Antarctica: Shelf C Quick Collapse

Larsen C calves trillion ton iceberg

A one trillion tonne iceberg – one of the biggest ever recorded – has calved away from the Larsen C Ice Shelf in Antarctica. The calving occurred sometime between Monday 10th July and Wednesday 12th July 2017, when a 5,800 square km section of Larsen C finally broke away. The iceberg, which is likely to be named A68, weighs more than a trillion tonnes.  Its volume is twice that of Lake Erie, one of the Great Lakes.

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A crack in the Larsen C ice shelf, which grew 17 kilometres in December

A crack in the Larsen C ice shelf, which grew 17 kilometres in December | Geology |

The impending separation of what’s expected to be one of the largest icebergs ever recorded just got a dramatic step closer, after an epic 180-km-long (111.8-mile) rift in Antarctica suddenly split in two.

Scientists have been watching this massive crack in the Larsen C ice shelf develop slowly for decades, but a series of rapid developments in the past year has now seen the rift divide into two separate paths, with a new secondary branch advancing 15 km (9.3 miles) in a matter of days.

“While the previous rift tip has not advanced, a new branch of the rift has been initiated,” says glaciologist Adrian Luckman from Swansea University in the UK.

“This is approximately 10 km (6.2 miles) behind the previous tip, heading towards the ice-front.”

With this new branch of the rift making a beeline for the Weddell Sea, there’s only 20 km (12.4 miles) of ice keeping a 5,000 sq km (1,930.5 sq mile) chunk of the shelf from floating adrift.

If – or, more likely, when – that happens, it would amount to the third largest loss of Antarctic ice in recorded history.

For context, depending on your local geography, that’s an iceberg about the size of Delaware – or roughly one-quarter the size of Wales.