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Volume 14, issue 4 | Copyright
Clim. Past, 14, 455-472, 2018
https://doi.org/10.5194/cp-14-455-2018
© Author(s) 2018. This work is distributed under
the Creative Commons Attribution 4.0 License.

Research article 09 Apr 2018

Research article | 09 Apr 2018

The sensitivity of the Greenland Ice Sheet to glacial–interglacial oceanic forcing

Ilaria Tabone1,2, Javier Blasco1,2, Alexander Robinson1,2,a, Jorge Alvarez-Solas1,2, and Marisa Montoya1,2 Ilaria Tabone et al.
  • 1Universidad Complutense de Madrid, 28040 Madrid, Spain
  • 2Instituto de Geociencias, Consejo Superior de Investigaciones Cientificas-Universidad Complutense de Madrid, 28040 Madrid, Spain
  • anow at: Faculty of Geology and Geoenvironment, University of Athens, 15784 Athens, Greece

Abstract. Observations suggest that during the last decades the Greenland Ice Sheet (GrIS) has experienced a gradually accelerating mass loss, in part due to the observed speed-up of several of Greenland's marine-terminating glaciers. Recent studies directly attribute this to warming North Atlantic temperatures, which have triggered melting of the outlet glaciers of the GrIS, grounding-line retreat and enhanced ice discharge into the ocean, contributing to an acceleration of sea-level rise. Reconstructions suggest that the influence of the ocean has been of primary importance in the past as well. This was the case not only in interglacial periods, when warmer climates led to a rapid retreat of the GrIS to land above sea level, but also in glacial periods, when the GrIS expanded as far as the continental shelf break and was thus more directly exposed to oceanic changes. However, the GrIS response to palaeo-oceanic variations has yet to be investigated in detail from a mechanistic modelling perspective. In this work, the evolution of the GrIS over the past two glacial cycles is studied using a three-dimensional hybrid ice-sheet–shelf model. We assess the effect of the variation of oceanic temperatures on the GrIS evolution on glacial–interglacial timescales through changes in submarine melting. The results show a very high sensitivity of the GrIS to changing oceanic conditions. Oceanic forcing is found to be a primary driver of GrIS expansion in glacial times and of retreat in interglacial periods. If switched off, palaeo-atmospheric variations alone are not able to yield a reliable glacial configuration of the GrIS. This work therefore suggests that considering the ocean as an active forcing should become standard practice in palaeo-ice-sheet modelling.

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The response of the Greenland Ice Sheet (GrIS) to palaeo-oceanic changes on a glacial–interglacial timescale is studied from a modelling perspective. A 3-D hybrid ice-sheet–shelf model which includes a parameterization of the basal melting rate at the GrIS marine margins is used. The results show that the oceanic forcing plays a key role in the GrIS evolution, not only by controlling the ice retreat during the deglaciation but also by driving the ice expansion in glacial periods.
The response of the Greenland Ice Sheet (GrIS) to palaeo-oceanic changes on a...
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