When comparing offsets, you have to compare apples to apples. A new coal plant going on line in China can be offset by one going off line in Germany, or (gulp) the USA. For the person driving the Prius, it offsets the higher emission vehicle they would be driving anyway.

As for ethanol, or any other attempt at doing something helpful, I say have at it. Keep trying. Behind every success is a long line of failure. Look how affordable PV panels are now. Those were out of reach for the average electricity user as recently as ten years ago. Look how much improvement there is in fuel efficiency over the last ten years. Where could we be ten years from now?

"Never doubt that a small group of thoughtful, committed citizens can change the world; indeed it's the only thing that ever has." - Margaret Mead