Our planet is a waste of good rock
Why We Must Flee the Planet: The Geometry of Earth is All Wrong
Consider the Tonnage-to-Terran ratio, an index of how efficiently we use the planet: With the human population at six billion, the T-to-T ratio works out to about a trillion. In other words, for every lout strutting Earth's stage, there are about a trillion tons of Earth!
That's right: each of us is backed up by a trillion tons of natural infrastructure, a mostly useless collection of crushed iron core and creamy, hot magma, topped by a delicate continental crust. This, as you can easily surmise, is wasteful. It's possible to live the good life with 100 tons of housing (including some office space and a car or two), which is 10 billion times more efficient.
Everything I need to know I learned through Googling.