Abstract. A global carbon cycle is introduced into a zonally averaged energy balance climate model. The physical model components are similar to those of Budyko (1969) and Sellers (1969). The new carbon components account for atmospheric carbon dioxide concentrations and the terrestrial and oceanic storage of carbon. Prescribing values for the sum of these carbon components, it is found that inclusion of a closed carbon cycle reduces the range of insolation over which stable partial ice cover solutions may occur. This highly simplified climate model also predicts that the estimated release of carbon from fossil fuel burning over the next hundred years could result in the eventual melting of the ice sheets.

Keywords: climate, carbon cycle,zonal model, earth system modelling