Famed physicist Stephen Hawking, who happens to harbor serious concerns about AI, believes humans could be limited to living on Earth for just a thousand more years. Humanity will need to find a new place to set up shop if it's going to remain around for many more generations.
Hawking has made this claim in the past, so it appears to be something he truly believes. While he usually doesn't delve into what he thinks will make Earth inadequate, he has said it'll be difficult to "avoid disaster" for very long.
Like Elon Musk, another individual with AI concerns, Hawking is supportive of efforts to make humans a multiplanetary species.