Pubs.GISS: Abstract of Durham et al. 1989

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Durham et al. 1989

Durham, R., R.B. Schmunk, and J.W. Chamberlain, 1989: Comparative analysis of the atmospheres of early Earth and early Mars. Adv. Space. Res., 9, 139-142, doi:10.1016/0273-1177(89)90219-6.

A surface partial pressure of CO₂ of at least 1.3 bars is required in order to sustain liquid water on Mars. We assume that the primitive atmospheres of Mars and Earth were similar and that present differences are a result of their different distances from the Sun and their different masses. We then use a one-dimensional radiative-convective atmospheric model to determine if a 1.3 bar CO₂ partial pressure on Mars is consistent with the climatic conditions thought to have existed on Earth four billion years ago. The Earth atmosphere was evidently then stable against a runaway greenhouse, so that huge amounts of liquid water could accumulate on the surface. We find that these terrestrial codnitions are consistent with a high CO₂ partial pressure on Mars, which produces liquid water at perihelion if not during the entire orbit.