Warming in the Western Mediterranean Fuels Wetter European Storms and Heightens Extreme Flood Potential Rapid Mediterranean warming brings extreme floods risks for Europe

The Mediterranean Sea is warming rapidly, with profound implications for regional hydroclimate extremes. The Gulf of Genoa, a critical source region for European storm systems, has exhibited a 1.17°C increase in sea surface temperature (SST) between 2010 and 2020. This study links accelerated SST warming to enhanced atmospheric moisture availability, suggesting a substantial increase in storm precipitable water and precipitation intensity. Intermittent marine heatwaves might further elevate storm total precipitable water (TPW), increasing the likelihood of extreme rainfall events. Projections indicate that, under current warming trajectories, storms originating from the Gulf of Genoa may contain up to twice the moisture content by 2040, substantially amplifying heavy rains across Europe. Such extreme rainfall events are a significant threat to European cities, potentially resulting in catastrophic flooding. These findings emphasize the emerging role of oceanic warming in modulating mid-latitude storm dynamics, provide a potential explanatory framework for recent catastrophic floods, and underscore the urgent need for revised hydrological models, expanded flood management strategies, and adaptive risk governance in a rapidly changing climate.