Just how much are the oceans mitigating the planet's temperature rise? Quite a bit, according to a Science study published Friday. Previous research has shown oceans' ability to take on heat and keep air temperatures lower than predicted, but the new study documents just how much that phenomenon's affecting the water below.
Researchers led by Yair Rosenthal at Rutgers University reconstructed temperatures in one part of the Pacific Ocean and found that its middle depths have been warming some 15 times faster over the past 60 years than at any other time over the past 10,000 years. It's as if the oceans have been acting as a battery, absorbing the excess charge created by the greenhouse effect, which leaves less to warm the surface of the planet, where we'd notice it.
Obviously, we don't have records for ocean temperatures over the past 10,000 years; researchers sampled levels of various elements in organisms found buried in ocean sediments, using that data to estimate previous temperatures.
The recent spike in ocean heat helps explain why air-temperature increases haven't been as large as forecasted, but that doesn't mean the oceans can keep us cool forever. "We may have underestimated the efficiency of the oceans as a storehouse for heat and energy," Rosenthal said. "It may buy us some time — how much time, I really don't know. But it's not going to stop climate change."