[Minn]

If that was the case, then a full tank of gas for an average sedan would weigh close to a quarter-ton

I think what they do is say that the fuel provides the carbon part, and the air provides the oxygen part. So when one ounce of fuel is burned, it combines with the ambient oxygen to produce 75 million tons of planet killing CO2.

[E Rocc]

75 million tons of planet killing CO2.

AKA "what trees and other plants breathe".

I see a promo campaign here: Save the trees. Make CO2.

Of course, plants absorb CO2 and produce oxygen.

-Eric