Jeez. This is crazy. You're all whipping each other up into a frenzy of misinformation and panic.
Stephen Hawking's views are way, way outside of mainstream scientific thinking. That doesn't mean he's wrong, but it does mean that there's absolutely no consensus of opinion around this viewpoint. Which leads me to believe that we don't have only 100 years to colonize another planet and that we're going to be absolutely fine where we are.
Just for the heck of it, why not spend a completely week immersing yourself in the work of the many scientists who aren't catastrophizing about the end of the world. There are plenty of them out there, and - despite what you might think - they're not multimillionaire weirdos, shills for the oil companies or random eccentrics. Do that, and see how you feel afterwards.
I'm amazed at the numbers of people who are happy for the government to increase their taxes in the name of being "green". I'm sure they'd happily increase tax at the drop of a hat given half a chance, but believing that governments can control the climate is absolutely ridiculous! Why would you want to surrender your power (and your money) in this way?
We should be incredibly grateful for fossil fuels. Incredibly grateful. We'd all be dead in 3 weeks without them. And developing countries desperately need them in order to start enjoying anything like the standards of living we have.
People have always - throughout recorded history - made catastrophic predictions about the end of the world. It seems to be part of the human condition. What these predictions often cannot take into consideration is advances in science and technology and human beings' incredible ability to adapt, survive and thrive even in the most adverse conditions.