The British Antarctic Survey (BAS) has released new footage of the ice crack that expects to produce a giant berg. The 175km-long crack runs through the Larsen C Ice Shelf on the eastern side of the Antarctic Peninsula. A block of ice a quarter the size of Wales will break away into the Weddell Sea if it propagates just 20 km more.
While recovering instrumentation, scientists gathered the new video that had been placed on the ice shelf. Uncertainty about the stability of the region means researchers cannot set up camp as they would normally do, and instead make short visits in a Twin Otter plane. The most recent armed attack enabled the researchers also to fly along the length of the crack, which is 400-500m wide in places, to assess its status.
No one can exactly say when the iceberg will calve, but it could take place anytime. It would be one of the biggest ever recorded if it runs till 5,000 sq. km. Interest will center on how the breakage will affect the remaining shelf structure when it splits. The Larsen B Ice Shelf further to the north famously shattered following a similar large calving event in 2002. The issue is important because floating ice shelves normally act as a buttress to the glaciers flowing off the land behind them.
The glaciers subsequently boost up in the absence of the shelf in case of Larsen B. And it is the land ice not the floating ice in a shelf that adds to sea level rise. If Larsen C were to go the same way it would continue a trend across the Antarctic Peninsula. In recent decades, a dozen major ice shelves have come apart, significantly retreated or lost substantial volume which includes Prince Gustav Channel, Larsen Inlet, Wilkins, Jones Channel, Larsen A, Larsen B, Wordie and Muller.
The removal of the ice would also enable scientists to study the uncovered seabed. The immediate investigation chanced upon new species when Larsen B broke away. Under the Antarctic Treaty, no fishing activity would be permitted in the area for 10 years. The big bergs that break away from Antarctica are monitored from space. They will often drift out into the Southern Ocean where they can become a hazard to shipping.
Object B-15 was the biggest iceberg recorded in the satellite era. Covering an area of some 11,000 sq. km., it came away from the Ross Ice Shelf in 2000. After six years fragments of the super-berg passed by New Zealand. In 1956, a berg of roughly 32,000 sq. km. bigger than Belgium was dotted in the Ross Sea by a US Navy icebreaker. But there were no satellites at that time to follow up.