Scorching seas from the Mediterranean to the Atlantic edge of Europe are not just a summer anomaly — they bear the clear imprint of human-driven climate change, scientists say, with ripple effects expected for marine life and the coastal economies that depend on it.
Europe’s seas have not escaped the extreme heat that many countries have endured this summer.
Last month, the average temperature in the Mediterranean was 27C, the highest for any July on record, while an offshore buoy near Mallorca recorded 33C in early August.
Human-caused climate change has added about two degrees of warming to the Mediterranean and around 1.4C to Western European seas, according to an analysis by the World Weather Attribution (WWA) group, which uses peer-reviewed methods to assess global warming’s role in extreme weather events.
“This has the potential to completely reshape ecosystems that coastal communities rely on for food and income, and drive damaging extreme weather on land too,” said Claire Bergin, a climate scientist at Maynooth University and co-author of the study.
A flamingo seen in the Mediterranean sea
Looking across multiple hotspots, the researchers concluded that this year’s peak sea temperatures in the eastern and western Mediterranean, as well as along the Bay of Biscay and the Iberian coast, would have been “virtually impossible” without human-caused climate change.
In the Celtic Sea, off Ireland and Britain, the most extreme temperatures recorded would have been expected only about once a century in a world without human-caused climate change, it found.
Hotter seas can load the air above them with more moisture, pushing up humidity and overnight temperatures in coastal areas, and they can also help set the stage for intense storms later in the year.
Greenhouse gas emissions, mainly from burning fossil fuels, have raised the planet’s average temperature to around 1.4C above pre-industrial levels, according to the World Meteorological Organization.
With the baseline already warmer, the high-pressure atmospheric systems that drive heatwaves can climb to even higher temperatures.
An aerial view of beachgoers along the coast of Kanali, in the Preveza region of Greece
Sharp jumps in sea temperature can trigger mass die-offs of species such as corals and scramble food supplies for birds and mammals, with impacts cascading through food chains.
John Bruno, a marine ecologist at the University of North Carolina, said some species were shifting northward in search of cooler waters, but many organisms could be left behind.
“We are rapidly approaching the absolute biological limits of adaptation for many species,” he said.
According to the WWA analysis, about 90% of the Bay of Biscay and 80% of the western Mediterranean have experienced marine heatwave conditions this year.
Without global warming, that figure would have been closer to 40%.
