Jan 11, 2023 - Energy & Environment

Ocean heat content hits record high, a sign of global warming

Data: John Abraham, University of St. Thomas; Chart: Axios Visuals

Ocean heat content hit a record high in 2022, a new study found, in a clear indication of continued global warming.

The big picture: The research, published in the journal Advances in Atmospheric Sciences, indicates that ocean warming is leading to widespread changes throughout the sea, with salty areas getting saltier and fresh regions of the ocean getting fresher.

  • This alters key ocean currents that distribute heat around the world.
  • The two-dozen researchers involved in the study found that the vertical slice of the ocean from 0 to 2,000 meters deep gained about 10 zettajoules of heat between 2021 and 2022.
  • This heat is equal to about 100 times the world’s electricity generation in 2021, according to a statement.

Context: Warmer waters are also tied to stronger, wetter hurricanes, heat waves, droughts and heavy precipitation events, studies show.

  • Ocean warming is altering the basics of the hydrological cycle, allowing storms to pick up more moisture that then gets wrung out over land, and changing atmospheric circulation in ways that favor extreme events.
  • For example, study co-author Kevin Trenberth of the National Center for Atmospheric Research said warm waters in the Indian Ocean helped lead to both record heat in Pakistan and parts of India last year, as well as the deadly flooding that affected much of Pakistan in the late summer.
  • Similarly, the ongoing atmospheric river events in California are being made worse by warm ocean temperatures in parts of the Pacific Ocean, Trenberth told Axios via email.

What they’re saying: “If you want to know how fast the globe has warmed and if you want to look into the future climate, the answer is in the oceans,” study co-author John Abraham of the University of St. Thomas told Axios via email.

  • "It tells us the past and helps us project into the future," he said.
  • "Our latest analysis shows is that once again, ocean heat content sets record after record, consistently every year, regardless of factors like El Niño that have a more substantial impact on the surface," said climate researcher Michael Mann of the University of Pennsylvania, in an email.
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