One way to measure income inequality is to look at the share of all income that goes to the top income earners. The chart plots this for all seven South American countries with comparable 2022 pre-tax income estimates in the World Inequality Database.

The difference between the left and right bars is which earners they cover: the richest 10% on the left, the richest 0.1% on the right.

Looking at the left-hand bars, Colombia ranks top. It has the highest share going to the richest 10%, followed by Chile, Brazil, and Peru — in these four countries, the top 10% share earns more than half of all income. This is high relative to other countries around the world.

But looking at the dark blue bars on the right, the rankings change. Peru’s richest 0.1% receive about 22% of income, the highest in the region by far, and actually the highest in the world that year.

This chart shows just two metrics, but you would also get different pictures if you looked at Gini coefficients or the distribution of wealth instead.

So, what is the most unequal country in South America? It depends on what metric you look at. This is a region with high inequalities, but different indicators will tell you different stories depending on which part of the distribution you examine, and how incomes are measured.

Most people in the world would think very little before flicking on the lights, charging a mobile phone or turning on a laptop to read this.

But that’s a very different reality from the almost 700 million people in the world who have no access to electricity. While this number is large, it has halved this century, falling from 1.35 billion to 675 million. You can see this in the chart.

However, this progress has been far from even. The number has fallen across all regions except Sub-Saharan Africa, where it has increased.

That doesn’t mean no progress has been made: the share of people in Sub-Saharan Africa with electricity has doubled, rising from 26% to 53%. But population growth has outpaced this expansion, meaning the number of people without electricity has still risen.

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.

Most of the world's poorest people still rely on solid fuels — such as crop waste, dung, wood, and charcoal — for cooking and heating.

These fuels generate household air pollution when they’re burned. This has health impacts for those who breathe them in, and can increase the risk of a range of illnesses, including cardiovascular disease, stroke and some cancers.

Estimates from the Institute for Health Metrics and Evaluation suggest that indoor air pollution causes almost three million premature deaths each year. That’s three million people dying earlier than they otherwise would without this pollution.

As shown on the chart, deaths from indoor pollution have fallen as more people get access to cleaner cooking fuels. Improving access to clean energy could prevent many more early deaths.

Cervical cancer death rates among women in the United Kingdom have fallen by around 80% since 1950. You can see this reduction in the chart.

This progress happened for a couple of key reasons.

The first was the introduction of population-level screening programs in 1988. Across the UK, women are invited to get a regular smear test to detect precancerous changes or cervical cancer cases early, when treatment has much better odds of success.

Another, and more recent innovation, which could put the UK on the path to eradicating cervical cancer completely, is the rollout of the human papillomavirus (HPV) vaccine. This protects someone from the HPV infection, which can later develop into cervical cancer.

In schools across the country, girls in their early teens are offered the HPV vaccine, effectively offering them long-lasting protection. I was one of the first cohorts of girls in the UK to receive this, and it’s something I’m incredibly grateful for.

The UK is not alone in its progress: a number of countries have managed to reduce cervical cancer death rates in recent decades.

France generates two-thirds of its electricity from nuclear power, making it the country’s dominant power source.

As the chart shows, that’s far more than the average across Europe, which is 20%, and the world as a whole, at 9%.

Nuclear power is a low-carbon electricity source, giving France a very clean electricity mix for decades.

Per unit of electricity, France emits far less greenhouse gas than its neighbors and has some of the lowest-carbon power in the world. The global average, based on lifecycle emissions, is 472 grams of carbon dioxide equivalents (CO₂e) per kilowatt-hour of electricity generated. In France, this figure is 42 grams.

In every region of Africa, hunger is more prevalent than a decade ago.

The chart shows the increase in the share of the population that is undernourished, comparing 2014 and 2024 (the most recent year available). These estimates come from the Food and Agriculture Organization of the United Nations.

The situation across Africa is dire. In Middle Africa, where hunger is most acute, almost 1 in 3 people are undernourished. In Eastern Africa, the figure is roughly 1 in 4. Across Africa as a whole, it's 1 in 5.

This marks a reversal of a longer positive trend: over the preceding decades, hunger had been falling across much of the world, including parts of Africa. That progress has now stalled or gone into reverse. Conflict, extreme weather, and the economic disruption of the COVID-19 pandemic have all contributed.

The concept of “leapfrogging” is popular in development. It suggests that, as they develop, lower-income countries can skip intermediate technologies or systems and go straight to the modern equivalent.

One example of this is the use of landlines and mobile phones.

The landline telephone was invented in 1876 and became a dominant form of communication across Europe and North America. As you can see in the chart, it was increasingly adopted in the United States and the United Kingdom throughout the 20th century.

However, mobile phone adoption increased rapidly in the 1990s, and landlines have declined since the millennium. Mobile phones have become a substitute.

But many countries have almost skipped landline adoption entirely. Ghana and Nigeria are good examples: landline subscriptions have remained extremely low, and instead, mobile phone adoption has exploded.

Even after years of working with global health data, one statistic that I’m always struck by is the number of people who die by suicide every year. In 2023, it was estimated to be around three-quarters of a million.

That means suicides account for more than 1 in every 100 deaths in the world.

But a world where so many die from suicide is not inevitable. We know this because global suicide rates have fallen by an estimated 40% since the 1990s.

You can see this in the chart: rates have fallen from 15 to 9 deaths per 100,000 people over the last thirty years.

The large differences between countries also suggest that there are things that can be done to reduce this number even further.

Some technologies central to the clean energy transition depend on rare earth elements. The permanent magnets found in many electric vehicle motors and wind turbine generators rely on them. They are also used in some military hardware.

China dominates global production of rare earths; in 2024, it accounted for nearly 70% of the global total.

But the picture is not as concentrated when you examine which countries have rare-earth reserves. That is what the chart shows, plotting production and reserve shares side by side. China still holds the most known reserves, but at 49%, this is substantially lower than its production share.

Brazil holds 23% of reserves and is barely mining them. India, Vietnam, and Russia also hold significant reserves, but only a small fraction of current output.

The large gap between where reserves are located and where mining occurs partly reflects China's early investment in mining infrastructure and processing capacity, which other producers have not yet matched. Other countries hold the geological potential but have not yet developed the infrastructure to convert it into production at scale.