The HadCM3 AOGCM has been coupled with a dynamic 3D model of the Green-landice sheet that includes a visco-elastic solid Earth model. The AOGCM exchangesinformation with the sheet model once a year. Precipitation and temperature anomalies are passed to the ice sheet model, which calculates ablation (using a degree-day scheme), ice dynamics and basal rebound. The ice sheet model passes back to the GCM an updated orography and freshwater fluxes. Iceberg calving fluxes are applied evenly to the sea region adjacent to Greenland whilst runoff enters the ocean at coastal points. When a GCM grid cell changes from ice-covered to ice-free or vice-versa, the surface characteristics are modified appropriately. A multiple-century experiment is being undertaken, starting from the present-day ice sheet, with four times the pre-industrial atmospheric CO2 concentration, to determine the rate of ice ablation, the effect on oceanic circulation and local climate, and the feedback of orographic and climate change on the ice sheet mass balance. Over the first 200 years, the contribution to global average sea level rise as a result of loss of mass from the ice sheet is about 5 mm/yr.