0 and $0, therefore we should require a minimum of 20 flights at a tax of $5,000 each to guarantee the opposite effect! Of course, perhaps it's less about where

0 and $0, therefore we should require a minimum of 20 flights at a tax of $5,000 each to guarantee the opposite effect! Of course, perhaps it's less about where the CO2 came from and more about how much is in the air. The former was a bit more fun to think about though :).