We're on the horns of two competing crises: Global Warming vs. Resource Depletion....
Our Petro-Industrial economy is based on stuff we drill or mine from the earth. And there's only so much of that stuff. As we go forward, it takes more and more energy to refine poorer and poorer ores into finished goods.
For now, the only source of energy that delivers the volumes of energy needed for said refining is fossil fuel. And the CO2 it produces sticks around for hundreds or thousands of years.
We keep thinking that the current economic slowdown is the usual air-in-the-gas-line glitch and, with a little government stimulus, the economic engine will be humming again just like always. It won't. We need to radically rethink our whole way of life.
If you want to read more, I recommend this book:
http://richardheinberg.com/bookshelf/the-end-of-growth-book
