The effect of land distribution on Neo-Archean atmospheric circulation and surface climate

The continental distribution and surface conditions of a planet strongly impact its climate. Continents on Earth are believed to have emerged above sea level in the Archean Eon, although the exact timing and emerged surface area are widely debated. We use the Isca climate model, a framework for the modelling of idealised planetary atmospheres, to explore the climatic impact of various land-ocean configurations on a 2.7 Ga Archean Earth. We find that the addition of land consistently produces a global cooling and introduces hemispheric asymmetry to the large-scale atmospheric circulation and equator-to-pole temperature gradient. The magnitude of the climate response increases with overall land fraction, while the degree of hemispheric asymmetry is more sensitive to the difference in land fraction between hemispheres. These effects are driven by changes in the surface energy balance, which are caused by the distribution of land and associated changes in albedo and the availability of water for evaporation. These results are comparable to similar work on tidally-locked exoplanets, and further highlight the importance of including land in climate simulations for Archean Earth and Earth-like exoplanets, particularly if the goal is an assessment of a planet’s habitability.