Climate Change: Oceans May Have Reached Their Limits of Heat Storage

First Posted: Jul 17, 2015 08:44 AM EDT

As temperatures warmed, our ocean kept the heat in check. Extra heat from greenhouse gases was trapped in the subsurface waters of the Pacific and Indian oceans. This accounted for the global slowdown in global surface temperature. Now, though, it seems as if the oceans have reached their limit-and we're going to see some major warming very soon.

During the 20^th century, greenhouse gas concentrations increased and trapped more heat on Earth. This caused global surface temperatures to also increase. Starting in the early 2000s, though, greenhouse gases continued to trap extra heat, and global surface temperature stopped climbing for about a decade and even cooled a bit.

In this latest study, the researchers analyzed direct ocean temperature measurements, including observations from a global network of about 3,500 ocean temperature probes known as the Argo array.

So what did they find? A specific layer of the Indian and Pacific oceans between 300 and 1,000 feet below the surface has been accumulating more heat than previously recognized. The Pacific Ocean, in particular, is the primary source of the subsurface warm water found in the study, though some of that water has been pushed to the Indian Ocean.

"The western Pacific got so warm that some of the warm water is leaking into the Indian Ocean through the Indonesian archipelago," said Veronica Nieves, lead author of the new study, in a news release. "Given the fact the Pacific Decadal Oscillation seems to be shifting to a warm phase, ocean heating in the Pacific will definitely drive a major surge in global surface warming."

Cooler surface temperatures are related to something called the Pacific Decadal Oscillation, which is a climate pattern that moves in a 20- to 30-year cycle. It has been in a cool phase during the entire time surface temperatures showed cooling, bringing cooler-than-normal water to the eastern Pacific and warmer water to the western side.

With the new changes to the climate pattern, it could be that we may be in for some warming. As shifts in the Pacific occur, heat could be released and may raise Earth's average surface temperature quite a bit.

The findings are published in the journal Science.