# Why are there no CO2 snowfalls on Earth?

The CO2 phase diagram shows that at atmospheric pressure and about -78 °C temperature CO2 becomes solid:

Wikipedia confirms this:

At 1 atmosphere (near mean sea level pressure), the gas deposits directly to a solid at temperatures below $−78.5\ \mathrm{^\circ C}$ ($−109.3\ \mathrm{^\circ F}; 194.7 ~\mathrm{K}$) and the solid sublimes directly to a gas above $−78.5\ \mathrm{^\circ C}$.

The lowest temperature measured on Earth is about -90 °C (Vostok station). Does this not mean that CO2 should fall as snow at the poles?

• please avoid duplicate questions on SE sites – bummi May 29 '15 at 12:41
• There is simply not enough CO2 in the atmosphere for that – Gimelist May 30 '15 at 11:36