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Destabilisation of an Arctic Ice Cap Triggered by a Hydro-thermodynamic Feedback to Summer-melt : Volume 8, Issue 3 (23/05/2014)

By Dunse, T.

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Book Id: WPLBN0004023027
Format Type: PDF Article :
File Size: Pages 35
Reproduction Date: 2015

Title: Destabilisation of an Arctic Ice Cap Triggered by a Hydro-thermodynamic Feedback to Summer-melt : Volume 8, Issue 3 (23/05/2014)  
Author: Dunse, T.
Volume: Vol. 8, Issue 3
Language: English
Subject: Science, Cryosphere, Discussions
Collections: Periodicals: Journal and Magazine Collection, Copernicus GmbH
Publication Date:
Publisher: Copernicus Gmbh, Göttingen, Germany
Member Page: Copernicus Publications


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Dunse, T., Hagen, J. O., Schuler, T. V., Reijmer, C. H., Schellenberger, T., & Kääb, A. (2014). Destabilisation of an Arctic Ice Cap Triggered by a Hydro-thermodynamic Feedback to Summer-melt : Volume 8, Issue 3 (23/05/2014). Retrieved from

Description: Department of Geosciences, University of Oslo, P.O. Box 1047, Blindern, 0316 Oslo, Norway. Mass loss from glaciers and ice sheets currently accounts for two-thirds of the observed global sea-level rise and has accelerated since the 1990s, coincident with strong atmospheric warming in the Polar Regions. Here we present continuous GPS measurements and satellite synthetic aperture radar based velocity maps from the Austfonna ice cap, Svalbard, that demonstrate strong links between surface-melt and multiannual ice-flow acceleration. We identify a hydro-thermodynamic feedback that successively mobilizes stagnant ice regions, initially frozen to their bed, thereby facilitating fast basal motion over an expanding area. By autumn 2012, successive destabilization of the marine terminus escalated in a surge of the ice cap's largest drainage basin, Basin-3. The resulting iceberg discharge of 4.2 ± 1.6 Gt a−1 over the period April 2012 to May 2013 triples the calving loss from the entire ice cap. After accounting for the terminus advance, the related sea-level rise contribution of 7.2 ± 2.6 Gt a−1 matches the recent annual ice-mass loss from the entire Svalbard archipelago. Our study highlights the importance of dynamic glacier wastage and illuminates mechanisms that may trigger a sustained increase in dynamic glacier wastage or the disintegration of ice-sheets in response to climate warming, which is acknowledged but not quantified in global projections of sea-level rise.

Destabilisation of an Arctic ice cap triggered by a hydro-thermodynamic feedback to summer-melt

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