A City on Mars, by Kelly and Zach Weinersmith

“The richest people in America are funding a new space race,” wrote a commentator in the Guardian, because the billionaires “are making plans to get the hell out of here.” It’s a story I’ve heard plenty of times: the wealthy want to escape earth. Their space programmes are their own private lifeboats and the rest of us will go down with our climate-ravaged planet-shaped Titanic.

If there is any reality to this story, it is both an unlikely and an unwise plan. The reasons why are all set o...