1Department of Geosciences, University of Massachusetts, 611 N. Pleasant St, Amherst, MA 01003, USA
2School of Earth and Environment, Earth and Environment Building, University of Leeds, Leeds, LS2 9JT, UK
3Department of Earth Sciences, Faculty of Geosciences, Utrecht University, Budapestlaan 4, 3584 CD Utrecht, the Netherlands
4Institute for Marine and Atmospheric Research, Utrecht (IMAU), Utrecht University, P.O. Box 80005, 3508 TA Utrecht, the Netherlands
5School of Geographical Sciences, University of Bristol, University Road, Bristol, BS8 1SS, UK
6British Geological Survey, Keyworth, Nottingham, UK
7Atmosphere and Ocean Research Institute, The University of Tokyo, Kashiwa 277-8568, Japan
8Japan Agency for Marine-Earth Science and Technology, Yokohoma 236-001, Japan
9Earth and Environmental Systems Institute, Pennsylvania State University, University Park, PA 16802, USA
10UJF – Grenoble 1/CNRS, Laboratoire de Glaciologie et Géophysique de l'Environnement (LGGE) UMR5183, Grenoble, 38041, France
*now at: Department of Geography, University of Cambridge, Cambridge, CB2 3EN, UK
Received: 08 May 2014 – Discussion started: 09 Jul 2014
Abstract. The understanding of the nature and behavior of ice sheets in past warm periods is important for constraining the potential impacts of future climate change. The Pliocene warm period (between 3.264 and 3.025 Ma) saw global temperatures similar to those projected for future climates; nevertheless, Pliocene ice locations and extents are still poorly constrained. We present results from the efforts to simulate mid-Pliocene Greenland Ice Sheets by means of the international Pliocene Ice Sheet Modeling Intercomparison Project (PLISMIP). We compare the performance of existing numerical ice sheet models in simulating modern control and mid-Pliocene ice sheets with a suite of sensitivity experiments guided by available proxy records. We quantify equilibrated ice sheet volume on Greenland, identifying a potential range in sea level contributions from warm Pliocene scenarios. A series of statistical measures are performed to quantify the confidence of simulations with focus on inter-model and inter-scenario differences. We find that Pliocene Greenland Ice Sheets are less sensitive to differences in ice sheet model configurations and internal physical quantities than to changes in imposed climate forcing. We conclude that Pliocene ice was most likely to be limited to the highest elevations in eastern and southern Greenland as simulated with the highest confidence and by synthesizing available regional proxies; however, the extent of those ice caps needs to be further constrained by using a range of general circulation model (GCM) climate forcings.
Revised: 30 Oct 2014 – Accepted: 18 Nov 2014 – Published: 05 Mar 2015
Koenig, S. J., Dolan, A. M., de Boer, B., Stone, E. J., Hill, D. J., DeConto, R. M., Abe-Ouchi, A., Lunt, D. J., Pollard, D., Quiquet, A., Saito, F., Savage, J., and van de Wal, R.: Ice sheet model dependency of the simulated Greenland Ice Sheet in the mid-Pliocene, Clim. Past, 11, 369-381, doi:10.5194/cp-11-369-2015, 2015.