Re: Ethanol may not be "Green"
Its kind of a sad fact, but the OPEC oil ministers and Hugo Chavez, by limiting oil production and keeping oil prices at around US$100 a barrel, have probably done more to reduce greenhouse emissions than ethanol production. Price elasticity - when prices increase, consumption decreases - is in fact a very effective way to reduce emissions.
So the correct answer for limiting greenhouse emissions - a carbon tax. And this is not a tax for tax sake - you would be pricing the "externality", or societal cost of additional carbon emissions. For every ton of CO2 (or greenhouse gas equivalent) you emit, pay a tax ($/Ton). This allows for producers and consumers to optimize their energy consumption (e.g. choose natural gas as a fuel rather than coal, which for every BTU of energy produces 2-3 times the carbon) and encourages investment in energy conservation, carbon sequestration, reforestation and other forms of off-sets. A carbon tax would let good 'ol Adam Smith's invisible hand do its job and reduce greenhouse emissions in the most efficient way.
But it will be a brave politico that proposes a carbon tax, and it would need to be global, not just limited to the shores of one country - otherwise energy intensive industries would move to "tax free" countries, and continue to emit the same levels of carbon.
Tough problem, no easy answers.
Rob.