A crack in the Larsen C ice shelf, a massive formation on the northermost part of the Antarctic mainland, is set to create an iceberg the size of Norfolk by the end of March. Scientists have been monitoring the formation of the crack since it first started developing two years ago, but this summer the process considerably sped up and shows no signs of stopping, stoking fears that the complete break-up of the ice shelf is in sight.
Though this might sound unprecedented, Larsen C is only the last in line of ice shelves that have disappeared from the Antarctic Peninsula over the past couple of decades. All told, four have already collapsed on the east side of the peninsula, with a few more disappearing from the west side, since the dramatic event that shattered the first Larsen ice shelf (Larsen A) in 1995. In 2002, the most alarming show of global warming happened in this part of the world as Larsen B, an ice shelf that used to border Larsen C on the north, collapsed over the space of a couple of weeks, eaten away by warm currents brushing it from below and pools of water forming on its surface, which were maintained by the 24-hour sun of the Antarctic summer.
Ice shelves are formed only in the coldest regions of the world at points where glaciers or ice sheets flow into water, forming floating masses of ice that can stretch hundreds of kilometres into the sea. They usually grow until large cleaving events like the one set to happen in the near future for Larsen C, trim huge portions of them. Scientists have been cautious in linking this crack to global warming, but have warned that the overall thinning of Antarctic ice will undoubtedly lead to these events becoming more rapid in the near future. This could be catastrophic for the continent as ice shelves essentially provide plugs for many glaciers that might become unstable if they disintegrate.
Researchers who have in the past camped on Larsen C in order to carry out seismology experiments have not done so this season, due to fears that the ice could break up at any moment.
While the floating iceberg set to imminently break away from Larsen C will not affect global water levels, they could rise by 10cm if all of the ice Larsen C currently holds back were to melt.