Local ocean readings of around 30C provide a worrying glimpse of what is going on in the wider Mediterranean this summer.
ADVERTISEMENTSpain has sweltered under three heatwaves so far this summer, with temperatures reaching up to 43C in the southeast. But it's the heat of the sea that has some experts especially concerned.
The Mediterranean "is on fire" meteorologist Marta Almarcha wrote in a post for Spain’s eltiempo.es weather portal yesterday.
Last week, a sea surface temperature of 30C was recorded by a tide gauge in Pollença, Mallorca.
Coastal areas around France and western Italy are also setting very high temperatures for this time of year. In fact, almost the entire Mediterranean basin is suffering a marine heatwave, Almarcha added.
Marine heatwaves are defined as extreme rises in ocean temperature for an extended period of time - and they’re getting more frequent globally with climate change.
According to the EU’s Copernicus service, average sea surface temperatures have been hotter than the respective month of the year for 15 months up until July.
Where in Europe is experiencing extreme marine heat?
In recent weeks, the eastern Mediterranean has seen temperatures spike - particularly close to shores.
On 5 August, the average temperature for the whole Mediterranean was 27.35C. That’s 1.98C higher than normal, eltiempo reports.
Though it’s a little under the Med’s highest-ever recorded average temperature of 28.71 - hit last July - isolated readings paint a worrying picture of what’s going on beneath the waves.
Installed by the SOCIB (Balearic Islands Coastal Observing and Forecasting System), the tide gauge in Pollença, Mallorca recorded up to 30.50C on 30 July.
Other sites around the country have also seen the mercury creep up. A Valencia buoy marked 28.42C on Monday, while a Barcelona buoy hit 28.30C.
Meanwhile, Météo-France reports that two buoys located off the eastern coast of Corsica and the eastern coast of Monaco both saw the water temperature reach 30C on Monday.
The French weather agency notes that these buoys are located some distance offshore and that the water temperature on the beach can be even higher.
Tunisia too has been seeing “exceptional” temperatures including 30.2C yesterday, coastal scientist Dr. Oula Amrouni posted on X.
What is the impact of marine heatwaves?
Sea surface temperatures have also reached up to 30C around the coast of Malta, well above the usual average for late July and early August.
ADVERTISEMENTMarine researcher Adam Gauci from the Oceanography Marine Research Group of the University of Malta has warned that these hotter waters can significantly impact marine habitats.
Some species may relocate to cooler waters, causing a biodiversity drain around coasts.
“The rise in temperatures also increases the risk of harmful algal blooms, which can be toxic to marine life and, eventually, humans,” he told Malta Today. The national news site noted that the sea had turned green in several Maltese bays by the end of July.
What is the Mediterranean forecast for the rest of August?
Spain is bracing for its fourth heatwave of the summer from Friday, and the sea will be feeling the heat too.
ADVERTISEMENTThe ocean experts at Mercator Ocean International (MOi) are forecasting an increase in the intensity of marine heatwaves in the western Mediterranean basin for 10 August.
Eltempio says that temperatures are set to stay high in the Eastern Mediterranean too - in the range of 28 to 30C off the coasts of Türkiye, Egypt and Libya, as well as southern Greece and Italy.
The sea is also expected to get hotter near Valencia, southern Catalonia and the Balearic Islands.
