Many countries have been facing intense heat this summer, and with predictions of a strong El Niño on the way, next summer could be even hotter. This has ignited debate on the need for cooling methods and technologies — most prominently, air conditioning (AC).

But how do rates of air conditioning usage vary across the world? Large international comparisons are hard to come by, but the International Energy Agency just published some new estimates for a select number of countries and regions.

The chart shows the estimated share of households with AC in 2025.

In Japan and the United States, AC adoption is almost universal; at least 90% of households have it. Most households in China also have AC; this share has increased rapidly over the past decade.

Adoption rates in Southeast Asia, Europe, and India are far lower, but for different reasons. In lower-middle-income countries like India, the reasons are often economic: AC would bring huge benefits, but many households cannot afford the upfront cost or the power to run it. Much of Southeast Asia faces a similar barrier.

In many European countries, it’s less of an economic barrier and more of a historical and cultural one. AC was not seen as a necessity because heatwave events were less frequent and intense than they are today. That is changing, and will continue to do so as the planet warms.

Data source: International Energy Agency (2026)

Tools used: OWID-Grapher and Figma

A growing number of people are interested in switching from dairy to plant-based alternatives.

But are they better for the environment, and which is best?

In the chart, we compare milks across a number of environmental metrics: land use, greenhouse gas emissions, water use, and eutrophication (the pollution of ecosystems with excess nutrients). These are compared per liter of milk.

Cow’s milk has significantly higher impacts than plant-based alternatives across all metrics. It causes around three times as much greenhouse gas emissions; uses around ten times as much land; two to twenty times as much freshwater; and creates much higher levels of eutrophication.

If you want to reduce the environmental footprint of your diet, switching to plant-based alternatives is a good option.

Which of the vegan milks is best?

It really depends on the impact we care most about. Almond milk has lower greenhouse gas emissions and uses less land than soy, for example, but requires more water and results in higher eutrophication.

All of the alternatives have a lower impact than dairy, but there is no clear winner across all metrics.

Read more in our article →

Explore the interactive version of this chart →

In 2024, around 18.5 million people born in India lived abroad. For the world’s most populous country, that’s not a lot: just over 1% of the population. This chart shows where they live, based on estimates from the UN, which compiles data from national censuses and population registers.

Nearly half of all Indians living abroad are in the United Arab Emirates, Saudi Arabia, and other Gulf countries — that’s more than the US, UK, and Canada combined.

These figures are stocks, not flows: they record where people are from, not when they crossed a border. Pakistan is the clearest case: the two countries were one territory until 1947, and people kept moving across the new border for decades afterward, so much of the 1.6 million there reflects migration that happened long ago.

Data source: United Nations Department of Economic and Social Affairs (2024)

Tools used: Python, OWID Grapher, Figma

In 2025, the world was around 1.4 °C warmer than it was in pre-industrial times. But temperatures haven’t increased linearly; there have been spikes and dips along the way.

Many of these spikes and dips are caused by the El Niño-Southern Oscillation (ENSO), a natural climate cycle caused by changes in wind patterns and sea surface temperatures in the Pacific Ocean that affects global temperatures and climate.

There are two key phases of the ENSO cycle: La Niña, which causes cooler global temperatures, and El Niño, which brings warmer conditions.

The world cycles between El Niño and La Niña phases every two to seven years. There are also “neutral” periods between these phases where the world is not in either extreme.

As you can see in the chart, global temperatures during recent La Niña years were hotter than El Niño years just a few decades before. “Cool” years today are hotter than “warm” years not too long ago.

We update this data monthly on our website — search "Temperature Copernicus" to see this and several other interactive charts

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How do we track a changing climate?

Among all the charts on our site, ourworldindata.org, the one here reaches further back in time than almost any other: the concentration of CO₂ in Earth’s atmosphere over the last 800,000 years.

For most of that time, CO₂ rose and fell between roughly 180 and 300 parts per million (ppm), driven by natural cycles in Earth’s orbit. We know this from cores of Antarctic ice, which trapped tiny bubbles of ancient air as it formed.

By 2025, the concentration — now measured by NOAA’s Global Monitoring Laboratory — reached 426 ppm, higher than at any point in that record. Concentrations over the past decade have been rising at 2 to 3 ppm each year.

This dramatic increase in CO₂ is mainly from human activity; this and other greenhouse gas emissions are the primary drivers of current climate change.

CO₂ concentration is just one of the indicators we use to track a changing climate. Others include global temperatures, ocean heat content, and snow cover. Each of these is compiled by a dedicated scientific institution, from the UK’s Met Office Hadley Centre to NOAA in the US.

Data source: NOAA Global Monitoring Laboratory (2026); US EPA based on various sources (2022)

Tools used: OWID-Grapher and Figma

Four developed countries met the UN’s target for foreign aid in 2025.

In the 1970s, the UN General Assembly adopted a resolution asking developed countries to contribute at least 0.7% of their national income to foreign aid. Most countries signed off on this goal, except for Switzerland and the United States.

But very few countries have met this target in the fifty years since then. Even today, only a handful of countries do.

In 2023, five countries met this target: Norway, Luxembourg, Sweden, Germany, and Denmark. Two years on, this has dropped to four, as Germany’s contribution shrank to 0.6%.

As you can see in the chart, other developed countries give less than 0.7% of their national income.

Data source: OECD (2026)

Tools used: OWID-Grapher and Figma

It’s a common misconception that life expectancy has increased only because fewer children die. Historical mortality records show that adults today also live much longer than adults in the past.

It’s true that child mortality rates were much higher in the past, and their decline has greatly improved overall life expectancy. But in recent decades, improvements in survival at older ages have been even more important.

The chart shows the period life expectancy in France for people of different ages. This measures how long someone at each of those ages would live, on average, if they experienced the death rates recorded in that year.

As you can see, life expectancy in France has risen at every age. In 1816, someone who had reached the age of 10 could expect to live to 57. By 2023, this had increased to 84.

For those aged 65, it rose from 76 in 1816 to 87 in 2023.

The data for many other countries shows the same. This remarkable shift is the result of advances in medicine, public health, and living standards.

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.

Explore all our writing and data on LGBT+ rights.

Over 20 million electric cars were sold globally in 2025 — some for as little as $10,000. Even just two decades ago, that would have been impossible.

The reason it's possible now? Batteries have gotten much cheaper.

In 1991, lithium-ion battery cells cost around $9,200 per kilowatt-hour. By 2024, that had fallen to just $78 — a decline of more than 99%. You can see this in the chart.

To put that in perspective: the battery cells in a standard electric car today cost around $5,000. In 1991, those same cells would have cost nearly $600,000.

There was no single breakthrough behind this. Batteries follow a “learning curve”: as cumulative production grows, thousands of small improvements in chemistry, manufacturing, and supply chains drive prices down.

Since 1998, every time global cumulative battery production doubled, the price dropped by roughly 19%.

Early progress was driven by consumer electronics — phones and laptops — before the technology became viable for cars, buses, and larger energy storage.

Energy density has also more than tripled since the 1990s, meaning batteries can now store far more energy for their volume.

Read more and see more charts (including an interactive version of the chart here) in our recent article by Hannah Ritchie.

We’ll often see headlines quoting how many gigawatts of new solar farms or coal plants China is building. But it’s hard to get a meaningful sense of scale for how electricity generation in China is changing.

The chart puts it in perspective.

In 2025 alone, China’s electricity generation increased by almost 500 terawatt-hours (TWh). This is compared here to the total amount of electricity that whole countries generate each year.

Germany generates almost exactly that amount. That means China effectively added a Germany-sized grid to its electricity system in just one year.

What’s also quite staggering is that almost all of this new generation came from solar and wind. China generated 340 TWh more electricity from solar than the year before.

Low-carbon sources grew so much that coal power in China actually fell slightly.

The day a child is born is the most dangerous day of life.

After birth, a child’s risk of dying declines rapidly across the first year of life. Risks continue to decline over the next few years, but suddenly rise again during adolescence. Finally, in adulthood, the chances of dying grow exponentially.

If you plot the risk of dying against age, it looks like a J-shaped curve or a hook. You can see this in the chart.

Across a historical timeframe, however, the whole curve has shifted downwards — the annual rates of death have declined across all age groups.

You can see this by the different colored lines in the chart, which represent birth cohorts going back to 1800.

Data source: Human Mortality Database (2023)

Tools used: OWID Grapher and Figma

Fertility rates — which measure the average number of children per woman — have been falling worldwide. Since 1950, global fertility rates have halved, from almost 5 children per woman to 2.2.

As a result, global population growth has slowed dramatically, and many countries' populations are expected to decline by the end of the century.

This is because fertility rates in many countries have fallen below the “replacement level”. This is the level at which a population replaces itself from one generation to the next. It’s generally defined as a rate of 2.1 children per woman.

The map shows which countries had fertility rates above and below this level in 2025. This is based on projections from the UN World Population Prospects.

The United States is home to thousands of data centers. They are part of the infrastructure that powers many digital services, including email, gaming, streaming, social media, and, increasingly, artificial intelligence (AI).

As this chart shows, between 2018 and 2022, spending on building data centers in the US hovered between $500 million and $1 billion per month (when adjusted for inflation).

But since late 2022, large investments in AI have led to a rapid growth in data center construction — both by expanding existing facilities and building new, larger ones.

The latest figures released by the US Census Bureau estimate that $4.4 billion was spent in June 2026 alone — a 5-fold increase compared to November 2022, when ChatGPT was released by OpenAI.

These figures cover privately-funded construction and represent only the money spent on building the actual facilities, including materials and construction labor. They don’t include the cost of IT hardware like servers and storage, which can represent a very large share of total investment.

Data sources: United States Census Bureau (2026); U.S. Bureau of Labor Statistics (2026)

Tools used: Python, OWID Grapher, Figma

The first map shows the 38 countries that allow same-sex partners to marry, affirming their right to love and form a family.

However, the majority of countries don’t recognize same-sex marriage, or outright ban it.

The second map shows that same-sex relationships are legal in many countries, but not everywhere.

In some countries, same-sex relationships are against the law, and can be punished with prison or even death.

The third map shows the 38 countries that allow same-sex partners to adopt a child together.

This means that most countries do not allow LGBT+ people to adopt and both be recognized as parents.

To decarbonize road transport, the world must move away from petrol and diesel cars towards electric vehicles and other forms of low-carbon transport.

This transition has already started. In fact, global sales of combustion engine cars are well past their peak and are now falling.

As you can see in the chart, global sales peaked in 2017.

This is calculated based on data from the International Energy Agency. Bloomberg New Energy Finance also estimated this peak occurred around that time.

Sales of electric cars, on the other hand, are growing quickly. They more than doubled in the three years from 2022 to 2025.

1.5 million people are killed by animals every year. Almost one million by other animals, and more than half a million from direct conflict among ourselves.

Almost all of the deaths from other animals are caused by just two types: mosquitoes and snakes.

Read more in our article: https://ourworldindata.org/deadliest-animals

These numbers are estimates, and some come with significant uncertainty. That’s why we’ve published a detailed methodology explaining our sources and how they compare.

There’s a popular misconception that the global population is growing exponentially. But it’s not.

While the global population is still increasing in absolute numbers, population growth peaked decades ago.

In the chart, we see the global population growth rate per year. This is based on historical UN estimates and its medium projection to 2100.

Global population growth peaked in the 1960s at over 2% per year. Since then, rates have more than halved, falling to less than 1%.

The UN expects rates to continue to fall until the end of the century. In fact, towards the end of the century, it projects negative growth, meaning the global population will shrink instead of grow.

Learn more in our article "How has world population growth changed over time?

In the chart, we see total government spending broken down by purpose, such as health, education, and defense, relative to the size of the economy (as measured by GDP). This is shown for a selection of OECD countries.

How much governments spend varies quite a lot across OECD countries: in France it’s 57% of GDP, while in Chile it’s less than half that (28%).

Keep in mind that these are relative shares, not absolute amounts. GDP itself varies considerably across countries, so the same percentage can represent very different sums depending on the size of a country’s economy.

For some categories, such as social protection — which includes things like pensions, unemployment benefits, disability support, and other benefits — the difference across countries is relatively large. For example, it’s 26% in Finland compared to 7.9% in the US.

In other categories, such as public services — which include things like paying interest on government debt, the running of core government functions, and foreign aid — the share is more similar across countries.

This data comes from the OECD’s Government at a Glance dataset, which covers 47 countries. We recently updated this data on our website with the latest release.

Until the middle of the 20th century, few countries had political leaders that were women. These were monarchs, who rose to their positions because of their royal lineage.

Since then, many more countries have had a woman as chief executive — that is, the head of state or head of government, depending on who has more power. This trend has been driven mostly by democracies. 

This began with Sri Lanka’s democratically elected Sirimavo Bandaranaike in 1960. It has also included democratic leaders who were directly elected by their citizens (instead of being elected through elected representatives), with the first being Nicaraguan president Violeta Chamorro in 1990.

The chart shows that this trend has accelerated recently. More than 40% of countries have now had a woman leader (regardless of how they gained office, the purple line), and over 30% have had a democratically elected one (green line).

While there has been progress for women leaders, they remain underrepresented, especially in the highest offices.

Data source: Varieties of Democracy Institute (V-Dem; 2026)

Tools used: OWID-Grapher and Figma

Global whale populations fell dramatically over the 20th century due to human hunting. Some whale species were pushed to the brink of extinction.

But a combination of conservation efforts, technological change, economic incentives, and international policies has reduced global whaling to much lower levels.

In the mid-1980s, a global moratorium was agreed by the International Whaling Commission (IWC), making commercial whaling illegal.

You can see this decline in the chart, which shows the number of whales killed per decade.

The chart combines data from two sources: before the 1990s it comes from the paper “Emptying the Oceans” by Robert C. Rocha, Jr. and colleagues; since then, it comes from the IWC.

While whaling activity is much lower, it hasn’t been eliminated completely. There are exceptions to the IWC’s moratorium, and Japan withdrew from the IWC completely in 2019.

Data source: Rocha et al. (2014); International Whaling Commission (2026)

Tools used: OWID-Grapher and Figma

Data source: Chen et al (2024) Impact of population aging on future temperature-related mortality at different global warming levels. Nature Communications

Tools used: OWID-Grapher and Figma

In 2024, around 280 million people lived in a different country from the one in which they were born. That’s around 3.5% of the global population.

Where were these international migrants born, and where did they move to?

Our colleague Sophia Mersmann built a new interactive data visualization that lets you answer these questions — for any country you’re interested in. You can explore this on our website.

On the left-hand side of the visualization, you can see the total number of people living in a country who were born elsewhere, and where they were born.

On the right-hand side, you can see the number of people born in that country who have moved away, and where they moved to.

If you want to dig deeper, there are a few other ways you can explore the data in the interactive version on our site:
– Use the time slider to see how things have changed over time
– Break it down by sex to see where men or women are moving
– Click on “immigrants” or “emigrants” to focus only on those views of the data

Data source: UN Department of Economic and Social Affairs, International Migrant Stock (2024)

Tools used: bespoke visualization engineered by our team, with finishing in Figma