Warm ocean water attacking edges of Antarctica's ice shelves

phys.org | 3/14/2016 | Staff
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Satellite images show polynyas (open-water regions) forming at the ends of basal channels beneath shear margins of the East Getz Ice Shelf. A new study in Science Advances illuminates how warm ocean water and ice dynamics conspire to weaken the edges of Antarctica's ice shelves, making them more vulnerable to breakup Credit: Karen Alley/The College of Wooster and NASA MODIS/MODIS Antarctic Ice Shelf Image Archive at the National Snow and Ice Data Center, CU Boulder.

Upside-down "rivers" of warm ocean water are eroding the fractured edges of thick, floating Antarctic ice shelves from below, helping to create conditions that lead to ice-shelf breakup and sea-level rise, according to a new study.

Findings - Today - Science - Advances - Process

The findings, published today in Science Advances, describe a new process important to the future of Antarctica's ice and the continent's contribution to rising seas. Models and forecasts do not yet account for the newly understood and troubling scenario, which is already underway.

"Warm water circulation is attacking the undersides of these ice shelves at their most vulnerable points," said Alley, who earned her Ph.D. at the University of Colorado Boulder, in the National Snow and Ice Data Center, part of CIRES. Alley is now a visiting assistant professor of Earth Sciences at The College of Wooster in Ohio. "These effects matter," she said. "But exactly how much, we don't yet know. We need to."

Ice - Shelves - Ocean - Edges - Ice

Ice shelves float out on the ocean at the edges of land-based ice sheets, and about three-quarters of the Antarctic continent is surrounded by these extensions of the ice sheet. The shelves can be hemmed in by canyon-like walls and bumps in the ocean floor. When restrained by these bedrock obstructions, ice shelves slow down the flow of ice from the interior of the continent toward the ocean. But if an ice shelf retreats or falls apart, ice...
(Excerpt) Read more at: phys.org
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