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Ice shelves buckle under weight of meltwater lakes

For the first time, a research team co-led by National Science Foundation-funded scientists, has directly observed an Antarctic ice shelf bending under the weight of ponding meltwater on top, a phenomenon that may have triggered the 2002 collapse of the Larsen B ice shelf. And ice shelf flexure could potentially impact other vulnerable ice shelves, causing them to break up, quickening the discharge of ice into the ocean and contributing to global sea level rise. The team was inspired to look closer at the causes of ice shelf weakening after analyzing the catastrophic break up of the Larsen B ice shelf. That breakup made headlines in 2002 as 1,250 square miles of ice broke away into the ocean; the scientists noticed that in the months leading up to the breakup, the ice shelf was dotted with over 2000 meltwater lakes. Meltwater lakes can contain water weighing 50 thousand to 2 million tons each, and that pushes downward on the ice, creating an indent. If the lake drains, this indent pops back up. If the resultant stress is large enough, the ice surrounding the lake basin weakens, and may start to break, the researchers predict.

Visit Website | Image credit: Alison Banwell/University of Colorado, Boulder