An Antarctic suspense story has come to an end with one of the largest icebergs ever observed breaking off the Larsen C Ice Shelf. The slow-motion breakup was closely monitored by scientists, who say that the 6,000 km² (2,300 mi²) ice floe now adrift in the sea is 190 m (625 ft) thick, weighs more than a trillion tonnes, and represents 10 percent of the shelf.

If one thing characterizes the Earth's ice caps, it's that they are dynamic. Far from acting like the inmates of an ice cube tray, the ice that makes them up is forever growing, shrinking, flowing, and cracking. According to the British Antarctic Survey (BAS), the splitting off of the Larsen C berg, which is likely to be named A68, is part of a normal process and might not be a direct result of climate change in the region.

The breakup of the Larsen C Ice Shelf has been anticipated for some time, and the spread of the 170-km (105-mi) crack that now fully separates the berg from the shelf has been monitored by Antarctic scientists led by the University of Swansea and ESA's Copernicus Sentinel-1 satellites. The ice flow is still abutting the shelf in the Antarctic winter ice, but it will eventually drift out into the Antarctic Ocean, where it will need to be monitored as a hazard to navigation.

BAS says that the calving is an opportunity to study how stable the remaining shelf is, and how life in the vicinity will react to the newly opened seabed.

"This story has just got even more interesting," says BAS remote sensing analyst Andrew Fleming. "Our glaciologists will now be watching closely to see whether the remaining Larsen C Ice Shelf becomes less stable than before the iceberg broke free, and our biologists will be keen to understand how new habitats formed by the loss of the ice are colonized."

In the video below, Prof. David Vaughan of BAS discusses the calving event and its implications.

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