Identifying vulnerability factors associated with heatwave mortality : a spatial statistical analysis across Europe

In recent decades, Europe has experienced severe heatwaves with significant mortality impacts. While hazard and exposure are key factors, vulnerability drivers play a crucial role in shaping these outcomes. However, few studies have examined these drivers at a continental scale. This study presents the first dynamic heat vulnerability assessment for Europe, incorporating spatial and temporal dimensions through ordinary least squares regression. Subnational (NUTS2) heatwave mortality data is used as the dependent variable, while independent variables include high-resolution raster data on heat hazard parameters, estimated population exposure, and socio-economic, demographic, and environmental vulnerability factors at both raster and subnational (NUTS2) scales. Our results (adjusted R2 = 0.662) identify foreign citizenship and urbanization as the most influential drivers, with a 1% increase in the percentage of foreign citizens and the size of urban areas associated with a 12.1% and 7.3% rise in heatwave-related mortality, respectively. Based on these findings, we construct the European heat vulnerability index for 2000-2019 as a weighted sum of the identified drivers, using the regression coefficients as weights. The results suggest that foreign citizens may face increased heat vulnerability due to intersecting socioeconomic factors. Policy recommendations include promoting inclusive integration measures to address disparities among foreign populations, and prioritizing sustainable urban planning and nature-based solutions to enhance resilience in rapidly urbanizing areas, ensuring equitable access to green spaces.