A series of climate-change projections are conducted with LOVECLIM, a three-dimensional Earth system model of intermediate complexity that consists of a quasi-geostrophic atmospheric model (ECBILT), an ice-ocean general circulation model (CLIO), a dynamical model of the terrestrial biomass (VECODE), a thermomechanical model of the Greenland and Antarctic ice sheets (AGISM), and a model of the oceanic carbon cycle (LOCH). The global carbon cycle in the model is simulated by both VECODE and LOCH. ECBILT takes into account the topography and surface albedo changes computed by the ice-sheet model. CLIO accounts for the freshwater and latent heat fluxes resulting from the melt of the ice sheets and icebergs. The forcing of the AGISM by ECBILT-CLIO is considered in perturbation mode to avoid any systematic errors and to deal with the rather coarse-resolution of the climate model. We first perfom simulations with prescribed carbon-dioxyde concentrations in order to compare the model results with other studies.An ensemble of experiments over the last 500 years is first carried out aiming at validating the model against recontructions (Figures 1 and 2). The model is forced by two natural forcings: the changes in solar irradiance and volcanic eruptions. The anthropogenic forcings considered are the increase in greenhouse-gas concentrations, including troposheric ozone, as well as the evolution of the sulphate-aerosol load in the atmosphere. The model also accounts for the land-cover changes due to human activities.Climate changes during the 21st century are then studied through ensemble simulations performed with the model driven by various IPCCs SRES scenarios for greenhouse-gas and sulphate-aerosol concentrations. The model performance is assessed by comparing its results with similar results obtained by climate general circulation models.Idealised experiments are finally performed over the third millennium focusing mainly on the North Atlantic climate. In those simulations, the forcings are fixed to their 2100 values until the end of the millennium. A particular attention is paid to the change in freshwater flux from the Greenland ice sheet and its possible impact on the World Oceans thermohaline circulation. A sensitivity study over the third millenium is also carried out in order to assess the ice-sheet contribution to the modelled future climate change