ALBERT

Description: Pliocene Ice Sheet Modelling Intercomparison Project (PLISMIP) – experimental design Geoscientific Model Development Discussions, 4, 2661-2686, 2011 Author(s): A. M. Dolan, S. J. Koenig, D. J. Hill, A. M. Haywood, and R. M. DeConto During the mid-Pliocene Warm Period (3.264 to 3.025 million yr ago), global mean temperature was similar to that predicted for the next century and atmospheric carbon dioxide concentrations were slightly higher. Sea level was also higher than today, implying a reduction in the extent of the ice sheets. Thus, the mid-Pliocene Warm Period provides a unique testing ground to investigate the stability of the Earth's ice sheets and their contribution to sea level in a warmer-than-modern world. Climate models and ice sheet models can be used to enhance our understanding of ice sheet stability, however, uncertainties associated with different ice-sheet modelling frameworks/approaches mean that a rigorous comparison of numerical ice sheet model simulations for the Pliocene is essential. As an extension to the Pliocene Model Intercomparison Project (PlioMIP; Haywood et al., 2010, 2011a), the Pliocene Ice Sheet Modelling Intercomparison Project (PLISMIP) will address these uncertainties. Here we outline the PLISMIP experimental design and initialisation conditions that have been adopted to simulate the Greenland and Antarctic ice sheets under present day and warm mid-Pliocene conditions. Not only will this project provide a new benchmark in the simulation of ice sheets in a past warm period, but the analysis of model sensitivity to various uncertainties could directly inform future predictions of ice sheet and sea level change.