Antarctic summer brings more bad news


B. McPherson
It will take a few hundred years for it all to go, but go it will

Antarctica is entering its winter season, but the summer has seen accelerated melting of the vast ice sheets. In 2014 we found that the Western Ice Sheet was flowing rapidly into the ocean and melting. Research conducted this summer on the eastern part of that continent has found that that side of the continent is also spilling its hoard of ice into the Austral Ocean.

Warmer ocean temperatures have infiltrated under the Western Ice Sheet and accelerated the flow and melt rate. If the whole ice sheet were to melt, it would raise the ocean levels and average of 10 feet(3 metres). This summer scientists found a previously unknown ocean trough that can allow warm, for the Antarctic, water to seep under the Totten Glacier on the east coast. The Totten Glacier acts as a brake or plug to keep the interior ice from flowing to the ocean. Like the ice shelf in the west, the Glacier’s seaward edge is now found to be floating on ocean water. Previously it was assumed that it was grounded on solid land.

“Now we know the ocean is melting ice in an area of the glacier that we thought was totally cut off before,” 

Glaciers build up when more precipitation falls and freezes than melts. Over time ice-sheets can reach depths that sequester so much water that it affects ocean levels. When more ice melts than is replaced ocean levels rise.

In the Northern Hemisphere, the Arctic Sea Ice has been thinning and melting. Greenland is seeing land that has not been bare of ice since settlement by humans. This is contributing to a creeping rise in sea level. The further one moves towards the poles, the greater the sea level change.

Sources:
Washington Post                           
Nature Geoscience                         
NASA Jet Propulsion Lab             

Jackson School of Geoscience                  

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