Impacts of warm water on Antarctic ice shelf stability through basal channel formation

Citation:
Alley, KE, Scambos TA, Siegfried MR, Fricker HA.  2016.  Impacts of warm water on Antarctic ice shelf stability through basal channel formation. Nature Geosci. advance online publication: Nature Publishing Group

Date Published:

2016/03

Keywords:

climate change cryospheric science

Abstract:

Antarctica’s ice shelves provide resistance to the flow of grounded ice towards the ocean. If this resistance is decreased as a result of ice shelf thinning or disintegration1, acceleration of grounded ice can occur, increasing rates of sea-level rise. Loss of ice shelf mass is accelerating, especially in West Antarctica, where warm seawater is reaching ocean cavities beneath ice shelves2. Here we use satellite imagery, airborne ice-penetrating radar and satellite laser altimetry spanning the period from 2002 to 2014 to map extensive basal channels in the ice shelves surrounding Antarctica. The highest density of basal channels is found in West Antarctic ice shelves. Within the channels, warm water flows northwards, eroding the ice shelf base and driving channel evolution on annual to decadal timescales. Our observations show that basal channels are associated with the development of new zones of crevassing, suggesting that these channels may cause ice fracture. We conclude that basal channels can form and grow quickly as a result of warm ocean water intrusion, and that they can structurally weaken ice shelves, potentially leading to rapid ice shelf loss in some areas.

Notes:

n/a

DOI:

10.1038/ngeo2675