I watched an episode of Space last night on Canvas. It was all about how we need to establish ourselves on other planets, through Terraforming.
Terraforming is a process of planetary engineering, specifically directed at enhancing the capacity of an extraterrestrial planetary environment to support life. The ultimate in terraforming would be to create an uncontained planetary biosphere emulating all the functions of the biosphere of the Earth---one that would be fully habitable for human beings. There's loads to find about this online, like this Google directory, where I found Red Colony.com, which focusses on making Mars our new home.
One of a hundred things could happen that would make Earth uninhabitable at any moment, and our only sanctuary would be a terraformed Mars. An asteroid collision, volcano eruption, overpopulation explosion, natural resource depletion, ozone layer depletion, nuclear or biological warfare... just a few of the things that could happen leaving the human race with no way out. The survival of the human race is more important than preserving a planet. We must expand from Earth and begin terraforming as soon as possible.
I wonder what the human species will be like after having lived and evolved for generations on completely different planets. Or maybe it'll never happen. Maybe we'll destroy earth long before we get a chance to explore the universe. I wonder.