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.

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.

Lung cancer kills more than two million people every year, making it the most fatal cancer globally.

While a number of factors increase the risk, the 20th century brought one like no other: smoking.

There is now plenty of epidemiological evidence linking smoking to lung cancer, but we can also see it in the patterns of death over decades. The chart shows death rates from lung, trachea, and bronchus cancers among men in a selection of high-income countries. Each shows a very clear rise and fall over the late 20th century.

This pattern mirrors smoking rates, with a lag. The timing and height of each peak depend on when and how strongly smoking took hold: early in the United Kingdom, later in Japan.

You also see this rise and fall among women, shifted later, since they took up smoking after men did.

Today, most smokers live in low- and middle-income countries, who are at different stages of this curve. Helping people quit or preventing them from starting in the first place would save many lives for decades to come.