Warm ocean sharpening ice of Antarctica

An international team of scientists led by the British Antarctic Survey (British Antarctic Survey) found that warm ocean currents are the main cause of the loss of ice in Antarctica.

The researchers used data from the laser for ICESat, from satellites NASA, whose goal is to change the thickness of the fixing of the ice shelves of Antarctica.

Ice shelves — floating or in part on the bottom of the glaciers flowing from the coast, in the form of thinning to the edge of plates, ending cliff.

Of the 54 ice shelves in Antarctica 20 harbor due to warm ocean currents, and most of them are located in the western part of the continent.

And inside the glaciers that flow down to the shore and absorb thinned ice shelves, accelerated and began to deliver more water into the sea than contribute to sea level rise.

Lead author Dr Hamish Pritchard (Hamish Pritchard), of the British Antarctic Survey, said: "In most of the thinning of the Antarctic ice shelf is impossible to explain the melting of snow on the surface, so the reason must lie in the warm ocean currents that cause the ice to melt from below."

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Examined by a new method the entire coastal zone of Antarctica, scientists have identified a clear pattern: in all cases the ocean melts ice shelves, and the interior — accelerate the movement. And that is what is responsible for the acceleration of the melting of ice on the continent and therefore sea level rise.

"What's really interesting is how sensitive are the glaciers. Some shelves are thinning at a few meters per year, resulting in a sea of drains billions of tons of ice. This confirms the idea that the ice shelves play an important role in slowing the glaciers that feed them, and set the level of ice loss of the Antarctic ice sheet, "- says Pritchard.

However, the question arises as to why this is happening right now. "We believe that this is due to changes in the movement of winds. Antarctic winds change with the climate, and this affects the strength and direction of ocean currents. As a result, under the floating ice appear warm water. These studies and our new results show that the glaciers of Antarctica to quickly respond to changes in climate. "

The picture is different in the eastern part of the Antarctic Peninsula (the long piece of land directed toward South America). Here thinning of ice shelves can be attributed directly to the warm summer breezes.

Both models — the warm ocean currents and the summer wind — are dangerous because of changes in the patterns of movement of winds.

This study is part of international efforts to improve the understanding of the interaction between ice and climate in order to improve the accuracy of forecasts of growth in sea level.

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