London : A massive chunk of ice in Antarctica is on the brink of breaking off and is now hanging on to the parent ice shelf by a thin thread just 20 kilometres long, say scientists who found a rift that has grown by another 10 kilometres since the year began.
Latest satellite data shows that the rift is likely to lead to one of the largest icebergs ever recorded. The imagery was acquired on January 19 by European Space Agency’s Sentinel-1 satellites.
It shows a 10 kilometres (km) growth of the rift in the Larsen C ice shelf in Antarctica, since January 1, bringing its total length to 175 km.
“We can report a further extension of the rift which threatens to calve an iceberg measuring more than 5,000 square km in area from the Larsen C Ice Shelf,” said Adrian Luckman of Swansea University in the UK.
The rift has continued to grow parallel to the shelf edge, so the iceberg remains attached by 20 kilometres of ice. When it calves, the Larsen C Ice Shelf will lose more than 10 per cent of its area to leave the ice front at its most retreated position ever recorded; this event will fundamentally change the landscape of the Antarctic Peninsula.
We have previously shown that the new configuration will be less stable than it was prior to the rift, and that Larsen C may eventually follow the example of its neighbour Larsen B, which disintegrated in 2002 following a similar rift-induced calving event.
A long-running rift in the Larsen C ice shelf grew suddenly in December and now just 20km of ice is keeping the 5,000 sq km piece from floating away. Researchers said the loss of a piece a quarter of the size of Wales will leave the whole shelf vulnerable to future break-up.Larsen C is approximately 350m thick and floats on the seas at the edge of West Antarctica, holding back the flow of glaciers that feed into it.
Researchers have been tracking the rift in Larsen C for many years, following the collapse of the Larsen A ice shelf in 1995 and the sudden break-up of the Larsen B shelf in 2002.
Last year, researchers reported that the Larsen C rift was growing fast. But in December the speed of the rift went into overdrive, growing by a further 18km in just a couple of weeks. What will become a massive iceberg now hangs on to the shelf by a thread just 20km long.