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.