Concern about tropical deforestation has often focused on local climate or ecological change. Less research has been carried out on its possible effects on the global climate, although possible mechanisms for such an occurrence have been proposed. Here we use a general circulation model (GCM) to show that complete Amazonian deforestation can result in changes in the climate far afield from the region of deforestation. In particular, the model predicts statistically significant changes to winter rainfall over the NE Atlantic, extending towards western Europe. These are associated with large-scale circulation changes in middle and high latitudes. Simulation of these circulation changes with a simple model confirms the physical mechanism responsible (planetary wave propagation) implying that the result is robust and relatively independent of the GCM used. ¿ 2000 American Geophysical Union