And I hate packing, so if a terrible catastrophe is imminent, of course I’d rather move the planet itself rather than trying to decide what would fit onto a spaceship ark.

James Davis Nicholl has a post on tor.com about that: (Semi)-plausible strategies for moving a whole damn planet.

You’re living on a perfectly good planet in orbit around a perfectly acceptable star—and then suddenly, the neighbourhood goes to crap and you have to move. For a lot of people, this means marching onto space arks.

Recapitulating Noah on a cosmic scale is such a pain, though. All that packing. All that choosing who to take and who to leave behind. And no matter how carefully you plan things, it always seems to come down to a race between launch day and doomsday.

Why not, therefore, just take the whole darned planet with you?

Fun topic! I had not realized there were so many (or any at all) books in which this happened. Amazingly, I just happened not to read any of the books Nicholl refers to.