World's oceans were warmest on record, again, in 2021: study
For the sixth straight year, the world's oceans were warmer in 2021 than at any time before, according to a new study.
Researchers found that in 2021 the upper 2,000 metres of the oceans absorbed 14 more zettajoules than in 2020. For context, the annual global energy consumption by humans is estimated to be half a zettajoule. A zettajoule is equal to one joule, a unit of energy, plus 21 zeros.
"The ocean heat content is relentlessly increasing globally, and this is a primary indicator of human-induced climate change," Kevin Trenberth, distinguished scholar at the U.S. National Center for Atmospheric Research and co-author of the study, said in a news release. "In this most recent report, we updated observations of the ocean through 2021, while also revisiting and reprocessing earlier data."
The study, published Tuesday in the peer-reviewed Advances in Atmospheric Sciences, summarizes data from the Institute of Atmospheric Physics at the Chinese Academy of Sciences and the National Centers for Environmental Information of the U.S. National Oceanic and Atmospheric Administration.
The research looked into the role of natural weather variations, such as the warming and cooling phases El Nino and La Nina, which greatly affect regional temperature changes. In spite of these phenomena, analyses indicated significant ocean warming across the globe since the 1950s.
"With model experiments, our study shows that the pattern of ocean warming is a result of human-related changes in atmospheric composition," said Lijing Cheng, associate professor with the International Center for Climate and Environmental Sciences and lead author of the study. "As oceans warm, the water expands and sea level rises. Warmer oceans also supercharge weather systems, creating more powerful storms and hurricanes, as well as increasing precipitation and flood risk."
Ocean heat content is one of the best indicators of climate change, the researchers say.
"The oceans are absorbing most of the heating from human carbon emissions," said Michael Mann, distinguished professor of atmospheric science at The Pennsylvania State University and co-author of the study. "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. Better awareness and understanding of the oceans are a basis for the actions to combat climate change."
The researchers also say rising ocean temperatures can affect the amount of carbon dioxide in the air.
"As well as absorbing heat, currently, the ocean absorbs 20 to 30 per cent of human carbon dioxide emissions, leading to ocean acidification," Cheng said. "However, ocean warming reduces the efficiency of oceanic carbon uptake and leaves more carbon dioxide in the air."
RISKIN REPORTS
CTVNews.ca Top Stories
As Canada's RCMP marks 150th anniversary, a look at what it says needs to change
After years of reports and allegations detailing a 'toxic' workplace, Canada's RCMP says it is trying to evolve, focusing on diversity in its organization and repairing relationships with communities as it marks its 150th anniversary.

Former Mississauga, Ont. mayor Hazel McCallion dies at 101
Former Mississauga, Ont. mayor Hazel McCallion, nicknamed 'Hurricane Hazel,' has died. She was 101 years old. Premier Doug Ford said McCallion died peacefully at her home early Sunday morning.
Once-in-a-lifetime discovery: Indigenous jacket that may be a century old turns up in small U.K. town
When 1990s suede fringe jackets started making a comeback last year, a U.K.-based vintage clothing company decided to order four tonnes of suede from a supplier in the United States. Along with that shipment came a once-in-a lifetime discovery.
'Cloud of dishonour:' Memphis police disband unit that beat Tyre Nichols
The Memphis police chief on Saturday disbanded the unit whose officers beat to death Tyre Nichols as the nation and the city struggled to come to grips with video showing police pummelling the Black motorist.
Trudeau remembers 'trailblazer' Hazel McCallion as tributes pour in for late Mississauga mayor
Late Mississauga Mayor Hazel McCallion is being remembered for the many ways she contributed to not only to the city she led for 36 years, but also the province and country following her death on Sunday morning.
Majority of affordable homes approved under federal program not yet constructed
The federal government has set aside billions of dollars to quickly build affordable housing across the country, but delays in construction suggest many of the projects approved for funding are missing their deadlines.
How to get over the 'mental hurdle' of being active in the winter
When the cold and snow have people hunkering down, these outdoor enthusiasts find motivation in braving the Canadian winter through community and sport.
'Don't be numb to this': Battling despair over gun deaths
When President Joe Biden signed a bill last year to fight gun violence -- the first such measure to pass Congress in a generation -- a substantial majority supported it. But 78 per cent said they believed it would do little or nothing at all, a survey by the Pew Research Center found.
W5 EXCLUSIVE | Interviewing a narco hitman: my journey into Mexico's cartel heartland
W5 goes deep into the narco heartland to interview a commander with one of Mexico's most brutal cartels. W5's documentary 'Narco Avocados' airs Saturday at 7 pm on CTV.