Many cities across East Asia and Latin America have grown quickly over the last few decades. Since 1950, São Paulo’s population has grown sixfold. Shanghai’s nearly tenfold.

This rapid growth is now ending. São Paulo is near its population peak, and Shanghai is projected to peak around 2050.

The fastest-growing megacities are now emerging elsewhere. In the chart, you can see various examples: Karachi in South Asia, and Dar es Salaam, Addis Ababa, and Luanda in Africa.

Luanda, the capital of Angola, is an interesting case. It gets much less attention than well-established megacities, but as the chart shows, it's on track to overtake São Paulo in about 20 years and Shanghai in about 60.

In this dataset from the European Commission's Joint Research Centre, only 24 of today’s 100 largest cities are projected to still be growing by 2100; of those, 12 are in Africa, and 5 are in South Asia.

Of course, these rely on projections — often many decades ahead — and those come with a lot of uncertainty. Nonetheless, they provide a useful perspective on what the future of cities across the world might look like.

Growing up in the United Kingdom in the 1990s and early 2000s, almost all the eggs in our supermarket came from battery hens, those raised in small wire enclosures.

The living conditions in these cages are terrible. Birds get the space equivalent of an A4 sheet of paper. They don’t have the room to carry out their natural behaviors, such as nesting, perching, or dust bathing.

That has changed in recent decades. You can see this in the chart, which shows the conditions under which eggs are produced in the UK. Free-range eggs have increased from just 10% to 75%.

The use of caged hens has fallen, and the types of caged enclosures have also changed. Battery cages were banned in 2012, so legally, all cages since then have been “enriched” ones, which provide slightly more space.

Still, these do not give hens the freedom and room they’d have in barns or free-range farms. Studies suggest that moving hens from enriched cages to cage-free systems reduces the time they spend in pain by more than half.

And given that most eggs in the UK are now free-range, it’s possible to reduce this pain even further.

The increase in the world’s population is not exponential. The global population is growing, but the growth rate has declined since its peak six decades ago.

The chart shows the annual rate of global population growth according to historical estimates and projections from the UN World Population Prospects.

The growth rate peaked in 1963 at over 2% per year, and since then, it has more than halved, falling to less than 1% by 2020.

The UN demographers expect rates to continue falling until the end of the century, eventually leading to negative growth rates and a shrinking global population.

A person’s access to doctors depends heavily on the income level of the country they live in.

High-income countries have around ten times as many doctors per person as low-income ones. You can see this in the chart, which shows the number of medical doctors per 1,000 people.

The global average is around 1.9 doctors per 1,000. Low-income countries have around one-fifth of that figure.

These figures include generalist physicians and specialists.

Chronic malnutrition in early childhood can slow development and growth, leaving children shorter than expected for their age. That’s the focus of the chart: the share of children under five who are stunted, meaning they are much shorter than expected for healthy growth.

The consequences of stunting persist beyond childhood, affecting both physical health and cognitive development.

Guatemala has one of the highest stunting rates in the world: almost half of children younger than five are stunted according to survey estimates published by the World Health Organization.

Guatemala’s rate is the highest in its region, by far. In the chart, you can see it compared to a selection of other nearby countries – its rate is twice that of Haiti, the next-highest country and a much poorer one.

My colleagues Hannah Ritchie and Tuna Acisu recently wrote about what countries with high stunting today can learn from Japan. Over the 20th century, Japan reduced childhood stunting from over 70% to under 5%, and the decline from around Guatemala's current level to under 5% took place within a generation.

In the thirty years since I was born, fertility rates in my country, the United Kingdom, have not changed much. In 1993, the fertility rate was 1.8 births per woman. Thirty years later, it had dropped only slightly, to 1.6 births.

Elsewhere, the change has been much more dramatic; fertility rates have dropped sharply and are now similar to those in the UK.

You can see this in the chart, which shows the change in fertility rates from 1993 (in blue) to 2023 (in red). In Qatar and Iran, rates dropped from almost 4 births per woman to 1.7.

Fertility rates have fallen a lot across Asia and South America, too — Malaysia and Colombia are two examples (my colleague Esteban previously wrote about the latter). This marks a much faster demographic transition than many countries experienced historically.

Convergence isn’t the whole story, though. Here, I’ve picked countries with fertility rates that are similar to the UK’s today. But some have fallen far below these levels: in Chile and Thailand, the fertility rate was 1.2 births per woman in 2023, and may have fallen even further.

Five years ago, almost no one in Latin America bought an electric car. Today, the situation is different: electric cars now make up a meaningful and fast-growing share of new car sales.

The chart shows this trend across several of the region’s largest car markets, alongside the US for comparison.

The data tracks the share of new passenger cars sold that are electric, which includes both fully battery-electric cars and plug-in hybrids.

In five years, Colombia went from nearly zero to 10%, catching up to the US.

In other countries in the region, adoption took off a bit later, but is now rising fast too. Mexico, for example, went from 2% to 7% in a single year (2024–2025).

An important part of this reflects policies. Many Latin American countries, like Colombia, offer tax breaks and other incentives for buying electric cars.

Dozens of companies worldwide develop large AI models, but it can be difficult to get a sense of where the most-used ones tend to come from.

OpenRouter is a large platform that allows users to interact with and write software on top of AI models through a single interface. It includes all the models from large companies like Google, OpenAI, Anthropic, Meta, DeepSeek, and Alibaba, as well as many, many others.

I analyzed the data published by OpenRouter on the 50 most used models each day since January 2025 and calculated the average monthly presence by origin country of the models.

As you can see on the chart, US-based companies still account for most models in OpenRouter’s top 50. But their presence has declined, and China-based companies have grown rapidly, from 5 models in the daily top 50 at the beginning of 2025 to 20 in May 2026.

Very few top-50 models come from companies outside the United States and China. Canada was represented early in 2025 by Cohere’s Command R models, while France remains represented by Mistral AI’s NeMo model.

A technology that more people use every year is, so far, almost entirely the product of two countries.

In the 20th century, obesity was a health problem that mostly affected today’s rich countries. In the 21st century, it has emerged as a health challenge almost everywhere. Many low- and middle-income countries have seen rapid increases in the share of people defined as overweight or obese.

In the chart, you can see this rise for Pakistan. In the last 20 years, the share of adults defined as overweight has more than doubled, and the share defined as obese has more than tripled. Now, almost 60% of adults are overweight, and one-quarter are obese.

These are modeled estimates from the World Health Organization based on national surveys of height and weight. Body Mass Index (BMI) is a person’s weight in kilograms divided by the square of their height in meters. An adult is defined as overweight if their BMI is 25 or greater, and obese at 30 or greater.

Pakistan’s own domestic surveys often report even higher figures; that’s because they have a lower BMI threshold for being overweight and obese, which reflects the fact that South Asian populations can have higher health risks at a lower level of BMI.

Obesity is a health problem because it increases the risk of developing a range of conditions, such as cardiovascular disease, strokes, diabetes, and various cancers.

In Europe, the supply of dairy products is far higher than in other parts of the world.

This chart shows milk supply per person across the world’s regions, with data from the Food and Agriculture Organization of the United Nations.

It’s based on supply — the amount of milk available for consumption — which includes consumer waste, so it is slightly higher than the amount that people actually consume.

As you can see, the per capita supply in Europe is more than two and a half times the global average. People across Africa and Asia have far less available.

These numbers include dairy products such as yogurt and cheese, based on how much milk is used to produce them, but they do not include butter.

How likely is it that a 15-year-old girl will eventually die from a pregnancy-related cause?

Researchers at the UN and the World Bank combined available birth and mortality data with statistical models to answer this question. Their estimates assume that the country’s fertility and mortality rates remain constant throughout the teenager’s lifetime (an important assumption I’ll get to later). The chart shows their results.

In Chad, the Central African Republic, and Nigeria, the estimated lifetime risk is around 4%. This is dire: it means about 1 in 25 girls would eventually die from a pregnancy-related cause.

Women in many other African countries also face substantial risks, and much of Sub-Saharan Africa has a rate above 1%. By comparison, estimates in most other regions are considerably lower, and across Europe the risk is below 0.1%.

The very high risks for the countries on the left of the chart reflect two factors that compound: they have some of the highest maternal mortality rates in the world, and the average number of births per woman in these countries is also high. They face a high mortality risk per pregnancy, multiplied by five or six pregnancies over a lifetime.

Maternal mortality rates per pregnancy and fertility rates are falling in these countries. Both of these declines would substantially reduce the lifetime risks. The results in the chart assume they stay at current levels, but that doesn’t have to be the case.

At the turn of the millennium, one-in-five adults in India smoked tobacco, and almost half of all adults were using any form of tobacco, including products that are chewed or sniffed.

But over the past two decades, rates of both have roughly halved. You can see this in the chart.

Some countries have seen a decline in smoking among men, but a rise among women. This is not the case in India: tobacco use has fallen substantially for both sexes.

This decline has huge implications. Each year, smoking causes almost one million Indians to die earlier than they otherwise would. Since smoking-related diseases can take decades to develop, this recent decline in smoking rates will result in fewer deaths in the future.

Smokeless tobacco tends to have lower health risks because people are not inhaling smoke. But it still increases the risk of oral, throat, and esophageal cancers, gum disease, and other conditions.

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. To allow for comparisons over time, the data is adjusted for inflation and expressed in prices for the year 2000.

In the early 14th century, one million lumen-hours — a standard lighting measure — would have cost around £34,000 in 2000 prices. By 2023, this had fallen to £2.15, a 16,000-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 1,600 lumens. Therefore, running one such bulb for 24 hours would produce about 40,000 lumen-hours.

That means that 1 million lumen-hours today would require continuously keeping a standard 100-watt incandescent bulb on for about 26 days. Achieving the same amount of light with candles would require 120 candles burning at once for that entire 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.

Spending on the hardware that trains and runs artificial intelligence has grown rapidly over the past years. One of the clearest indicators of how rapidly spending has increased is the revenue of American chipmaker NVIDIA.

The company accounts for around 85% of the global market for AI chips. These are graphics processing units (GPUs), originally built for video games but well-suited to the parallel computation AI training requires.

The chart shows NVIDIA's quarterly revenue in US dollars, split by end market — sales to data-center customers (cloud providers and AI companies) in green, and sales for gaming, consumer devices, and cars in red.

In early 2014, data centers and AI accounted for just 5% of its revenue; gaming was the biggest single segment. Twelve years later, the ratio has flipped: data centers and AI now make up over 90% of revenue. The revenue in this segment has grown 1,300-fold over the period, from $57 million to more than $75 billion per quarter.

The data centers and AI segment was already growing fast between 2014 and 2022, with revenue doubling every 16 months on average. ChatGPT's release in late 2022, alongside the broader push to deploy AI at scale, has accelerated that pace: since then, revenue has doubled every 11 months.

How much of the world’s fish stocks are overfished? Fisheries scientists often answer this question with a specific metric: the “maximum sustainable yield” — this is the largest catch that can be taken from a fish stock without depleting it to the point that future catches decline.

When a stock is fished at a rate above this level, it is considered overfished.

The Food and Agriculture Organization (FAO) of the United Nations estimates that just over one-third of the world’s assessed fish stocks are overfished. As the chart shows, this has increased from around 10% in the mid-1970s.

Getting high-quality global estimates of this metric is difficult; many regions have formal assessments of fish stocks and catch rates, but many fish stocks across Africa, Asia, and South America are not assessed rigorously. To get global estimates, the UN FAO combines these formal assessments with expert opinion and extrapolations based on available national and regional data.

The FAO’s report — The State of World Fisheries and Aquaculture 2024 — provides more detailed breakdowns of which species are overfished.

On the Iberian Peninsula, Spain and Portugal have scaled up solar and wind power almost in step.

In the chart, you can see the share of electricity coming from solar and wind. Both countries generated over 40% of their electricity from these sources in 2025. That was higher than the European Union average of 30%.

The two countries have very similar geographies and share an electricity market. They also have weak connections to the rest of the European electricity grid, forcing them to generate clean power at home rather than rely on imports.

Wind power is more prevalent in Portugal, while solar is ahead in Spain.

For most of human history, more people were born each year than died. Populations grew very slowly for most of this history, then rapidly in recent centuries, as child mortality plummeted and people lived longer.

But this is changing. As the map shows, deaths now outnumber births in a growing number of countries across Europe and East Asia.

The balance of births and deaths tells us about a country’s “natural population change” — whether it would grow or shrink without any international migration. Where deaths outnumber births, the population will shrink unless enough people move in from abroad to make up the gap.

Coal generates one-third of the world’s electricity, more than any other source.

But zoom into the country level, and the picture is much more varied. The map shows which source generated the most power in each country in 2024 or 2025 (the latest year available).

Thanks to large reserves, coal dominates across Asia. It’s the largest source in China, India, Indonesia, and Malaysia. These are huge power producers, which is why coal is so dominant at a global level.

Across most other regions, it’s mostly a mix of gas and hydropower. On islands and parts of North Africa, it’s oil.

Europe has the most diverse mix, with nuclear power dominating generation in countries such as France and Finland, and solar and wind overtaking fossil fuels as the largest sources in countries such as Spain and Germany.

Solar and wind are growing quickly in many countries; when these sources are combined as “variable renewables”, they become the largest source in six more countries: the Netherlands, Portugal, Greece, the United Kingdom, Belgium, and Pakistan.

At the turn of the millennium, Australia got more than 80% of its electricity from coal. This has dropped to less than 45%.

The chart shows how the country’s electricity mix has changed in recent decades.

In the 2000s and early 2010s, coal was initially replaced by gas, with only moderate growth in solar and wind. But in the last five years, solar and wind have been deployed much more quickly. Gas is now on the decline, too. In 2023, solar overtook gas to become Australia’s second-largest electricity source.

While coal is declining, it still supplies much more of Australia’s power than most high-income countries.

Unsafe sanitation is responsible for hundreds of thousands of deaths each year. It increases the risk of many fatal diseases, including cholera, diarrhea, dysentery, hepatitis A, typhoid, and polio.

Unfortunately, over 40% of the world does not have access to safe sanitation facilities. This is based on estimates from the WHO/UNICEF’s Joint Monitoring Programme for Water Supply, Sanitation and Hygiene.

The chart shows the share of the global population that has access to safe sanitation over time. While rates have increased, particularly over the last decade, they still fall far short of the UN’s target of universal access in 2030.

Increasing access to safe sanitation would save many lives from preventable infectious diseases.