Heat-related mortality in Europe during 2024 and health emergency forecasting to reduce preventable deaths.

Successive record-breaking summer temperatures, both globally and in Europe, raise the urgent question of how to better protect vulnerable populations. Here we quantified the heat-related mortality burden during the summers of 2022-2024, and assessed the forecast skill of a new generation of continental-wide, impact-based early warning systems during health emergencies. We fitted epidemiological models with the newly created, format-homogeneous daily mortality database of the EARLY-ADAPT project, covering 654 contiguous regions across 32 European countries, which represents the entire urban and rural population of 539 million people. We estimated 62,775 (95% confidence interval = 36,765-84,379) heat-related deaths in 2024, largely exceeding the burden in 2023 (50,798; 29,442-68,610), but somewhat smaller than that of 2022 (67,873; 38,465-92,455). We demonstrated that health emergencies can be forecast with high confidence at least 1 week in advance, even for highly vulnerable regions and population subgroups. These findings have implications for public health agencies and end users, given that the adoption of the system would enable reliable heat-health emergency alerts within the time window that is relevant for stakeholders to take effective actions to reduce preventable deaths.