Unprecedented sea temperatures “much higher than anything models have predicted,” climate experts warn

Temperatures are both rising in the countryside and at sea, where climate experts are sounding the alarm about unprecedented sea surface temperatures in the North Atlantic.

With El Niño’s returnTemperatures are expected to remain above average and could impact sea ice levels, fisheries and corals.

“We are in uncharted territory and can expect more records to fall as El Niño continues to develop and as these effects continue into 2024,” said Christopher Hewitt, director of climate services at the World Meteorological Organization, on Monday. “This is worrying news for the planet.”

The National Oceanic and Atmospheric Administration warned in late June that ocean heatwaves could hit half the world’s oceans by September. Researcher Dillon Amaya said that such widespread high temperatures had never been observed in the decades-long measurements made by the organization’s Physical Sciences Laboratory.

“We typically assume that only about 10% of the world’s oceans are ‘hot enough’ to qualify as an ocean heatwave. So it’s remarkable that 40% or 50% is being reached, even with long-term warming,” Amaya said.

Global sea temperatures reached record highs for this time of year in May and June. The temperatures are also “much higher than anything the models predicted,” said Dr. Michael Sparrow, head of the world climate research department of the World Meteorological Organization.

Some of these high temperatures already existed before El Nino — linked to high sea temperatures — has even begun, the European Union’s Copernicus Climate Change Service pointed out in a July report.

With warmer temperatures, Antarctic sea ice “reached its lowest extent in June since satellite observations began, at 17% below average, significantly exceeding the previous June record,” according to Copernicus. The region is usually considered relatively stable compared to the Arctic, Sparrow said.

Experts warn that high sea temperatures also lead to coral bleaching, which can leave corals vulnerable to deadly diseases. NOAA calls coral bleaching “one of the most visible and damaging marine ecological impacts of persistently rising ocean temperatures.” Coral-based ecosystems serve as nurseries for fish.

Rising sea temperatures can also affect fishing. As sea temperatures rise, marine life migrates toward the poles to stay cool, according to NOAA. This can mean that fish are out of reach of fishermen. According to the agency, the US marine fisheries and seafood industry provided approximately 1.7 million jobs and $253 billion in revenue in 2020.

Warmer seawater can kill fish because it contains less oxygen than cooler water. In June, Thousands of dead fish washed up along the Texas Gulf Coast due to a “low dissolved oxygen event.”

Marine heatwaves can also create “hot spots” of harmful algae that produce a toxin, domoic acid, that can build up in shellfish and make them dangerous to eat, according to NOAA.

According to NASA, around 90% of global warming takes place in the ocean. Scientists attribute widespread heat in global ocean waters to human-caused climate change.