Science

Human-caused climate change fuels hottest February on record, all-time high ocean warming

For the ninth straight month, Earth has obliterated global heat records — with February, the winter as a whole and the world's oceans setting new high-temperature marks, according to the European Union climate agency Copernicus.

EU climate agency says temperatures past internationally set threshold for long-term warming

A person stands on a long boat that sits on a mostly dried up river bed.
Scientists say most of the record heat is from human-caused climate change, brought on by carbon dioxide and methane emissions from the burning of coal, oil and natural gas. Above, a farmer crosses an almost completely dried up canal in southern Vietnam amid a heatwave in February, 2024. (Tan Dien/AFP/Getty Images)

For the ninth straight month, Earth has obliterated global heat records — with February, the winter as a whole and the world's oceans setting new high-temperature marks, according to the European Union climate agency Copernicus.

The latest record-breaking in this climate change-fuelled global hot streak includes sea surface temperatures that weren't just the hottest for February, but eclipsed any month on record, soaring past August 2023's mark and still rising at the end of the month.

And February, as well the previous two winter months, soared well past the internationally set threshold for long-term warming, Copernicus reported Wednesday.

The last month that didn't set a record for hottest month was in May 2023 and that was a close third to 2020 and 2016. Copernicus records have fallen regularly from June on.

February 2024 averaged 13.54 C, breaking the old record from 2016 by about an eighth of a degree.

February was 1.77 C warmer than the late 19th century, Copernicus calculated.

Only last December was more above pre-industrial levels for the month than February was.

In the 2015 Paris Agreement, the world set a goal of trying to keep warming at or below 1.5 C.

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More than a natural effect

Copernicus's figures are monthly and not quite the same measurement system for the Paris threshold, which is averaged over two or three decades.

But Copernicus data shows the last eight months, from July 2023 on, have exceeded 1.5 degrees of warming.

Climate scientists say most of the record heat is from human-caused climate change brought on by carbon dioxide and methane emissions from the burning of coal, oil and natural gas.

Additional heat comes from a natural El Niño, a warming of the central Pacific that changes global weather patterns.

"Given the strong El Niño since mid-2023, it's not surprising to see above-normal global temperatures, as El Niños pump heat from the ocean into the atmosphere, driving up air temperatures.

But the amount by which records have been smashed is alarming," said Woodwell Climate Research Centre climate scientist Jennifer Francis, who wasn't part of the calculations.

"And we also see the ongoing 'hot spot' over the Arctic, where rates of warming are much faster than the globe as a whole, triggering a cascade of impacts on fisheries, ecosystems, ice melt, and altered ocean current patterns that have long-lasting and far-reaching effects," Francis added.

Record high ocean temperatures outside the Pacific, where El Niño is focused, show this is more than the natural effect, said Francesca Guglielmo, a Copernicus senior climate scientist.

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The North Atlantic sea surface temperature has been at record level — compared to the specific date — every day for a solid year since March 5, 2023, "often by seemingly-impossible margins," according to University of Miami tropical scientist Brian McNoldy.

Those other ocean areas "are a symptom of greenhouse-gas trapped heat accumulating over decades," Francis said in an email. "That heat is now emerging and pushing air temperatures into uncharted territory."

"These anomalously high temperatures are very worrisome," said Cornell University climate scientist Natalie Mahowald.

"To avoid even higher temperatures, we need to act quickly to reduce CO2 emissions."

This was the warmest winter — December, January and February — by nearly a quarter of a degree, beating 2016, which was also an El Niño year.

The three-month period was the most any season has been above pre-industrial levels in Copernicus record keeping, which goes back to 1940.

Francis said on a 1-to-10 scale of how bad the situation is, she gives what's happening now "a 10, but soon we'll need a new scale because what's a 10 today will be a five in the future unless society can stop the buildup of heat-trapping gases."

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Worst coral bleaching event possible

Marine scientists with the U.S. National Oceanic and Atmospheric  Administration (NOAA) already warned this week that a fourth global mass coral bleaching event is likely unfolding in the Southern Hemisphere, driven by warming waters.

"It's looking like the entirety of the Southern Hemisphere is probably going to bleach this year," said ecologist Derek Manzello, the coordinator of NOAA's Coral Reef Watch which serves as the global monitoring authority on coral bleaching risk.

"We are literally sitting on the cusp of the worst bleaching event in the history of the planet," he said Tuesday.

A diver swims in the dark blue ocean above a grey and white bleached coral reef.
Divers swim past bleached corals in the waters of Raja Ampat Regency in east Indonesia's West Papua region in November 2023. (Lillian Suwanrumpha/AFP/Getty Images)

Corals bleach under heat stress, expelling the colourful, helpful algae that live in their tissues, leaving behind a pale skeleton.

This makes them vulnerable to starvation and disease, and many die. This can lead to the collapse of fragile reef ecosystems, with coastlines left unprotected from erosion and storms and fisheries falling short.

The last global mass coral bleaching event ran from 2014 to 2017, during which time the Great Barrier Reef lost nearly a third of its corals. Preliminary results suggest that about 15 per cent of the world's reefs saw large coral die-offs in this event.

ABOUT THE AUTHOR

Seth Borenstein is a journalist with The Associated Press.

With files from Reuters