Huh? Even if you assume that the CO2 in your canister was captured as a byproduct of refining petroleum or captured from the emissions of a power plant, we are talking about an insanely minuscule amount of CO2. If there is no market for captured CO2, it will just be released into the atmosphere. The key is that the CO2 is a byproduct. It's going to be created whether or not you use it to inflate your tires. I appreciate that you are well intended, but this seems to be taking good intentions to an illogical extreme.

There is a very good chance that you will want to replace the saddle.