Antarctica’s Larsen C ice shelf and A68 iceberg Deimos Imaging
A massive chunk of ice that broke off from the Larsen ice shelf in Antarctica in July has begun to drift out to sea. New satellite images show the huge piece of ice is moving further out to sea after it finally broke away from mainland Antarctica. The iceberg is around four times the size of Greater London.
Scientists have been tracking the ice since cracks formed in the ice shelf in 2014. Professor Stef Lhermitte, of Delft University in the Netherlands, shared the latest satellite images of A68 on Twitter. He said: "After some initial back-and-forth movement, Larsen C's iceberg A68 seems on drift now."
#LarsenC 's iceberg #A68 continues to drift in the today's 16/9 vs. 13/9 @ESA_EO#sentinel1 composites pic.twitter.com/e8ncIv59v9— Stef Lhermitte (@StefLhermitte) September 16, 2017
The slow drifting of #LarsenC 's #A68 iceberg from @NASAEarth 's #MODIS and #VIIRS. Check the polynya (open sea) when the drift starts. pic.twitter.com/DBtNH9o3Ys
— Stef Lhermitte (@StefLhermitte) September 15, 2017
Scientists worried the ice shelf would break into smaller chunks of ice that would be difficult to track via satellite. If these chunks drifted into shipping lanes they could prove to be potentially devastating for efficient cargo shipping. It seems that the iceberg is currently drifting as a whole section. Lhermitte shared a graphic that compared A68's position on Saturday to another image taken on Wednesday that highlighted the movement of the mass away from the Antarctic shelf.
While the exact reason for the ice shelf to break away is unknown scientists say it is ‘normal’ for these breaks to occur. Ice breaks like this are known as ‘calving’. Dr. Natalie Robinson, a marine physicist at New Zealand’s National Institute of Water and Atmospheric Research, told media this event was different from other ice collapses in the area that could be due to warming oceans. This was contradicted by Professor Nancy Bertler of the Antarctic Research Centre at Victoria University of Wellington, who said that said that the hole in the ozone layer and global warming had been contributing factors for the sudden break-up of 'numerous ice shelves' in the region 'some of which have been shown to have existed for 10,000 years or more'.
The drifting chunk of ice has been named iceberg A-68. It roughly measures 5,800 square kilometers (2,240 square miles). The drifting ice block could remain intact floating on the seas for years before it breaks apart. New satellite imagery shows the ice in great detail. Previously scientists had struggled to get clear pictures of A-68 as bad weather through the winter months hindered the satellites' ability to capture photography. 'These images are striking - easily the best I have seen since calving," Adrian Luckman, a glaciologist at Swansea University and a member of the Antarctic research program Project Midas, told online media.
The movement of the ice opens up exciting new opportunities for scientific research. Previous big calving events have led to the discovery of new species. Scientists are keen to discover just what effect the loss of A-68 will have on the rest of the Larsen shelf. While they aren't exactly sure where A-68 will drift to, scientists have some idea based on previous research and the movement of currents. Thomas Rackow and colleagues from the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, are continuing their long-term research on the ice, they say, "It will most likely follow a northeasterly course, heading roughly for South Georgia and the South Sandwich Islands," Dr Rackow told BBC News. "It will be very interesting to see whether the iceberg will move as expected, as a kind of 'reality-check' for the current models and our physical understanding."