99 percent of the atmosphere is Nitrogen and Oxygen with Nitrogen making up 80 to 90 percent of that. All the N2 keeps the Oxygen from Exploding. which is why the Russians use natural atmosphere in their space vehicles. all the other gases combined make up the last 1 percent. CO2 is a pittance of the Atmosphere. If we want to stop CO2 build-up put all the ship traffic back into large sailing ships. there are 15 huge ships that can not go thru the Panama canal that together create more CO2 than all the Cars in the world. but doing that would be "less profitable".