Actually the major issues are; low atmospheric pressure and radiation (which is related to atmosphere density, as is temperature). So live underground in air-t

Actually the major issues are; low atmospheric pressure and radiation (which is related to atmosphere density, as is temperature). So live underground in air-tight domes, at least in the beginning before industry takes off. To actually fix the cold, pressure and breath-ability? My bet is on either a heavily optimized artificially created vegetation that exploits Mar's soils enough to generate greenhouse gases, or, more realistically, shit loads of (or massive) machines doing that same thing. Here's to hoping 3D printing-esque evolutions in technology and automation permit this to happen within 150 years instead of 500.