Climate science in any real sense is only about as old as I am (as per this bio of one of its founders) and it reached maturity at about the same time I did – years ago, that is. But it is still learning, as I hope I am, and still making important new discoveries. Here’s a very good example, a paper published this month in one of the world’s greatest journals, Nature.
I will quote the Abstract, the authors’ summary, in full:
Drought is one of the most common and complex natural hazards affecting the environment, economies and populations globally. However, there are significant uncertainties in global drought trends, and a limited understanding of the extent to which a key driver, atmospheric evaporative demand (AED), impacts the recent evolution of the magnitude, frequency, duration and areal extent of droughts. Here, by developing an ensemble of high-resolution global drought datasets for 1901–2022, we find an increasing trend in drought severity worldwide.
Our findings suggest that AED has increased drought severity by an average of 40% globally. Not only are typically dry regions becoming drier but also wet areas are experiencing drying trends. During the past 5 years (2018–2022), the areas in drought have expanded by 74% on average compared with 1981–2017, with AED contributing to 58% of this increase. The year 2022 was record-breaking, with 30% of the global land area affected by moderate and extreme droughts, 42% of which was attributed to increased AED.
Our findings indicate that AED has an increasingly important role in driving severe droughts and that this tendency will likely continue under future warming scenarios.
Source: Gebrechorkos, S.H., Sheffield, J., Vicente-Serrano, S.M. et al. Warming accelerates global drought severity. Nature (2025). https://doi.org/10.1038/s41586-025-09047-2
What’s that in plain language?
Most people think droughts happen simply because it stops raining. But scientists have found another powerful force at play. As the air gets warmer, it increases what’s known as atmospheric evaporative demand, or AED.
Think of AED as a giant sponge in the sky. As it heats up, it pulls more and more moisture from the land below, drying out soil, draining rivers, and stressing plants, often faster than that moisture can be replaced.
We don’t know much about whether global warming increases the likelihood of drought, but the authors found that…
…AED has increased faster than precipitation rates, suggesting an alarming tendency towards drier conditions. … In warm areas, raising the temperature by just a couple degrees can dramatically increase the atmosphere’s ability to draw moisture from crops, rangelands, and forests…
This study reinforces past work showing that droughts will become more intense in a warming world. This has implications for global food and water security, which may in turn amplify political instability and conflict. Easier to see are more direct links between increased AED and wildfire. A thirsty atmosphere desiccates plants, which contributes to larger wildfires.
How science is shared
Those two quotes are from scitechdaily, a respected science news site which takes hard science stories and makes them more accessible. The Conversation does the same, and so do several others.
Scientific discoveries eventually make their way on to the more popular media, often via such intermediaries, at the same time as they are being circulated in the science community.
Sadly, it can take a while before they are properly absorbed, as I said in Too many 1-in-100-year floods in March.
