🌡️ 7 ways science can help us survive extreme heat

Last month, a London event on extreme heat was cancelled because of extreme heat. That would be funny if the problem were not killing so many people.

Europe is warming faster than any other continent. Extreme heat killed more than 180,000 people in Europe in just three summers, from 2022 to 2024. But the danger is not shared equally: people in poorer regions were more likely to die when temperatures rose.

And it is getting worse. Researchers comparing recent heat with Britain’s brutal summer of 1976 say climate change has made today’s heat hotter, more humid and far more widespread across Europe.

So, let’s look at solutions.

Solution 1: Plant more trees

During the 2022 heatwaves, London’s leafiest areas were 1.2°C cooler than those with the fewest trees. At night, the gap reached 2°C. Scientists estimate that London’s trees cut heat-related deaths by around 16% between 2015 and 2022. Planting far more trees could reduce them by up to 55%.

Solution 2: Sprinkle water

Since the 17th century, people in Japan have cooled the ground around their homes by sprinkling water on it. The tradition is called uchimizu, and people still practise it today. It works: experiments found that it cut air temperatures by up to 1.5°C at a height of two metres and by 6°C near the ground. The strongest cooling was in the shade.

Solution 3: Hang wet grass

Before air-conditioning, people in India hung wet screens made from grass roots over doors and windows. Hot air passing through lost some of its heat, cooling the room and making it smell better too. The idea works so well that modern data centres now use a more advanced version of the same trick.

Solution 4: Paint roofs white

White roofs reflect sunlight rather than absorb it. Researchers modelled what would have happened if every roof in London had been reflective during the hot summer of 2018. Average temperatures would have fallen by 0.8°C, and an estimated 249 heat-related deaths could have been avoided.

Solution 5: Put curtains outside

People usually try to block the sun with curtains or blinds inside the room. But external shades work much better by blocking heat before it reaches the window. In a small UK trial, roller blinds fitted outside cut peak indoor temperatures by 3.5°C and reduced cooling needs by 20%.

Solution 6: Use a fan first

Fans use around 30 times less electricity than central air-conditioning. An Australian study found that using fans before turning on the AC could cut cooling energy use and emissions by 76%, without making people less comfortable.

Solution 7: Make a heat plan

Planting trees and painting roofs take time. Warnings can help before the next heatwave. In India, Ahmedabad introduced South Asia’s first city heat action plan in 2013, combining forecasts, public alerts and preparations by health workers. Scientists estimated that the plan was associated with 1,190 fewer deaths a year.

And that’s it for today! Thanks for reading! If you enjoy the newsletter, share it with a friend or ten. And if you really enjoyed it, consider upgrading to a paid subscription: it helps support my work and means a lot.

Elia Kabanov is a science writer covering the past, present and future of technology (@metkere).

Cover art: Elia Kabanov feat. DALL-E.