Heatwaves are a growing global threat to human health, wellbeing and livelihoods.

Across 12 major European cities during the summer of 2025, a ten-day period of extreme heat led to 2,300 deaths – 1,500 of them were attributed to climate change amplifying temperatures by 1-4°C. Heatwaves were responsible for nearly half a million global deaths every year from from 2000 to 2019.

In addition to their health risks, European heatwaves in 2025 contributed to regional glaciers melting and wildfires hitting the largest area on record, according to a new report.

And it’s not just Europe, globally 2025 was ranked as one of three hottest years on record. Heatwaves are not going away: even after emissions targets are met, heatwaves will not return to pre-industrial levels for at least 1,000 years.

Governments across at least 47 countries have implemented heat action plans, such as the United Kingdom’s adverse weather and health plan and city-level plans across India.

These plans typically include early-warning systems, coordination between health and social authorities, and public messaging urging people to stay cool. People can try to implement a variety of measures, including staying in a cool environment, avoiding strenuous activity, drinking more water and wearing lighter clothes. These are theoretically simple steps, which is why heatwave deaths are so often called needless and preventable. But the realities of everyday life make adaptation far more........

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