Greenland surface mass balance as simulated by the Community Earth System Model. Part II: Twenty-first-century changes

For glaciated surfaces, CESM includes a sophisticated calculation of energy fluxes, surface albedo, and snowpack hydrology (melt, percolation, refreezing, etc.). To efficiently resolve the high SMB gradients at the ice sheet margins and provide surface forcing at the scale needed by ice sheet models, the SMB is calculated at multiple elevations and interpolated to a finer 5-km ice sheet grid.

During a twenty-first-century simulation driven by representative concentration pathway 8.5 (RCP8.5) forcing, the SMB decreases from 372 ± 100 Gt yr⁻¹ in 1980-99 to −78 ± 143 Gt yr⁻¹ in 2080-99. The 2080-99 near-surface temperatures over the GIS increase by 4.7 K (annual mean) with respect to 1980-99, only 1.3 times the global increase (+3.7 K). Snowfall increases by 18%, while surface melt doubles.