Past and future polar amplification of climate change: climate model

34 Abstract 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 new PMIP2 coupled atmosphere–ocean climate models systematically simulate a significant MH warming both in Greenland (but smaller than ice-core based estimates) and Antarctica (consistent with the range of ice-core based range). In both PMIP1 and PMIP2, 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