One of Antarctica’s ice shelves has shrunk by 85 percent in the past 17 years according to images taken by the European Space Agency (ESA)’s Envisat satellite and scientists say that climate change is the reason.
In 1995, the Larsen B ice shelf was 11,512 square kilometers (4,373 square miles), an area about the size of Qatar. Now it is only 1,670 sq km (634 miles). Prof. Helmut Rott of the University of Innsbruck said that the satellite’s images indeed “confirm the vulnerability of ice shelves to climatic warming and demonstrate the importance of ice shelves for the stability of glaciers upstream.”
Ice shelves are thick masses of floating ice made from runoff from glaciers and are attached to the shore. They differ from ice sheets, which are vast masses of glacier ice that cover Antarctica. Ice shelves are highly sensitive to changes in the temperature and can be hollowed out from below by warmer ocean currents. Ice sheets seem to be stable so far; were they to melt, sea levels would rise and endanger coastal cities and small island states.
Disintegration of the Larsen Ice Shelf
The Larsen ice shelf is a series of three ice shelves that run from north to south on the eastern side of the Antarctic Peninsula. The smallest shelf, A, disintegrated in 1995, says the ESA. C appears stable so far, but Envisat has revealed that it too is thinning and that “melt events” are occurring for longer periods in the summer.
Image from Wikimedia Commons
Again, Prof. Rott specifically points to global warming as a factor in the melting of ice shelves:
“The northern Antarctic Peninsula has been subject to atmospheric warming of about 2.5°C over the last 50 years – a much stronger warming trend than on global average, causing retreat and disintegration of ice shelves.”
This graphic shows how temperatures increased from 1981 to 2007 in Antarctica, contributing to the shrinking of the Larsen ice shelf.
The Envisat satellite has been in operation for twice as long as planned. Scientists are planning for it to make more observations of Earth’s ice caps, land, oceans and atmosphere for at least the next two years — such continued monitoring is crucial to predict what might happen to the much larger ice masses of West Antarctica, if warming spreads further south.
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