June 13, 2024
One of the most transformative changes in technology over the last few decades has been the massive drop in the cost of clean energy. Solar photovoltaic costs have fallen by 90% in the last decade, onshore wind by 70%, and batteries by more than 90%.
These technologies have followed a “learning curve” called Wright’s Law. This states that the cost of technology falls consistently as the cumulative production of that technology increases.
The chart shows the perfect example of this for solar power. This data comes from the International Renewable Agency, Greg Nemet, and Doyne Farmer & François Lafond.
On the horizontal axis, we have the cumulative installed capacity of solar panels, and on the vertical axis, the cost. Both are measured on logarithmic scales, and the trend follows a straight line. That means the fall in cost has been exponential.
Costs have fallen by around 20% every time the global cumulative capacity doubles. Over four decades, solar power has transformed from one of the most expensive electricity sources to the cheapest in many countries.
Technologies that follow Wright’s Law get cheaper at a consistent rate, as the cumulative production of that technology increases.
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Yesterday
Russia’s 2022 invasion of Ukraine has led to increased military spending not only in the two countries themselves but also in other neighboring countries.
The chart, using inflation-adjusted data from the Stockholm International Peace Research Institute, shows that Russia has increased its military spending to support the invasion, while Ukraine has expanded its budget tenfold to defend itself.
The war has also motivated several of Russia’s other neighbors to increase their military spending. For instance, in 2023, Poland almost doubled its military spending from 15 to 27 billion US$, and Finland raised its budget from 4.5 to 6.9 billion US$.
Other neighboring countries, like Lithuania and Estonia, have so far not made increases as dramatic but have returned to the longer-term expansion of their military budgets.
Some Western European countries, especially Denmark, have also already increased their military spending after Russia’s invasion.
Explore military spending data for every country →
October 03
The chart shows how incomes are spread in several countries in different world regions. The data comes from the excellent Luxembourg Income Study.
Blue points show the monthly after-tax income of someone who falls just inside the richest 10% of their country's population. Red points show the income of someone who falls just inside the poorest 10%. To allow for comparisons, all incomes are shown in international dollars, which account for differences in cost of living across countries.
The ratio between these two numbers gives us a measure of inequality known as the “P90/P10 ratio”.
In Norway, a country with very low inequality, this ratio is around 3. A person just inside the richest 10% has a monthly income of $5,490 — a little more than 3 times the $1,760 earned by someone just inside the poorest 10%.
In the United States, inequality is much higher, and the ratio is twice as large — around 6. The chart shows that the richest 10% are much richer than those in Norway, with incomes above $7,440. But, the poorest are also poorer, with incomes of less than $1,240.
In many countries, the ratio is between 4 and 6. But in the most unequal countries, it is much higher. In South Africa, the ratio is 22. Those in the bottom decile are among the poorest people in the world, living on less than $110 per month. In contrast, the richest 10% earn $2,490 or above — higher than the incomes of half the UK population and nearly a third of the US population.
Explore incomes across the distribution for other countries in our dedicated Data Explorer →
October 02
Cobalt is a critical element in many lithium-ion battery technologies, which are used in most consumer electronics such as mobile phones and laptops; and more recently, in electric vehicles.
Almost three-quarters of the world’s cobalt is mined in the Democratic Republic of Congo (DRC).
However, the DRC produces virtually none of the world’s refined cobalt — the mineral used in final products. Most of the world’s refined cobalt is made in China.
You can see this in the chart, which shows each country’s share of global mined and refined cobalt production in 2021. This data comes from the US Geological Survey (USGS) and British Geological Survey (BGS).
While lithium-ion battery technologies that use cobalt are dominant today, alternative battery chemistries that don’t use cobalt are emerging.
Explore more data on which countries produce the world’s critical minerals →
October 01
Most electoral democracies are younger than the oldest people who live in them.
The chart shows that almost two dozen democracies are younger than 18 — as young as the children in these countries. Others are only as old as their young adults. This is based on data from Regimes of the World.
In these younger democracies, most people have experienced life under authoritarian rule, and older people lacked democratic political rights for most of their lives.
A larger group of countries have been electoral democracies for one to three generations. In these countries, children and young adults have only known life in a democracy, but their parents and grandparents have experienced non-democratic rule.
Only ten countries have been democratic for more than 90 years. In these places, democracy is older than almost all of their citizens.
Read more in our article on the age of democracies →
September 30
Obesity rates have increased across the world over the last 50 years, but at varying speeds and from different starting positions.
The chart shows the change in the share of adults who are defined as “overweight” or “obese” across a range of countries. It is based on the latest data from the World Health Organization (which only goes up to 2016).
Rates have increased worldwide — from Australia and the United States to India and Nigeria — but tend to be higher in richer countries where food supplies are more plentiful and affordable for the population.
This is measured based on body mass index (BMI), which takes account of someone’s height and weight. It’s a crude measure, but it gives us quick insights into how people’s metabolic health is changing.
Explore global data on overweight and obesity rates →
September 27
New petrol and diesel cars are becoming a rarity in Norway.
In 2023, 93% of new cars sold in the country were electric. This is shown in the chart, based on data from the International Energy Agency.
This is a rapid increase from a decade ago when just 6% of new cars were electric.
Here, “electric cars” include fully battery-electric and plug-in hybrid cars (which have a smaller battery and also have a combustion engine). But in Norway, battery-electric cars now dominate: in 2023, 85% were fully electric, compared to just 8% of plug-in hybrids.
Explore the data for other countries in our dedicated article →
September 26
This chart shows average temperatures in the 1940s and 2010s compared to the average from 1991-2020. These differences — called temperature anomalies — help us see how temperatures have changed. We source this data from the European Centre for Medium-Range Weather Forecasts (ECMWF) ERA5 project.
Globally, the 1940s were 0.66°C cooler than the 1991-2020 average, while the 2010s were 0.2°C warmer. This means that over about 70 years, the global average temperature increased by approximately 0.86°C. Compared to pre-industrial times, the current global average temperature is estimated to have risen by approximately 1.3°C.
Ireland is the only country where temperatures in the 1940s were similar to the 2010s.
Every other country has seen temperatures increase over this period, with some experiencing more than several degrees of warming.
This illustrates how local climate variations can differ from global trends. The effects can vary from place to place, but global warming remains a broad phenomenon.
Explore decadal temperature anomalies in other countries →
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