A boom and bust cycle in population sounds a little scary, especially with a world economy based on growth in size rather than quality. It's going to be painful either way. More is not better. You can't grow forever. You can try to keep the boom from going too high, because the higher the boom, the greater the bust.
Population growth has momentum, like a truck.
You can't stop it all at once. The timing was not right for serious consideration of the health of the Earth in the 20th century, but it is now. We're all trying to get ready for a second awareness movement. I think it'll be deeper. I spoke at this place called Nuci's last night.