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Euronews
22-05-2025
- Science
- Euronews
UK scientists alarmed by sudden surge in sea temperatures this spring
The seas around the UK are heating up fast, and scientists are raising the alarm. Earlier this week, the BBC reported that parts of the North Sea, English Channel and Irish coast are now as much as 4°C warmer than average, in what UK scientists are calling a 'super intense' marine heatwave. With surface temperatures already the highest ever recorded in April and May since monitoring began 45 years ago, researchers are warning of potential knock-on effects for marine life, as well as the general well-being of beachgoers. And it's not just the ocean feeling the strain. The UK is coming to the end of one of the warmest, driest springs in more than a century. Forecasts suggest this could be a sign of an even hotter summer to come. Marine heatwaves happen when sea temperatures exceed seasonal averages for at least five consecutive days. They usually last about two weeks. This one has lasted more than two months, compounding the effects of human-induced climate change. In the North Atlantic, sea surface temperatures have been increasing by around 0.3°C per decade over the last 40 years, according to the Met Office. 'Before we started having this exceptional weather this spring, the waters were already in a hotter state,' Dr Ségolène Berthou of the UK Met Office told the BBC. The hotter sea temperatures are in part a result of the UK's exceptionally warm, dry spring. In an article published in The Conversation, Matthew Patterson and Simon H Lee, both researchers at the University of St Andrews, explained that a high-pressure system has prevented cooler, wetter conditions from moving in – a 'blocked' or 'stuck' weather pattern that has led to devastating wildfires and sowed chaos across UK farmlands. The weak winds and strong spring sunshine that have accompanied this high-pressure system have allowed heat to build on the ocean's surface, too. Though marine heatwaves are still a relatively new phenomenon for the UK, they're expected to become more frequent and intense as the climate warms. Scientists are concerned the current flare-up may disrupt marine ecosystems, altering breeding cycles, enabling blooms of harmful algae or attracting jellyfish that thrive in warmer waters. Jellyfish sightings off UK coasts jumped 32 per cent following a marine heatwave that raised sea temperatures up to 4°C above average, according to the BBC. So far, the temperatures have not exceeded critical thresholds for mass marine die-offs. But the UK may only be seeing the beginning. Researchers caution that the long-term implications are unclear, since marine heatwaves have rarely affected cooler British waters. While the current marine heatwave may weaken slightly in the coming days as weather patterns shift, scientists say this could be a temporary dip. Forecasts suggest warm, dry conditions are likely to return, raising the risk of more extreme temperatures later this summer – both on sea and land. Oceans act as vast heat reservoirs, and warmer waters can push up air temperatures as sea breezes carry heat inland. That's what happened in May last year, when a brief marine heatwave contributed to unusually high land temperatures across the UK. With ocean heat running high and El Niño now fading, forecasters expect 2025 to rank among the hottest years on record. The Met Office has even warned of 'more than double the normal chance' of a hotter-than-average summer. As summer looms, the sea around Britain may offer an early warning of what's to come.
Wales Online
22-05-2025
- Climate
- Wales Online
Record sea heatwave grips Wales but not all visitors will be welcome
Our community members are treated to special offers, promotions and adverts from us and our partners. You can check out at any time. More info Exotic sea creatures could start being washed up on Welsh beaches as water temperatures soar, scientists believe. The UK and Ireland in the grip of a marine heat wave with some waters now 4C warmer than usual for the time of year. Already a surge in sea and land temperatures has seen more people flocking to beaches, with warmer waters reducing the cooling effect of sea breezes. However, Britain's waters remain distinctly chilly for most swimmers and toe-dippers. The heatwave is most intense in the Celtic Sea and off the west coast of Ireland, where current sea surface temperatures are up to 4C warmer, according to the Met Office. Around the UK coastline, the sea is 1.5C-2.5C warmer, with hotspots in Cardigan Bay and along the North Wales coast. These temperatures are 'what we would usually expect around mid-June,' said the national forecaster. Classing the event as 'extreme', the Met Office said surface temperatures (SSTs) reached levels for April and May that were the highest since satellite monitoring began in 1982. Not only is the heatwave significant due to its intensity, observers have been surprised by its longevity. So far it's lasted more than two months: usually, marine heatwaves in UK waters dissipate after two to four weeks. Sea temperatures are finally expected to start dropping in the coming days as cooler weather settles over Britain. Dr Ségolène Berthou, scientific manager for regional coupled modelling at the Met Office, said: 'The heatwave is the result of several overlapping factors. Prolonged high-pressure systems brought a dry, sunny spring and weak winds and waves, creating ideal conditions for warming. 'This means the sea started to warm mid-February, one month earlier than usual. Additionally, the waters around the UK were already warmer than usual coming out of winter, a trend that has been building over the past 40 years, with an average increase of 0.3C per decade.' Join the North Wales Live Whatsapp community now (Image: Met Office/Ostia) Climate change is causing oceans to warm around the globe and is making marine heatwaves more likely. On May 19 the average UK sea surface temperature reached 12.69C – well above the country's marine heatwave threshold for May (11.3C). Scientists suspect warmer waters could increase the annual influx of jellyfish to UK shores. Already a number of sightings have been made of the huge barrel jellyfish washed up on beaches in Gwynedd and Ceredigion. A marine expert has warned it could see other exotic and unusual sea creatures arriving on Welsh shores in greater numbers. Frankie Hobro, director of Anglesey Sea Zoo, Brynsiencyn, believes some may pose a greater risk to beachgoers, underlining the need for greater awareness of marine medicine. Some might be first-time visitors, other more mature versions of juveniles currently spotted in UK waters. While many will be welcome, such as bluefin tuna, sunfish and basking sharks, others will not, she said. Candidates include pufferfish and Box jellyfish, one of the most poisonous animals on Earth. Others already on British beaches could become more of a pest, such as the weever fish. This little critter buries itself in the and can deliver an excruciating sting. Another occasional visitor which also packs a powerful sting is the Portuguese man o' war, which could arrive in larger numbers and sizes, said Frankie. (Image: Peter Southwood/Wiki) Algal blooms are also expected to become more commonplace due to calmer and warmer seas., with patches of green algae developing that can threaten other marine life. On the plus side, bioluminescence displays next to beaches may become more numerous and spectacular. However, heat stress could drive other marine life away from Britain's shores. 'There is no escape from the heat for sea creatures within it,' Frankie told North Wales Live. 'They can't turn on air conditioners under water, or escape it.' While the warmer waters might be discernible to some swimmers, they are still distinctly nippy for the casual bather. Dr Berthou said temperatures in the North Sea have already peaked, whereas west Ireland and the Celtic Sea are currently experiencing their highest levels. During marine heatwave events, a layer of warm water forms at the surface. She added: 'This layer acts like a lid, trapping heat near the surface and preventing it from mixing into deeper, cooler waters. 'It can be compared to a layer of olive oil floating on water; this thin surface layer allows heat from solar radiation to accumulate near the surface. When this layer forms, surface temperatures can increase fast: the last nine days have seen a sudden additional 1C warming.' Dr Jonathan Tinker, a Met Office marine climate scientist, said the prolonged warming can amplify land heatwaves by reducing the cooling effect of sea breezes and by altering rainfall patterns. Sign up for the North Wales Live newsletter sent twice daily to your inbox He added: 'With projections suggesting UK summer sea temperatures could rise by up to 2.5C by 2050, such events are likely to become more frequent, intense and longer-lasting. Marine heatwaves offer a glimpse into how changing ocean conditions could shape future weather conditions.' Find the weather forecast where you live
North Wales Live
22-05-2025
- Climate
- North Wales Live
Record sea heatwave grips Wales but not all visitors will be welcome
Exotic sea creatures could start being washed up on Welsh beaches as water temperatures soar, scientists believe. The UK and Ireland in the grip of a marine heat wave with some waters now 4C warmer than usual for the time of year. Already a surge in sea and land temperatures has seen more people flocking to beaches, with warmer waters reducing the cooling effect of sea breezes. However, Britain's waters remain distinctly chilly for most swimmers and toe-dippers. The heatwave is most intense in the Celtic Sea and off the west coast of Ireland, where current sea surface temperatures are up to 4C warmer, according to the Met Office. Around the UK coastline, the sea is 1.5C-2.5C warmer, with hotspots in Cardigan Bay and along the North Wales coast. These temperatures are 'what we would usually expect around mid-June,' said the national forecaster. Classing the event as 'extreme', the Met Office said surface temperatures (SSTs) reached levels for April and May that were the highest since satellite monitoring began in 1982. Not only is the heatwave significant due to its intensity, observers have been surprised by its longevity. So far it's lasted more than two months: usually, marine heatwaves in UK waters dissipate after two to four weeks. Sea temperatures are finally expected to start dropping in the coming days as cooler weather settles over Britain. Dr Ségolène Berthou, scientific manager for regional coupled modelling at the Met Office, said: 'The heatwave is the result of several overlapping factors. Prolonged high-pressure systems brought a dry, sunny spring and weak winds and waves, creating ideal conditions for warming. 'This means the sea started to warm mid-February, one month earlier than usual. Additionally, the waters around the UK were already warmer than usual coming out of winter, a trend that has been building over the past 40 years, with an average increase of 0.3C per decade.' Join the North Wales Live Whatsapp community now Climate change is causing oceans to warm around the globe and is making marine heatwaves more likely. On May 19 the average UK sea surface temperature reached 12.69C – well above the country's marine heatwave threshold for May (11.3C). Scientists suspect warmer waters could increase the annual influx of jellyfish to UK shores. Already a number of sightings have been made of the huge barrel jellyfish washed up on beaches in Gwynedd and Ceredigion. A marine expert has warned it could see other exotic and unusual sea creatures arriving on Welsh shores in greater numbers. Frankie Hobro, director of Anglesey Sea Zoo, Brynsiencyn, believes some may pose a greater risk to beachgoers, underlining the need for greater awareness of marine medicine. Some might be first-time visitors, other more mature versions of juveniles currently spotted in UK waters. While many will be welcome, such as bluefin tuna, sunfish and basking sharks, others will not, she said. Candidates include pufferfish and Box jellyfish, one of the most poisonous animals on Earth. Others already on British beaches could become more of a pest, such as the weever fish. This little critter buries itself in the and can deliver an excruciating sting. Another occasional visitor which also packs a powerful sting is the Portuguese man o' war, which could arrive in larger numbers and sizes, said Frankie. Algal blooms are also expected to become more commonplace due to calmer and warmer seas., with patches of green algae developing that can threaten other marine life. On the plus side, bioluminescence displays next to beaches may become more numerous and spectacular. However, heat stress could drive other marine life away from Britain's shores. 'There is no escape from the heat for sea creatures within it,' Frankie told North Wales Live. 'They can't turn on air conditioners under water, or escape it.' While the warmer waters might be discernible to some swimmers, they are still distinctly nippy for the casual bather. Dr Berthou said temperatures in the North Sea have already peaked, whereas west Ireland and the Celtic Sea are currently experiencing their highest levels. During marine heatwave events, a layer of warm water forms at the surface. She added: 'This layer acts like a lid, trapping heat near the surface and preventing it from mixing into deeper, cooler waters. 'It can be compared to a layer of olive oil floating on water; this thin surface layer allows heat from solar radiation to accumulate near the surface. When this layer forms, surface temperatures can increase fast: the last nine days have seen a sudden additional 1C warming.' Dr Jonathan Tinker, a Met Office marine climate scientist, said the prolonged warming can amplify land heatwaves by reducing the cooling effect of sea breezes and by altering rainfall patterns. Sign up for the North Wales Live newsletter sent twice daily to your inbox He added: 'With projections suggesting UK summer sea temperatures could rise by up to 2.5C by 2050, such events are likely to become more frequent, intense and longer-lasting. Marine heatwaves offer a glimpse into how changing ocean conditions could shape future weather conditions.'
Yahoo
22-05-2025
- Climate
- Yahoo
UK sea temperatures soar after exceptionally warm Spring
Temperatures in the seas around the UK and Ireland have soared in the past week with some areas now 4C warmer than normal, with potential implications for marine life and people going swimming. The heatwave is most intense off the west coast of Ireland as well as pockets off the coasts of Cornwall and Devon, according to scientists at the National Oceanography Centre and the Met Office. Sea temperatures in April and the first half of May were the highest recorded during those months since monitoring began 45 years ago. Climate change is causing oceans to warm around the globe and is making marine heatwaves like this one more likely. Scientists expect 2025 to be one of the hottest years on record for air temperatures. "It's super intense at the moment. The marine heatwave has really soared this week," says Dr Ségolène Berthou at the Met Office. Dr Zoe Jacobs, who is based at the National Oceanography Centre, first noticed the unusual marine temperatures a few weeks ago. She found that pockets of the UK had been coming in and out of a mild heatwave since late 2024. That heat intensified and spread in March and has now surged. A marine heatwave is defined as sea temperatures that exceed the seasonal threshold for more than five consecutive days. In the UK the marine heatwave threshold for May is 11.3C. On 19 May the average sea surface temperature reached 12.69C. The entire west coast of the UK is now about 2.5C above average. A large portion of Scottish waters are 2-3C warmer than usual for the time of year. "It started in the North Sea and the Celtic Sea. Now the North Sea has cooled down a bit but the west of Ireland is extremely hot," says Dr Barthou. One of warmest Springs on record is driving the surge, as high temperatures and weak winds warm the top layer of the ocean. Marine heatwaves in the UK are thought to be a relatively new phenomenon but they are expected to increase in frequency and intensity. It is still a bit of a mystery how exactly they will affect marine life, but the signs so far are not good. "The interesting thing is that this started in winter and spring, when most people assume marine heatwaves are only in summer," says Dr Jacobs. People swimming off the west coast of the UK and Ireland may notice the warmer temperatures, although the waters are still cooler than at their peak in late summer. The worst impacts on species are likely to have been avoided for now because the temperatures have not gone above the upper limit that marine life can tolerate, explains Dr Jacobs. But it may be disrupting species' breeding patterns and could bring an influx of jellyfish that like warmer waters, including the huge barrel jellyfish, to seas and beaches. It could also cause harmful algae to grow out of control, creating wide patches of green algae that can poison other life. Previous heatwaves have caused harmful blooms of algae and in 2018 caused mass mortality among mussels. In 2023, jellyfish sightings increased by 32% following a marine heatwave with temperatures 3-4C above average. The heat could also encourage different fish to move into UK waters, including the bluefin tuna, potentially increasing the amount of fish to catch. Normally 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. 'Shrinking Nemo': Smaller clownfish sound alarm on ocean heat 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 A simple guide to climate change Oceans break heat record, with grim implications
