UK Experiences Intense Marine Heatwave Amid Rising Ocean Temperatures
The Met Office has reported that UK waters are currently experiencing an "extreme" marine heatwave, as global ocean temperatures reach unprecedented levels. Scientists have expressed concern that these elevated temperatures could trigger "mass-mortality events" for various marine species.
Forecasters attribute the rapid development of these high sea temperatures to last month's heat dome, which caused much of Europe to endure record-breaking heatwaves. Experts have noted that such atmospheric conditions would have been impossible without the influence of the climate crisis.
The peak of summer has arrived in the UK this week, with forecasts indicating temperatures could exceed 30°C for up to ten consecutive days. Dr Ségolène Berthou, an air-sea interaction specialist at the Met Office, explained that these atmospheric conditions are driving the marine heatwave.
“The ocean didn’t have enough time to cool down between the two land heatwaves,”
Oceans absorb over 90% of the excess energy in the Earth's system, primarily due to the combustion of fossil fuels.
Dr Berthou noted that this is the third and most intense marine heatwave the UK has experienced this year, with average sea temperatures approximately 2°C above normal. Certain locations have reached "severe" conditions, where water temperatures are 4-5°C warmer than usual. She added,
“There’s no sign of an end to it.”
Global Sea Surface Temperatures Reach New Highs
The Copernicus Climate Change Service and the Copernicus Marine Service have confirmed that global sea surface temperatures have reached record highs for this time of year, surpassing levels recorded in 2023 and earlier in 2024. These developments were anticipated following the emergence of El Niño conditions, which scientists predict will be the strongest in decades.
The UN secretary general, António Guterres, emphasized the urgency of the situation, stating,
“The only effective response is climate action equal to the crisis: ending the addiction to fossil fuels, accelerating the shift to renewables, protecting the most vulnerable, and delivering early warning systems for all.”
Impacts on Marine Life and Fisheries
Professor John Pinnegar, principal scientist and lead adviser at the Centre for Environment, Fisheries and Aquaculture Science, warned that extreme marine heatwave conditions can lead to "mass-mortality events" among some marine species and alter the distribution of commercially important fish and shellfish.
He further explained,
“Prolonged periods of elevated sea water temperatures can also encourage new species to visit UK waters, establish new populations, potentially shaking up UK ecosystems.”
Recent observations have noted the presence of octopuses off the south-west coast of England last year, which has transformed both the fishing industry and the marine ecosystem. Notably, a record 100 tonnes of octopus were sold in a single day at Brixham market last month.
