Nature can reclaim what is lost
According to the New Scientist, the area around Chernobyl has returned to a wilderness state, including roving wolves and bears. There was an intermediate stage where feral dogs, rats and mice were plentiful, followed by reversion to an almost completely pre-human state. This gives us reason to be optimistic about the fate of the world. Nature is robust. Balance is eventually restored, even after a catastrophic environmental event such as the Chernobyl nuclear disaster.