Originally Posted by CliffordK

As others have mentioned, it is mostly a closed cycle, but fertilizer is produced using petroleum. Tractors generally run with petroleum, and there is also transportation costs. Even water often takes energy.

But, one should calculate the difference between energy consumption as a couch potato vs active athlete. Are you driving your EV to the gym to burn some calories?

The best way to reduce your carbon footprint... is to reduce the number of children.