The Ice Sheet Model Intercomparison Project for CMIP6 (ISMIP6) brings together the world’s leading ice sheet and climate modeling groups in a unified Coupled Model Intercomparison Project (CMIP) framework for the first time. ISMIP6 is led by a nine-member steering committee with representatives from multiple institutions in Europe, Asia and the U.S. (including DOE). The primary goals of ISMIP6 are to provide the scientific community with a framework for estimating the sea-level contribution from the Greenland and Antarctic Ice Sheets in a changing climate, and to assess the impact of large ice sheets on the climate system. The experimental design consists of three parts:

• Analysis of ice-sheet-relevant variables from traditional climate simulations (which do not include dynamic ice sheets)
• Standalone ice sheet simulations, driven by forcing data sets derived from CMIP climate simulations and other sources
• Simulations with atmosphere–ocean climate models, coupled to dynamic ice sheet models; these simulations have become feasible with the latest generation of climate models.

ISMIP6 simulations are already under way, with studies of the effects of model initialization on the evolution of the Greenland and Antarctic Ice Sheets. The key simulations for projecting ice-sheet mass loss and sea-level rise will begin in 2017, as modeling centers carry out the core CMIP simulations of pre-industrial, historical and future climate.