Oceans Break Heat Record for Fourth Year in a Row

Oceans hit their warmest levels on record for the fourth consecutive year in 2022, according to a new report by two dozen scientists. Previous heat records were broken in 2021, 2020 and 2019, and all of the top six hottest levels have occurred in the last six years.

It’s an ominous sign of the speed at which the world is warming.

The world’s oceans are massive heat sinks—they absorb as much as 90 percent of the excess heat in the atmosphere. And because the air is swiftly warming, driven by greenhouse gas emissions, the oceans are soaking up more and more heat as time goes on.

The new record was published Wednesday, just days after scientists from Europe’s Copernicus Climate Change Service announced that 2022 was the planet’s fifth hottest year on record. The years 2016, 2020, 2019 and 2017 all rank in the top five as well, according to the agency.

It’s all part of a long-term pattern of planetary warming, oceans and atmosphere alike.

The oceans report, led by scientist Lijing Cheng of the Chinese Academy of Sciences, notes that every decade since 1958—when scientists first began keeping reliable measurements of ocean heat—has been hotter than the last. And the warming has accelerated over time. Since the late 1980s, the rate at which the ocean stores up heat has increased by three- to fourfold.

Some areas are warming faster than others. Four major basins hit their own regional heat records in 2022, including the North Pacific, North Atlantic, Mediterranean Sea and Southern Ocean.

That’s not all. The report also finds that the oceans are growing more stratified, meaning warm and cold water masses aren’t mixing as easily and are instead getting stuck on top of one another, like layers in a cake.

Stratification can make it harder for heat, oxygen and vital nutrients to be transported throughout the water column. That can damage marine ecosystems and trap heat near the surface of the water, where it can then proceed to further warm the atmosphere.

Rising ocean heat has other serious implications for the rest of the planet.

Water expands as it warms. That means the oceans take up more space as they store more heat, contributing to rising sea levels.

Warming oceans also contribute to changing weather patterns around the world. They have a major influence on the world’s hydrological cycles, contributing to more intense droughts in some places and more extreme rainfall in others. Warm waters also provide fuel for tropical cyclones, increasing the intensity of hurricanes.

The past year was a record-breaker for extreme weather around the world as well. Europe saw unprecedented summer heat. China experienced a record-breaking drought. The U.S. suffered heat waves, wildfires, floods and hurricanes. A recent report from NOAA found that the U.S. experienced 18 climate-related disasters in 2022 that each exceeded $1 billion in damages.

These patterns will continue as the world keeps warming, climate models predict. Meanwhile, the oceans will continue steadily absorbing more heat.

“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 study co-author Michael Mann, a climate scientist at the University of Pennsylvania, in a statement. “Better awareness and understanding of the oceans are a basis for the actions to combat climate change.”

Reprinted from E&E News with permission from POLITICO, LLC. Copyright 2023. E&E News provides essential news for energy and environment professionals.