Massive Glacier in East Antarctica Shows Signs of Vulnerability

The Cryosphere, February 11

The massive Denman Glacier in East Antarctica, a 19 km-wide stream of ice that flows over the deepest undersea canyon of the continent, holds 1.5m of sea-level rise and is beginning to show signs of instability; potentially in response to the warming ocean at its base. During the past 50 years, the floating (marine-based) end of the glacier has accelerated its flow by 36%; and the ground-based portion of the glacier behind has sped up by 17%.  Perhaps most significantly, the point where the Denman becomes marine-based has retreated an incredible 5 km in only 21 years, with water invading under this previously land-based portion.  Like most of the vulnerable West Antarctic Ice Sheet, Denman Glacier rests on downward-sloping bedrock that deepens into a bowl 50 km further inland, meaning that invading seawater will flow downhill and more quickly eat away at the glacier’s base.  Authors suggest that Denman’s rapid changes and growing instability could be the result of such warmer ocean water flowing along the base of the glacier, together with recent calving events that changed its geometry. East Antarctica has been thought to be less vulnerable to human-caused climate change; these recent observations indicate the potential for rapid destabilization also of some portions of the East Antarctic ice sheet.

https://tc.copernicus.org/articles/15/663/2021/

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