Antarctic Sea Ice Area in CMIP6

Roach, Lettie A. Dörr, Jakob Holmes, Caroline R. Massonnet, François [UCL] Blockley, Edward W. Notz, Dirk Rackow, Thomas Raphael, Marilyn N. O'Farrell, Siobhan P. Bailey, David A. Bitz, Cecilia M. et al.[show all]

(eng) Fully coupled climate models have long shown a wide range of Antarctic sea ice states andevolution over the satellite era. Here, we present a high-level evaluation of Antarctic sea ice in 40 modelsfrom the most recent phase of the Coupled Model Intercomparison Project (CMIP6). Many models capturekey characteristics of the mean seasonal cycle of sea ice area (SIA), but some simulate implausiblehistorical mean states compared to satellite observations, leading to large intermodel spread. Summer SIAis consistently biased low across the ensemble. Compared to the previous model generation (CMIP5),the intermodel spread in winter and summer SIA has reduced, and the regional distribution of sea iceconcentration has improved. Over 1979–2018, many models simulate strong negative trends in SIAconcurrently with stronger-than-observed trends in global mean surface temperature (GMST). By the endof the 21st century, models project clear differences in sea ice between forcing scenarios.