Antarctic sea ice hits an all-time high, NASA blames global warming



Antarctic sea ice has hit a new record maximum, but scientists say this is even more proof of global warming.

Satellite imagery from last month shows the ice shelf surrounding the planet's southern-most continent passed 20 million-square-kilometers (7.72 million-square-miles) for the first time since 1979, according to NASA.

Scientists only began keeping track of Antarctic sea ice in 1979, so this represents a new known-record.

Despite this development, experts still believe it is proof the planet is warming.

"The planet as a whole is doing what was expected in terms of warming," said Claire Parkinson, a senior scientist at NASA's Goddard Space Flight Center.

"Sea ice as a whole is decreasing as expected, but just like with global warming, not every location with sea ice will have a downward trend in ice extent."

Arctic sea ice has decreased at a rate of about 21,000 square-miles per year since the 1970s, according to the space agency, but Antarctic sea ice has gained about 7,300 square-miles annually.

Despite these gains, the southern ice shelf had never exceeded 7.2 million-square miles, experts said.

Another expert believes the southern shelf has expanded because Antarctica does not have the natural barriers present around the North Pole.

"Part of it is just the geography and geometry. With no northern barrier around the whole perimeter of the ice, the ice can easily expand if conditions are favorable," said Walt Meier, a research scientist at Goddard.

Other factors at play could be changing wind patterns, a hole in the Ozone layer and even a constant low-pressure system over the continent.

"The winds really play a big role," Meier said. Gusts from Antarctica's interior push colder temperatures further out to sea and can cause the ice to rapidly expand.

Snow falling onto thin, barely noticeable ice can also play a part, scientists say. As it pushed the thin layer of slush and ice below the surface, it causes more water to cool and thickens the frozen layer at the top.

Initially warmer waters created by the Ozone hole only serve to further strengthen these storms before their snowfall causes the water to freeze over.

Warmer oceans have also been fingered as the main culprit in the Polar Vortex slamming the United States with bitter cold air last winter.

Scientists believe warmer water from global warming is destabilizing polar air masses and causing them to shift south, causing colder and snowier winters in many regions.

But these are all just theories. No one knows for sure what is causing the Antarctic ice sheet to expand so rapidly.

"There hasn't been one explanation yet that I'd say has become a consensus," said Parkinson. The Antarctic sea ice is one of those areas where things have not gone entirely as expected.

"So it's natural for scientists to ask, 'OK, this isn't what we expected, now how can we explain it?'"

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