The ocean's temperature was hotter than ever in 2022, scientists say

Alarmingly, rising ocean temperatures have a trickle-down effect on human food systems and weather patterns

Published January 18, 2023 5:45AM (EST)

Earth melting (Getty Images/bestdesigns)
Earth melting (Getty Images/bestdesigns)

As time progressed from 2021 to 2022, climate scientists remarked on what a banner year it had been for global warming. Among other records, experts noted that the Earth's oceans were hotter in 2021 than at any other time in the planet's history.

Yet now that 2022 has drawn to a close, climate scientists must be feeling déjà vu all over again — as 2022 marked another alarming year of climate records being broken. The most ominous, perhaps, relates (again) to the temperatures of the world's oceans. 

In the year 2022, the top 2,000 meters of Earth's oceans acquired roughly 14 zettajoules of heat — roughly 145 times the amount of energy generated by humans for electricity on this planet over the same period of time.

"In 2022, the world's oceans, as given by OHC, were again the hottest in the historical record and exceeded the previous 2021 record maximum," a group of global warming experts wrote in a new report for the journal Advances in Atmospheric Sciences. The term "OHC" is short for "ocean heat contact," a catch-all term for the saltiness (or salinity), different layers of temperatures and other factors that ultimately contribute to global oceanic temperatures.

As the Earth warms and the oceans warm along with it, scientists expect to see a domino effect of weather-related crises. The temperature of the oceans affects weather patterns, sea life, and in turn, ecosystems that humans depend on for survival. 

Over the course of the 365 days in the year 2022, the top 2,000 meters of Earth's oceans acquired roughly 14 zettajoules of heat, or 14,000,000,000,000,000,000,000 joules. For comparison, this is roughly 145 times the amount of energy generated by humans for electricity on this planet over the same period of time. Because oceans absorb more than 90 percent of the excess heat caused by global warming, that number is expected to go up even further unless greenhouse gas emissions are reduced.

The authors also noted that one of the year's most notable developments, rampant wildfires, could plausibly be explained by the ocean's overheating. As droughts worsen due to the oceans overheating, the affected regions will be at an increased risk of experiencing wildfires. In addition, as the warm water in the ocean evaporates at higher quantities, there will be increased flooding due to the more voluminous rainfall.


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Another consequence of the ocean's warming — and perhaps the biggest direct consequence — will be the destabilization of important current systems. In particular, the Atlantic meridional overturning circulation (AMOC) is already showing signs of destabilization. The conveyor belt of ocean currents is essential to the fishing industry and maintaining stable weather. If it radically changes it will cause more frequent and more severe hurricanes, alter the tides, annihilate ocean life, spread pollution and cause sea levels to rise.

Speaking to Salon in September about the sea level rise caused when warming oceans melt glaciers, Dr. William Sweet — a scientist at the National Oceanic and Atmospheric Administration (NOAA) — observed that this particular symptom of climate change is already upon us. He referred specifically to a pair of studies that analyzed melting of the Thwaites Glacier and Greeland's ice sheet. Just as a a glass window develops cracks if there are structural problems near its base, the spiderwebs of growing and criss-crossing fractures along the Thwaites Glacier by the warming ocean are at risk of eventually causing the whole pane to shatter. A similar process is at work with the Greenland ice shelf. The two studies in question addressed those phenomena.

 "Sea level rise is already affecting us, here and now, and will continue to grow in severity during the coming decades."

"These studies provide additional evidence about future-possible rises in sea level that the public needs to be aware of," Sweet wrote to Salon. "Sea level rise is already affecting us, here and now, and will continue to grow in severity during the coming decades."

In order for the planet to be saved, carbon emissions need to be reduced to zero as quickly as possible. Dr. Kevin Trenberth of the National Center for Atmospheric Research (NCAR) told Salon last year that "we really need to get to net-zero [emissions], and many countries have plans but not enough actions to support those." (Trenberth also contributed to the recent report.)

In the meantime, the group behind this report will continue to monitor the temperature of the world's oceans.

"In the future, the group will focus on understanding the changes of the earth's major cycles and improve the future projections of earth's heat, water and carbon changes," study second author Dr. John Abraham from the University of St. Thomas said in a statement. "This is the basis for human[s] to prepare for the future changes and risks."


By Matthew Rozsa

Matthew Rozsa is a professional writer whose work has appeared in multiple national media outlets since 2012 and exclusively at Salon since 2016. His diverse interests are reflected in his interview, including: President Jimmy Carter (1977-1981), Israeli Prime Minister Ehud Barak (1999-2001), animal scientist and autism activist Temple Grandin, inventor Ernő Rubik, comedian Bill Burr ("F Is for Family"), novelist James Patterson ("The President's Daughter"), epidemiologist Monica Gandhi, theoretical cosmologist Janna Levin, voice actor Rob Paulsen ("Animaniacs"), mRNA vaccine pioneer Katalin Karikó, philosopher of science Vinciane Despret, actor George Takei ("Star Trek"), climatologist Michael E. Mann, Washington Gov. Jay Inslee (2013-present), dog cognition researcher Alexandra Horowitz, Libertarian presidential candidate Gary Johnson (2012, 2016), comedian and writer Larry Charles ("Seinfeld"), Democratic vice presidential nominee Joe Lieberman (2000), Ambassador Michael McFaul (2012-2014), economist Richard Wolff, director Kevin Greutert ("Saw VI"), model Liskula Cohen, actor Rodger Bumpass ("SpongeBob Squarepants"), Senator John Hickenlooper (2021-present), Senator Martin Heinrich (2013-present), Egyptologist Richard Parkinson, Rep. Eric Swalwell (2013-present), media entrepreneur Dan Abrams, actor R. J. Mitte ("Breaking Bad"), theoretical physicist Avi Loeb, biologist and genomics entrepreneur William Haseltine, comedian David Cross ("Scary Movie 2"), linguistics consultant Paul Frommer ("Avatar"), Maryland Gov. Martin O'Malley (2007-2015), computer engineer and Internet co-inventor Leonard Kleinrock and right-wing insurrectionist Roger Stone.

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