Projections and uncertainties of future winter windstorm damage in Europe

Extratropical winter windstorms are among the most significant natural hazards in Europe in terms of fatalities and economic losses, and windstorm impacts projections under climate change in Europe are considerably uncertain. This study combines state-of-the-art climatic projections from 29 global climate models participating in CMIP6, with the open-source weather and climate impact-risk assessment model CLIMADA to obtain a set of relevant projections for future windstorm-induced damages over Europe. Spatial patterns of the future changes in windstorm damages projected by the multi-model ensemble show a median increase in the damages in northwestern and northern-central Europe, and a median decrease over the rest of Europe, in agreement with an eastward extension of the North Atlantic storm track into Europe. We combine all 29 available climate models in an ensemble of opportunity approach and find evidence for an overall increase in future windstorm loss events, with events with return periods of 100 years under current climate becoming events with return periods of less than 20 years under future SSP585 climate. Using an uncertainty-sensitivity quantification analysis, we find that the climate model uncertainty dominates the uncertainty in the projections of damages related to frequent events, but that stochastic uncertainty hinders the uncertainty quantification for more extreme events. Our findings demonstrate the importance of climate model uncertainty for the CMIP6 projections of extratropical winter windstorms in Europe, and emphasize the increasing need for risk mitigation and management due to extreme weather in the future.