Evolution of Intense Heat Wave Hazard and Heat-Related Mortality in Europe

Heat waves have emerged as a health hazard over Europe in recent decades with severe episodes of morbidity and mortality reported in the recent past during major heat waves. Several studies have investigated the temperature-mortality associations across Europe establishing the impact of rising temperature on increasing human health risk. In addition to these associations, the influence of changing characteristics (frequency, intensity, and duration) and dry and humid heat wave trends at different spatial and temporal scales would enhance the understanding of the rising risk to human health in the region. In the present study, the impact of intensity, frequency, and duration of heat wave events (dry and humid) was analyzed for Northern, Southern, Eastern and Western European regions using weekly all-cause mortality record from 976 contiguous NUTS 3 regions from 2001–2024 (obtained from EUROSTAT) and meteorological data comprising of daily mean temperature and relative humidity (derived from hourly ERA5 Land hourly dataset). 

A two-stage modeling framework was employed: i) quasi-Poisson time series regression models used to estimate temperature-mortality associations for each region ii) mixed-effects meta-regression models were applied to derive pooled estimates of heat-related mortality across different regions of Europe, incorporating between-region heterogeneity heatwave effect across Europe. The results indicate the southern European region to be most affected by heat related mortality however, the inconsistency in the health data constraints adding limitations to derive robust spatio-temporal patterns based on the present long-term records. The study observed a consistent increase in heat attributed to deaths in the past decade which rises with increasing age and varies by gender reflecting rising vulnerability to extreme heat. The findings suggest the need for immediate targeted adaptation measures to protect the most at-risk populations and future risk associated with heat extremes.