Here are the facts, and they are irrefutable:
Earth isn't expanding and neither are Earth's resources. The materials we use to make the things we buy are finite. However, we do have an infinitely expanding pattern of population growth, of goods production, of human consumption, and of need generation.
Someday this will end. That's a fact, Jack.
Whether it ends because we wisely switch to a sustainable economy or just because we use everything up and die off is exactly what's at stake these days. Our species is at a crossroads. It's that simple.
As this video, entitled "The Story of Stuff: Consumerism" points out, 99% of all the things we buy are in the trash heap six months later. That level of materials throughput is simply not sustainable - given the inconvenient truth about the planet.