Coupled simulations of Greenland Ice Sheet and climate change up to AD 2300

Abstract

Recent observations indicate a high sensitivity of the Greenland Ice Sheet (GrIS) to climate change. We examine the coupling between the GrIS surface mass balance, elevation, and dynamical flow with one of the few coupled GrIS and atmosphere-ocean general circulation models. Bidirectional coupling from the early Holocene reveals a growing present-day GrIS in the absence of anthropogenic forcing. We identify atmospheric sources of biases in the simulated present-day GrIS and assess the GrIS sensitivity to future greenhouse gas forcing through three Representative Concentration Pathways and their extensions and to climate variability. The elevation-surface mass balance feedback contributes to future GrIS mass loss with 8-11% (by 2100), depending on the forcing scenario, and 24-31% (by 2300). Climate variability causes a 2.5 times spread in the magnitude of the simulated present-day GrIS mass trends in a three-member ensemble. Our results represent a first step toward more advanced higher resolution coupled modeling of GrIS and climate evolution.