It's a good line but the functional difference between overpopulated and overburdened is so minuscule as to be non-existent. It is our nature, by the fact of our existence, to use resources. Switching semantics might help, though, since the religious among us are so resistant to birth control and educating women--both of which would impact our population problem. For some reason, telling people there are too many of us really upsets a big chunk of society who put having children in the same category as having cars and guns--their sacred personal freedoms they'd kill to hold onto.