Study: Oceans have retained more heat than previously thought

The world’s oceans have been soaking up far more excess heat in recent decades than scientists realized, suggesting that Earth could be set to warm even faster than predicted in the years ahead, according to new research published Wednesday.

Over the past quartercentury, the Earth’s oceans have retained 60 percent more heat each year than scientists previously had thought, said Laure Resplandy, a geoscientist at Princeton University who led the study published Wednesday in the journal Nature. The difference represents an enormous amount of additional energy, originating from the sun and trapped by the Earth’s atmosphere — more than 8 times the world’s energy consumption, year after year.

In the scientific realm, the new findings help to resolve l ong- running doubts about the rate of the warming of the oceans prior to the year 2007, when reliable measurements from devices called “Argo floats” were put to use worldwide. Before that, different types of temperature records — and an overall lack of them — contributed to murkiness about how quickly the oceans were heating up.

The higher- than- expected amount of heat in the oceans means more heat is being retained within the Earth’s climate system each year, rather than escaping into space. In essence, more heat in the oceans signals that global warming itself is more advanced than scientists thought.

“We thought that we got away with not a lot of warming in both the ocean and the atmosphere for the amount of CO2 that we emitted,” said Resplandy, who published the work with experts from the Scripps Institution of Oceanography and several other institutions in the U.S., China, France, and Germany. “But we were wrong. The planet warmed more than we thought. It was hidden from us just because we didn’t sample it right. But it was there. It was in the ocean already.”

Wednesday’s study also could have important policy implications. If ocean temperatures are rising more rapidly than previously calculated, that could leave nations even less time to cut the world’s emissions of carbon dioxide, in hopes of limiting global warming to the ambitious goal of 1.5 degrees Celsius above preindustrial levels.

The world already has warmed 1 degree Celsius since the late 19th century. Scientists backed by the United Nations reported earlier this month that with warming projected to steadily increase

Meanwhile, the Trump administration has continued to roll back regulations aimed at reducing carbon emissions from vehicles, coal plants and other sources.