The gains from sea ice increase in Antarctica do not cancel out the loss from the accelerated decrease in Arctic sea ice of the last decades, a study by NASA has found.As a whole, the planet has been shedding sea ice at an average annual rate of 35,000 square kilometers since 1979, the findings showed."Even though Antarctic sea ice reached a new record maximum this past September, global sea ice is still decreasing," said author of the study Claire Parkinson, climate scientist at NASA's Goddard Space Flight Centre in Greenbelt, Maryland.
"That is because the decreases in Arctic sea ice far exceed the increases in Antarctic sea ice," Parkinson explained.
The researcher used data collected by NASA and US Department of Defense satellites for her study spanning from November 1978 to December 2013.Over the 35-year period, the global ice decrease has accelerated: in the first half of the record (1979-96), the sea ice loss was about 21,500 square kilometers per year. This rate more than doubled for the second half of the period (1996 to 2013), when there was an average loss of 50,500 square kilometers per year."So when the area of sea ice coverage is reduced, there is a smaller sea ice area reflecting the sun's radiation back to space. This means more retention of the sun's radiation within the Earth system and further heating," Parkinson said. It is unlikely that the Antarctic sea ice expansion will accelerate and overturn the global sea ice negative trend in the future, the study added.The study was appeared in the Journal of Climate.