Extreme Marine Heatwave Hits UK Waters
The Met Office has announced that UK waters are currently experiencing an "extreme" marine heatwave, with sea temperatures averaging 2C above normal and some areas reaching 4-5C warmer. This rapid warming follows last month's heat dome, which brought Europe its worst-ever heatwave—an event scientists say would have been impossible without the climate crisis.
Dr Ségolène Berthou, an air-sea interaction specialist at the Met Office, explained that atmospheric conditions are driving the marine heatwave. "The ocean didn't have enough time to cool down between the two land heatwaves," she said. Oceans absorb more than 90% of the excess energy in the Earth system, primarily from burning fossil fuels.
Third and Most Intense Marine Heatwave This Year
Berthou noted that this is the third and most intense marine heatwave the UK has seen in 2023. Some areas have reached "severe" conditions, with water temperatures 4-5C above usual. "There's no sign of an end to it," she added. The Met Office forecasts that the UK could see temperatures exceeding 30C for up to 10 consecutive days this week.
The Copernicus Climate Change Service and Copernicus Marine Service confirmed that global sea surface temperatures have surpassed previous records for this time of year, set in 2023 and 2024. This was anticipated following the development of El Niño conditions, which scientists forecast to be the strongest in decades.
UN Secretary General Calls for Urgent Climate Action
UN Secretary General António Guterres urged the world to treat El Niño conditions as "the urgent climate warning it is." He said: "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."
Risk of Mass Mortality Events for Marine Species
Prof John Pinnegar, principal scientist at the Centre for Environment, Fisheries and Aquaculture Science, warned that extreme marine heatwaves can cause "mass-mortality events" for some marine species and alter the distribution of commercially important fish and shellfish. He said: "Prolonged periods of elevated sea water temperatures can also encourage new species to visit UK waters, establish new populations, potentially shaking up UK ecosystems."
Last year, record numbers of octopuses were found off the south-west coast of England, transforming the fishing industry and marine ecosystem. A record 100 tonnes of octopus was sold in one day at Brixham market last month.
