Population control and eugenics is the answer.
Sterilize people who insist on having more than 2 children and those who don't have the brains should not reproduce.
We start with the religious nutjobs.
'Go Forth and Multiply' type of people.
This way we reduce uncontrolled demand/consumption.
Instead of waiting for them to overpopulate before we resort to either soft or hard kill to take them out.
Better to not have these humans born than to have to kill them later to sustain the future of the entire human race.