“It will have a similar impact on the environment as wildfires on land.” 

The one major signifier of surfing in Europe is that you have to deal with cold water. In the UK, it is the wave-rich north-east coast, where the cold water is the coldest. Surfers up there are the hardest in the land, dealing with the North Sea’s frigid seas. In January, average water temps hover around 6 degrees C, in August they manage a frigid 15.3.

Yet this summer has seen water temperatures climb. The European Space Agency’s satellite data show the sea surface temperature in the North Sea, from Durham to Aberdeen, is more than 5°C higher than the average during this time of year. Similar extreme heat hikes have also been recorded off the West Coast of Ireland. The map below shows sea surface temperatures on 18 June 2023, compared with the long-term (1981-2016) average.

The data shows that we are currently experiencing a marine heatwave which has been classified as Category 4, or extreme, which is incredibly unusual for this time of year.

“The warming of the seas around the UK coincides with a global trend of rising air and ocean surface temperatures in recent months. According to data from the Met Office dating back to 1850, both April and May 2023 witnessed the highest-ever recorded global sea surface temperatures.

Yet this isn’t restricted to the North Sea. Pretty much all of the northeast Atlantic is now in a marine heatwave state. Inshore temperatures off the southwest UK remain at 18 degrees C, more than 3 degrees above the long-term average for June.

Daniela Schmidt, Professor of Earth Sciences at the University of Bristol, said: “The extreme and unprecedented temperatures show the power of the combination of human-induced warming and natural climate variability like El Niño.”

For surfers, on the surface at least, abnormal water temperatures are a rare treat. There’s been a constant supply of small, but fun, swells on the Cornish and Devon coasts. Lukas Skinner has been tearing apart the beachies, stripping down to a short arm steamer!

Sam Bleakley was also spotted surfing in boardshorts at Gwenver with the family in earlyish June, which is about as rare as a unicorn being struck by a bolt of lightning from Halley’s Comet.

And yet, as surfers adjust to the warmer conditions, this marine heatwave off the UK poses a serious threat to ecosystems and the coastal communities that rely on them. It also raises questions about longer-term climate impacts.

Experts said marine heatwaves have a similar impact on the environment as wildfires on land, destroying organisms that store carbon such as kelp. The damage caused is also harmful to humanity, which relies on oceans for oxygen, storm protection, and food.

If there was an uncontrolled fire raging through the Exmoor forest, or burning what’s left of the Scottish Highlands, the press and public’s reaction would be huge. Yet, strangely, apart from the warnings from members of the marine and climate science community, the response has been muted.

“It’s a huge worry that the ecosystem has not experienced these temperatures at this time of year before,” said Dr. Jules Kajtar of the National Oceanography Centre, Southampton. “Warming oceans can make waters more acidic and drive a decrease in oxygen levels in the water.”

The marine heatwave also risks killing large numbers of fish and crustaceans, and will also affect invertebrates along the bottom like crabs, shellfish, and coral reefs. Jellyfish and poisonous algae could become more dangerous to beachgoers as sea temperatures climb.

At the same time, the extent of the sea ice in the Antarctic is the lowest on record for this date by a large margin. At the other pole, the additional surface heating we are seeing now will eventually find its way into the Arctic Ocean via ocean currents through the Fram Strait and the Norwegian Sea, leading to more ice loss.

The marine heatwave comes after the first 11 days of June were the hottest ever recorded worldwide for this time of year, the EU’s Copernicus climate and weather monitoring service reported.

“As long as we are not dramatically cutting emissions, these heatwaves will continue to destroy our ecosystems,” concluded Dr. Schmidt. “But as this is happening below the surface of the ocean, it will go unnoticed.”