Projected changes in European hail damage risk to buildings: Insights from 3 °C Pseudo Global Warming simulations with a km-scale regional climate model

Severe hailstorms are among the most destructive weather phenomena in Europe, with the recent hail seasons of 2022 and 2023 both causing record losses above 5 billion euros. This highlights the importance of assessing hail risk in a warming climate. We approach this question by leveraging 11-year convection-resolving climate simulations using the COSMO model with the hail growth module HAILCAST. Comparing a 3 °C warming scenario to present-day simulations, we observe a generally increasing trend in expected hail damage to buildings, with a 42% increase over the calibration region in Switzerland and pronounced spatial variability across Europe. Assuming a building vulnerability as calibrated over Switzerland, 24 of 28 countries show an increasing potential for hail damage, despite only 11 with increasing overall hail frequency. Given the concentration of hail damages into few events with limited spatial extent, we observe a large variability in modelled hail damage based on sampling uncertainty within the 11-year simulations, which locally mostly exceeds the change signal. Larger spatial aggregation increases the confidence in the climate change signal, with the overall damage potential over Europe increasing by 25%–42% in the 3 °C warming scenario. On top of the change signal, we provide a spatially resampled hail event set for explicit risk assessments and a new technique to calibrate impact functions for climate simulations to observed data.