The warming Mediterranean and implications for hail risk

The Mediterranean Sea has warmed rapidly in recent years (Copernicus Marine Service). In new research using climate model simulations, I work with Stephen Cusack of Stormwise to show that greenhouse gas emissions are the dominant driver of this warming. Other human pollution, such as aerosols, temporarily slowed the trend, but as cleaner air policies take effect that offset is disappearing. The conclusion is clear: human emissions are responsible, and the Mediterranean is unlikely to cool down anytime soon. For hail risk across Europe, that means elevated risks are here to stay.

The past few summers illustrate the potential of this warming. The summers of 2022 through 2024 brought record average daily temperatures that neared or exceeded 28 °C, and 2025 is not far behind (Copernicus Marine Service). A hotter Mediterranean can provide more fuel for storms, and evidence suggests it has already contributed to damaging hail events in Italy, France, and Switzerland (see Piper et al., 2019; Kopp et al., 2023).

For the insurance market, knowing what drives extreme events is key to preparing for the future. While further research is needed to refine projections of European hail risk in the coming decades, this work shows that a warm Mediterranean is here to stay.