As a prophet, Hawking is a good physicist. The idea that we should leave earth to fix things is a deeply Protestant and Puritan impulse that has roots going all the way back to Abraham and even Noah.
The idea is this: The Righteous must “come out from them and be separate. Touch no unclean thing and I will receive you” saith the Lord (or, in this case, Gaia or maybe Terraformed Mars). A great cleansing is required. In the Noah account, the cleansing is by water. With Abraham, it’s achieved by moving from Ur to the Canaan. With Moses, it’s by moving from Egypt to the Promised Land. And with the Puritans, it is achieved by moving from sinful quasi-papist England to the New World and founding a City on a Hill.
With Hawking, the chosen people and royal priesthood of Truly True Scientific people need to flee the wretch and sinful race to another planet and start over. It’s an intensely religious narrative with only one source in the western tradition–and one to which Hawking is wholly oblivious.
Me: I think it’s like a religious crank on a street corner saying the Lord commands you to burn down your house and go live in the desert in anticipation of the magical palace God will cause to grow there. Sure, with God all things are possible. But God is precisely what Hawking excludes from the equation. Abraham had assurances that Hawking does not give. It therefore strikes me as… imprudent… to leave a perfectly functional and serviceable ecosystem to go somewhere we would have to invent one from scratch on a planetary scale. It would be a thousand times easier to rebuild New York in Antarctica than to start even a modest and lasting civilization on Mars or the moon. At least with Antarctica, you don’t have to import all your air.
Hawking is treated as a prophet because he wears the priestly garment of a lab coat and is therefore believed to Know Things when he pops off like this. I see no reason to buy that proposition.