> Plus you have to consider that both Antarctica and the Sahara Desert are more habitable than any known extraterrestrial location, yet hardly anyone is living in either.
WHat's the incentive to live there where there are better places to live, still available ?
That's the point. We aren't nearly at the point where we can no longer sustain growth here on earth. I think in the event that that did happen, we'd soon explore living in Antarctica than on Mars.
Not especially - developed countries have had declining birth rates for a while now, with several below the replacement rate.
Plus you have to consider that both Antarctica and the Sahara Desert are more habitable than any known extraterrestrial location, yet hardly anyone is living in either.