I see no reason to suspect there's much overlap there, and in any case this misrepresents both arguments. Climate change doesn't need to render the planet uninhabitable to all life in order to devastate human civilization; if we are forced to abandon the coasts, it will be the biggest refugee crisis in human history by orders of magnitude, and hundreds of millions will die in the resulting chaos and scramble for resources. Meanwhile, Mars is a barren tomb world, and, at best, living in a colony there will be a physically and psychologically exhausting prospect, and has no chance at exhibiting any real self-sufficiency for hundreds of years at best, let alone anything resembling civilization.