posts: 3217
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| 3217 | Light at Night | light-at-night | page | publish | <!-- wp:html --> <!-- formatting-options toc:false bodyClassName:topic-page --> <!-- /wp:html --> <!-- wp:owid/sticky-nav --> <!-- wp:navigation-link {"label":"Introduction","url":"#introduction","kind":"custom","isTopLevelLink":false} /--> <!-- wp:navigation-link {"label":"Key Insights","url":"#key-insights-on-light-at-night","kind":"custom","isTopLevelLink":false} /--> <!-- wp:navigation-link {"label":"Research \u0026amp; Writing","url":"#research-writing","kind":"custom","isTopLevelLink":false} /--> <!-- wp:navigation-link {"label":"Charts","url":"#interactive-charts-on-light-at-night","kind":"custom","isTopLevelLink":false} /--> <!-- wp:navigation-link {"label":"Endnotes","url":"#endnotes","kind":"custom","isTopLevelLink":false} /--> <!-- wp:navigation-link {"label":"Cite This Work","url":"#citation","kind":"custom","isTopLevelLink":false} /--> <!-- wp:navigation-link {"label":"Reuse This Work","url":"#licence","kind":"custom","isTopLevelLink":false} /--> <!-- /wp:owid/sticky-nav --> <!-- wp:owid/front-matter --> <!-- wp:columns {"className":"front-matter"} --> <div class="wp-block-columns front-matter"><!-- wp:column --> <div class="wp-block-column" id="introduction"><!-- wp:paragraph --> <p id="introduction">Being able to switch on the light at night is something that most people today take for granted. But for those that live, or have lived where there is no artificial light, you can appreciate how important it is. After sunset, working, reading, and many other aspects of living become impossible. </p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>Unfortunately, this is still the reality for many people today, and it was the default for everyone in the past.</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>By following the history of the light – the transitions from candles to lamps to lightbulbs – and the developments that make these accessible, we can learn a lot about technological innovation and economic changes over the centuries.</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>The price of light has fallen by more than 99.9% since 1700. And its efficiency has increased 1000-fold. This has made light at night available to more and more people.</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>On this page, you can find data, visualizations, and writing about changes in efficiency, price, and access to lighting.</p> <!-- /wp:paragraph --></div> <!-- /wp:column --> <!-- wp:column --> <div class="wp-block-column"><!-- wp:group {"className":"related-topics"} --> <div class="wp-block-group related-topics"><!-- wp:paragraph --> <p>Related topics</p> <!-- /wp:paragraph --> <!-- wp:list --> <ul><li><a href="http://ourworldindata.org/energy">Energy</a></li><li><a href="http://ourworldindata.org/poverty" data-type="page">Poverty</a></li><li><a href="http://ourworldindata.org/technological-change">Technological Change</a></li></ul> <!-- /wp:list --></div> <!-- /wp:group --></div> <!-- /wp:column --></div> <!-- /wp:columns --> <!-- /wp:owid/front-matter --> <!-- wp:owid/key-insights-slider {"title":"Key insights on Light at Night","slug":"key-insights-on-light-at-night"} --> <!-- wp:owid/key-insight {"title":"The price of lighting has fallen by more than 99.9% since 1300","slug":"the-price-of-lighting-has-fallen-by-more-than-99-9-since-1300"} --> <!-- wp:paragraph --> <p>Economic historians have reconstructed the price of light over the very long run for the United Kingdom. This data shows that the price of lighting has plummeted in recent centuries.</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>If we look at long-run datasets on the price of lighting in the UK, we see that prices fell by more than 99.9% from 1300 to the early 2000s.</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>In the 1300s, one million units of lighting — a lumen-hour — would have cost around £40,800 in 2000 prices. By 2006, this had fallen to £2.90. That is a 14,000-fold decline.</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>This reduction in prices has transformed the availability of light across the world.</p> <!-- /wp:paragraph --> <!-- wp:owid/technical-text --> <!-- wp:heading {"level":5} --> <h5>What you should know about this data</h5> <!-- /wp:heading --> <!-- wp:list --> <ul><li>This data is sourced from the study by Roger Fouquet and Peter Pearson.{ref}Fouquet, R., & Pearson, P. J. (2006). Seven centuries of energy services: The price and use of light in the United Kingdom (1300-2000). The energy journal, 27(1).{/ref}</li><li>To calculate the price of lighting – today or historically – three different prices need to be known: (1) the prices of the relevant energy source, (2) the equipment to provide this light (e.g. a kerosene lamp), (3) how efficiently the available technology at the time can turn the energy into light. The latter is referred to as the ‘lighting technology efficiency’ in the literature and is measured in units of energy used for each lumen-hour of light generated.</li><li>The authors adjust these prices for inflation over time; the full series is measured in prices of the year 2000.</li><li>Prices are weighted from the combination of lighting sources at any given period of time. For example, prices of lighting from candles, whale oil, and gas will differ. The average price is, therefore, weighted by the share of each source in total lighting consumption.</li></ul> <!-- /wp:list --> <!-- /wp:owid/technical-text --> <!-- wp:html --> <iframe src="https://ourworldindata.org/grapher/the-price-for-lighting-per-million-lumen-hours-in-the-uk-in-british-pound?yScale=log" loading="lazy" style="width: 100%; height: 600px; border: 0px none;"></iframe> <!-- /wp:html --> <!-- /wp:owid/key-insight --> <!-- wp:owid/key-insight {"title":"The efficiency of lighting has increased 1000-fold since 1700","slug":"the-efficiency-of-lighting-has-increased-1000-fold-since-1700"} --> <!-- wp:paragraph --> <p>The efficiency of lighting – how much light you produce per unit of energy input – has increased by orders of magnitude over the last few centuries.</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>We see this in this chart which shows the change in the efficiency of lighting in the United Kingdom from 1700 to 2000.{ref}Fouquet, R., & Pearson, P. J. (2006). Seven centuries of energy services: The price and use of light in the United Kingdom (1300-2000). The energy journal, 27(1).{/ref} </p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>In 1700, the average efficiency of lighting was 30 lumen-hours per kilowatt-hour (kWh). By 2000, this had increased almost 1000-fold to 25,000 lumen-hours.</p> <!-- /wp:paragraph --> <!-- wp:owid/technical-text --> <!-- wp:heading {"level":5} --> <h5><strong>What you should know about this data</strong></h5> <!-- /wp:heading --> <!-- wp:list --> <ul><li>This data is sourced from the study by Roger Fouquet and Peter Pearson.{ref}Fouquet, R., & Pearson, P. J. (2006). Seven centuries of energy services: The price and use of light in the United Kingdom (1300-2000). The Energy Journal, 27(1).{/ref}</li><li>The total efficiency of lighting is weighted for the different sources in the total lighting supply. For example, the efficiency of lighting from candles, whale oil, and gas will differ. The average efficiency is, therefore, weighted by the share of each source in total lighting consumption.</li></ul> <!-- /wp:list --> <!-- /wp:owid/technical-text --> <!-- wp:html --> <iframe src="https://ourworldindata.org/grapher/efficiency-of-lighting-in-the-united-kingdom-lumen-hours-per-kilowatt-hour" loading="lazy" style="width: 100%; height: 600px; border: 0px none;"></iframe> <!-- /wp:html --> <!-- /wp:owid/key-insight --> <!-- wp:owid/key-insight {"title":"Many countries have moved from candles to gas, to kerosene, and then to electricity","slug":"many-countries-have-moved-from-candles-to-gas-to-kerosene-and-then-to-electricity"} --> <!-- wp:paragraph --> <p>An important driver of the improvements in lighting efficiency has been the transition from one energy source to another.</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>The chart shows the share of lighting in the United Kingdom that comes from different sources, from 1700 to 2000.</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>In the 1700s, almost all of the UK’s lighting came from candles. By the 1800s, this had diversified to include <a href="https://ourworldindata.org/whaling">whale oil</a> and gas too. The 1900s saw the entry of kerosene. And by the year 2000, all of the UK’s lighting came from electricity.</p> <!-- /wp:paragraph --> <!-- wp:html --> <iframe src="https://ourworldindata.org/grapher/lighting-sources-uk?tab=chart&country=Candles~Whale+Oil~Gas~Kerosene~Electricity" loading="lazy" style="width: 100%; height: 600px; border: 0px none;"></iframe> <!-- /wp:html --> <!-- /wp:owid/key-insight --> <!-- wp:owid/key-insight {"title":"Lighting has gotten cheaper and more efficient by moving from one source to another","slug":"lighting-has-gotten-cheaper-and-more-efficient-by-moving-from-one-source-to-another"} --> <!-- wp:paragraph --> <p>Lighting has become more efficient over time for two key reasons:</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>First, the efficiency of a given source – for example, candles, gas, or electricity increased over time.</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>But, more importantly, people have switched from less to more efficient sources.</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>We can see both of these effects in the chart, which looks at the efficiency of different lighting sources in the United Kingdom over time. These are measured as the amount of light (in lumen-hours) that is produced from one unit of energy (a kilowatt-hour).</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>We can see how the efficiency of each source increased. The efficiency of candles increased from 28 to 80 lumen-hours from 1700 to 1900. Gas increased from 68 to 880 lumen-hours between 1800 and 1950.</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>But even larger are the leaps in the transitions from one source to another. Moving from candles to gas increased efficiency from tens to hundreds of lumen-hours. And moving from gas to electricity increased this again from hundreds to thousands.</p> <!-- /wp:paragraph --> <!-- wp:html --> <iframe src="https://ourworldindata.org/grapher/efficiency-lighting-uk-sources?tab=chart&yScale=log&country=Candles~Electricity~Gas~Whale+Oil~Kerosene" loading="lazy" style="width: 100%; height: 600px; border: 0px none;"></iframe> <!-- /wp:html --> <!-- /wp:owid/key-insight --> <!-- wp:owid/key-insight {"title":"Global maps of lighting can tell us a lot about the distribution of prosperity in the world","slug":"global-maps-of-lighting-can-tell-us-a-lot-about-the-distribution-of-prosperity-in-the-world"} --> <!-- wp:paragraph --> <p>For many people on lower incomes, lighting at night is a luxury. The poorest people can’t afford to use light at night, or only very little. This is visible from space, as this image shows.</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>By looking at satellite images, we can infer the changes in economic development. Light at night is brightest in areas that are densely populated, and those with higher levels of economic prosperity.</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>We can see this in the satellite image <a href="https://earthobservatory.nasa.gov/features/NightLights">from NASA</a>. The richest regions of the world – Europe and North America – are shown most prominently. People in other areas of the world – parts of Africa most prominently – are <a href="https://ourworldindata.org/energy-poverty-air-pollution">living in energy poverty</a>.</p> <!-- /wp:paragraph --> <!-- wp:owid/technical-text --> <!-- wp:heading {"level":5} --> <h5><strong>What you should know about this data</strong></h5> <!-- /wp:heading --> <!-- wp:list --> <ul><li>This satellite image is sourced from <a href="https://earthobservatory.nasa.gov/features/NightLights">NASA</a>.</li><li>Several other studies have shown that light density at night reflects standards of living well, both across geographic regions and across time. Some of these papers are:<ul><li>Christopher Small & Christopher D. Elvidge (2013) – Night on Earth: Mapping decadal changes of anthropogenic night light in Asia. International Journal of Applied Earth Observation and Geoinformation. Volume 22, June 2013, Pages 40–52. Online here.</li><li>Henderson, Storeygard, and Weil (2011) – “Measuring Economic Growth from Outer Space,” American Economic Review, 102(2), 994-1028. This paper is online here.</li><li>Chen and Nordhaus (2011) – “Using Luminosity Data as a Proxy for Economic Statistics,” Proceedings of the National Academy of Sciences, 108(21), 8589—8594.</li><li>Tilottama Ghosh, Rebecca L. Powell, Christopher D. Elvidge, Kimberly E. Baugh, Paul C. Sutton and Sharolyn Anderson (2010) – Shedding Light on the Global Distribution of Economic Activity. The Open Geography Journal, 2010, 3, 147-160 147.</li></ul></li></ul> <!-- /wp:list --> <!-- /wp:owid/technical-text --> <!-- wp:image {"id":14602,"sizeSlug":"full","linkDestination":"none"} --> <figure class="wp-block-image size-full"><img src="https://owid.cloud/app/uploads/2013/12/Night-Light-NASA-August-2017-cropped.png" alt="" class="wp-image-14602"/></figure> <!-- /wp:image --> <!-- /wp:owid/key-insight --> <!-- wp:owid/key-insight {"title":"Observing light at night can tell us about changes in poverty levels","slug":"observing-light-at-night-can-tell-us-about-changes-in-poverty-levels"} --> <!-- wp:paragraph --> <p>As people leave the deepest poverty behind, they gain access to the luxury of having light at night. We can often track country developments by looking at the brightness of artificial light.{ref}Several papers have shown that light density at night reflects standards of living well, both across geographic regions and across time. Some of these papers are:</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>Christopher Small & Christopher D. Elvidge (2013) – Night on Earth: Mapping decadal changes of anthropogenic night light in Asia. International Journal of Applied Earth Observation and Geoinformation. Volume 22, June 2013, Pages 40–52. Online here.</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>Henderson, Storeygard, and Weil (2011) – “Measuring Economic Growth from Outer Space,” American Economic Review, 102(2), 994-1028. This paper is online here.</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>Chen and Nordhaus (2011) – “Using Luminosity Data as a Proxy for Economic Statistics,” Proceedings of the National Academy of Sciences, 108(21), 8589—8594.</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>Tilottama Ghosh, Rebecca L. Powell, Christopher D. Elvidge, Kimberly E. Baugh, Paul C. Sutton and Sharolyn Anderson (2010) – Shedding Light on the Global Distribution of Economic Activity. The Open Geography Journal, 2010, 3, 147-160 147.{/ref}</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>The two images below show two satellite images that researchers Maxim Pinkovskiy and Xavier Sala-i-Martin used to study how poverty levels changed.{ref} Maxim Pinkovskiy and Xavier Sala-i-Martin (2016) – Lights, Camera … Income! Illuminating the National Accounts-Household Surveys Debate. The Quarterly Journal of Economics (2016) 131 (2): 579-631. doi: 10.1093/qje/qjw003 Online at http://qje.oxfordjournals.org/content/131/2/579.full?etoc.{/ref} </p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>Poverty rates <a href="https://ourworldindata.org/grapher/share-of-population-in-extreme-poverty?tab=chart&country=IND~PAK~BGD">have plummeted</a> across many countries in South Asia – such as India, Pakistan, and Bangladesh – over the last few decades. We see evidence of this from the satellite images: nighttime light is much brighter in 2010 than 16 years earlier.</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p></p> <!-- /wp:paragraph --> <!-- wp:image {"id":7749,"sizeSlug":"full","linkDestination":"none"} --> <figure class="wp-block-image size-full"><img src="https://owid.cloud/app/uploads/2013/12/Satellite-images-of-India-by-night-–-Sala-I-Martin-paper.png" alt="" class="wp-image-7749"/></figure> <!-- /wp:image --> <!-- /wp:owid/key-insight --> <!-- /wp:owid/key-insights-slider --> <!-- wp:owid/research-and-writing --> <!-- wp:group {"className":"wp-block-research-and-writing"} --> <div class="wp-block-group wp-block-research-and-writing"><!-- wp:heading --> <h2 id="research-writing">Research & Writing</h2> <!-- /wp:heading --> <!-- wp:group {"className":"research-and-writing__top"} --> <div class="wp-block-group research-and-writing__top"><!-- wp:owid/card {"title":"The world's energy problem","linkUrl":"https://ourworldindata.org/worlds-energy-problem","mediaId":37652,"mediaUrl":"https://owid.cloud/app/uploads/2020/11/Screen-Shot-2020-11-26-at-10.33.19.png","mediaAlt":""} --> <!-- wp:paragraph --> <p>The world faces two energy problems: most of our energy production still produces greenhouse gas emissions, and hundreds of millions lack access to energy entirely.</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>Max Roser</p> <!-- /wp:paragraph --> <!-- /wp:owid/card --> <!-- wp:group {"className":"research-and-writing__top-right"} --> <div class="wp-block-group research-and-writing__top-right"><!-- wp:owid/card {"title":"Global whaling peaked in the 1960s","linkUrl":"https://ourworldindata.org/whaling","mediaId":54662,"mediaUrl":"https://owid.cloud/app/uploads/2022/11/Whaling-featured-image.png","mediaAlt":""} --> <!-- wp:paragraph --> <p>Intense whaling for light and oil drove many of the world’s whale species close to extinction. But a dramatic decline in whale hunting since then has given them hopes of recovery.</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>Hannah Ritchie</p> <!-- /wp:paragraph --> <!-- /wp:owid/card --></div> <!-- /wp:group --></div> <!-- /wp:group --></div> <!-- /wp:group --> <!-- /wp:owid/research-and-writing --> <!-- wp:owid/all-charts /--> | {
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2023-02-09 08:00:00 | 2024-03-05 09:19:03 | [
"Max Roser",
"Hannah Ritchie"
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Light at night was once expensive everywhere. In some places people are still lacking light at night, while in other places light became extremely cheap. | 2015-04-28 08:27:23 | 2023-02-09 10:56:08 | https://ourworldindata.org/wp-content/uploads/2023/02/Light-at-Night.png | {
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Being able to switch on the light at night is something that most people today take for granted. But for those that live, or have lived where there is no artificial light, you can appreciate how important it is. After sunset, working, reading, and many other aspects of living become impossible. Unfortunately, this is still the reality for many people today, and it was the default for everyone in the past. By following the history of the light – the transitions from candles to lamps to lightbulbs – and the developments that make these accessible, we can learn a lot about technological innovation and economic changes over the centuries. The price of light has fallen by more than 99.9% since 1700. And its efficiency has increased 1000-fold. This has made light at night available to more and more people. On this page, you can find data, visualizations, and writing about changes in efficiency, price, and access to lighting. Related topics * [Energy](http://ourworldindata.org/energy) * [Poverty](http://ourworldindata.org/poverty) * [Technological Change](http://ourworldindata.org/technological-change) Economic historians have reconstructed the price of light over the very long run for the United Kingdom. This data shows that the price of lighting has plummeted in recent centuries. If we look at long-run datasets on the price of lighting in the UK, we see that prices fell by more than 99.9% from 1300 to the early 2000s. In the 1300s, one million units of lighting — a lumen-hour — would have cost around £40,800 in 2000 prices. By 2006, this had fallen to £2.90. That is a 14,000-fold decline. This reduction in prices has transformed the availability of light across the world. ##### What you should know about this data * This data is sourced from the study by Roger Fouquet and Peter Pearson.{ref}Fouquet, R., & Pearson, P. J. (2006). Seven centuries of energy services: The price and use of light in the United Kingdom (1300-2000). The energy journal, 27(1).{/ref} * To calculate the price of lighting – today or historically – three different prices need to be known: (1) the prices of the relevant energy source, (2) the equipment to provide this light (e.g. a kerosene lamp), (3) how efficiently the available technology at the time can turn the energy into light. The latter is referred to as the ‘lighting technology efficiency’ in the literature and is measured in units of energy used for each lumen-hour of light generated. * The authors adjust these prices for inflation over time; the full series is measured in prices of the year 2000. * Prices are weighted from the combination of lighting sources at any given period of time. For example, prices of lighting from candles, whale oil, and gas will differ. The average price is, therefore, weighted by the share of each source in total lighting consumption. <Chart url="https://ourworldindata.org/grapher/the-price-for-lighting-per-million-lumen-hours-in-the-uk-in-british-pound?yScale=log"/> The efficiency of lighting – how much light you produce per unit of energy input – has increased by orders of magnitude over the last few centuries. We see this in this chart which shows the change in the efficiency of lighting in the United Kingdom from 1700 to 2000.{ref}Fouquet, R., & Pearson, P. J. (2006). Seven centuries of energy services: The price and use of light in the United Kingdom (1300-2000). The energy journal, 27(1).{/ref} In 1700, the average efficiency of lighting was 30 lumen-hours per kilowatt-hour (kWh). By 2000, this had increased almost 1000-fold to 25,000 lumen-hours. ##### **What you should know about this data** * This data is sourced from the study by Roger Fouquet and Peter Pearson.{ref}Fouquet, R., & Pearson, P. J. (2006). Seven centuries of energy services: The price and use of light in the United Kingdom (1300-2000). The Energy Journal, 27(1).{/ref} * The total efficiency of lighting is weighted for the different sources in the total lighting supply. For example, the efficiency of lighting from candles, whale oil, and gas will differ. The average efficiency is, therefore, weighted by the share of each source in total lighting consumption. <Chart url="https://ourworldindata.org/grapher/efficiency-of-lighting-in-the-united-kingdom-lumen-hours-per-kilowatt-hour"/> An important driver of the improvements in lighting efficiency has been the transition from one energy source to another. The chart shows the share of lighting in the United Kingdom that comes from different sources, from 1700 to 2000. In the 1700s, almost all of the UK’s lighting came from candles. By the 1800s, this had diversified to include [whale oil](https://ourworldindata.org/whaling) and gas too. The 1900s saw the entry of kerosene. And by the year 2000, all of the UK’s lighting came from electricity. <Chart url="https://ourworldindata.org/grapher/lighting-sources-uk?tab=chart&country=Candles~Whale+Oil~Gas~Kerosene~Electricity"/> Lighting has become more efficient over time for two key reasons: First, the efficiency of a given source – for example, candles, gas, or electricity increased over time. But, more importantly, people have switched from less to more efficient sources. We can see both of these effects in the chart, which looks at the efficiency of different lighting sources in the United Kingdom over time. These are measured as the amount of light (in lumen-hours) that is produced from one unit of energy (a kilowatt-hour). We can see how the efficiency of each source increased. The efficiency of candles increased from 28 to 80 lumen-hours from 1700 to 1900. Gas increased from 68 to 880 lumen-hours between 1800 and 1950. But even larger are the leaps in the transitions from one source to another. Moving from candles to gas increased efficiency from tens to hundreds of lumen-hours. And moving from gas to electricity increased this again from hundreds to thousands. <Chart url="https://ourworldindata.org/grapher/efficiency-lighting-uk-sources?tab=chart&yScale=log&country=Candles~Electricity~Gas~Whale+Oil~Kerosene"/> For many people on lower incomes, lighting at night is a luxury. The poorest people can’t afford to use light at night, or only very little. This is visible from space, as this image shows. By looking at satellite images, we can infer the changes in economic development. Light at night is brightest in areas that are densely populated, and those with higher levels of economic prosperity. We can see this in the satellite image [from NASA](https://earthobservatory.nasa.gov/features/NightLights). The richest regions of the world – Europe and North America – are shown most prominently. People in other areas of the world – parts of Africa most prominently – are [living in energy poverty](https://ourworldindata.org/energy-poverty-air-pollution). ##### **What you should know about this data** * This satellite image is sourced from [NASA](https://earthobservatory.nasa.gov/features/NightLights). * Several other studies have shown that light density at night reflects standards of living well, both across geographic regions and across time. Some of these papers are: <Image filename="Night-Light-NASA-August-2017-cropped.png" alt=""/> As people leave the deepest poverty behind, they gain access to the luxury of having light at night. We can often track country developments by looking at the brightness of artificial light.{ref}Several papers have shown that light density at night reflects standards of living well, both across geographic regions and across time. Some of these papers are: Christopher Small & Christopher D. Elvidge (2013) – Night on Earth: Mapping decadal changes of anthropogenic night light in Asia. International Journal of Applied Earth Observation and Geoinformation. Volume 22, June 2013, Pages 40–52. Online here. Henderson, Storeygard, and Weil (2011) – “Measuring Economic Growth from Outer Space,” American Economic Review, 102(2), 994-1028. This paper is online here. Chen and Nordhaus (2011) – “Using Luminosity Data as a Proxy for Economic Statistics,” Proceedings of the National Academy of Sciences, 108(21), 8589—8594. Tilottama Ghosh, Rebecca L. Powell, Christopher D. Elvidge, Kimberly E. Baugh, Paul C. Sutton and Sharolyn Anderson (2010) – Shedding Light on the Global Distribution of Economic Activity. The Open Geography Journal, 2010, 3, 147-160 147.{/ref} The two images below show two satellite images that researchers Maxim Pinkovskiy and Xavier Sala-i-Martin used to study how poverty levels changed.{ref} Maxim Pinkovskiy and Xavier Sala-i-Martin (2016) – Lights, Camera … Income! Illuminating the National Accounts-Household Surveys Debate. The Quarterly Journal of Economics (2016) 131 (2): 579-631. doi: 10.1093/qje/qjw003 Online at http://qje.oxfordjournals.org/content/131/2/579.full?etoc.{/ref} Poverty rates [have plummeted](https://ourworldindata.org/grapher/share-of-population-in-extreme-poverty?tab=chart&country=IND~PAK~BGD) across many countries in South Asia – such as India, Pakistan, and Bangladesh – over the last few decades. We see evidence of this from the satellite images: nighttime light is much brighter in 2010 than 16 years earlier. <Image filename="Satellite-images-of-India-by-night-–-Sala-I-Martin-paper.png" alt=""/> ## Research & Writing The world faces two energy problems: most of our energy production still produces greenhouse gas emissions, and hundreds of millions lack access to energy entirely. Max Roser Intense whaling for light and oil drove many of the world’s whale species close to extinction. But a dramatic decline in whale hunting since then has given them hopes of recovery. Hannah Ritchie | {
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"rendered": "\n<!-- formatting-options toc:false bodyClassName:topic-page -->\n\n\n\t<div class=\"sticky-nav-contents\">\n<li class=\" wp-block-navigation-item wp-block-navigation-link\"><a class=\"wp-block-navigation-item__content\" href=\"#introduction\"><span class=\"wp-block-navigation-item__label\">Introduction</span></a></li>\n\n<li class=\" wp-block-navigation-item wp-block-navigation-link\"><a class=\"wp-block-navigation-item__content\" href=\"#key-insights-on-light-at-night\"><span class=\"wp-block-navigation-item__label\">Key Insights</span></a></li>\n\n<li class=\" wp-block-navigation-item wp-block-navigation-link\"><a class=\"wp-block-navigation-item__content\" href=\"#research-writing\"><span class=\"wp-block-navigation-item__label\">Research & Writing</span></a></li>\n\n<li class=\" wp-block-navigation-item wp-block-navigation-link\"><a class=\"wp-block-navigation-item__content\" href=\"#interactive-charts-on-light-at-night\"><span class=\"wp-block-navigation-item__label\">Charts</span></a></li>\n\n<li class=\" wp-block-navigation-item wp-block-navigation-link\"><a class=\"wp-block-navigation-item__content\" href=\"#endnotes\"><span class=\"wp-block-navigation-item__label\">Endnotes</span></a></li>\n\n<li class=\" wp-block-navigation-item wp-block-navigation-link\"><a class=\"wp-block-navigation-item__content\" href=\"#citation\"><span class=\"wp-block-navigation-item__label\">Cite This Work</span></a></li>\n\n<li class=\" wp-block-navigation-item wp-block-navigation-link\"><a class=\"wp-block-navigation-item__content\" href=\"#licence\"><span class=\"wp-block-navigation-item__label\">Reuse This Work</span></a></li>\n</div>\n\n\n\n<div class=\"wp-block-columns front-matter\">\n<div class=\"wp-block-column\" id=\"introduction\">\n<p id=\"introduction\">Being able to switch on the light at night is something that most people today take for granted. But for those that live, or have lived where there is no artificial light, you can appreciate how important it is. After sunset, working, reading, and many other aspects of living become impossible. </p>\n\n\n\n<p>Unfortunately, this is still the reality for many people today, and it was the default for everyone in the past.</p>\n\n\n\n<p>By following the history of the light \u2013 the transitions from candles to lamps to lightbulbs \u2013 and the developments that make these accessible, we can learn a lot about technological innovation and economic changes over the centuries.</p>\n\n\n\n<p>The price of light has fallen by more than 99.9% since 1700. And its efficiency has increased 1000-fold. This has made light at night available to more and more people.</p>\n\n\n\n<p>On this page, you can find data, visualizations, and writing about changes in efficiency, price, and access to lighting.</p>\n</div>\n\n\n\n<div class=\"wp-block-column\">\n<div class=\"wp-container-65e6e28135576 wp-block-group related-topics\">\n<p>Related topics</p>\n\n\n\n<ul><li><a href=\"http://ourworldindata.org/energy\">Energy</a></li><li><a href=\"http://ourworldindata.org/poverty\" data-type=\"page\">Poverty</a></li><li><a href=\"http://ourworldindata.org/technological-change\">Technological Change</a></li></ul>\n</div>\n</div>\n</div>\n\n\n\n\t<block type=\"key-insights\">\n\t\t<title>Key insights on Light at Night</title>\n <slug>key-insights-on-light-at-night</slug>\n <insights>\n\t<block type=\"key-insight\">\n\t\t<title is-hidden=\"0\">The price of lighting has fallen by more than 99.9% since 1300</title>\n <slug>the-price-of-lighting-has-fallen-by-more-than-99-9-since-1300</slug>\n <content>\n\n<p>Economic historians have reconstructed the price of light over the very long run for the United Kingdom. This data shows that the price of lighting has plummeted in recent centuries.</p>\n\n\n\n<p>If we look at long-run datasets on the price of lighting in the UK, we see that prices fell by more than 99.9% from 1300 to the early 2000s.</p>\n\n\n\n<p>In the 1300s, one million units of lighting \u2014 a lumen-hour \u2014 would have cost around \u00a340,800 in 2000 prices. By 2006, this had fallen to \u00a32.90. That is a 14,000-fold decline.</p>\n\n\n\n<p>This reduction in prices has transformed the availability of light across the world.</p>\n\n\n\t<div class=\"wp-block-owid-technical-text\">\n\t\t\n\n<h5>What you should know about this data</h5>\n\n\n\n<ul><li>This data is sourced from the study by Roger Fouquet and Peter Pearson.{ref}Fouquet, R., & Pearson, P. J. (2006). Seven centuries of energy services: The price and use of light in the United Kingdom (1300-2000). The energy journal, 27(1).{/ref}</li><li>To calculate the price of lighting \u2013 today or historically \u2013 three different prices need to be known: (1) the prices of the relevant energy source, (2) the equipment to provide this light (e.g. a kerosene lamp), (3) how efficiently the available technology at the time can turn the energy into light. The latter is referred to as the \u2018lighting technology efficiency\u2019 in the literature and is measured in units of energy used for each lumen-hour of light generated.</li><li>The authors adjust these prices for inflation over time; the full series is measured in prices of the year 2000.</li><li>Prices are weighted from the combination of lighting sources at any given period of time. For example, prices of lighting from candles, whale oil, and gas will differ. The average price is, therefore, weighted by the share of each source in total lighting consumption.</li></ul>\n\n\n\t</div>\n\n\n<iframe src=\"https://ourworldindata.org/grapher/the-price-for-lighting-per-million-lumen-hours-in-the-uk-in-british-pound?yScale=log\" loading=\"lazy\" style=\"width: 100%; height: 600px; border: 0px none;\"></iframe>\n\n</content>\n\t</block>\n\n\t<block type=\"key-insight\">\n\t\t<title is-hidden=\"0\">The efficiency of lighting has increased 1000-fold since 1700</title>\n <slug>the-efficiency-of-lighting-has-increased-1000-fold-since-1700</slug>\n <content>\n\n<p>The efficiency of lighting \u2013 how much light you produce per unit of energy input \u2013 has increased by orders of magnitude over the last few centuries.</p>\n\n\n\n<p>We see this in this chart which shows the change in the efficiency of lighting in the United Kingdom from 1700 to 2000.{ref}Fouquet, R., & Pearson, P. J. (2006). Seven centuries of energy services: The price and use of light in the United Kingdom (1300-2000). The energy journal, 27(1).{/ref} </p>\n\n\n\n<p>In 1700, the average efficiency of lighting was 30 lumen-hours per kilowatt-hour (kWh). By 2000, this had increased almost 1000-fold to 25,000 lumen-hours.</p>\n\n\n\t<div class=\"wp-block-owid-technical-text\">\n\t\t\n\n<h5><strong>What you should know about this data</strong></h5>\n\n\n\n<ul><li>This data is sourced from the study by Roger Fouquet and Peter Pearson.{ref}Fouquet, R., & Pearson, P. J. (2006). Seven centuries of energy services: The price and use of light in the United Kingdom (1300-2000). The Energy Journal, 27(1).{/ref}</li><li>The total efficiency of lighting is weighted for the different sources in the total lighting supply. For example, the efficiency of lighting from candles, whale oil, and gas will differ. The average efficiency is, therefore, weighted by the share of each source in total lighting consumption.</li></ul>\n\n\n\t</div>\n\n\n<iframe src=\"https://ourworldindata.org/grapher/efficiency-of-lighting-in-the-united-kingdom-lumen-hours-per-kilowatt-hour\" loading=\"lazy\" style=\"width: 100%; height: 600px; border: 0px none;\"></iframe>\n\n</content>\n\t</block>\n\n\t<block type=\"key-insight\">\n\t\t<title is-hidden=\"0\">Many countries have moved from candles to gas, to kerosene, and then to electricity</title>\n <slug>many-countries-have-moved-from-candles-to-gas-to-kerosene-and-then-to-electricity</slug>\n <content>\n\n<p>An important driver of the improvements in lighting efficiency has been the transition from one energy source to another.</p>\n\n\n\n<p>The chart shows the share of lighting in the United Kingdom that comes from different sources, from 1700 to 2000.</p>\n\n\n\n<p>In the 1700s, almost all of the UK\u2019s lighting came from candles. By the 1800s, this had diversified to include <a href=\"https://ourworldindata.org/whaling\">whale oil</a> and gas too. The 1900s saw the entry of kerosene. And by the year 2000, all of the UK\u2019s lighting came from electricity.</p>\n\n\n\n<iframe src=\"https://ourworldindata.org/grapher/lighting-sources-uk?tab=chart&country=Candles~Whale+Oil~Gas~Kerosene~Electricity\" loading=\"lazy\" style=\"width: 100%; height: 600px; border: 0px none;\"></iframe>\n\n</content>\n\t</block>\n\n\t<block type=\"key-insight\">\n\t\t<title is-hidden=\"0\">Lighting has gotten cheaper and more efficient by moving from one source to another</title>\n <slug>lighting-has-gotten-cheaper-and-more-efficient-by-moving-from-one-source-to-another</slug>\n <content>\n\n<p>Lighting has become more efficient over time for two key reasons:</p>\n\n\n\n<p>First, the efficiency of a given source \u2013 for example, candles, gas, or electricity increased over time.</p>\n\n\n\n<p>But, more importantly, people have switched from less to more efficient sources.</p>\n\n\n\n<p>We can see both of these effects in the chart, which looks at the efficiency of different lighting sources in the United Kingdom over time. These are measured as the amount of light (in lumen-hours) that is produced from one unit of energy (a kilowatt-hour).</p>\n\n\n\n<p>We can see how the efficiency of each source increased. The efficiency of candles increased from 28 to 80 lumen-hours from 1700 to 1900. Gas increased from 68 to 880 lumen-hours between 1800 and 1950.</p>\n\n\n\n<p>But even larger are the leaps in the transitions from one source to another. Moving from candles to gas increased efficiency from tens to hundreds of lumen-hours. And moving from gas to electricity increased this again from hundreds to thousands.</p>\n\n\n\n<iframe src=\"https://ourworldindata.org/grapher/efficiency-lighting-uk-sources?tab=chart&yScale=log&country=Candles~Electricity~Gas~Whale+Oil~Kerosene\" loading=\"lazy\" style=\"width: 100%; height: 600px; border: 0px none;\"></iframe>\n\n</content>\n\t</block>\n\n\t<block type=\"key-insight\">\n\t\t<title is-hidden=\"0\">Global maps of lighting can tell us a lot about the distribution of prosperity in the world</title>\n <slug>global-maps-of-lighting-can-tell-us-a-lot-about-the-distribution-of-prosperity-in-the-world</slug>\n <content>\n\n<p>For many people on lower incomes, lighting at night is a luxury. The poorest people can\u2019t afford to use light at night, or only very little. This is visible from space, as this image shows.</p>\n\n\n\n<p>By looking at satellite images, we can infer the changes in economic development. Light at night is brightest in areas that are densely populated, and those with higher levels of economic prosperity.</p>\n\n\n\n<p>We can see this in the satellite image <a href=\"https://earthobservatory.nasa.gov/features/NightLights\">from NASA</a>. The richest regions of the world \u2013 Europe and North America \u2013 are shown most prominently. People in other areas of the world \u2013 parts of Africa most prominently \u2013 are <a href=\"https://ourworldindata.org/energy-poverty-air-pollution\">living in energy poverty</a>.</p>\n\n\n\t<div class=\"wp-block-owid-technical-text\">\n\t\t\n\n<h5><strong>What you should know about this data</strong></h5>\n\n\n\n<ul><li>This satellite image is sourced from <a href=\"https://earthobservatory.nasa.gov/features/NightLights\">NASA</a>.</li><li>Several other studies have shown that light density at night reflects standards of living well, both across geographic regions and across time. Some of these papers are:<ul><li>Christopher Small & Christopher D. Elvidge (2013) \u2013 Night on Earth: Mapping decadal changes of anthropogenic night light in Asia. International Journal of Applied Earth Observation and Geoinformation. Volume 22, June 2013, Pages 40\u201352. Online here.</li><li>Henderson, Storeygard, and Weil (2011) \u2013 \u201cMeasuring Economic Growth from Outer Space,\u201d American Economic Review, 102(2), 994-1028. This paper is online here.</li><li>Chen and Nordhaus (2011) \u2013 \u201cUsing Luminosity Data as a Proxy for Economic Statistics,\u201d Proceedings of the National Academy of Sciences, 108(21), 8589\u20148594.</li><li>Tilottama Ghosh, Rebecca L. Powell, Christopher D. Elvidge, Kimberly E. Baugh, Paul C. Sutton and Sharolyn Anderson (2010) \u2013 Shedding Light on the Global Distribution of Economic Activity. The Open Geography Journal, 2010, 3, 147-160 147.</li></ul></li></ul>\n\n\n\t</div>\n\n\n<figure class=\"wp-block-image size-full\"><img loading=\"lazy\" width=\"1880\" height=\"858\" src=\"https://owid.cloud/app/uploads/2013/12/Night-Light-NASA-August-2017-cropped.png\" alt=\"\" class=\"wp-image-14602\" srcset=\"https://owid.cloud/app/uploads/2013/12/Night-Light-NASA-August-2017-cropped.png 1880w, https://owid.cloud/app/uploads/2013/12/Night-Light-NASA-August-2017-cropped-150x68.png 150w, https://owid.cloud/app/uploads/2013/12/Night-Light-NASA-August-2017-cropped-400x183.png 400w, https://owid.cloud/app/uploads/2013/12/Night-Light-NASA-August-2017-cropped-768x351.png 768w, https://owid.cloud/app/uploads/2013/12/Night-Light-NASA-August-2017-cropped-750x342.png 750w\" sizes=\"(max-width: 1880px) 100vw, 1880px\" /></figure>\n\n</content>\n\t</block>\n\n\t<block type=\"key-insight\">\n\t\t<title is-hidden=\"0\">Observing light at night can tell us about changes in poverty levels</title>\n <slug>observing-light-at-night-can-tell-us-about-changes-in-poverty-levels</slug>\n <content>\n\n<p>As people leave the deepest poverty behind, they gain access to the luxury of having light at night. We can often track country developments by looking at the brightness of artificial light.{ref}Several papers have shown that light density at night reflects standards of living well, both across geographic regions and across time. Some of these papers are:</p>\n\n\n\n<p>Christopher Small & Christopher D. Elvidge (2013) \u2013 Night on Earth: Mapping decadal changes of anthropogenic night light in Asia. International Journal of Applied Earth Observation and Geoinformation. Volume 22, June 2013, Pages 40\u201352. Online here.</p>\n\n\n\n<p>Henderson, Storeygard, and Weil (2011) \u2013 \u201cMeasuring Economic Growth from Outer Space,\u201d American Economic Review, 102(2), 994-1028. This paper is online here.</p>\n\n\n\n<p>Chen and Nordhaus (2011) \u2013 \u201cUsing Luminosity Data as a Proxy for Economic Statistics,\u201d Proceedings of the National Academy of Sciences, 108(21), 8589\u20148594.</p>\n\n\n\n<p>Tilottama Ghosh, Rebecca L. Powell, Christopher D. Elvidge, Kimberly E. Baugh, Paul C. Sutton and Sharolyn Anderson (2010) \u2013 Shedding Light on the Global Distribution of Economic Activity. The Open Geography Journal, 2010, 3, 147-160 147.{/ref}</p>\n\n\n\n<p>The two images below show two satellite images that researchers Maxim Pinkovskiy and Xavier Sala-i-Martin used to study how poverty levels changed.{ref} Maxim Pinkovskiy and Xavier Sala-i-Martin (2016) \u2013 Lights, Camera \u2026 Income! Illuminating the National Accounts-Household Surveys Debate. The Quarterly Journal of Economics (2016) 131 (2): 579-631. doi: 10.1093/qje/qjw003 Online at http://qje.oxfordjournals.org/content/131/2/579.full?etoc.{/ref} </p>\n\n\n\n<p>Poverty rates <a href=\"https://ourworldindata.org/grapher/share-of-population-in-extreme-poverty?tab=chart&country=IND~PAK~BGD\">have plummeted</a> across many countries in South Asia \u2013 such as India, Pakistan, and Bangladesh \u2013 over the last few decades. We see evidence of this from the satellite images: nighttime light is much brighter in 2010 than 16 years earlier.</p>\n\n\n\n<p></p>\n\n\n\n<figure class=\"wp-block-image size-full\"><img loading=\"lazy\" width=\"2834\" height=\"1812\" src=\"https://owid.cloud/app/uploads/2013/12/Satellite-images-of-India-by-night-\u2013-Sala-I-Martin-paper.png\" alt=\"\" class=\"wp-image-7749\" srcset=\"https://owid.cloud/app/uploads/2013/12/Satellite-images-of-India-by-night-\u2013-Sala-I-Martin-paper.png 2834w, https://owid.cloud/app/uploads/2013/12/Satellite-images-of-India-by-night-\u2013-Sala-I-Martin-paper-150x96.png 150w, https://owid.cloud/app/uploads/2013/12/Satellite-images-of-India-by-night-\u2013-Sala-I-Martin-paper-400x256.png 400w, https://owid.cloud/app/uploads/2013/12/Satellite-images-of-India-by-night-\u2013-Sala-I-Martin-paper-768x491.png 768w, https://owid.cloud/app/uploads/2013/12/Satellite-images-of-India-by-night-\u2013-Sala-I-Martin-paper-750x480.png 750w\" sizes=\"(max-width: 2834px) 100vw, 2834px\" /></figure>\n\n</content>\n\t</block>\n</insights>\n\t</block>\n\n\n\n<div class=\"wp-container-65e6e2814b28b wp-block-group wp-block-research-and-writing\">\n<h2 id=\"research-writing\">Research & Writing</h2>\n\n\n\n<div class=\"wp-container-65e6e2814ae60 wp-block-group research-and-writing__top\"> <div class=\"wp-block-owid-card with-image\" data-no-lightbox>\n <a href=\"https://ourworldindata.org/worlds-energy-problem\">\n <figure><img width=\"768\" height=\"428\" src=\"https://owid.cloud/app/uploads/2020/11/Screen-Shot-2020-11-26-at-10.33.19-768x428.png\" class=\"attachment-medium_large size-medium_large\" alt=\"\" loading=\"lazy\" srcset=\"https://owid.cloud/app/uploads/2020/11/Screen-Shot-2020-11-26-at-10.33.19-768x428.png 768w, https://owid.cloud/app/uploads/2020/11/Screen-Shot-2020-11-26-at-10.33.19-400x223.png 400w, https://owid.cloud/app/uploads/2020/11/Screen-Shot-2020-11-26-at-10.33.19-800x446.png 800w, https://owid.cloud/app/uploads/2020/11/Screen-Shot-2020-11-26-at-10.33.19-150x84.png 150w, https://owid.cloud/app/uploads/2020/11/Screen-Shot-2020-11-26-at-10.33.19-1536x856.png 1536w, https://owid.cloud/app/uploads/2020/11/Screen-Shot-2020-11-26-at-10.33.19.png 1844w\" sizes=\"(max-width: 768px) 100vw, 768px\" /></figure>\n <div class=\"text-wrapper\">\n <div class=\"title\">The world’s energy problem</div class=\"title\">\n <div class=\"description\">\n \n\n<p>The world faces two energy problems: most of our energy production still produces greenhouse gas emissions, and hundreds of millions lack access to energy entirely.</p>\n\n\n\n<p>Max Roser</p>\n\n\n </div>\n </div>\n </a>\n </div>\n\n\n<div class=\"wp-container-65e6e2814a91f wp-block-group research-and-writing__top-right\"> <div class=\"wp-block-owid-card with-image\" data-no-lightbox>\n <a href=\"https://ourworldindata.org/whaling\">\n <figure><img width=\"768\" height=\"402\" src=\"https://owid.cloud/app/uploads/2022/11/Whaling-featured-image-768x402.png\" class=\"attachment-medium_large size-medium_large\" alt=\"\" loading=\"lazy\" srcset=\"https://owid.cloud/app/uploads/2022/11/Whaling-featured-image-768x402.png 768w, https://owid.cloud/app/uploads/2022/11/Whaling-featured-image-400x209.png 400w, https://owid.cloud/app/uploads/2022/11/Whaling-featured-image-800x419.png 800w, https://owid.cloud/app/uploads/2022/11/Whaling-featured-image-150x79.png 150w, https://owid.cloud/app/uploads/2022/11/Whaling-featured-image.png 1200w\" sizes=\"(max-width: 768px) 100vw, 768px\" /></figure>\n <div class=\"text-wrapper\">\n <div class=\"title\">Global whaling peaked in the 1960s</div class=\"title\">\n <div class=\"description\">\n \n\n<p>Intense whaling for light and oil drove many of the world\u2019s whale species close to extinction. But a dramatic decline in whale hunting since then has given them hopes of recovery.</p>\n\n\n\n<p>Hannah Ritchie</p>\n\n\n </div>\n </div>\n </a>\n </div></div>\n</div>\n</div>\n\n\n\n\t<block type=\"all-charts\"></block>",
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"rendered": "Light at night was once expensive everywhere. In some places people are still lacking light at night, while in other places light became extremely cheap.",
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