In a BBC article, ostensibly about Low-carbon energy, the real agenda is made clear:
"New technologies will be required if the world economy is to grow without accelerating climate change."
The base assumption in all talks about climate change, Peak Oil, and the future of human civilization is the growth economy. One thing we do know about the undefinable word "sustainable," is that a growth economy isn't.
The only form of "economy" among the members of any successful species on Earth is a steady state economy. No species can expand indefinitely, taking more and more resources from other species in the neighborhood. There is a scientific name for species that continue to overstep their bounds: extinct.