A giant iceberg is expected to break away from the Larsen C ice shelf, predict researchers from Swansea University. It would be the 10 largest break offs ever recorded.
The Larsen C ice shelf is approximately 350 metres thick. Floating on the seas at the edge of West Antarctica, it holds back the flow of glaciers that feed into it.
Researchers have been tracking a rift in Larsen C for many years after the collapse of the Larsen A ice shelf in 1995 and the sudden break-up of the Larsen B shelf in 2002.
That long-running rift grew suddenly in December, growing by a further 18 kilometres in just a couple of week. Now just 20 kilometres of ice is all that is keeping the 5,000 square kilometre piece of ice shelf from floating away, predict researchers from Swansea University. Should that occur, it would leave the entire shelf vulnerable to future break-up.
For project leader Professor Adrian Luckman, this is a matter of when, not if.
“If it doesn’t go in the next few months, I’ll be amazed,” he said in a statement, adding “It’s so close to calving that I think it’s inevitable.”
Luckman believes that this is a geographical event, not a climate one, but adds that climate warming likely played a role in bringing forward the anticipated separation of the iceberg.
The researchers are especially concerned by how any break-off will impact the rest of the ice shelf, given that its neighbour, Larsen B, disintegrated spectacularly in 2002 following a similar large calving event.
“We would expect in the ensuing months to years further calving events, and maybe an eventual collapse – but it’s a very hard thing to predict, and our models say it will be less stable; not that it will immediately collapse or anything like that, said Luckman.”
The resulting iceberg from the shelf will not raise sea levels, but if the shelf breaks up even more, it could result in glaciers that flow off the land behind it to speed up their passage towards the ocean, which would in turn impact sea levels.
According to estimates, if all the ice that the Larsen C shelf currently holds back entered the sea, global waters would rise by 10 centimetres.
Image credit: Swansea University