We've been worrying about overpopulation for my whole life and now we're supposed to worry that we aren't making enough babies? Sorry, but no. I think fewer babies is a good solution to the problems you mention and many more. I remember in high school biology learning that populations increase until they reach the max their environment (food, habitat, etc.) will allow, and then they decrease. We've reached our maximum. We need to die off if we want enough resources to go around. And we most definitely do want that!