Hydrogen, Oil, Enthanol, Gas etc... It doesn't matter what we use as we will still harm the environment.
Even with electric powered cars the electricity still has to be generated by some power source (oil/wind/solar) and massive amounts of money and energy will have to be spent it R&D to develop this.
The truth is the population is increasing and the bigger population makes more demands on the planet. Therefore, anything the Green parties put in place to help the environment is only a stop gap. Akin to giving a dying man a glass of water.
Nobody wants to go back to pre industrial life and embrace agriculture so its about time world governments really grabbed the bull by the horns and came up with a master plan.
We need to colonise another planet! I am sure there are plenty out there and we would be better advised to try and find them rather than spending fortunes trying to come up with ways to "save the earth" which is only prolonging the agony of the sick patient.
I have seen the movie Avatar and there are lessons to be learnt here on how to subdue the native population when we find a suitable planet.