Clean technology, while a huge opportunity, will not go to scale in time to prevent a global economic and social crisis.
Considering all the comments on my talk, The Earth is Full, I would sum up by saying that everyone pretty much agrees we face some serious ecological and resource limits. The debate is will these naturally be dealt with in the normal course of technological and market processes, or will they result in a serious global economic crisis. My view is strongly that a crisis is inevitable and that it will be an economic crisis - but that will then trigger a war level of mobilisation that will drive massive technological change. So relying on technology to prevent the crisis is wrong.