Delaware Sized Iceberg Poised to Break Away From West Antarctic Larsen C Shelf

RawStory

An expanse of ice roughly the size of Delaware is close to breaking off from the warming Antarctic ice shelf to form one of the world’s largest-ever icebergs, scientists said Thursday.

Satellite data showed that the West Antarctic Larsen C shelf is poised to shed an ice block measuring about 5,000 square kilometres (1,900 square miles).

“The rift in Larsen C is likely to lead to one of the largest icebergs ever recorded,” said Swansea University in Wales, whose scientists are monitoring the creeping crack.

The rift, which is threatening to carve off a finger-shaped iceberg about 350 metres thick, expanded by 17 kilometres (11 miles) in six days, leaving just a 13-kilometre thread attaching it to the main ice sheet.

“There appears to be very little to prevent the iceberg from breaking away completely.”

Larsen C is the most northerly of the Antarctic ice shelves, as well as the largest. The calving of the iceberg would see it lose about a tenth of its total area, shrinking it to its smallest size on record.

On its own, the huge ice cube would not add to sea level rise.

But its detachment may render the remainder of the Larsen C shelf unstable and vulnerable to collapse, which would release vast amounts of water, scientists say.

The West Antarctic ice sheet holds enough frozen water to raise the average sea level by about six metres (20 feet).

Two smaller shelves on the eastern side of the Antarctic peninsula have already collapsed.

The first, Larsen A, was lost in 1995. Seven years later, the Larsen B shelf followed — at 3,250 square kilometres, it was the size of Rhode Island.

The Larsen B event had no precedent since the end of the last Ice Age some 12,000 years ago, according to glaciologists.