The amount of manmade heat absorbed by the world’s oceans has doubled since 1997, according to a study
released yesterday in the journal Nature Climate Change. Scientists have long known that the oceans absorb more than 90 percent of manmade heat, but the study’s figures give a new and more accurate accounting for that process over a period of 150 years. According to the study, the oceans absorbed 150 zettajoules of energy between 1865 and 1997 — and an additional 150 zettajoules in just the past 18 years. “The changes we’re talking about, they are really, really big numbers,” said co-author Paul Durack, an oceanographer at the Lawrence Livermore National Lab in California. “They are nonhuman numbers.” Put in perspective, the amount of energy absorbed by the oceans since 1997 is the equivalent to a Hiroshima-sized bomb being exploded every second for 75 years.