Study: How Deep, Old Waters Delay Antarctic Ocean Warming

A new study from the University of Washington and Massachusetts Institute of Technology revealed that ocean currents are the reason behind the delayed warming of the Antarctic Ocean while the rest of planet is significantly warmer.

Previously, scientists believed that the delayed warming in the Atlantic Ocean was caused by the heat taken up at the surface mixing downward, but the new study, published in the journal Nature Geoscience showed that the heat was actually being carried away from Antarctica, northward along the surface.

According to the study, strong westerly winds surrounding Antarctica pushes the surface water north, allowing the very deep, cold water to get drawn toward the surface off the coast of Antarctica. This cold water came from such great depths that it will take centuries before it experiences the effects of global warming.

"The Southern Ocean is unique because it's bringing water up from several thousand meters [as much as 2 miles]," said Kyle Armour, a UW assistant professor of oceanography and of atmospheric sciences and lead author of the study, in a statement. "It's really deep, old water that's coming up to the surface, all around the continent. You have a lot of water coming to the surface, and that water hasn't seen the atmosphere for hundreds of years."

For the study, researchers analyzed oceanographic observations and general circulation model simulations to further understand the delayed warming of Antarctic Ocean.

Their models revealed that the northward flow of the Atlantic Ocean's surface continues all the way to arctic. This explains the commonly used inconsistent pattern of warming in the Arctic and Antarctic by climate change deniers. The models suggests that the ocean's surface water that experienced most of the global warming are being sent and clumped in the North Pole, explaining why the Arctic oceans and sea ice are being burdened by global warming, while the Antarctic oceans and sea ice remain oblivious.

"The oceans are acting to enhance warming in the Arctic while damping warming around Antarctica," Armour explained. "You can't directly compare warming at the poles, because it's occurring on top of very different ocean circulations."

Researchers believe that their findings can greatly help developing future predictions of ocean temperatures.