Are Ice Ages Affected by the Freezing Out of CO2 in Antarctica?
The freezing point of carbon dioxide is -78.5C.


The temperature at which carbon dioxide sublimates is not a fixed value. It instead is a function of the partial pressure of carbon dioxide. That value of -78.5° C is the temperature at which CO2 sublimates given a partial CO2 pressure of one atmosphere. The temperature needed to have CO2 sublimate given a partial pressure of 40 pascals is much lower than that.

The Clausius-Clayperon relation can be used to estimate the temperature at which a substance will sublimate for a given partial pressure. Using the parameter values for CO2 from James et al., I get a temperature of 131 kelvins (-142° C) for the sublimation point of CO2 at a partial pressure of 40 pascals or 0.4 millibar. Using a slightly different parameterization, Agee et al. calculate that a temperature of 133 kelvins (-140° C) is needed to make CO2 sublimate from our atmosphere.


  Are Ice Ages Affected by the Freezing Out of CO2 in Antarctica?


Carbon dioxide levels are very low during glaciations (colloquially, ice ages, but we're in an ice age right now). Using the parameterization from James et al. yields a temperature of 127 K (-146° C) as the sublimation temperature for a partial pressure of 18 Pa (0.18 millibar), or 180 ppm CO2. The Earth cannot get that cold, so no, ice ages are not affected by the freezing out of CO2 in Antarctica.



References:

Agee, Ernest, Andrea Orton, and John Rogers. "CO2 snow deposition in Antarctica to curtail anthropogenic global warming." Journal of Applied Meteorology and Climatology 52.2 (2013): 281-288.

James, Philip B., Hugh H. Kieffer, and David A. Paige. "The seasonal cycle of carbon dioxide on Mars." Mars (1992): 934-968.