I thought this was an interesting editorial from yesterday's Week in Review section in the Sunday New York Times (May 24, 2009): Editorial: Getting Ethanol Right . I haven't gone back to dig up the original news article, but here's the interesting bit:
Congress hoped the ethanol mandate would produce a more climate-friendly fuel that could help reduce oil imports. But just to make sure, it stipulated that ethanol from any source be cleaner than conventional gasoline. It handed the job of measuring emissions to the E.P.A., and told it to consider the fuel’s entire life cycle.
This included counting the greenhouse gases released when forests or grasslands are plowed under and planted to make up for the crops used to make ethanol. When the E.P.A.’s scientists counted these indirect effects, corn ethanol emitted more greenhouse gases than gasoline over a 30-year period.
Yes, you read that correctly. Moving from "dirty" gasoline and diesel to supposedly environmentally friendly ethanol creates more greenhouse emissions than just burning the gasoline and diesel directly. My understanding is that this is because of all the fuel and hydrocarbons used in the farming, fertilizing, and manufacture of the ethanol. This is big news to a lot of people, though I must thank Arsen Darnay for having opened my eyes to this particular reality several years ago. Arsen's taken a great interest in matters of "peak oil" and energy over the past few years, and he had dug up this notice on his own. (I believe it may have been part of his research for an essay in the Encyclopedia of Products and Industries -- Manufacturing, but Arsen if you are reading this and can recall where you wrote up that little snippet, I'd like to revise this entry to properly credit it.)[Arsen subsequently cited David Pimentel's article "Ethanol Fuel: Energy Balance, Economics, and Environmental Impacts are Neagive." as a good starting point.]
What I find most surprising is that this discovery is apparently genuine news to official Washington and the Beltway, and has set policy-makers on their ear. Had nobody done the math beforehand? Not even some paid hack for Exxon-Mobil? This isn't to say that ethanol doesn't have value in local emissions reduction, that there might not be more efficient ways to make it in the future, or that we should abandon ethanol research. But the current process of intensive agriculture to grow corn just isn't a net gain for planet Earth.
One of the other items that Arsen pointed out along those lines is that our current technology for growing all of our food is so heavily reliant on a net input of energy from fossil fuels that a post-peak-oil energy crash may very well lead to a crash in the global food supply. That's a scary thought for a planet with an ever-burgeoning human population.
Mostly, though, I'm interested in the item because it once again points out how very complicated environmentalism can be. Even the simplest and most isolated of biological systems are incredibly complex, and every action is sure to have unintended consequences. We see examples of this all over the place. A century of wildfire suppression in National Forests has created overgrowth that has worsened fire problems. An environmentally minded move away from nuclear power has led to a great increase in power generation from coal, which may pose an even greater threat in the form of greenhouse emissions.
I myself joined our water management board nearly ten years ago with an eye towards finding "greener" ways of managing our lake and soon found myself arguing in favor of the more widespread use of some herbicides because the damage that some invasive plant species (notably Eurasian milfoil and starry stonewort) did to the lake's ecosystem was greater than the damage done by the herbicides. In an ideal world we would never need to use herbicides in our waterways, but in the real world sometimes the most practical approach is the best compromise.
About all we can do is our best to think through all the consequences of our actions, and to be willing to change course when we learn more. In general, I think folks do the best they can with the former, but sometimes I worry that the second is sadly lacking. Right now it seems to me that there could be a strong environmental case to be made for pro-nukes and anti-ethanol policies. Yet I doubt the environmental movement is ready to go there.