Climate control on Venus: Comparison of the carbonate and pyrite models

We review two models describing the Venus climate system: the carbonate and pyrite models. It has been argued carbonate and pyrite are potentially important minerals controlling the climate of Venus, though existence of either minerals has not been confirmed. Although it used to be proposed that carbonation reaction might explain the Venus' atmospheric CO₂ abundance, it is unlikely Venus' surface is reactive enough to control the Venus' massive CO₂ atmosphere. Venus' surface carbonate is also able to affect the climate through the reaction with atmospheric SO₂ to form anhydrite. Under the carbonate model the climate state is not in equilibrium and would be unstable due to the reaction between carbonate and SO₂. On the other hand, pyrite-magnetite reaction is proposed to explain the Venus' atmospheric SO₂ abundance. Under pyrite-magnetite reaction, however, the climate would be stabilized such that the existing climate state is maintained over a geological timescale, while some observational facts such as atmospheric abundance of SO₂ and surface temperature could also be reasonably explained.