Moderate Greenland ice sheet melt during the last interglacial constrained by present-day observations and paleo ice core reconstructions
P.M. Langebroek1 and K.H. Nisancioglu2,31Uni Research Climate, Bjerknes Centre for Climate Research, Allégaten 55, 5007 Bergen, Norway 2Department of Earth Science, University of Bergen and Bjerknes Centre for Climate Research, Allégaten 70, 5007 Bergen, Norway 3Centre for Earth Evolution and Dynamics, Postbox 1028 Blindern, University of Oslo, 0315 Oslo, Norway
Received: 20 Jan 2016 – Accepted for review: 27 Jan 2016 – Discussion started: 28 Jan 2016
Abstract. During the last interglacial period (LIG, ~ 130–115 ka before present, ka = 1000 yr) summer temperatures over Greenland were several degrees higher than today. It is likely that the Greenland ice sheet (GIS) was smaller than today, contributing to the reconstructed sea-level highstand of the LIG. However, the range of simulated GIS melt is large, and the location of the melt is uncertain. Here, we use temperature and precipitation patterns simulated by the Norwegian Earth System Model (NorESM) to investigate the volume, extent and stability of the GIS during the LIG. Present-day observations of ice sheet size, elevation and stability, together with paleo elevation information from five deep ice cores, are used to evaluate our ensemble of GIS simulations. Accepted simulations indicate a maximum GIS reduction equivalent to a global mean sea-level rise of 0.8–2.2 m compared to today, with most of the melt occurring in the southwest. The timing of the maximum ice melt over Greenland is simulated between 124 and 122 ka.
We furthermore suggest a preferred mean value for the basal sliding parameter, relatively high PDD factors and an average to high atmospheric temperature lapse rate based on training the SICOPOLIS ice sheet model to observations and available LIG proxy data.
Langebroek, P. M. and Nisancioglu, K. H.: Moderate Greenland ice sheet melt during the last interglacial constrained by present-day observations and paleo ice core reconstructions, The Cryosphere Discuss., doi:10.5194/tc-2016-15, in review, 2016.