Simple, we can find ways to warm up the atmosphere on Mars.. Genetic engineer plants to survive the atmosphere on Mars.. Have comets crash on the planet to do all sort of stuff. I think you would have loved living in the dark ages..
Good you already agree to pansporia. What makes you think we are a result of chance when mechanics (engineering) are a simpler solution?
You and I have grossly different definitions of 'simple.'
We can't warm up the atmosphere of Earth, a placed designed for us, enough to halt the crop failures in Siberia, and Canada, but we're going to do it on a planet we can't live on? This stuff is definately for dreamers.