While there is an incredibly broad consensus among climate scientists that climate change is both real and primarily caused by human activity, that doesn’t mean they every detail has been worked out. Surface temperatures have been steady in recent years and while the consensus view has been that the oceans were acting as heat sinks, keeping the air cool even though the planet as a whole is getting warmer, no one was sure where the heat was actually being trapped. Researchers at the University of Washington think they’ve found the answer in the changing speed of the Atlantic Ocean.
“The finding is a surprise, since the current theories had pointed to the Pacific Ocean as the culprit for hiding heat,” said UW professor Ka-Kit Tung who wrote the recent paper with co-author and visiting professor Xianyao Chen. “But the data are quite convincing and they show otherwise.”
Atlantic can store heat in its depths
The mechanism for storing heat depends on the Atlantic current that flows from the equator toward the northern Atlantic near Iceland. When the current is slow the warmer water has tie to dissipate its heat as it moves north, but when the current speeds up the salty water sinks faster than it can cool off, resulting in warmer waters at lower depths. The researchers identified the same pattern in the 1970s as they see today, although there is a lot more heat and salinity stored in the first couple hundred meters than there was last time around.
If this research is correct, it means that the earth’s surface will get hotter in discrete steps, with rapid acceleration like we saw in the 90s followed by periods of calm like we’re seeing now, and the next phase of acceleration is still at least a few years away.
Conflating surface temperature with global warming leads to confusion
As you might guess, there’s a lot of confusion surrounding the findings, largely due to years of misinformation from climate change deniers. While surface temperatures haven’t been increasing since the turn of the century, global warming is still being observed through buoys that sample oceanic temperatures around the world and satellite readings (not to mention receding glaciers and other natural indicators). It’s been a mystery why the two aren’t moving in lock-step, and the new research from UW certainly doesn’t have a consensus, but the inevitable conflation of global warming with surface temperature shows just how politically loaded the entire topic has become.