> What happens when 1.5B come knocking because if they stay they die?

Like let them build few of those sci-fi domes and let them keep buying disposable bottled oxygen? I don't get the pessimism. India makes its own rockets. Pakistan has nukes. Why are they supposed to be incapable of holding the nation together on Mars-like Earth?

Tokyo is already hitting 40C/100F at >90% RH during summers. It's already mildly unsurvivable. Nobody cares. Maybe in 10-20 years we'd be wearing spacesuits, but do anyone seriously think the equatorial regions will be uninhabitable and land prices on northern Europe is going to skyrocket???

The fact people already live in some of the hottest places in the world today should speak a little to human resiliency.