Key facts
- Human-caused climate change is the main driver of record-breaking sea temperatures around Europe.
- Last month, the Mediterranean Sea averaged 27 C, the highest for July on record.
- Analysis indicates peak sea temperatures in several European regions would have been virtually impossible without global warming.
- Marine heatwave conditions have affected up to 90% of the Bay of Biscay and 80% of the western Mediterranean this year.
- Scientists warn of severe consequences for marine ecosystems and coastal communities, including species die-offs and disrupted food supplies.
Human-caused climate change was the primary driver of recent record-breaking sea temperatures around Europe, scientists reported, warning of severe consequences for marine ecosystems and coastal communities.
Last month, the average temperature in the Mediterranean was 27 degrees Celsius (81 Fahrenheit), the highest for any July on record, while an offshore buoy near Mallorca recorded 33 C in early August. An analysis by the World Weather Attribution (WWA) group found that human-caused climate change has added approximately 2 C of warming to the Mediterranean and around 1.4 C to Western European seas.
According to Claire Bergin, a climate scientist at Ireland's Maynooth University and a co-author of the study, this warming has the potential to completely reshape ecosystems that coastal communities rely on for food and income, and drive damaging extreme weather on land. The analysis determined that peak sea temperatures recorded this year in the eastern and western Mediterranean and along the Bay of Biscay and Iberian coast would have been "virtually impossible" without human-caused climate change. In the Celtic Sea, off Britain and Ireland, the most extreme temperatures recorded would have been expected only about once a century in a world without human-caused climate change.
Hotter seas increase humidity and overnight temperatures in coastal areas and can help fuel intense storms. Greenhouse gas emissions have raised the planet's average temperature to around 1.4 C above pre-industrial levels, according to the World Meteorological Organization. This hotter baseline means that high-pressure atmospheric systems causing heatwaves can reach higher temperatures. Sea temperature spikes can cause mass die-offs of species such as corals and disrupt food supplies for birds and mammals, with knock-on effects through food chains. Marine ecologist John Bruno noted that some species are moving north to seek cooler waters, but not all can adapt, stating, "We are rapidly approaching the absolute biological limits of adaptation for many species."
The WWA analysis also found that about 90% of the Bay of Biscay and 80% of the western Mediterranean have experienced marine heatwave conditions this year, a figure that would have been closer to 40% without global warming.