There seems to be some controvesy on how much green house gas emissions are saved by use of ethanol. It all depends on how in depth one caluclates the carbon balance and includes things like fertilizer, shipping, and i would add for oil security. The greenhouse gas emissions from military defense operations to protect the oil supply line is significant. I think the major advantage of ethanol is that it more directly takes solar energy and converts it into fuel, that is it doesnt take a prehistoric time scale to do it, as in the case of oil. If we can get to cellulose based ethanol the data gets even better.
The gulf oil blow out makes ethanol look a lot more green friendly than oil/gasoline. I read today that it might take 2-3years to complete a drill hole in the Arctic and the same for a relief well should it be needed in case of a blow out. No way regualtors are going to risk taking 2-3 years to drill a relif well while a blow out spills oil under the arctic ice. So if arctic oil stays off limits due to technical challenges oil and gasoline costs will climb long term. ethanol in 2010 might be weak but longer term has potential. biofuels have environmtal costs as well but less and less risky.
I suppose there is no way to incorporate the green house gas emission in fighting things like the gulf oil blow out. Other environmental factors like oil pollution and ground water pollution dwarf the green house gas problem imo. The latest gulf oil accident is going to put some deep ocean oil off limits for some time and require more costly regualtions to be met. Beaufort sea drilling is getting requirments on same season relief well capabiltiy, and moratroium on off shore oil in Georges Bank off canada is extended 3 more years to 2015. Higher oil in long term means higher gasoline means higher ethanol. Short term who knows, long term higher oil, higher ethanol, higher food costs etc.