The Problem with Overpopulation Predictions
The problem with overpopulation predictions is that they assume that humans are animals. Animal populations often show a boom-and-bust pattern caused by overshoot. If humans are animals we must beware of overshoot, which means we must be concerned about overpopulation long before there is any real evidence of it.
On the other hand, ecologically speaking humans are plants. (Plants rarely have overshoot problems.) When there are more of a species of animal there is less of what that animal eats. When there are more of a species of plant, the resources the plant needs either increase (soil) or stay the same (sunlight).
The only resources that humans treat the way animals do are fossil fuels and wild fish. Both of those should be obsolete soon.
Tree huggers have a point (but not the one they think they're making).