Trajectory toward a long, slow population collapse. It's hard to imagine what gets world population back up to replacement rate (2.1 children per woman) once it

Trajectory toward a long, slow population collapse. It's hard to imagine what gets world population back up to replacement rate (2.1 children per woman) once it dips below. Children are expensive and technology makes having them far more optional than it ever has been in history. The world's population is aging out of its fertility years. Once we're below 2.1 the trajectory will be down, short of some severe cultural or societal change. The environment will be ok. Concerns about overpopulation destroying sustainability are 'fighting the last war.'