June 12, 2024
In the last two centuries, the price of lighting has decreased drastically.
You can see this in the chart, which plots historical data from Roger Fouquet and Peter Pearson. To allow for comparisons over time, the data is adjusted for inflation and expressed in prices for the year 2000.
In the 1300s, one million lumen-hours — a standard lighting measure — would have cost around £40,800 in 2000 prices. By 2006, this had fallen to £2.90, a 14,000-fold decline.
Innovations in lighting appliances, fuels, infrastructures, and institutions during the 19th and 20th centuries made this progress possible.
To put this in perspective, consider that a standard 100-watt incandescent light bulb today can emit about 1,700 lumens. Therefore, running one such bulb for 24 hours would produce about 50,000 lumen-hours. That means that 1 million lumen-hours today would require continuously keeping a standard 100-watt incandescent bulb on for about 25 days. Achieving the same amount of light with candles would require burning more than 100 candles every day for that period.
Most people today take the ability to switch on a light at night for granted. But those who live or have lived without artificial light can appreciate how important it is.
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Yesterday
In the 1970s, oil spills from tankers — container ships transporting oil — were common. Between 70 and 100 spills occurred per year. That’s one or two spills every week.
This number has fallen by more than 90% since then. In the last decade, no year has had more than ten oil spills, as shown in the chart.
The quantity of oil spilled from tankers has also fallen dramatically. Over the last decade, the average is less than 10,000 tonnes per year, compared to over 300,000 tonnes in the 1970s.
February 26
In the past, forests around the world were cut down on a massive scale. We lost some of the world’s richest ecosystems.
In recent decades, the picture has become more complex. Deforestation has not ended, but it is no longer happening everywhere. Since 1990, some regions have continued to lose large areas of forest, while others have slowed this long-run trend — and even reversed it.
The map shows regional changes in forest area based on the latest data from the Food and Agriculture Organization of the United Nations.
Deforestation has been particularly large in South America and Africa. At the same time, the forested area has expanded in Europe, North and Central America, and large parts of Asia.
These gains show that deforestation is not inevitable. When pressure on land falls, forests can return.
February 24
The Netherlands was the first country to legalize same-sex marriage in 2001. Since then, almost 40 other countries have followed suit.
You can see this in the chart, based on data from Pew Research. By 2025, same-sex marriage was legal in 39 countries.
Last year, two countries were added to the total. Thailand became the first country in Southeast Asia to legalize same-sex marriage, and a same-sex marriage bill also took effect in Liechtenstein.
February 21
The share of the world population living in extreme poverty has never declined as rapidly as in the past three decades.
The decline in China was particularly fast, and given that one in six people in the world lives there, we’re often asked whether the decline in global poverty was only due to the decline in China.
The chart shows the data that answers this question. In blue, we see the global decline. In red, we see the decline if we exclude China from the data. In the world outside of China, 33% lived in extreme poverty in 1990; by 2025, this share was down to 12%.
The large economic growth that lifted 940 million Chinese people out of extreme poverty since 1990 was a major contributor to the global decline in poverty. But the non-Chinese world also achieved a very large reduction.
It is not true that the global decline in poverty was only due to China. Extreme poverty has declined in China and the rest of the world.
February 19
Forty years ago in Japan, two babies were born for every person who died. Twenty years ago, these numbers were equal. And today, the ratio has reversed: one baby is born for every two people who die.
In the chart, you can see this change in the number of births and deaths over time.
Since deaths now greatly outnumber births, and because immigration is low, Japan’s population has started to shrink.
February 17
Debates over whether religion is booming or dying are common. What does the data say?
Most countries lack long-term data on religious identity, but results from the Pew Research Center offer insights into changes over the decade from 2010 to 2020. (Unfortunately, 2020 is the most recent year for which we have comparable global data.)
At a global level, there was barely any change. The share of people identifying with any religion dropped by just one percentage point, from 77% to 76%.
But religious affiliation did drop significantly across many countries in Europe, the Americas, and Oceania. You can see this drop for a selection of countries in the chart.
In Australia, rates dropped from 75% to 58%. In the United States and Chile, the percentage has decreased from roughly 85% to 70%.
So while religious affiliation is stable in many parts of the world, this data shows religion is becoming less prominent in others.
Note that this data is based on self-identification with any religion; it doesn’t tell us about changes in practices or rituals, such as prayer or attending services.
February 14
This chart shows one way to compare automated manufacturing across countries — it plots the number of robots per 1,000 manufacturing employees.
The chart shows very large differences between countries. South Korea stands out, with more than one robot for every ten manufacturing workers.
Singapore comes second, and China ranks third, close to Germany. The United States sits in the middle, close to the European average, below Switzerland, Denmark and Slovenia.
This perspective shows industrial robot adoption in relative terms. In another Data Insight, I looked at robot adoption in absolute terms. From that perspective, China stands out by a large margin: it’s a large economy with a huge manufacturing sector, and it has by far the largest stock of industrial robots.
Much of this expansion has happened recently: China’s annual installations increased 12-fold over a decade, helping it catch up to South Korea in terms of robots per worker.
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