04 October 2021
Nearly 25% of world population exposed to deadly city heat

Concrete and asphalt as well as scarce vegetation in urban areas lead to higher temperatures, study shows.

Exposure to deadly urban heat has tripled since the 1980s, and now affects nearly a quarter of the world’s population, a study has found.

Scientists put the worrying trend down to the combination of rising temperatures and growing numbers of people living in urban areas, and warned of its potentially fatal impact.

In recent decades, hundreds of millions of people have moved from rural areas to cities, which are now home to more than half the world’s population. Amid surfaces such as concrete and asphalt, which trap and concentrate heat, and little vegetation, temperatures are generally higher in urban areas.

“This has broad effects,” said Cascade Tuholske, the lead author of the study published in the journal PNAS and a postdoctoral researcher at Columbia University’s Earth Institute. “It increases morbidity and mortality. It impacts people’s ability to work, and results in lower economic output. It exacerbates pre-existing health conditions.

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