Global temperatures are increasing. Sea levels are rising. Ice sheets in
many areas of the world are retreating. Yet there’s something peculiar
going on in the oceans around Antarctica: even as global air and ocean
temperatures march upward, the extent of the sea ice around the southern
continent isn’t decreasing. In fact, it's increasing.
Sea ice at the other end of the world has been making headlines in
recent years for retreating at a breakneck pace. Satellite measurements
show that, on average, Arctic sea ice has decreased by four percent per
decade since the late 1970s, explained Claire Parkinson, a cryospheric
scientist at NASA's Goddard Space Flight Center in Greenbelt, Md., who
has been tracking the movements of the ice for 30 years. Antarctic sea
ice, in contrast, has expanded northward by about 1 percent — the
equivalent to 100,000 square kilometers (38,610 square miles) — per
decade.
Why is there such a drastic difference in the behavior of the two poles?
Scientists from Goddard and the University of Washington, Seattle,
recently described three theories — ozone depletion, changing ocean
dynamics, and the flooding of sea ice — for what's happening in the
Southern Ocean around Antarctica.
READ MORE: http://www.nasa.gov/topics/earth/features/antarctic_melting.html
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