The oceanic sensitivity of the Greenland Ice Sheet

Resumen

The large-scale ocean circulation and the ocean temperature are known to affect the present-day ice configuration. The recent observed acceleration of Greenland’s marine-terminating glaciers and its associated thinning are thought to directly be linked to increasing ocean temperatures. High water temperatures are responsible for ice-shelf melting and inhibit grounding-line advance, contributing to ice mass variations and potential sea level changes through enhanced ice discharge. Despite the relevant role of the oceanic influence on the Greenland Ice Sheet (GrIS), little has been investigated in this direction. In this work the ice-ocean interaction is studied using a three-dimensional hybrid ice-sheet model. The model features the capability to simulate ice sheets, ice shelves and ice streams as it applies both Shallow Ice Approximation (SIA) and Shallow Shelf Approximation (SSA). Here we investigate the effect of the variation of oceanic temperatures on the GrIS expansion and retreat throughout the two last glacial cycles through changes in basal melting. This work shows a very high-sensitivity of the GrIS to oceanic changes. Small variations in the oceanic patterns can trigger significant changes in the GrIS configuration. The results thus confirm that the ice-ocean interaction is a crucial factor driving Greenland’s marine-terminating ice adjustments.