Four general circulation models, forced by mean annual insolation and having an energy balance ocean, have been run for pole-to-pole continents: (1) low relief, 750 m average elevation; (2) high plateau, 1500 m average elevation; (3) mostly low, 750 m, but with 3 km mountains on the west, and (4) mostly low, 750 m, but with 3 km mountains on the east. The high plateau continent emphasizes the contrast between high and low pressure systems. Marginal mountains on either coast enhance moisture transport from the west to the continental interior, but mountains on the east eliminate the tropical wet belt and produce the most arid scenario. In none of the experiments do zonal climate boundaries trend steeply equatorward from east to west. All of the models produce more arid continental conditions than exist today.
