Sustainability by Numbers

Deforestation is nearly always reported and measured based on the country where it happens. In high-income countries, deforestation rates are now very low (we did most of our forest clearing a century or more ago to make space for agriculture). On net, many are gaining forest through planting and natural regeneration. But consumers also contribute to deforestation through imports.

Last month, the International Energy Agency (IEA) published its estimates of electric car sales data for 2025. I updated all of this data in our charts on Our World in Data, if you want to dive into more detail. Here, I wanted to share just a few headline figures, then go on to tackle the question of how long it takes for electric car sales to translate into cars on the road. First, the interesting figures from the new data. Its EV share has been stuck on 10% for several years.

Over the past year, I’ve written a few articles about the energy (and carbon) footprint of individual use of artificial intelligence, mostly in the form of asking LLMs (or chatbots) questions. The problem is that until recently, the latest figures from organisations such as the International Energy Agency were for 2024. It’s hard to have a serious conversation about AI's energy use with data from before AI really took off.

Cuts to USAID have received a decent amount of public attention over the last year. Understandably so: the United States is the world’s largest aid donor in pure dollar terms (even though it’s far down the list when compared to the size of the economy).

One of the cheapest ways we could limit global warming today is by reducing aviation contrails. I’m not going to go into the mechanics of contrails — what they are, how they’re formed, and how they drive global warming — here, because I covered this in much more detail in another Substack.

Three things for today. First, thank you very much to everyone who played around with the Energy Comparison Tool that I published yesterday, and wrote to me with feedback. I received many emails and comments with great suggestions.1 I feel lucky to have an audience that is so engaged in trying to build something useful. As promised, I read them all and I’m working on improvements. I’ll add a change/update log to the tool, so you can follow what’s changed.

Without data, it’s incredibly hard to get a sense of scale. One area where this is extremely apparent is in energy use and carbon emissions. It’s hard to know what matters a lot, and what very little. A lot of my work with data is about getting a sense of whether something is big or small, effective or not. Is that a big number? To help, I’ve built an interactive tool that lets you compare the energy use of different products and activities: from lighting and cooking, to heating and driving.

Diabetes is growing much faster in South Asia and Africa than in Europe or North America. Which country has the highest rates of diabetes? Many people would guess the United States. Perhaps Canada or Australia? Mexico? The United Kingdom? According to the International Diabetes Federation, it’s Pakistan. Take a look at the map below, which plots the prevalence of diabetes among 20 to 79-year-olds. Now, this data is what we call “age-standardised”.

People think the world is getting worse. That’s what almost any survey of opinions across the world would tell you. Things are bad, have been getting worse, and that will continue. Back in 2015, YouGov asked more than 18,000 adults exactly this question: whether the world was getting better, worse, or neither. Those who thought the world was getting better were in the firm minority. Below, you can see the results across various countries. Overall, rich countries were more pessimistic.

Some of you might have seen a post online that goes like this: “The media has told you that the bees are dying. But look at this chart: there are more bees than ever!” They’ll then show a chart like this: Or similar data showing the global production of honey and beeswax: Now, there’s nothing wrong with this data. It is published by the Food and Agriculture Organisation of the United Nations. You’ll find similar data from the US Department of Agriculture (USDA).