Description
Abstract: The evolution of Martian climate is linked to a transition in the surface temperature pattern. Snow/ice caps tend to accumulate on mountaintops early in Mars history, but they are located at the poles in the modern era. Previous work suggested that the transition is due to a reduction in air density over geologic time. Here we show that it is, rather, due to a weaker greenhouse effect by using global climate simulations. The transition in global temperature pattern is further linked to the change of the temperature structure. With weaker greenhouse effects, the air above the lowlands cools slower with height. Our work reveals a novel connection between climate and geomorphology, which may work over a broad range of planetary environments.