While the heatwave has since lessened in the north-east Atlantic, according to non-profit science organization Mercator Ocean International, another in the western Mediterranean now appears to be intensifying, particularly around the Strait of Gibraltar. This week, sea surface temperatures along the coasts of Southern Spain and North Africa were 2-4C (3.6-7.2F) higher than they would normally be at this time of year, with some spots 5C (9F) above the long-term average. Extreme marine temperatures have also recently been observed around Ireland, the UK and in the Baltic Sea, as well as areas near New Zealand and Australia. More recently, scientists suspect a possible heatwave south of Greenland in the Labrador Sea. “We are having these huge marine heatwaves in different areas of the ocean unexpectedly evolve very early in the year, very strong and over large areas,” says Karina von Schuckmann, an oceanographer at Mercator Ocean.
Carlo Buontempo, director of the European Union’s Copernicus Climate Change Service, says scientists expect big temperature variations in the Pacific Ocean associated with the El Nino weather pattern, a phase of planet-warming weather which is just beginning, although NOAA is monitoring a large heatwave in the Gulf of Alaska that has been sitting offshore since late 2022. But what we’re currently seeing in the North Atlantic is “truly unprecedented”, says Buontempo. Scientists are still trying to unravel its full causes. […] More broadly, experts say the persistence of recent marine heatwaves is a worrying sign about how climate change is unfolding, alongside heatwaves on land, unusual melting of snow cover in the Himalayas and a loss of sea ice. Von Schuckmann notes that, even if humans stopped pumping CO2 into the air tomorrow, the oceans would continue to warm up for many years yet. “I am concerned as a climate scientist that we are further than we thought we are.”
