• Posted April 8, 2026

Combo Heat Waves/Droughts Will Affect Billions A Year By 2100, Researchers Project

Extreme heat waves combined with bone-dry droughts will occur five times more often by century’s end under current climate policies, a new study says.

These dangerous heat wave/drought combos are already more common and will continue to increase as climate change affects the globe, researchers reported April 7 in the journal Geophysical Research Letters.

“Heat and drought amplify each other,” increasing the risk of wildfires, lost crops and heat-related deaths, lead researcher Di Cai, a climate scientist at the Ocean University of China, said in a news release.

“In compound hot-dry extremes, they lead to water restrictions and unstable food prices,” Cai said. “For outdoor workers, it is dangerous.”

For the new study, researchers analyzed 152 different simulations based on eight climate models. They defined hot-dry events as days with a temperature in the top 10% and at least moderate drought.

There were roughly four hot-dry events a year between 2001 and 2020, twice as many as during the pre-industrial period from 1850 to 1900.

These extreme hot-dry events could occur up to 10 times a year on average by the century’s end, with some lasting up to 15 days, researchers projected.

By then, the risk of hot-dry days at any given time will be more than five times what it was between 1961 and 1990, researchers said.

This risk will mainly affect more than a quarter (28%) of the global population, or nearly 2.6 billion people, researchers projected.

“When you get to almost 30% of the global population affected by this, it’s very critical,” senior researcher Monica Ionita, a climatologist at the Alfred Wegener Institute in Germany, said in a news release.

"It should make us consider much, much more deeply our actions in the future," she added.

By comparison, less than 7% of the global population is expected to face that level of heat wave/drought risk in the 2030s, the study said.

People living in low-income tropical nations that contribute a small fraction of humanity’s greenhouse gas emissions are likely to see the greatest impact.

“For lower-income countries, there is a huge unfairness here,” Cai said. “It’s hard to fund air conditioning. It’s hard to fund health care. There is no backup if water runs out. It’s not just a climate science issue; it is about basic, daily life.”

Ionita said she had anticipated a slightly slower pace of change, ending at a figure of maybe 10% or 15% by the year 2100.

“By the end or middle of the century, maybe my children will not be able to experience the life that I have now,” Ionita said.

Limiting emissions could avert a lot of this risk, researchers found.

If all nations fully implement the climate action plans they contributed under the Paris Agreement – and take more binding long-term pledges – about 18% of the global population would face increased risk of hot-dry extremes by the end of the century.

That’s still a lot of people – 1.7 billion – but nearly a third fewer than would be affected under the current trajectory, researchers said.

“The choices we make today will directly affect the daily lives of billions of people in the future,” Cai said.

More information

The CIMA Foundation has more on drought and heat waves.

SOURCE: American Geophysical Union, news release, April 7, 2026