Why is Antarctic sea ice growing?
NEW YORK. April 3. KAZINFORM It's a global warming paradox. As air and sea temperatures rise, Arctic sea ice is rapidly and uniformly dwindling. In 2012, Arctic sea ice declined so much that the loss "utterly" obliterated the previous record, set in 2007, according to the U.S. National Snow and Ice Data Center.
As of 2012, the area of Arctic sea ice around the North Pole had shrunk to 1.58 million square miles (4.1 million square kilometers)-the smallest measurement since 1979, when satellite observations began.
But in Antarctica, where sea ice is more scattered and driven by wind and waves, there's another story-ice is increasing in places.
In September of last year, satellite data indicated that Antarctica was surrounded by the greatest area of sea ice ever recorded in the region: 7.51 million square miles (19.44 million square kilometers), according to the center.
Previous studies pointed to snow: Global warming has warmed Antarctic air, and warmer air holds more moisture, which in turn creates more precipitation. That means more snow is falling on Antarctica, and more of the white stuff makes the top layers of the ocean less salty and thus less dense. These layers became more stable, preventing warm currents in the deep ocean from rising and melting sea ice.
Now, a new study has pinpointed another culprit: melting ice shelves. As ice shelves that ring the southernmost continent disintegrate in warming temperatures, the fresh water that flows from them accumulates in a cool
and fresh surface layer on top of the ocean. This cool layer then shields the surface ocean from the warmer, deeper waters that are melting the ice shelves, Kazinform quotes National Geographic.
The study "shows that global warming can cause regional cooling, and that's quite counterintuitive," said study leader Richard Bintanja, of the Royal Netherlands Meteorological Institute.
"Most people think if you warm the whole system, it will warm everywhere," he said.
Also counterintuitively, a colder Antarctica may contribute to a rise in sea levels. Colder temperatures mean less snow on the ice sheets, which makes more water stay in the ocean, he pointed out.
Overall, loss of polar ice has contributed about 11.1 millimeters (0.03 feet) to global sea levels since 1992, research shows. Sea levels are rising at a rate of 3.2 millimeters a year.
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