Researchers from the ISGlobal research center, in collaboration with the RECETOX center at the Faculty of Science, Masaryk University, published a study in Nature Medicine estimating that over 180,000 deaths in Europe during the summer seasons of 2022, 2023, and 2024 were linked to heat. In the Czech Republic, 2024 was by far the worst year in terms of heat-related mortality over the past three years.
The year 2024 broke several temperature records: it was the hottest year in recorded history, and its summer was the warmest ever. The study, led by ISGlobal in cooperation with RECETOX, estimates that between June 1 and September 30, 2024, there were 62,775 heat-related deaths across Europe. In comparison, summer 2023 saw around 50,800 deaths, and summer 2022 nearly 67,900 deaths. The results were published in Nature Medicine.
“Compared to the rest of Europe, the situation in the Czech Republic was reversed. The year 2024 was by far the worst of the three years assessed in terms of heat-related deaths,” says Tomáš Janoš, lead author of the study and researcher at ISGlobal and RECETOX, Faculty of Science, Masaryk University.
The study analyzed 654 regions in 32 European countries. The country with the highest estimated number of heat-related deaths in 2024 was Italy, followed by Spain, Germany, Greece, and Romania. In the Czech Republic, the study estimates that 544 people died due to high temperatures during the summer of 2024—significantly more than in previous years.
When adjusted for population size, the countries with the highest heat-related mortality rates in 2024 were Greece, Bulgaria, and Serbia. In 2022 and 2023, Greece also had the highest estimated mortality rate. In total, 15 out of the 32 countries experienced both the highest number of deaths and the highest mortality rates due to heat during the summer of 2024.
“Although summer 2024 was the hottest on record according to the Copernicus programme, the number of heat-related deaths across Europe was slightly higher in summer 2022. This is because in some highly vulnerable regions included in our study, summer 2022 was actually warmer. Therefore, the overall European average temperature may not fully reflect mortality. In both 2022 and 2024, the highest temperatures occurred in southwestern and southeastern Europe—areas particularly vulnerable to heat,” explains Janoš.
“Europe is the fastest-warming continent—twice as fast as the global average. Within Europe, the Mediterranean and southeastern regions are emerging as hotspots of climate change, facing the greatest health impacts and expected to see a significant rise in heat-related mortality throughout the 21st century,” adds Janoš.
Part of the study evaluated the Forecaster.health tool, developed under the ERC Proof-of-Concept grants HHS-EWS and FORECAST-AIR. This tool uses epidemiological models to transform weather forecasts into daily health risk alerts for heat, tailored to specific regions and population subgroups. The analysis shows that the tool is highly reliable, capable of issuing alerts at least one week in advance when conditions indicate exceptional mortality risk.
“While the pan-European system shows the direction research in early warning systems could take, we still lack a system that specifically reflects the conditions of the Czech Republic. Without significant adaptation—including the development of such early warning systems—we can expect a substantial increase in heat-related deaths in Central Europe and the Czech Republic during this century,” concludes Janoš.
Sabina Cerulová originally planned to study veterinary medicine, but coincidence, the covid‑19 pandemic, and her bachelor’s project led her to research at RECETOX. Today, she studies a rare genetic mutation responsible for severe symptoms in a specific patient, and she works with animal models, microbiome, and advanced imaging methods.
