a given train or bus journey. This data thererfore reflects average capacities in the United States, but will vary from country-to-country.</p>\n\n\n\n<iframe src=\"https://ourworldindata.org/grapher/energy-intensity-transport?country=Amtrak~Bus~Domestic+flight~International+flight~Motorcycle~~Transit+motor+bus~Truck+%28with+trailer%29~Truck~\" loading=\"lazy\" style=\"width: 100%; height: 600px; border: 0px none;\"></iframe>\n\n\n\n<h2>CO<sub>2</sub> emissions from transport</h2>\n\n\n\n<h3>Per capita transport emissions from transport</h3>\n\n\n\n<p>This interactive shows the average per capita emissions of carbon dioxide from transport each year. This includes road, train, bus and domestic air travel but <em>does not </em>include international aviation and shipping.</p>\n\n\n\n<iframe src=\"https://ourworldindata.org/grapher/per-capita-co2-transport?stackMode=absolute&amp;region=World\" loading=\"lazy\" style=\"width: 100%; height: 600px; border: 0px none;\"></iframe>\n\n\n\n<h3>Total transport emissions</h3>\n\n\n\n<p>This interactive shows the emissions of carbon dioxide from transport each year. This includes road, train, bus and domestic air travel but <em>does not </em>include international aviation and shipping.</p>\n\n\n\n<iframe src=\"https://ourworldindata.org/grapher/co2-emissions-transport?stackMode=absolute&amp;time=earliest..latest&amp;region=World\" loading=\"lazy\" style=\"width: 100%; height: 600px; border: 0px none;\"></iframe>\n\n\n\n<h3>CO<sub>2</sub> emissions by mode of transport</h3>\n\n\n\n<p>Transport accounts for around one-fifth of global carbon dioxide (CO<sub>2</sub>) emissions <em>[24% if we only consider CO<sub>2</sub> emissions from energy]</em>.{ref}The <em>World Resource Institute</em>\u2019s Climate Data Explorer <a href=\"https://www.climatewatchdata.org/data-explorer/historical-emissions?historical-emissions-data-sources=cait&amp;historical-emissions-gases=co2&amp;historical-emissions-regions=All%20Selected&amp;historical-emissions-sectors=total-including-lucf%2Ctransportation&amp;page=1&amp;sort_col=country&amp;sort_dir=ASC\">provides data</a> from CAIT on the breakdown of emissions by sector. In 2016, global CO<sub>2</sub> emissions (including land use) were 36.7 billion tonnes CO<sub>2</sub>; emissions from transport were 7.9 billion tonnes CO<sub>2</sub>. Transport therefore accounted for 7.9 / 36.7 = 21% of global emissions. </p>\n\n\n\n<p>The IEA <a href=\"https://www.iea.org/data-and-statistics/?country=WORLD&amp;fuel=CO2%20emissions&amp;indicator=TotCO2\">looks at CO<sub>2</sub> emissions</a> from energy production alone \u2013 in 2018 it reported 33.5 billion tonnes of energy-related CO<sub>2</sub> [hence, transport accounted for 8 billion / 33.5 billion = 24% of energy-related emissions.{/ref}</p>\n\n\n\n<p>How do these emissions break down? Is it cars, trucks, planes or trains that dominate?</p>\n\n\n\n<p>In the chart here we see global transport emissions in 2018. This data is <a href=\"https://www.iea.org/data-and-statistics/charts/transport-sector-co2-emissions-by-mode-in-the-sustainable-development-scenario-2000-2030\">sourced from</a> the <em>International Energy Agency (IEA)</em>.&nbsp;</p>\n\n\n\n<p>Road travel accounts for three-quarters of transport emissions. Most of this comes from passenger vehicles \u2013 cars and buses \u2013 which contribute 45.1%. The other 29.4% comes from trucks carrying freight.</p>\n\n\n\n<p>Since the entire transport sector accounts for 21% of total emissions, and road transport accounts for three-quarters of transport emissions, road transport accounts for 15% of total CO<sub>2</sub> emissions.</p>\n\n\n\n<p>Aviation \u2013 while it often gets the most attention in discussions on action against climate change \u2013 accounts for only 11.6% of transport emissions. It emits just under one billion tonnes of CO<sub>2</sub> each year \u2013 around 2.5% of total global emissions <em>[we look at the role that air travel plays in climate change in more detail in an upcoming article]</em>.&nbsp;International shipping contributes a similar amount, at 10.6%.&nbsp;</p>\n\n\n\n<p>Rail travel and freight emits very little \u2013 only 1% of transport emissions. Other transport \u2013 which is mainly the movement of materials such as water, oil, and gas via pipelines \u2013 is responsible for 2.2%.</p>\n\n\n\n<figure class=\"wp-block-image size-large\"><img loading=\"lazy\" width=\"800\" height=\"315\" src=\"https://owid.cloud/app/uploads/2020/10/Transport-CO2-emissions-by-mode-bar-chart-800x315.png\" alt=\"\" class=\"wp-image-36825\" srcset=\"https://owid.cloud/app/uploads/2020/10/Transport-CO2-emissions-by-mode-bar-chart-800x315.png 800w, https://owid.cloud/app/uploads/2020/10/Transport-CO2-emissions-by-mode-bar-chart-400x158.png 400w, https://owid.cloud/app/uploads/2020/10/Transport-CO2-emissions-by-mode-bar-chart-150x59.png 150w, https://owid.cloud/app/uploads/2020/10/Transport-CO2-emissions-by-mode-bar-chart-768x303.png 768w, https://owid.cloud/app/uploads/2020/10/Transport-CO2-emissions-by-mode-bar-chart-1536x606.png 1536w, https://owid.cloud/app/uploads/2020/10/Transport-CO2-emissions-by-mode-bar-chart.png 1674w\" sizes=\"(max-width: 800px) 100vw, 800px\" /></figure>\n\n\n\n<h4>Towards zero-carbon transport: how can we expect the sector\u2019s CO<sub>2</sub> emissions to change in the future?</h4>\n\n\n\n<div class=\"wp-block-columns\">\n<div class=\"wp-block-column\">\n<p>Transport demand is expected to grow across the world in the coming decades as the global population increases, incomes rise, and more people can afford cars, trains and flights. In its <em>Energy Technology Perspectives</em> report, the International Energy Agency (IEA) expects global transport (measured in passenger-kilometers) to double, car ownership rates to increase by 60%, and demand for passenger and freight aviation to triple by 2070.{ref}IEA (2020), <a href=\"https://www.iea.org/reports/energy-technology-perspectives-2020\">Energy Technology Perspectives 2020</a>, IEA, Paris.{/ref} Combined, these factors would result in a large increase in transport emissions.</p>\n\n\n\n<p>But major technological innovations can help offset this rise in demand. As the world shifts towards lower-carbon electricity sources, the rise of electric vehicles offers a viable option to reduce emissions from passenger vehicles.</p>\n\n\n\n<p>This is reflected in the IEA\u2019s <em>Energy Technology Perspective</em> report. There it outlines its \u201cSustainable Development Scenario\u201d for reaching net-zero CO2 emissions from global energy by 2070. The pathways for the different elements of the transport sector in this optimistic scenario are shown in the visualization.</p>\n\n\n\n<p>We see that with electrification- and hydrogen- technologies some of these sub-sectors could decarbonize within decades. The IEA scenario assumes the phase-out of emissions from motorcycles by 2040; rail by 2050; small trucks by 2060; and although emissions from cars and buses are not completely eliminated until 2070, it expects many regions, including the European Union; United States; China and Japan to have phased-out conventional vehicles as early as 2040.</p>\n\n\n\n<p>Other transport sectors will be much more difficult to decarbonize.</p>\n\n\n\n<p>In a paper published in <em>Science</em>, Steven Davis and colleagues looked at our options across sectors to reach a net-zero emissions energy system.{ref}Davis, S. J., Lewis, N. S., Shaner, M., Aggarwal, S., Arent, D., Azevedo, I. L., &#8230; &amp; Clack, C. T. (2018). <a href=\"https://science.sciencemag.org/content/360/6396/eaas9793.full\">Net-zero emissions energy systems</a>. <em>Science</em>, 360(6396).{/ref} They highlighted long-distance road freight (large trucks), aviation and shipping as particularly difficult to eliminate. The potential for hydrogen as a fuel, or battery electricity to run planes, ships and large trucks is limited by the range and power required; the size and weight of batteries or hydrogen fuel tanks would be <em>much</em> larger and heavier than current combustion engines.{ref}Cecere, D., Giacomazzi, E., &amp; Ingenito, A. (2014). <a href=\"https://www.sciencedirect.com/science/article/pii/S0360319914011847\">A review on hydrogen industrial aerospace applications</a>. <em>International Journal of Hydrogen Energy</em>, <em>39</em>(20), 10731-10747.{/ref}<sup>,</sup>{ref}Fulton, L. M., Lynd, L. R., K\u00f6rner, A., Greene, N., &amp; Tonachel, L. R. (2015). <a href=\"https://onlinelibrary.wiley.com/doi/full/10.1002/bbb.1559\">The need for biofuels as part of a low carbon energy future</a>. <em>Biofuels, Bioproducts and Biorefining</em>, 9(5), 476-483.{/ref}</p>\n\n\n\n<p>So, despite falling by three-quarters in the visualized scenario, emissions from these sub-sectors would still make transport the largest contributor to energy-related emissions in 2070. To reach net-zero for the energy sector as a whole, these emissions would have to be offset by \u2018negative emissions\u2019 (e.g. the capture and storage of carbon from bioenergy or <a href=\"https://www.iea.org/reports/direct-air-capture\">direct air capture</a>) from other parts of the energy system.</p>\n\n\n\n<p>In the IEA\u2019s net-zero scenario, nearly two-thirds of the emissions reductions come from technologies that are not yet commercially available. As the IEA states, \u201cReducing CO<sub>2</sub> emissions in the transport sector over the next half-century will be a formidable task.\u201d{ref}IEA (2020), <a href=\"https://www.iea.org/reports/energy-technology-perspectives-2020\">Energy Technology Perspectives 2020</a>, IEA, Paris.{/ref}</p>\n</div>\n\n\n\n<div class=\"wp-block-column\">\n<h6>Global CO2 emissions from transport in the IEA&#8217;s Sustainable Development Scenario to 2070{ref}IEA (2020), <a href=\"https://www.iea.org/reports/energy-technology-perspectives-2020\">Energy Technology Perspectives 2020</a>, IEA, Paris.{/ref}</h6>\n\n\n\n<figure class=\"wp-block-image size-large\"><img loading=\"lazy\" width=\"800\" height=\"505\" src=\"https://owid.cloud/app/uploads/2020/10/IEA-Transport-to-2070-800x505.png\" alt=\"\" class=\"wp-image-36827\" srcset=\"https://owid.cloud/app/uploads/2020/10/IEA-Transport-to-2070-800x505.png 800w, https://owid.cloud/app/uploads/2020/10/IEA-Transport-to-2070-400x253.png 400w, https://owid.cloud/app/uploads/2020/10/IEA-Transport-to-2070-150x95.png 150w, https://owid.cloud/app/uploads/2020/10/IEA-Transport-to-2070-768x485.png 768w, https://owid.cloud/app/uploads/2020/10/IEA-Transport-to-2070-1536x970.png 1536w, https://owid.cloud/app/uploads/2020/10/IEA-Transport-to-2070.png 1732w\" sizes=\"(max-width: 800px) 100vw, 800px\" /></figure>\n</div>\n</div>\n",
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    "excerpt": {
        "rendered": "Explore trends in transport technologies and emissions across the world.",
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    },
    "date_gmt": "2021-09-24T13:42:00",
    "modified": "2023-06-09T19:20:39",
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    "categories": [
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    "menu_order": 116,
    "ping_status": "closed",
    "authors_name": [
        "Hannah Ritchie",
        "Max Roser"
    ],
    "modified_gmt": "2023-06-09T18:20:39",
    "comment_status": "closed",
    "featured_media": 45158,
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        "thumbnail": "/app/uploads/2021/09/transport-thumbnail-150x79.png",
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