The decline of biodiversity at the hands of modern humans likely started even before the last Ice Ages. Recently some scientists have proposed a scenario called “Pleistocene re-wilding,” which offers an optimistic agenda for 21st-century conservation to bring back animals that disappeared from North America 13,000 years ago.

What could be the pros and cons of populating the area with animals such as lions, cheetahs, hyenas, elephants, camels, etc.? Would that help bring back some of the lost biodiversity?