Do you really think that adopting a sustainable way of life is unfeasible, while establishing a self-sustaining colony on another planet is? Many of the changes I am talking about are already taking place. For example,
renewables have recently become a viable alternative (http://www.sciencealert.com/india-says-the-cost-of-solar-pow...) and population growth is projected to taper off after 2050 (http://abcnews.go.com/Technology/story?id=98371).
The only thing that can hold these solutions back is strong opposition from the beneficiaries of the current system. They will fight back, but I think that the odds are stacked against them.
Yes, I do. Ultimately there is no such thing as a sustainable way of life, thanks to the second law of thermodynamics. It's not that long until the sun burns out - by which time we'll have to have figured out how to settle not only on other planets but in other solar systems.