Hawking says we need to colonize other planets--and I believe that is sound advice.
While Mother Earth has an incredible ability to rejuvenate and self-heal, let's face it, the planet cannot sustain us forever in our current state.
According to the United Nations, the world population is expected to hit 9.22 billion by 2075, and life expectancy is expected to rise varying across countries from 66 to 97 by 2100.
Moreover, according to research institution, Transatlantic Academy (May 2012), over the next 10-20 we are likely to see "accelerating demand for most natural resource commodities...increasingly volatile markets, [and] scarcities are likely to be more common."
In the absence of major technological breakthroughs, increased social equity, and peaceful coexistence on this planet, we will need to find resources outside of Earth and colonize other planets--this is our future.
Already, as reported by National Geographic (10 April 2013), the administration has funded NASA to capture an asteroid and set it in orbit around the moon to not only study and develop capabilities to help protect our planet from a collision, but also to eventually be able to mine asteroids for precious minerals.
As much as we love Earth--although sometimes we don't show it by being gluttonous with its resources, polluting, destroying the ozone, and generally not following sustainable practices--we need to have a "Plan B" whereby we explore for water, food, land, minerals, and energy elsewhere and be ready to make a move to survive another 6000 years and more. ;-)
(Source Photo: Andy Blumenthal)