GENEVA (AP) — The international Red Cross and the United Nations are urging people and governments to do more to beat the heat, by preparing better for heat waves like recent ones from Sacramento, California, to Somalia to Sichuan, China, that could take many lives in the future.

U.N. humanitarian aid agency OCHA and the International Federation of Red Cross and Red Crescent Societies issued Monday their first joint report, chronicling the devastation of past scorchers and laying out ways to prepare for and limit the damage of future ones.

The report, “Extreme Heat: Preparing for the Heatwaves of the Future,” said 38 heat waves accounted for the deaths of more than 70,000 people worldwide from 2010 to 2019 — a likely underestimate of the real toll — on top of the fallout on lives and livelihoods.

That toll made up more than one-sixth of the more than 410,000 deaths from disasters linked to extreme weather and climate over the same span, the report said, citing previous Red Cross calculations.

“Heat waves account for some of the deadliest disasters on record,” Martin Griffiths, who heads OCHA, told reporters. “Devastating droughts like the one pushing Somalia to the brink of famine are made far deadlier when they combine with extreme heat. We can expect more of these in the future. Indeed, things are only going to get far worse as climate change continues to spiral out of control.”

On the checklist of steps, the two organizations say some humanitarian groups are testing the rollout of emergency housing, “green” roofs, cooling centers and changes to school calendars to mitigate the impact of heat waves, which many scientists say have become more frequent because of human-made climate change.

Beyond that, governments were encourages to boost early-warning systems about heat waves and give more training and funding to local responders who often are first on site when heat waves hit. The agencies say better coordination between humanitarian groups, development organizations and weather experts is needed, too.

The U.N. and OCHA warn in particular about the outsize impact on developing countries: They cite figures that Bangladesh, for example, experienced as much as a 20% increase in deaths on heat wave days compared with an average day.

Heat waves can drive people to flee their hot homelands — adding to migration to cooler countries.

“It’s grossly unjust that fragile countries must bear deadly loss and damage from extreme heat when they are unambiguously and clearly and evidently the least responsible for climate change,” said Griffiths.

“Wealthier countries have the resources to help their people adapt and have made promises to do so. Poorer countries who are not responsible for these torturous heatwaves do not have those resources.”