I won't get into the carbon emission, fossil fuel, academic global warming debate, however I think it is fair to say that with the current price of fossil fuel, the world will very rapidly develop alternate and far more cost effective energy sources.
Thirty years ago Lockheed had a proposal to develop an H2 powered passenger aircraft comparable to the DC10, which was killed off by the then much lower price of fossil fuel.
The traditional suppliers of fossil fuel can only screw the rest of the world for so long, before alternate energy sources become very financially viable!
Hydro, wind and solar energy have been available for many years. I'm sure other sources of energy will become available. The transition will be driven by economics alone.
Tail Wheel