Relentless rise of ocean heat content drives deadly extremes

By | January 11, 2023

Inside Climate News reports:

Ocean heat content reached a new record high for the fourth year in a row, scientists said Wednesday as they released their annual measurements of ocean heat accumulating down to a depth of more than a mile.

The findings published in the journal Advances in Atmospheric Science show that just in the past year, the planet’s seas absorbed about 10 Zetta joules of heat—equivalent to 100 times the world’s total annual electricity production.

The scientists found that the warmth keeps working its way deeper into the ocean, as greenhouse gases have trapped so much heat that the oceans’ deeper waters will continue to warm for centuries after humans stop using fossil energy.

Oceans cover 71 percent of Earth’s surface and have absorbed more than 90 percent of the heat energy trapped by greenhouse gases since the start of the industrial age, dominating the global climate system. Measuring their temperature is one of the best ways to accurately track how Earth’s fever has kept rising since 2016, when the global average surface temperature peaked.

Co-author John Fasullo, a climate scientist with the National Center for Atmospheric Research, said there are still open technical questions about the use of ocean heat content as a metric of climate change, “but our expectation is that ocean heat content more clearly resolves the march of climate change relative to other indices, such as surface temperature, which have more year to year variability.”

Since most of the heating from global warming is accumulating in the oceans, it’s a logical place “if you’re looking for a clear measure of our warming climate,” said co-author Michael Mann, director of the Center for Science, Sustainability & the Media at the University of Pennsylvania. “And our latest analysis shows that ocean heat content sets record after record, consistently every year,” regardless of other factors that cause the global average surface temperature to fluctuate within the overall upward trend.

Mann said another way to understand the amount of heat trapped in the oceans by global warming in 2022 is to visualize it as equivalent to the energy of seven nuclear bombs exploding every single second of the year. [Continue reading…]

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