A new study has revealed that the Larsen C Ice Shelf, whose neighbours Larsen A and B collapsed in 1995 and 2002, is thinning from both its surface and beneath.
For years scientists were unable to determine whether it is warming air temperatures or warmer ocean currents that is causing the Antarctic Peninsula’s floating ice shelves to lose volume and become more vulnerable to collapse. This new study takes an important step forward in assessing Antarctica’s likely contribution to future sea-level rise.
The research team combined satellite data and eight radar surveys captured during a 15-year period from 1998-2012 and found that Larsen C Ice Shelf lost an average of 4 metres of ice and had lowered by an average of one metre at the surface.
Lead author Paul Holland from British Antarctic Survey (BAS) said that they now know that two different processes are causing Larsen C to thin and become less stable, adding that air is being lost from the top layer of snow (called the firn), which is becoming more compacted, probably because of increased melting by a warmer atmosphere. They know also that Larsen C is losing ice, probably from warmer ocean currents or changing ice flow.
Holland added that if this vast ice shelf, which is over two and a half times the size of Wales and 10 times bigger than Larsen B, was to collapse, it would allow the tributary glaciers behind it to flow faster into the sea. This would then contribute to sea-level rise.
The Antarctic Peninsula is one of the fastest warming regions on Earth, with a temperature rise of 2.5 degree C over the last 50 years.
The team, who continue to monitor the ice shelf closely, predict that a collapse could occur within a century, although maybe sooner and with little warning. A crack is forming in the ice which could cause it to retreat back further than previously observed. The ice shelf appears also to be detaching from a small island called Bawden Ice Rise at its northern edge.
The study appears in the journal The Cryosphere. (ANI)