Climate change is the main driver of Europe's rising sea temperatures, according to a new a study. It has directly added around 2°C of warming in the Mediterranean this summer and severely impacted ecosystems, researchers found.
"From the Atlantic waters off Ireland to the Mediterranean Sea, Europe's seas are experiencing an alarming surge in temperatures," says co-author Thomas Frolicher, an environmental physicist at the University of Bern, Switzerland.
"Our research shows clearly that this is being driven by climate change, in particular by the continued burning of fossil fuels," he adds.
Scientists from World Weather Attribution (WWA) group estimate that climate change added about 2°C of warming to the Mediterranean, and over 1.3-1.4°C to Western European seas.
They arrived at the figures by combining observational data and climate model simulations.
What's the impact of Europe's warming seas?
WWA says there is "evidence of severe ecological impacts", with species "shifting northwards to cooler waters, disrupting food chains, coastal fisheries and aquaculture".
"Impacts can spill into land too, with higher sea surface temperatures driving up humidity for coastal areas increasing the risks of extreme heat," the group says in a statement.
Marine ecologist John Bruno says it's surprising "how little warming it actually takes to tip organisms past that threshold to kill them".
"It's only about 1°C on coral reefs, for example."
He adds that some organisms benefit from heatwaves because of a preference for warmer temperatures or the disappearance of their natural enemies.
There is a "kind of reshuffling, reorganisation of communities. So we have what we call winners and losers", he says.
Oceans worldwide are facing record-high heat
According to the European Union's global warming monitor, the Copernicus Climate Change Service, the world's oceans hit record-high temperatures for a second straight month in July.
WWA says that some Mediterranean areas had recorded sea surface temperatures more than 6°C hotter than normal over the hottest two weeks of the month.
The group adds that climate change has driven marine heatwaves to spread across a larger part of European regions.
This year 90 per cent of the Bay of Biscay and Iberian coast region and 80 per cent of the Western Mediterranean have experienced marine heatwaves, it says.
Without the current 1.4°C of human-caused warming, only around 40 per cent of those areas would have been affected, it predicts.
Claire Bergin, study co-author and researcher at Maynooth University in Ireland, notes that "warmer waters for swimming may sound appealing to beachgoers in cooler countries like mine".
However, "the impacts on marine life beneath the surface are more serious".
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