How often have you sat on the beach, watching folks run into the surf, and hear someone exclaim, “the ocean feels like bathwater!”
It doesn’t happen all the time, but beachgoers often are surprised at how warm ocean water is.
Sadly, a new report shows that warm ocean water is becoming a constant.
The annual study, published in the journal Advances in Atmospheric Sciences, found 2021 was the hottest on record for the world’s ocean. That makes the past five years the hottest five on record for the oceans, dating back to the late 1950’s.
The new research is part of a long-term upward trend in ocean temperatures, that scientists say is overwhelmingly due to planet-warming fossil fuel emissions.
"We want to stress that global warming is actually ocean warming, and ocean warming has serious consequences," said Lijing Cheng, lead author on the report and climate and environmental science professor with the Institute of Atmospheric Physics at the Chinese Academy of Sciences. "Ocean warming keeps breaking records, which is a reminder that the world needs action to combat climate change."
What makes the finding even more disturbing is that 2021 was a record despite La Niña conditions in the Pacific Ocean which produced a cooler than average temperature pattern in the ocean around the equator.
“Ocean heat is a better indicator of the climate crisis that air temperatures,” Kevin Trenberth told CNN. He’s an author of the report and scientist at the National Center for Atmospheric Research in Colorado.
Greenhouse gas emissions from fossil fuels trap heat in the planet's atmosphere. The oceans, in turn, absorb 90 percent of the excess heat, which has led to an alarming increase in temperature.
"The impacts are perhaps subtle but profound," said Trenberth, “because warm oceans provide fuel to storms.”
Warmer oceans supercharge weather patterns to create more powerful storms, hurricanes, and intense rainfall, which leads to deadly flooding. 2021 saw plenty of examples, including Hurricane Ida in Louisiana and Mississippi and the deadly flooding cause by its remnants as it tracked up the coast, as well as Super Typhoon Rai in the Philippines.
The warming oceans are also bleaching coral reefs, which provide valuable habitat and threatens sea life and fish population. Those warming waters are also melting Arctic and Antarctic ice shelves, which is already adding to sea level rise.
Sea level rise makes coastal communities more vulnerable to high-tide flooding and storm surge. And because of salt-water intrusion, rising seas also threaten water supplies and agricultural lands.
While nations have set goals to reduce global warming, the report’s authors say urgent action is needed because the oceans will continue warming for decades after fossil fuel emissions are cut.
“Heat will continue to percolate into the ocean depths, so we really need to get to zero emissions quickly,” said Trenberth. “But in the meantime, we must prepare better and build resilience.”