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

A. J. Tedstone, Peter Nienow, Noel Gourmelen, Amaury Dehecq, Daniel Goldberg, Edward Hanna

Research output: Contribution to journalArticlepeer-review

Abstract

Ice flow along land-terminating margins of the Greenland Ice Sheet (GrIS)
varies considerably in response to fluctuating surface meltwater inputs to the icesheet bed which lubricate the ice-bed interface, resulting in periods of faster ice motion1,2. Stronger melting results in faster ice motion during summer, but slower motion over the subsequent winter due to the evolution of a more extensive drainage system at the ice-sheet bed, which drains high-pressure regions more efficiently2,3. However, the impact of hydro-dynamic coupling on ice motion over decadal timescales remains poorly constrained. Here we show that annual ice motion across a 8000 km2 land-terminating region of the west GrIS margin extending to 1100 m asl was 12% slower in 2007–2014 compared to 1985–1994, despite a corresponding 50% increase in surface meltwater production. Our findings suggest that hydrodynamic coupling in this section of the ablation zone resulted in net ice motion slowdown over decadal timescales — not speedup as previously postulated1. Increases in meltwater production from projected climate warming may therefore further reduce the motion of land-terminating margins of the GrIS, which suggests 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
JournalNature
Volume526
DOIs
Publication statusPublished - 29 Oct 2015

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