Monster iceberg breaks off Antarctica

A trillion-tonne iceberg, one of the largest ever recorded, has snapped off the West Antarctic ice shelf, scientists who have monitored the growing crack for years said on Wednesday.

“The calving occurred sometime between Monday, July 10 and Wednesday, July 12, when a 5,800-square kilometre (2,200-square mile) section of Larsen C (ice shelf) finally broke away,” the Swansea University said in a statement.

The massive ice cube, larger than the US state of Delaware, has a volume twice that of Lake Erie, one of the Great Lakes. It is about 350 metres (1,100 feet) thick.

“The iceberg weighs more than a trillion tonnes, but it was already floating before it calved away so has no immediate impact on sea level,” the team said. It will likely be named A68.

With the calving, the Larsen C ice shelf lost more than 12 per cent of its total surface area.

Icebergs calving from Antarctica are a regular occurrence. But given its enormous size, the latest berg will be closely watched as it travels, for any potential risk to shipping traffic.

The calving may have heightened the risk of the remaining ice shelf disintegrating, the Swansea team said. Ice shelves float on the sea, extending from the coast, and are fed by slow-flowing glaciers from the land.

They act as giant brakes, preventing glaciers from flowing directly into the ocean.

If the glaciers held in check by Larsen C spilt into the Antarctic Ocean, it would lift the global water mark by about 10 centimetres (four inches), researchers have said.

The calving of ice shelves occurs naturally, though global warming is believed to have accelerated the process.