Past and future polar amplification of climate change: climate model intercomparisons and ice-core constraints

Climate model simulations available from the PMIP1, PMIP2 and CMIP (IPCC-AR4) intercomparison projects for past and future climate change simulations are examined in terms of polar temperature changes in comparison to global temperature changes and with respect to pre-industrial reference simulations. For the mid-Holocene (MH, 6,000 years ago), the models are forced by changes in the Earth’s orbital parameters. The MH PMIP1 atmosphere-only simulations conducted with sea surface temperatures fixed to modern conditions show no MH consistent response for the poles, whereas the new PMIP2 coupled atmosphere– ocean climate models systematically simulate a significant MH warming both for Greenland (but smaller than ice-core based estimates) and Antarctica (consistent with the range of ice-core based range). In both PMIP1 and V. Masson-Delmotte (&) Æ M. Kageyama Æ P. Braconnot S. Charbit Æ E. Guilyardi Æ J. Jouzel Æ O. Marti Laboratoire des Sciences du Climat et de l’Environnement, (LSCE/IPSL, UMR CEA-CNRS 1572) L’Orme des Merisiers, Bâtiment 701, CEA Saclay, 91 191 Gif-sur-Yvette Cedex, France E-mail: [email protected] G. Krinner Æ C. Ritz Laboratoire de Glaciologie et de Géophysique de l’Environnement, (UMR 5183 CNRS-UJF), Domaine Universitaire, St Martin d’Hères, France A. Abe-Ouchi Center for Climate System Research, The University of Tokyo, Kashiwa, 277-8568 Japan M. Crucifix Æ C. D. Hewitt Hadley Centre for Climate Prediction and Research, Met Office, FitzRoy Road, Exeter, EX1 3 PB Devon, UK R. M. Gladstone Æ I. Ross Æ P. J. Valdes School of Geographical Sciences, University of Bristol, University Road, Bristol, BS8 1SS UK A. Kitoh Æ T. Motoi Climate Research Department, Meteorological Research Institute, 1-1 Nagamine, Tsukuba, Ibaraki, 305-0052 Japan A. N. LeGrande NASA Goddard Institute for Space Studies and Center for Climate Systems Research, Columbia University, New York, NY, USA U. Merkel IFM-GEOMAR, Duesternbrooker Weg 20, 24105 Kiel, Germany R. Ohgaito Æ A. Abe-Ouchi Frontier Research Center for Global Change (FRCGC), JAMSTEC, Yokohama City, 236-0001 Japan B. Otto-Bilesner Climate Change Research, National Center for Atmospheric Research, 1850 Table Mesa Drive, P.O. Box 3000, Boulder, CO, 80307 USA W. R. Peltier Æ G. Vettoretti Department of Physics, University of Toronto, 60 St. George Street, Toronto, ON, M5S 1A7 Canada S. L. Weber Climate Variability Research, Royal Netherlands Meteorological Institute (KNMI), P.O. Box 201, 3730 AE De Bilt, The Netherlands F. Wolk Institut d’Astronomie et de Géophysique G. Lemaı̂tre, Université catholique de Louvain, Chemin du cyclotron, 2, 1348 Louvain-la-Neuve, Belgium Y. Yu LASG, Institute of Atmospheric Physics, Chinese Academy of Sciences, P.O. Box 9804, Beijing, 10029 People’s Republic of China Climate Dynamics (2006) 26: 513–529 DOI 10.1007/s00382-005-0081-9 PMIP2, the MH annual mean changes in global temperature are negligible, consistent with the MH orbital forcing. The simulated last glacial maximum (LGM, 21,000 years ago) to pre-industrial change in global mean temperature ranges between 3 and 7 C in PMIP1 and PMIP2 model runs, similar to the range of temperature change expected from a quadrupling of atmospheric CO2 concentrations in the CMIP simulations. Both LGM and future climate simulations are associated with a polar amplification of climate change. The range of glacial polar amplification in Greenland is strongly dependent on the ice sheet elevation changes prescribed to the climate models. All PMIP2 simulations systematically underestimate the reconstructed glacial– interglacial Greenland temperature change, while some of the simulations do capture the reconstructed glacial– interglacial Antarctic temperature change. Uncertainties in the prescribed central ice cap elevation cannot account for the temperature change underestimation by climate models. The variety of climate model sensitivities enables the exploration of the relative changes in polar temperature with respect to changes in global temperatures. Simulated changes of polar temperatures are strongly related to changes in simulated global temperatures for both future and LGM climates, confirming that ice-core-based reconstructions provide quantitative insights on global climate changes.