The extreme sea temperatures recorded around Europe in July would have been virtually impossible without human-induced climate change, a study said Wednesday.
World Weather Attribution (WWA) researchers examined the Celtic Sea, the Bay of Biscay and the Iberian Peninsula, and the western and eastern Mediterranean.
July saw the world’s highest sea surface temperatures on record for the month, while record levels were measured along Europe’s Atlantic coast and in the western Mediterranean. Mediterranean waters were as much as 6C above normal in June.
Observations showed that temperatures increased by 1.2C in the Celtic region, 1.5C around the Bay of Biscay and the Iberian Peninsula, 3.1C in the western Mediterranean and 2.6C in the eastern Mediterranean.
Combining observations with climate models, researchers attributed around 2C of warming in the Mediterranean regions to human-caused climate change. The attributable increase was estimated at 1.4C around the Bay of Biscay and the Iberian Peninsula and 1.3C in the Celtic region.
In the Celtic region, climate change made the event around 30 times more likely. Temperatures observed in the other three regions would have been virtually impossible in a climate 1.4C cooler, the study found.
If global temperatures reach 2.8C above pre-industrial levels by the end of the century, events similar to those observed in 2026 could become another 1.3C to 1.9C hotter.
WWA warned that marine heat waves can cause mass deaths among corals, sponges, and macroalgae, disrupting food chains and affecting fish, seabirds, and marine mammals.
Warmer waters can also force species northward, alter fisheries and aquaculture, increase humidity and heat stress in coastal areas, and raise the risks of waterborne diseases and jellyfish-related beach closures.
Researchers said adaptation could strengthen resilience but could not fully offset the ecological effects of continued ocean warming, stressing the need for a rapid transition away from fossil fuels.