For the past few years, the corn-growing regions of America had high economic and environmental hopes pinned on corn ethanol production. Subsidizing legislation promised to help make the new product economically attractive, while providing residents of many corn-producing states with higher octane fuels at a lower price. Reduced carbon emissions would have the obvious impact of slowing global warming, higher demand for the crop could keep farms employing more people while still protecting margins.

But then things came apart. A worldwide food shortage hit, causing many leaders in developing nations to assail the US for burning food while others starved. This forced cutbacks in production, and a series of studies associated corn ethanol use with increased ozone risks, as well as carbon debts—that is, the amount of carbon released by conversion and nurturing of land used to grow corn ethanol—as much as 420 times higher than the fossil fuels they supplanted. Corn quickly went from biofuel leader to biofuel has-been.

Still, some dissent always followed the debate over corn ethanol crops, with the first serious challenges coming earlier this year. Researchers predicted that throughout much of the US, corn ethanol could be grown on existing or degraded farmland, which would slash the emissions created by starting up new biofuel production. Studies based on these hypotheses were carried out, and, indeed, returned data similar to the predictions—corn ethanol could be a viable alternative to fossil fuels in terms of carbon-reduction.

The corn industry has sprung into action with the news, touting its ethanol fuels as environmentally superior to gasoline. But while the data provided seems solid, I don't believe it should prompt a wide-scale reinvigoration of the corn ethanol industry. Better than gasoline—which has to be pumped out of the earth, shipped, refined, and shipped again before it enters the gas tank of your car—isn't nearly good enough to meet the needs of the world in time to head off the effects of global warming.

Plus, there's more at play here than just carbon. Corn crops still require massive amounts of arable land, which could just as easily be used to help stabilize the global food supply. Other biocrops, such as sweet sorghum offer reduced carbon impact in addition to providing a food source, while cellulosic ethanol can create a fuel source from essentially any leftover plant materials. And in terms of raw energy per square mile, it's tough to beat the output of aquatic biofuels such as seaweed and algae.

This isn't to say corn ethanol can't still play an important short-term role in creating a biofuel economy. Last time I checked, the US still produces a fair amount of corn ethanol, while most other biofuel industries are in their infancy. A ready supply of ethanol fuel creates incentives for carmakers to produce more ethanol-friendly engines, and a greater supply of flexible-fuel vehicles will increase consumer awareness to clean vehicle tech, while still reducing carbon dioxide emissions—just not by as much as sustainability advocates would like to see.

Photo by Flickr user Dodo-Bird