"I doubt it, where would it come from?
Thu Jun 14 03:39:47 2001

especially since it is almost a trace gase in our atmosphere."

Well I was thinking about how at one time- not too long ago, geological speaking- Earth's atmosphere had alot more CO2 in it.
Also the ocean contains a lot of CO2- this is a "point" often raise by environmental wackos "worried" a runaway affect with CO2- heat up the ocean "a bit" and "lots" CO2 gets released into atmosphere. CO2 would be very common in Earth's atmosphere if it wasn't for living plants- and it would O2 which would be very rare.
And finally and more likely, as Nick points out there is CO2 locked into some sedimentary rock- add enough heat and it's released.

"But earth really is a bad place to start, after all, I doubt as well that CO2 ice would exist here naturally as well."

True, but CO2 ice require very cold conditions (like Mars:)