The way to develop technologies that will save the earth's environment is to go to space or other worlds where there are no NIMBYs or reactionary fanatics or existing corporate kleptocracies, develop them to maturity, and then redeploy on the mother planet. Commercial fusion power, for instance, will probably always remain 'thirty years from now' as long as the unholy alliance of fossil fuel incumbents and so-called 'Greens' continues.

I like to add here: why don't we try a colony on the top of Mt Everest first? It is so much easier than going to Mars, what with (some) air and water already there. But otherwise pretty comparable. And no rockets needed.