Hmm maybe I seem to be a little stupid here but I heard that the worlds biggest offending Green house gas is infact Water Vapour which is over 50% naturally produced but I don't know as the validity of this point.

Still we're screwing up the environment which is bad personally I just think it is despicable that the automobile industry won't start mass producing Fuel Cell Cars (which if you've heard of them you'll know convert Hydrogen in to water and electric so totally clean energy since the hydrogen is generally produced through hydro-electric powerstations) Just because it will cost a lot to change the factories to make them.