Forced Changes and Internal Variability in Projections of European Storminess

Oral Presentation

Projections of changes in European storminess and associated risk potential are uncertain and highly variable. Some robust signals in changes to frequency and severity do exist, however these are subject to considerable model variability. Furthermore, year-to-year variations are very high, resulting in any forced changes from a warming climate being hard to detect. In this work we employ novel techniques in both generation of storm footprints, and assessment of future trends via a 
statistical method, to generate more robust estimates of changes to frequency and severity of European windstorms in an ensemble of CMIP6 models across a range of future climate scenarios. 

An assessment of the role of internal variability in projections is also made using a 15 member ensemble, with this variability compared to the range of projections from the 12 independent CMIP6 models. Projections of frequency of windstorms are uncertain, but increases in storm severity over NW Europe are robust in the highest forcing scenarios. Internal variability is smaller than model variability, however variability between ensemble members is still large for the most vulnerable regions of Europe. These results can act as guidance to risk modellers and those in the insurance sector.