David Suzuki, from this video.
There is a field called ‘ecological economics,’ which is basically economics with those ‘externalities’ factored in.
The interesting thing about it is that in classical economics, there are certain corrective equatiions that need to be performed, because economics does not in fact accurately predict the behavior and growth of the economy.
When you use ecological economics, however, factoring in those ‘externalities,’ the math becomes accurate and the corrective equations are not necessary.