MAP. View the marine heatwave currently affecting the coast of Nice

The average surface temperature of the Mediterranean Sea reached record levels at the beginning of August, surpassing the values ​​observed in 2023 at the same time.

Up to 29°C: this is the temperature recorded on the surface of the water in Nice, Tuesday, August 6. This figure rose to 30°C on Sunday, between 4:30 p.m. and 5 p.m., according to data recorded by one of the coastal buoys of the Center for Studies and Expertise on Risks, the Environment, Mobility and Development (Cerema) off the coast of Monaco. “We have seen for several years that water temperatures are between 3 and 4°C above the normal average”explained Claire Nouvian, founder and director of the Bloom association, on RTL on Monday, August 5. According to her, “The Mediterranean basin is warming 20% ​​faster than other bodies of water on Earth.”

The map below shows the extent of the warming that is currently affecting Mediterranean waters. Between July 24 and August 5, temperatures can be seen rising rapidly and very sharply between the coasts of Nice and Corsica.

This rise in temperatures can be explained by particularly warm atmospheric conditions and little winter cooling. Due to global warming, these marine heatwaves are becoming more frequent and persistent. Indeed, the seas and oceans absorb nearly a quarter of the CO2 emissions generated by human activities each year, and store 90% of the excess heat, as detailed by the UN. This mass of warm water is considered a major “carbon sink”.

Prolonged heatwaves across the Mediterranean this year have caused a drastic increase in average sea surface temperatures, surpassing the record set in 2023 on the same date on Sunday 4 August. This notable temperature rise is not limited to measurements recorded off the coast of Monaco and Nice, but is also observed in the Adriatic, as well as in the central and eastern regions of the Mediterranean.

These marine heatwaves represent a disaster for marine fauna, flora and ecosystems. Vulnerable species, such as corals, suffer significant thermal stress, causing bleaching phenomena and a significant decline in populations. The disruptions to natural habitats and food chains caused by these heatwaves can also lead to changes in migratory patterns, as well as a decline in reproduction.