The largest floating ice shelf on the Antarctic Peninsula is thinning out because of hotter air and ocean temperatures that are forcing it towards a meltdown that could add significantly to global sea level rise by as much as 1.64 feet or 50 cm, according to latest international study.

The research led by Paul Holland of the British Antarctic Survey (BAS) analyzed the Larsen C ice shelf, the fourth biggest ice shelf in the planet which covers 21,235 square miles (55,000 square kilometers) or almost twice the area of Belgium. The scientists work on the combination of eight radar surveys and satellite imagery data captured from 1998 to 2012 to discover that Larsen C has lost 4 meters or 13 feet of thickness of ice and had dropped by an average of one meter at the surface.

For years researchers have been unsuccessful to decide whether it is warmer ocean currents or warming air temperatures that were triggering the Antarctic Peninsula's floating ice shelves to shrink its volume and to be more susceptible to meltdown. The new study discovered both events play a part, but the key driver is the ice meltdown from below.

The main loss happened below the shelf where it drifts on gradually warm ocean tides. Around 0.92 feet or 28 centimeters each year across the whole area of the ice shelf is being consumed away from underneath.

Two smaller neighboring ice shelves on the east side of the Antarctic Peninsula have collapsed in the last twenty years. The first ice shelf, Larsen A, was gone in 1995. And in 2002, Larsen B with the size of the US state of Rhode Island, catastrophically followed.

"We expect that sea-level rise around the world will be something in excess of 50 cm higher by 2100 than it is at present and that will cause problems for coastal and low-lying cities. Understanding and counting up these small contributions from Larsen C and all the glaciers around the world is very important if we are to project, with confidence, the rate of sea-level rise into the future," Professor David Vaughan, BAS Director of Science and glaciologist, said.

The research was conducted by scientists from British Antarctic Survey, Scripps Institution of Oceanography, University of Kansas, University of Colorado and the United States Geological Survey.

Published in the journal The Cryosphere on Wednesday, the research was financially granted by the National Science Foundation in the US, Natural Environment Research Council in the UK, and other international funding organizations.

Photo: NASA Goddard Space Flight Center | Flickr

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