Droughts and heatwaves: by the end of the 21st century they will threaten 1/3 of the world’s population
Droughts and heatwaves are particularly severe when they occur simultaneously. A new study shows that the frequency of such extreme weather events will increase fivefold by the end of this century. The negative consequences will be felt especially by residents of poor countries in the tropical zone.
Intensification of extremes in the coming decades
The year 2024 was the warmest in the history of meteorological measurements, and there are many indications that another record will be set in the coming months, which is linked to the development of an exceptionally strong El Niño event. A study published on 7 April this year in the journal Geophysical Research Letters indicates that the rise in global average temperature will be accompanied by drought in many parts of the world. This accumulation of exceptionally difficult living conditions is expected to affect 28 percent of the global population by the end of the 21st century.
This alarming projection is based on a detailed analysis of past meteorological extremes in different regions of the world – in the years 2001-2020, simultaneous droughts and heatwaves were twice as frequent as in the pre-industrial period. Combining this finding with eight climate models based on scenarios presented in the Sixth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC), scientists calculated that over the next seven decades, hot-dry episodes will be more than five times more frequent than before.
The outlook for future generations is not optimistic. In the 2090s, heatwaves without precipitation may occur on average 10 times a year and last up to 15 days, almost three times longer than in the last quarter century. In some regions of the Earth, quality of life may deteriorate significantly.
Droughts and heatwaves – a dangerous interdependence
Di Cai, a climatologist at the Ocean University of China and the lead author of the study, emphasizes that droughts and heatwaves reinforce each other, leading to constraints in the supply of drinking water and rising food prices. Shortages negatively affect not only health and social well-being, but also the functioning of the energy sector and industry. Combined with high temperatures, they are catastrophic for crops and livestock.
During hot, rainless periods, the risk of life- and property-threatening wildfires also increases, as does mortality associated with high temperatures. These negative impacts will particularly affect farmers and people working outdoors.
Those who contribute the least suffer the most
Both droughts and heatwaves can, in light of current scientific knowledge, be easily linked to human-induced climate change. The researchers deliberately compared scenarios assuming different levels of greenhouse gas emissions with situations that consider only natural forces – for the latter, no significant trends were observed in either the frequency or duration of simultaneous drought and heatwave episodes.
The vast majority of emissions are generated by wealthy developed countries. Meanwhile, according to the authors of the study, the strongest intensification of simultaneous droughts and heatwaves will be experienced by the inhabitants of Mauritius and Vanuatu, two island countries with low levels of income per capita. Further down the ranking of places vulnerable to hot-dry episodes are Fiji, Samoa, and Timor-Leste, and the entire top fifteen is located in the tropical or equatorial zone.
According to the researchers, the growing interdependence between temperature and the climatic water balance will be most pronounced in countries of Central and South America, southern Europe, Africa, and southern Asia.
Source:
Cai, D., Lohmann, G., Chen, X., & Ionita, M. (2026). Compound hot-dry extremes amplify disproportionate climate risks for low-income nations. Geophysical Research Letters, 53, e2025GL118822. https://doi.org/10.1029/2025GL118822
