If the world was to become dangerously underpopulated, would you obligate procreation to save humans?

I think it might be somewhat impossible. Humans will fight for their right to survive, and they will have while doing it?:)LOL! But how can we capture all the humans to make sure life stops? You cant use gases you will kill wildlife too? So how can you do it? I think humans harm the earth, and a slight drop in population would do the whole world some good. We need to keep a steady flow of new people but only like 1/8 of what is happening now.