CO2 condensation is a serious limit to the deglaciation of Earth-like planets

It is widely believed that the carbonate-silicate cycle is the main agent to trigger deglaciations (through volcanism) by CO2 greenhouse warming on Earth and on Earth-like planets when they get in frozen state.

Using a 3D Global Climate Model, I explored the ability of frozen planets to escape from glaciation by accumulating enough gaseous CO2.

Artist view of the Earth in a global glaciation state, also called 'hard Snowball Earth'. It is assumed here that the poles of the planet are so cold that the CO2 in the atmosphere has condensed, forming permanent dry ice polar caps. Credit: M. Turbet and N. Chaniaud.

I found that Earth-like planets may never be able to escape from glaciation if they orbit at a distance ~30% larger than the Earth does around the Sun, because CO2 would condense at the poles forming permanent CO2 ice caps. This limits the amount of CO2 in the atmosphere and thus its greenhouse effect.

I also show that the amount of CO2 that can be trapped in the polar caps depends on the efficiency of CO2 ice to flow laterally as well as its gravitational stability relative to subsurface water ice. In particular, for planets with a significant surface water content like the Earth, CO2 ice deposits should be gravitationnally unstable and get burried beneath the water ice cover in few centuries. This would considerably increase the amount of CO2 trapped and further reduce the probability of deglaciation.
By Martin Turbet | Design by Andreas Viklund | Inspired by Aymeric Spiga