November 25, 2025
Seasonal influenza is sometimes seen as a mild illness, but it remains a major cause of death. In serious cases, it can cause deadly complications such as pneumonia, strokes, and heart attacks. Researchers estimate that the flu causes about 400,000 respiratory deaths and 300,000 cardiovascular deaths globally each year.
The flu is most dangerous for infants and older adults. The map here shows rates of respiratory deaths caused by the flu in adults aged 65 and over, averaged across 2002–2011 (excluding the 2009 Swine Flu pandemic).
The data shows that death rates tend to be higher in South America, Africa, and South Asia than in Europe or North America.
I come from South America, and I found this surprising: most of what I hear about flu deaths tends to come from richer countries in the Northern Hemisphere. But the map shows that the flu is also deadly, in some cases even more so, in other regions where poverty, worse underlying health, limited access to healthcare, and lower vaccination coverage contribute to higher mortality.
One explanation for my misperception might be that surveillance and reporting are stronger in the countries that I associate with deaths from flu. Another could also be age differences: people in high-income countries tend to be older, so their total number of deaths — the ones you actually hear about — may still be higher, even if rates are lower.
When you consider the total death toll, you realize that the numbers are very large on the whole. Recall that the map only includes respiratory deaths, so the overall mortality is actually higher if we include other flu-related complications like cardiovascular disease.
Even if you account for the uncertainty of estimates in low-income countries — due to limited testing and death registration — the overall pattern remains striking: seasonal influenza kills hundreds of thousands each year, with many of these deaths in South America, Africa, and South Asia.
Today
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.
June 13
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.
June 11
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.
June 9
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.
June 6
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.
June 4
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.
June 2
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.
