Abandon Earth
Stephen Hawking is known around the world as being a pretty smart man. Due to his intelligence when he speaks people actually listen (whether or not they process what he says is a different matter). Well Mr. Hawking made another statement saying humanity needs to leave Earth or face extinction.
This is the reason I'm such a strong supporter of advancing space exploration. The bottom line is we need to get off this rock as soon as possible. Furthermore we need to find a means of expanding beyond this solar system as well but right now the immediate goal should be to make another planet habitable. Any number of things could cause the destruction of this planet including a sizable chunk of space rock, nuclear war, and of course a pair of wolves swallowing the sun and moon.
Either way the priority of our race has been survival but few seem to understand that continued survival requires we take some of our eggs from this basket and move them to another basket.
EDIT 2010-08-09 12:49: Hawking and Hawkings are slightly (completely) different. Edits made to reflect this slight oversight. Also I can't type. Thanks for pointing it out Jeff.