It makes perfect sense as a politically-motivated decision. Some excuse was devised to destroy the pods, thus ending the debate forever of whether the Earth might one day return to a green space.

It also forced Dern's character into action, since he would have to return to Earth since his job of caring for the pods was about to end.

The film reminds me somewhat of 'Interstellar' — a once verdant world going dark and expelling the hero.