Researchers conduct routine maintenance on a research buoy

Researchers conduct routine maintenance on a research buoy in Biscayne Bay on August 3, 2023 in Miami, Florida. The buoy measures the bay waters' temperature and other environmental factors.

(Photo by Joe Raedle/Getty Images)

'Terrifying': Scientists Raise Alarm Over Unprecedented Global Ocean Heat

The global average ocean surface temperature is expected to rise even further in the coming months as El Niño strengthens.

Climate scientists on Friday said the rapidly rising temperature of the planet's oceans is cause for major concern, particularly as policymakers in the top fossil fuel emissions-producing countries show no sign of ending planet-heating oil and gas extraction.

The European Union's climate agency, Copernicus Climate Change Service, reported this week that the average daily global ocean surface temperature across the planet reached 20.96°C (69.7°F), breaking the record of 20.95°C that was previously set in 2016.

The record set in 2016 was reported during an El Niño event, a naturally occurring phenomenon which causes warm water to rise to the surface off the western coast of South America. The weather pattern was at its strongest when the high ocean temperature was recorded that year.

El Niño is forming this year as well, but has not yet reached its strongest point—suggesting new records for ocean heat will be set in the coming months and potentially wreak havoc in the world's marine ecosystems.

Samantha Burgess, deputy director of Copernicus, told the BBC that March is typically when the oceans are at their hottest.

"The fact that we've seen the record now makes me nervous about how much warmer the ocean may get between now and next March," she told the outlet.

The warming oceans are part of a feedback loop that's developed as fossil fuel emissions have increasingly trapped heat in the atmosphere.

Rising levels of carbon dioxide in the atmosphere are warming the oceans, leaving them less able to absorb the emissions and contributing to intensifying weather patterns.

"Warmer sea surface temperatures lead to a warmer atmosphere and more evaporation, and both of these lead to more moisture in the atmosphere which can also lead to more intense rainfall events," Burgess told "Today" on BBC Radio 4. "And warmer sea surface temperatures may also lead to more energy being available for hurricanes."

The warming ocean could have cascading effects on the world's ecosystems and economies, reducing fish stocks as marine species migrate to find cooler waters.

"We are seeing changes already in terms of species distributions, prevalence of harmful algae blooms popping up maybe where we would not necessarily expect them, and the species shifting from warmer southern locations up into the colder regions as well which is quite worrying," Helen Findlay, a biological oceanographer at the Plymouth Marine Laboratory in the United Kingdom, told The Evening Standard.

"We are also seeing more species coming up from the south, things like European anchovy or recently examples of Mediterranean octopus coming up into our waters and that is having a knock-on impact for the fish that we catch, and consequences of economics," she added.

Certain parts of the world's oceans provoked particular alarm among scientists in recent days, with water off the coast of Florida hitting 38.44°C—over 101°F—last week.

The National Oceanic and Atmospheric Administration told the BBC that ocean temperatures in that area typically hover between 23°C and 31°C at this time of year.

Since scientists first began measuring ocean temperatures using satellites and research buoys about four decades ago, the global average sea surface temperature has gone up by roughly 0.6°C.

On social media, climate scientists urged news outlets to explicitly connect the rising ocean temperatures to fossil fuel companies and the policymakers who are enabling them to continue fueling the climate emergency—such as British Prime Minister Rishi Sunak, who announced more than 100 new oil and gas licenses in the North Sea this week.

The New York Times this week reported "terrifying Earth breakdown but barely [mentioned] the cause is the fossil fuel industry," said National Aeronautics and Space Administration climate scientist Peter Kalmus.

"The more we burn fossil fuels, the more excess heat will be taken out by the oceans, which means the longer it will take to stabilize them and get them back to where they were," Burgess told the BBC.

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