Decadal slowdown of a land-terminating sector of the Greenland Ice Sheet despite warming

Andrew J. Tedstone*, Peter W. Nienow, Noel Gourmelen, Amaury Dehecq, Daniel Goldberg, Edward Hanna

*Corresponding author for this work

Research output: Contribution to journalArticle (Academic Journal)peer-review

88 Citations (Scopus)

Abstract

Ice flow along land-terminating margins of the Greenland Ice Sheet (GIS) varies considerably in response to fluctuating inputs of surface meltwater to the bed of the ice sheet. Such inputs lubricate the ice-bed interface, transiently speeding up the flow of ice. Greater melting results in faster ice motion during summer, but slower motion over the subsequent winter, owing to the evolution of an efficient drainage system that enables water to drain from regions of the ice-sheet bed that have a high basal water pressure. However, the impact of hydrodynamic coupling on ice motion over decadal timescales remains poorly constrained. Here we show that annual ice motion across an 8,000-km2 land-terminating region of the west GIS margin, extending to 1,100 m above sea level, was 12% slower in 2007-14 compared with 1985-94, despite a 50% increase in surface meltwater production. Our findings suggest that, over these three decades, hydrodynamic coupling in this section of the ablation zone resulted in a net slowdown of ice motion (not a speed-up, as previously postulated). Increases in meltwater production from projected climate warming may therefore further reduce the motion of land-terminating margins of the GIS. Our findings suggest that these sectors of the ice sheet are more resilient to the dynamic impacts of enhanced meltwater production than previously thought.

Original languageEnglish
Pages (from-to)692-695
Number of pages4
JournalNature
Volume526
Issue number7575
DOIs
Publication statusPublished - 28 Oct 2015

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