None of those things would make Earth less hospitable than Mars. A desert colony would still be better off than trying to survive on Mars, particularly once Earth's resources are cutoff. Mars is far more hostile than anything likely to happen to Earth over the next hundred million years.
It's not about hospitable. It's about survivable. There are large enough meteor strikes where you'd be better off on a self-sustaining Mars colony than anywhere on Earth.
It’s not about Mars being lower risk but independent risk. Someone could decide to keep copies of important documents in their vacation home not because it’s less likely to have a fire, but because it’s less likely for both houses to have a fire.
I used the wrong word when I said meteor. They’re too small. A comet or asteroid of 100km diameter would raise the temperature of the surface of the Earth by hundreds of degrees and then there’d be decades of darkness. https://www.sciencedirect.com/science/article/pii/S001632872...
