Nature, 8 July 2025

Tropical regions where heatwaves are already common will be hardest hit by this trend

Hot air: the most extreme heatwaves are accelerating the fastest

The frequency of the longest and most dangerous heatwaves is increasing as the planet warms, research suggests.

Scientists have long projected that extreme heat events would become more common because of rising greenhouse-gas concentrations, but questions about the rate of change remain. Cristian Martinez-Villalobos at the Adolfo Ibáñez University in Santiago and his colleagues analysed the frequency of long-lasting heatwaves in model projections of the future climate and also examined temperature records from 1982 to 2021.

They found that the frequency of long heatwaves is increasing faster than the average temperature is around the world, particularly in tropical regions where long heatwaves are already common.