Update 23/2/17: New aerial footage taken over Antarctica reveals the staggering size of the crack that's threatening to destroy the Larsen C ice shelf. Researchers from the British Antarctic Survey recorded the footage as they collected equipment for the Midas project. It follows on from a previous video which revealed the crack had grown 17 miles in just two months at the start of 2017.
This acceleration in the break forced British Antarctic Survey scientists at the Halley research station to relocate the base over fears the shelf would break and leave Halley at risk. Tractors were used to tow the base's eight modules at the start of February to move it 15 miles "inland". Now, it looks like that was the best move.
The 100-mile long, two-mile wide crack only has to travel a further 20 miles for the break to occur, creating a mammoth iceberg. “The iceberg is likely to break free within the next few months,” Adrian Luckman of Swansea University in Wales, part of Project Midas which has been tracking the break,told the New York Times. “The rift tip has moved from one region of likely softer ice to another, which explains its step-wise progress.”
Original story:
The giant crack that looks set to cast a record-breaking iceberg off out into the Antarctic is continuing to spread at an alarming rate.
Since January 1, the rift in the Larsen C ice shelf has grown more than 10km meaning a mere 20km is all that is connecting a block of ice comparable to a quarter of the size of Wales to its parent shelf. If, or more likely when, the iceberg splits, it will create one of the largest icebergs ever recorded measuring 5,000 sq km, according to researchers at Swansea and Aberystwyth universities, and the British Antarctic Survey.
A team of researchers from the universities has been closely watching and investigating the 350 metre-thick Larsen C ice shelf in West Antarctica as part of Project MIDAS, using imagery from the European Space Agency’s Sentinel-1 radar satellite, data gathered on-site and computer simulations. The team issued a statement to its website at the start of January, warning of the impending break: “After a few months of steady, incremental advance since the last event, the rift grew suddenly by a further 18km during the second half of December 2016. Only a final 20km of ice now connects an iceberg one quarter the size of Wales to its parent ice shelf.”
Footage captured by Nasa’s IceBridge mission in December showed a 70-mile-long, 300-foot-wide rift in Larsen C that cut to the base of the ice shelf. When the glacier inevitably breaks away from Larsen C as is expected, the shelf will lose an estimated 10 per cent of its mass. “This event will fundamentally change the landscape of the Antarctic Peninsula,” write the Project MIDAS researchers. “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.”
The prediction it is presenting here has massive implications. Larsen B is a smaller ice shelf, and had existed for 10,000 years when it began to disintegrate (Larsen A had already collapsed in the 1-1990s). In 2015, when it looked as though the remaining 1,600 sq km of Larsen B was finally doomed, Ala Khazendar of Nasa's Jet Propulsion Laboratory said: "Although it’s fascinating scientifically to have a front-row seat to watch the ice shelf becoming unstable and breaking up, it’s bad news for our planet. This ice shelf has existed for at least 10,000 years, and soon it will be gone." As Larsen B disintegrated, it left landlocked ice behind it vulnerable to melting.
In 2015, Paul Holland of the British Antarctic Survey told the Washington Post: “If Larsen C were to collapse at some point in the next 100 years, you’d expect within the few decades after that collapse, a much faster rate of sea level rise than if it hadn’t collapsed.” Estimates suggest that if Larsen C, which is almost the size of Scotland, were to completely disintegrate and no longer protect ground ice beyond from melting, sea levels could rise by 10cm. It is the ground ice melting, rather than glaciers, that dramatically impacts sea levels.
Project MIDAS told the BBC the event is not directly linked to climate change, but is an inevitable part of Antarctica’s geography - although the team suspects global warming has sped up the rift.
Professor Adrian Luckman of Swansea University said: "If it doesn't go in the next few months, I'll be amazed...We are convinced, although others are not, that the remaining ice shelf will be less stable than the present one.
“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."
This article was originally published by WIRED UK
