The air masses responsible for the increasingly frequent heatwaves in the Mediterranean come from Africa. When high-pressure areas, known as African anticyclones, stabilize over the basin for several days, they block the winds and trigger the rapid warming of surface waters.

The Italian research published in Nature

Clarifying the mechanism was a study by the Euro-Mediterranean Center on Climate Change (Cmcc) in Bologna, published in Nature Geoscience and coordinated by researcher Giulia Bonino. The analysis, which combined the expertise of oceanographers and meteorologists, examined 40 years of data (1982-2022) and as many as 123 marine heatwave events over more than 100,000 km².

Weak winds and extreme heat: the perfect combination

According to the study, the probability of a marine heatwave increases up to five times when persistent anticyclones coincide with weak winds. In these conditions, the sea stops dispersing heat, turning into a massive natural boiler.

Towards more accurate forecasts

For the researchers, the result represents a breakthrough: knowing the mechanisms that trigger the phenomenon means being able to improve prediction models and develop early warning strategies to protect ecosystems and economic activities related to the sea. "The Mediterranean is warming faster than the global average – the authors explain – and having reliable forecasts is now essential to face the climate challenges of the coming years."