Antarctica and Arctic Polar Opposites

Never let it be said that planet Earth made life easy for its scientists. A new NASA study has shown that, while the Arctic has been losing ice each summer, Antarctica has been gaining ice.

“There’s been an overall increase in the sea ice cover in the Antarctic, which is the opposite of what is happening in the Arctic,” said lead author Claire Parkinson, a climate scientist with NASA’s Goddard Space Flight Center, Greenbelt, Md. “However, this growth rate is not nearly as large as the decrease in the Arctic.”

The study shows that, from 1978 to 2010, the total extent of sea ice surrounding Antarctica in the Southern Ocean grew by roughly 6,600 square miles every year, with recent research adding that that growth rate has accelerated recently, up from an average rate of almost 4,300 square miles per year from 1978 to 2006.

Antarctica and Arctic Polar Opposites
September 2012 witnessed two opposite records concerning sea ice. Two weeks after the Arctic Ocean’s ice cap experienced an all-time summertime low for the satellite era (left), Antarctic sea ice reached a record winter maximum extent (right).

The study is based on data collected using passive-microwave data from NASA’s Nimbus 7 satellite and several Department of Defense meteorological satellites.

Parkinson and colleague Don Cavalieri found that not only was there an overall increase in ice, but that it wasn’t uniform around the whole of the continent.

The majority of the growth that has taken place in the study’s time frame took place in the Ross Sea, which gained a little under 5,300 square miles of sea ice per year. Modest increases were also seen in the Weddell Sea and Indian Ocean.

However, the Bellingshausen and Amundsen Seas lost approximately 3,200 square miles of ice each year.

“Winds off the Ross Ice Shelf are getting stronger and stronger, and that causes the sea ice to be pushed off the coast, which generates areas of open water, polynyas,” said Josefino Comiso, a senior scientist at NASA Goddard. “The larger the coastal polynya, the more ice it produces, because in polynyas the water is in direct contact with the very cold winter atmosphere and rapidly freezes,” which sees the ice expand further north as the winds keep blowing.

As the Arctic saw catastrophic record-breaking ice losses during the northern summer, Antarctica reached an all time record high for the satellite era of 7.49 million square miles — that’s approximately 193,000 square miles more than the 30 year average.

Source: NASA

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