Deep Oceans Not Warming As Previously Thought, Study Finds

The deepest reaches of earth’s oceans have not warmed significantly over the last decade, according to scientists at NASA’s Jet Propulsion Laboratory in California — a finding that undermines a leading theory as to why the pace of global warming has slowed over the last 15 years. Scientists have speculated that the recent slowdown in rising surface air temperatures was a result of heat accumulating in the deep ocean. But in a paper published in the journal Nature Climate Change, the NASA researchers concluded that the vast majority of sea level rise since 2005 was attributable to just two sources: upper ocean heat expansion and glacial melting. From this they inferred that the deep ocean was not also warming. In a separate paper published in the same journal, however, scientists from the Lawrence Livermore Laboratory noted that the upper ocean was absorbing between 24 and 58 percent more heat than was previously thought. That’s not enough to account for the pause in surface air warming, but the researchers suggest it is evidence that more accurate data on ocean warming is needed.