A massive crack has split the Pine Island glacier (PIG) in Antarctica, creating an iceberg the size of New York City.
Such breaks in the ice shelf, where the glacier extends off the land and floats above the water, happen fairly regularly – PIG also birthed icebergs in 2001 and 2007. But this crack took longer than usual to spread, allowing the ice shelf to grow for longer and resulting in a whopper of an iceberg.
The crack was first spotted by NASA in 2011. On Monday, the German Earth-observation satellite, TerraSAR-X, penetrated the Antarctic darkness with radar and confirmed that the break had spread across the whole 30-kilometre width of the ice shelf, calving a new iceberg into the Southern Ocean.
All eyes are on PIG because it is the longest and fastest-flowing glacier in Antarctica and it's at risk of collapse.
PIG drains about 10 per cent of the West Antarctic ice sheet. The ice flows from the sheet, along the glacier and melts, making PIG a significant contributor to rising sea levels. The thinning of the ice shelf makes PIG move, and melt, even faster and makes it more fragile.
"The crack and break itself isn't particularly unusual," says Adrian Jenkins of the British Antarctic Survey in Cambridge, UK. "What is more important is the continual thinning of the ice shelf, which has been, on average, a continuous process since Antarctic record keeping began."
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