High-obliquity simulations for the Archean Earth: Implications for climatic conditions on early Mars

Global climate model simulations using high-obliquity (70°), higher CO₂ and CH₄ but reduced O₃ concentrations produce warm climate conditions for Archean boundary conditions (reduced solar forcing). Solar radiation under high-obliquity is distribution in such a way as to warm high latitudes and cool low-latitudes. Global mean air temperatures of approximately 280°K are found with a 25% reduction in the solar forcing, 4760 ppmv CO₂ and 25 ppmv CH₄. High-obliquity could also explain why polar oceans on Mars may have occurred in its history. A substantial increase in the amount of insolation is accounted for if Mars had an obliquity of 70°.