An emergent constraint for the future frequency of European windstorms

Windstorms are one of the most damaging natural hazards in western Europe, yet large inter-model spread limits robust assessment of future frequency changes. Previous assessments have suggested an increasing frequency, however models often have equal and opposite future responses. Using a novel statistical technique to quantify trends in these damaging windstorms we show that the historical mid-latitude meridional pressure gradient explains much of the inter-model variability in projected windstorm frequency across a large CMIP6 ensemble. Constraining projections using the pressure gradient index reduces uncertainty lowers the likelihood of increasing windstorm frequency and indicates a robust decline in pan-European windstorm frequency over the twenty-first century. We present a plausible mechanism via atmosphere–ocean feedbacks important for the North Atlantic storm track and circulation. These results suggest extreme increases in windstorm frequency are unlikely, despite projected increases in storm severity, with important implications for future loss and impact assessments.