Northern Hemisphere snow cover varies greatly through the year, and the presence of snow has a large impact on interactions between the land surface and the atmosphere. This paper outlines the representation of snow cover in the Hadley Centre GCM, and compares simulated snow cover with satellite and ground-based observations. Climate warming in a simulation with increased concentrations of CO₂ and sulphate aerosols is found to lead to larger reductions in snow cover over North Ameriea and Europe than over Asia.