3 hours agoShareSaveGeorgina RannardClimate and science reporterShareSaveNormally marine heatwaves last around two weeks, so scientists are surprised at how long this one is persisting.”It is exceptional. We are about two and half months in, which is very long,” says Dr Barthou.Higher sea temperatures can push up land temperatures too, as sea breezes carry the heat off the ocean.That happened in May 2024 when a short marine heatwave contributed “significantly” to above-average land temperatures, according to the Met Office.In some parts of the world – including Australia, the US and the Pacific – marine heatwaves can destroy coral reefs or local fisheries, as well as vital seagrass meadows.The UK is usually more protected from these impacts because overall the waters are cooler. But scientists still don’t know very much about them and have a lot more to discover.A recent study led by Dr Jacobs found that the UK hotspots are the southern North Sea and the English channel, where heatwaves can last longer than other areas of the country. Oceans have absorbed 90% of the excess heat created by humans burning fossil fuels, and as a result have warmed overall by 1C.”Before we started having this exceptional weather this spring, the waters were already in a hotter state,” says Dr Barthou.In the North Atlantic, sea surface temperatures have been increasing by around 0.3C per decade over the last 40 years, according to the Met Office.The long spell of warm, dry weather is expected to break slightly this weekend.”The ocean lags behind the atmosphere by at least a few days, so it might be that into next week we might start to see the ocean cooling off,” says Dr Jacobs.But she says that this might be just a “temporary dip” as the longer-range forecast suggests the weather will warm up again.Graphics by Erwan Rivault …
