Climate change kills differently: heatwaves become more deadly, while storms claim fewer victims

Climate change is increasing the frequency and intensity of extreme weather events - from heatwaves and wildfires to floods and devastating storms. While material damage is steadily increasing, the impact on the number of deaths is more nuanced. Scientists point out that the effects on mortality differ significantly depending on the type of phenomenon, according to an analysis by AFP based on international data.

Globally, mortality associated with natural disasters has decreased in recent decades, especially in the case of storms and floods. But this positive trend is not found in the case of heatwaves, where the number of deaths is increasing.

More than 2.3 million people died from extreme weather events between 1970 and 2025, according to an AFP analysis of the EM-DAT database of the Centre for Epidemiological Research on Disasters (CRED), based in Belgium.

Between 2015 and 2025, the toll was 305,156 deaths, down from 354,428 in the previous decade. But the reduction does not mean that the phenomena have become less dangerous. "It is not because the events have not become more dangerous, but because we have become stronger in our ability to cope with them,” explains Marina Romanello, executive director of The Lancet Countdown program, which monitors the links between climate and health.

• Heatwaves, the "silent killer” of the 21st century

Extreme heatwaves are considered a "silent killer” mainly because their health effects are harder to quantify and can occur months or even years after the event. The elderly and those with pre-existing conditions are most vulnerable. Last year, half the world's population experienced more days than the historical average with a felt temperature of at least 32 degrees Celsius, according to data from the European Copernicus Observatory - a threshold known for its direct impact on mortality. "It is now very clear that extreme heat has become more deadly,” says Theodore Keeping, a researcher at Imperial College London. According to him, current climate models allow for the attribution of additional deaths to temperature increases generated by climate change. EM-DAT data shows that about 61,800 people died from heat waves in 2022, 48,000 in 2023, and the toll rose again to 66,825 deaths in 2024. However, experts warn that these figures are underestimates.

According to estimates from The Lancet Countdown, global heat-related mortality - defined in a broader sense than heatwave episodes - reached an annual average of 546,000 deaths between 2012 and 2021, up 63% compared to the 1990s.

• Storms and floods: fewer victims, persistent risks

In the case of floods and tropical cyclones, the number of victims has decreased, mainly due to improved early warning systems, reinforced infrastructure and the application of stricter building codes. Between 2015 and 2025, floods caused 55,423 deaths, down from 66,043 in the previous decade, and storms caused 36,652 deaths, down from 184,237 in the previous decade, according to EM-DAT. "We have advanced warning systems that can save lives, but the danger remains very high,” warns Tobias Grimm, chief climate scientist at German insurer Munich Re. According to Munich Re, natural disasters caused 17,200 deaths globally last year, mainly in the Asia-Pacific region and Africa. While the figure is higher than in 2024, when around 11,000 deaths were reported, it remains well below the 30-year average of 41,900 deaths annually.

Experts warn that while adaptation and infrastructure have reduced mortality in many cases, the effectiveness of these measures has limits. "We know for sure that climate events are becoming more frequent and intense. So far we have managed to flatten the mortality curve in many situations, but there is a limit when these events happen in rapid succession, without enough time for recovery,” emphasizes Marina Romanello.