There is a paradox discussed in Permaculture: “The problem becomes the solution.” Applying that to the population numbers, we may actually not have /enough/ people.
The problem of too many people becomes the solution: Get enough people acting rightly and many other problems get solved. Some Permaculturists believe the earth has the capacity for fifty billion people; it’s just that current resources are so poorly managed. We may not have enough people to solve so many of the world's pressing problems.
The alternative is to treat people like weeds. But we need a path of love, not fear.