In 2024, Europe experienced an unprecedented heatwave that shattered all previous temperature records, marking the year as the hottest in recorded history. Not only was the annual average temperature elevated, but the summer months from June through September were also the warmest on record. This extraordinary climatic event resulted in a staggering toll on public health. A comprehensive study conducted by the Barcelona Institute for Global Health (ISGlobal), with support from the ”la Caixa” Foundation, meticulously quantified the human cost of this heatwave. Their analysis estimated that 62,775 heat-related deaths occurred across 32 European countries during the summer of 2024. This figure represents a significant 23.6% increase compared to 50,800 estimated deaths in the summer of 2023, though it remains slightly below the nearly 67,900 deaths reported in the summer of 2022. These sobering results have been rigorously peer-reviewed and published in the prestigious journal Nature Medicine.
The geographical distribution of heat-related mortality reveals pronounced regional vulnerabilities. Italy emerged as the country most affected by heat mortality, with over 19,000 deaths attributable to elevated temperatures during the summer of 2024. Italy’s vulnerability is consistent with previous years’ data, where it also reported the highest number of heat-related deaths: approximately 13,800 in 2023 and 18,800 in 2022. Spain, often cited as highly susceptible due to its Mediterranean climate, logged the second-highest number of deaths in 2024, totaling more than 6,700. This represents a notable decrease from previous years, partly explained by comparatively lower summer temperatures in 2024 relative to 2022. Other countries with substantial mortality counts include Germany (about 6,300 deaths), Greece (around 6,000), and Romania (exceeding 4,900). This geographic pattern highlights the concentrated burden in southern and southeastern Europe.
Beyond absolute death counts, the study also analyzed heat-related mortality rates normalized by population size, revealing a more nuanced understanding of relative vulnerability. Greece exhibited the highest attributable mortality rate with 574 deaths per million inhabitants, followed closely by Bulgaria at 530 deaths per million, and Serbia with 379 deaths per million. Notably, these rates substantially exceeded those observed during the 2022 and 2023 summers, underscoring escalating risks despite variation in absolute temperatures. The substantial rise in mortality rates in countries like Greece and Bulgaria signifies heightened susceptibility possibly linked to infrastructural limitations, socioeconomic factors, or demographic vulnerabilities such as aging populations.
Age and sex disparities in heat mortality are pronounced and consistent across the years studied. The analysis showed that women suffered disproportionately, with heat-related deaths in 2024 being 46.7% higher among females compared to males. This disparity may reflect physiological differences, differential exposure, or underlying health conditions exacerbated by heat. Furthermore, individuals aged over 75 faced significantly elevated risk; their mortality rate was 323% higher than that of younger age groups. This stark vulnerability among the elderly aligns with physiological challenges in thermoregulation and the prevalence of pre-existing chronic conditions, emphasizing the need for targeted protection strategies.
Regional climatic variability adds complexity to the observed mortality patterns. While 2024 was the hottest year overall, some regions recorded higher peak temperatures in previous summers (2022 and 2023). For instance, southwest Europe experienced its most extreme heat in 2022, whereas southeastern Europe was hardest hit in 2024. This spatial heterogeneity underscores that average temperature peaks alone cannot fully predict mortality impacts. Instead, the interplay of localized heat exposure, population vulnerability, and the effectiveness of early warning and adaptation measures critically influences outcomes.
The study highlights the alarming rapidity with which Europe is warming—twice the global average—making it a frontline continent for the health impacts of climate change. The Mediterranean basin and southeastern Europe are emerging as climate hotspots where rising temperatures pose escalating threats to human health. Projections indicate that heat-related mortality will continue to increase substantially throughout the 21st century if mitigation and adaptation strategies remain insufficient. These findings underscore climate change not just as an environmental crisis but as a profound and present public health emergency.
In response to this urgency, the research incorporated an evaluation of Forecaster.health, an innovative heat-health early warning system developed under the European Research Council-funded projects HHS-EWS and FORECAST-AIR. This computational tool synthesizes epidemiological models with weather forecasts to generate operational heat alerts tailored by region and at-risk population groups. Tested during the 2024 summer, Forecaster.health proved highly reliable in issuing alerts one week ahead of exceptional mortality risk events. This lead time can be crucial for mobilizing healthcare resources and community interventions to prevent avoidable deaths.
Remarkably, in southern Europe—where heat-related mortality is most acute—Forecaster.health maintained robust reliability even beyond the typical seven-day forecast horizon. This finding suggests significant untapped potential for extending early warnings to maximize protective actions for vulnerable populations. The application of advanced computational modeling combined with epidemiological data represents a paradigm shift in public health preparedness, shifting from reactive responses to proactive prevention in the face of climate hazards.
The methodology underpinning the study’s mortality estimates involved sophisticated computational simulations. Researchers fitted their epidemiological models using detailed daily temperature observations and mortality records spanning the years 2015 to 2019, thereby capturing complex exposure-response relationships. Once calibrated, these models were applied to daily temperature data and weekly mortality figures for 2022 through 2024, allowing fine-grained calculations of heat-attributable deaths. This daily resolution approach marks an advancement over previous studies relying on coarser weekly mortality data, which had underestimated heat-related mortality by 5% to 20%.
To enhance accuracy, the team undertook a re-estimation of mortality for the 2022 and 2023 summers using the refined daily mortality data from the EARLY-ADAPT database. This reprocessing yielded higher and more precise mortality estimates, subsequently informing the 2024 analysis. Such methodological rigor ensures robust, reproducible results that more accurately reflect the growing human toll of increasing heat stress under climate change.
As Europe confronts escalating heat threats, the challenge extends beyond understanding mortality to implementing effective adaptation strategies. This study serves as a clarion call to policymakers and public health stakeholders to prioritize climate resilience measures, including improved urban design, heatwave preparedness, public education, and the integration of cutting-edge forecasting technology. Strengthening cross-border collaboration on heat-health early warning systems and expanding their coverage can reduce preventable deaths and safeguard vulnerable communities.
In sum, the 2024 heatwave’s catastrophic mortality underscores the profound human consequences of climate change in Europe. The combined use of high-resolution epidemiological modeling and innovative forecasting tools offers a pathway toward mitigating this burden. However, without urgent climate action and adaptive public health interventions, the continent faces a future where heat-related deaths become an increasingly frequent and devastating reality. The evidence presented by ISGlobal and its collaborators both documents a tragic milestone and points toward critical opportunities for averting further loss of life.
Subject of Research: Heat-related mortality in Europe due to extreme summer temperatures and the effectiveness of health emergency forecasting systems.
Article Title: Heat-related mortality in Europe during 2024 and health emergency forecasting to reduce preventable deaths
News Publication Date: 22-Sep-2025
Web References:
- Barcelona Institute for Global Health (ISGlobal): https://www.isglobal.org/en/
- Nature Medicine Article: https://www.nature.com/articles/s41591-025-03954-7
- Forecaster.health tool: https://forecaster.health/
- EARLY-ADAPT project: http://www.early-adapt.eu/
References:
Tomáš Janoš, Marcos Quijal-Zamorano, Natalia Shartova, Elisa Gallo, Raúl Fernando Méndez Turrubiates, Nadia Denisse Beltrán Barrón, Fabien Peyrusse, Joan Ballester. Heat-related mortality in Europe during 2024 and health emergency forecasting to reduce preventable deaths. Nature Medicine, September 2025. doi: 10.1038/s41591-025-03954-7
Keywords: Climate change, heat-related mortality, epidemiological modeling, heatwave, public health, climate adaptation, early warning systems, Forecaster.health, Mediterranean climate, age-related vulnerability, sex differences in health impacts
