Climate Change Caused Increased Melting of Sea Ice in Antarctica
(Photo : British Antarctic Survey)
Climate change and its consequences on Arctic have often been discussed on the other hand the reports on climate change in Antarctic have never been apt. There has been contrasting climate change observed across the Antarctic in recent decades.
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There is the first new evidence provided by the scientists from NERC's British Antarctic Survey (BAS) and NASA's Jet Propulsion Laboratory (JPL), Pasadena California the losses of the Antarctica's sea ice cover that is different from that of the Arctic.
The study focuses on the changes in the Antarctic sea ice changes that occurred over the last 20 years as a result of climate change.
The long term changes in the sea ice drift around Antarctica were showed by the four US Defense Meteorological satellites. They produced maps that were created by JPL using over 5 million individual daily ice motion measurements captured over a period of 19 years.
Lead author, Dr Paul Holland of BAS says: "Until now these changes in ice drift were only speculated upon, using computer models of Antarctic winds. This study of direct satellite observations shows the complexity of climate change. The total Antarctic sea-ice cover is increasing slowly, but individual regions are actually experiencing much larger gains and losses that are almost offsetting each other overall. We now know that these regional changes are caused by changes in the winds, which in turn affect the ice cover through changes in both ice drift and air temperature. The changes in ice drift also suggest large changes in the ocean surrounding Antarctica, which is very sensitive to the cold and salty water produced by sea-ice growth.
"Sea ice is constantly on the move; around Antarctica the ice is blown away from the continent by strong northward winds. Since 1992 this ice drift has changed. In some areas the export of ice away from Antarctica has doubled, while in others it has decreased significantly."
Sea ice plays a key role in the global environment. There exists a minimum sea ice cover at the poles during summer, whereas during winter freeze Antarctica ice cover expands to an area roughly twice the size of Europe. Ranging in thickness from less than a meter to several meters, the ice insulates the warm ocean from the frigid atmosphere above.
Apart from this the research also solves the mystery behind the difference in the amount of sea ice in both the Polar Regions. When Arctic witnessed a dramatic ice loss in recent decades, Antarctica witnessed increased loss in sea ice.
This small Antarctic increase is actually the result of much larger regional increases and decreases, which are now shown to be caused by wind-driven changes. In places, increased northward winds have caused the sea-ice cover to expand outwards from Antarctica. The Arctic Ocean is surrounded by land, so changed winds cannot cause Arctic ice to expand in the same way.
Dr Ron Kwok, JPL says, "The Antarctic sea ice cover interacts with the global climate system very differently than that of the Arctic, and these results highlight the sensitivity of the Antarctic ice coverage to changes in the strength of the winds around the continent."
The new research improves understanding of present and future climate change.
The research was published in this week's journal Nature Geoscience.