Ocean heating driven by human-caused climate crisis, scientists say, in sixth consecutive year record has been broken
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An oil platform stands offshore as cargo shipping container
ships wait in the Pacific Ocean to enter the port of Los
Angeles.
Photograph: Patrick T Fallon/AFP/Getty Images
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“The ocean heat content is relentlessly increasing, globally, and this is a primary indicator of human-induced climate change,” said Kevin Trenberth, a climate scientist at the National Center for Atmospheric Research in Colorado and co-author of the research, published in Advances in Atmospheric Sciences.
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Oceans in 2021 were the hottest ever recorded Five hottest years of global ocean temperature recorded since 1955, in zettajoules 
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Note: Average temperature of the top 2,000 meters of ocean water.
Zettajoules are a unit of energy equal to 10 to the power of 21
joules. Guardian graphic. Source: Cheng, et al., “Another Record: Ocean
Warming Continues through 2021 despite La Niña Conditions”,
2022. |
Warmer ocean waters are helping supercharge storms, hurricanes and extreme rainfall, the paper states, which is escalating the risks of severe flooding. Heated ocean water expands and eats away at the vast Greenland and Antarctic ice sheets, which are collectively shedding around 1tn tons of ice a year, with both of these processes fueling sea level rise.
Oceans take up about a third of the carbon dioxide emitted by human activity, causing them to acidify. This degrades coral reefs, home to a quarter of the world’s marine life and the provider of food for more than 500m people, and can prove harmful to individual species of fish.
As the world warms from the burning of fossil fuels, deforestation and other activities, the oceans have taken the brunt of the extra heat. More than 90% of the heat generated over the past 50 years has been absorbed by the oceans, temporarily helping spare humanity, and other land-based species, from temperatures that would already be catastrophic.
The amount of heat soaked up by the oceans is enormous. Last year, the upper 2,000 meters of the ocean, where most of the warming occurs, absorbed 14 more zettajoules (a unit of electrical energy equal to one sextillion joules) than it did in 2020. This amount of extra energy is 145 times greater than the world’s entire electricity generation which, by comparison, is about half of a zettajoule.
Long-term ocean warming is strongest in the Atlantic and Southern oceans, the new research states, although the north Pacific has had a “dramatic” increase in heat since 1990 and the Mediterranean Sea posted a clear high temperature record last year.
The heating trend is so pronounced it’s clear to ascertain the fingerprint of human influence in just four years of records, according to John Abraham, another of the study’s co-authors. “Ocean heat content is one of the best indicators of climate change,” added Abraham, an expert in thermal sciences at University of St Thomas.
“Until we reach net zero emissions, that heating will continue, and we’ll continue to break ocean heat content records, as we did this year,” said Michael Mann, a climate scientist at Penn State University and another of the 23 researchers who worked on the paper. “Better awareness and understanding of the oceans are a basis for the actions to combat climate change.”
Links
- (ScienceAlert) Warming Events Could Destabilize The Antarctic Ice Sheet Soon. Very Soon
- (AU) Climate Change Pushed Ocean Temperatures To Record High In 2020, Study Finds
- Climate Change Will Make World Too Hot For 60 Per Cent Of Fish Species
- (Scientific American) Marine Oxygen Levels Are The Next Great Casualty Of Climate Change
- (The Conversation) The Ocean Is Essential To Tackling Climate Change. So Why Has It Been Neglected In Global Climate Talks?
- (Washington Post) A Critical Ocean System May Be Heading For Collapse Due To Climate Change, Study Finds
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