This chart tracks the UN’s latest demographic projections for four large populations: India, China, Europe, and the United States. Together, they account for about half of today’s world population.

The curves are shaped by what the UN expects to happen to future fertility, life expectancy, and migration worldwide.

India and China are the world’s most populous countries today, and the UN projects that both will remain at the top through the end of the century. Yet their trajectories diverge sharply in these projections.

China’s population has already begun to fall and is projected to more than halve to around 630 million by 2100. India, by contrast, is expected to keep growing for nearly four more decades, reaching about 1.7 billion people in 2060 and gradually declining to around 1.5 billion.

In contrast, the United States and Europe are projected to change more gradually. The US is expected to grow slowly and steadily, reaching about 420 million people by the end of the century. Europe’s population, meanwhile, is projected to decline. Based on these figures, its population peaked around 750 million in 2020, and is expected to fall to about 590 million by 2100, not far from China’s projected level.

The UN’s model is the most widely used baseline for international population comparisons, but all population projections are sensitive to the underlying assumptions. Other research groups use different demographic assumptions about fertility, life expectancy, and migration to reach different long-term population figures.

Explore the UN projections in our Population & Demography Explorer, or compare them with alternative scenarios in the Wittgenstein Centre Human Capital Data Explorer →

The Global Wildfire Information System (GWIS) has published weekly data on the area burned by wildfires since 2012. At the beginning of August, Spain was on track for a relatively low year. Its running total for 2025 was below the average and far below former records.

But just two weeks later, it had overtaken all of these previous years. You can see this in the chart, which shows the cumulative wildfire burn across each year. Large outbreaks in mid-August meant the last record, set in 2022, was rapidly surpassed.

This global dataset from GWIS only dates back to 2012, so it is a relatively short record. However, the European Forest Fire Information System, based on data starting in 2006, also found that this year’s fires were the highest in two decades in Spain.

Portugal has also seen extremely large fires this year.

Note that consistent data is unavailable over longer periods, so it’s hard to give context to the scale of these fires compared to the more distant past.

See how large wildfires in your country have been compared to previous years →

Many of us take artificial light for granted. Most of us use it daily: we can read, cook, and do tasks indoors; students can study at night; and our communities and homes are safer when not cloaked in darkness.

It’s not just light that has been transformative, but cheap light. The price of lighting has fallen by more than 99.9% since the 1700s.

Changes in what we use to power lighting have been crucial to the plummeting costs. This chart, based on data from Fouquet and Pearson, shows these changes from 1700 to 2000.

In 1700, the typical British household lit its evenings with candles. In the 18th century, they started using whale oil, and by the 19th century, they saw the rise of burning gas. Kerosene briefly provided a fifth of light around 1900. With each transition, lighting became more efficient, and the costs dropped. But the defining transition has been to electricity. It now provides almost all of the UK’s artificial light.

For hundreds of millions of the world’s poorest, lighting at night is still a luxury, and will remain so until they get access to electricity.

Explore what the cost and distribution of lighting tell us about human development →

For most of the 2010s, Ecuador had some of the lowest murder rates in Latin America. According to data from the UN Office on Drugs and Crime, rates were often three or four times lower than the regional average.

But as you can see in the chart, homicide rates have risen steeply in the last few years. From 2020 to 2023, rates increased more than fivefold. To put this in context: the number of people murdered each year increased from roughly 1,400 to 8,200.

Ecuador went from being one of the safest countries in the region to having one of the highest murder rates, not only in Latin America, but in the world as a whole.

This increase in violence has been linked to Ecuador’s growing role in international drug trafficking and competition between criminal groups. Large outbreaks of prison violence, often involving rival gangs, have also contributed.

Estimates of homicide rates can vary between sources; read our explainer on differences between them →

Go back to China in the 1960s, and you’ll find that the average person ate very little meat. This isn’t surprising: most of the country lived in extreme poverty and could not afford it. Meat consumption is strongly correlated with income: as countries get richer, they tend to have more diverse, meat-heavy diets.

However, as the chart shows, meat supply per person has increased significantly over the last sixty years. In 1962, annual consumption was just 4 kilograms per person. By 2022, it had increased almost 18-fold to 70 kilograms.

It’s not only the amount of meat consumed that’s changed: people in China also eat a more diverse mix. In the 1960s and 1980s, almost all meat came from pork. Today, pork still dominates, but it is joined by more poultry and beef.

This change in diet matters for various reasons. More diversified diets (which are not only about animal products) tend to be more nutritious than monotonous staple-heavy diets that are common for people living in poverty. But this increase in meat consumption also comes with a large environmental impact and consequences for animal welfare.

Explore how meat consumption has changed in your own country →

Scientists can make an enormous difference in the world.

Take the researcher Sarah Gilbert, who has dedicated her career to developing vaccines. Over the last two decades, she has contributed to vaccines against the flu, MERS, Nipah virus, and Rift Valley fever. When she heard about the outbreak in China in January 2020, she began working on a vaccine, just in case. By the end of that year, the vaccine against COVID-19 was approved, saving an estimated 6.3 million lives in the following year alone. Without this effort, we would have faced a much darker reality, marked by lockdowns, overwhelmed health systems, and widespread suffering.

This chart lists many such scientists whose work saved many people’s lives. The estimates are taken from the web publication Science Heroes, where you can find profiles of these scientists.

It’s difficult to estimate the exact difference particular innovations have made, and I take all such estimates with a grain of salt. None of these scientists did their work in isolation; their innovations were achieved thanks to collaborative efforts and the earlier work of other researchers.

Our team spends much of its time counting deaths, but it’s equally important to know the number of lives saved — even though it is harder to estimate and involves much larger uncertainty. It’s inspiring to be reminded that creative, enterprising, and tenacious people can enormously contribute to our lives.

Fritz Haber and Carl Bosch, who invented synthetic fertilizers, are at the top of this list. My colleague Hannah Ritchie wrote an article about the difference their work has made: How many people does synthetic fertilizer feed? →