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By Julia Olmstead
A look at the impacts of biofuels production, in the U.S. and the world.
Great news! We can finally scratch "driving less" off our list of ways to curb global warming and reduce our dependence on foreign oil! Biofuels will soon not only replace much of our petroleum, but improve soil fertility and save the American farmer as well!
Sound too good to be true? Well, yes. But you could be excused for buying the hype.
Ethanol and biodiesel are being promoted as cures for our energy and environmental woes not just by flacks for corporations like Archer Daniels Midland, BP, and DuPont, but by many eco-minded activists and some prominent environmental groups like the Natural Resources Defense Council as well.
As intuitive as it may seem that fuel from plants would be more benign than petroleum-based fuels, the ecological impacts of biofuel production are more complicated, and wider-reaching, than an environmentalist might first imagine.
For years, some critics have claimed that corn-based ethanol has a negative "net energy balance" - that is, that ethanol requires more energy to produce than it delivers as fuel. But as biofuel production efficiencies have improved, critics have turned their focus to broader sustainability issues.
"Even if corn and soy biodiesel have positive energy balances, that's not enough," says Andy Heggenstaller, a graduate student at Iowa State University researching biofuel crop production. "Large-scale production of corn and soybeans has negative ecological consequences. If biofuels are based on systems that exacerbate soil erosion and water contamination, they're ultimately not sustainable."
Stalk in Trade
Corn is one of the planet's most energy-intensive crops. Industrial corn production requires huge quantities of synthetic nitrogen fertilizers (derived primarily from natural gas) and petroleum-based pesticides like atrazine, a known endocrine disrupter. Soybeans need less nitrogen, but farmers douse bean fields with other nutrients and with chemicals like Roundup to keep them pest-free.
The effects of corn and soybean production in the Midwest include massive topsoil erosion, pollution of surface and groundwater with pesticides, and fertilizer runoff that travels down the Mississippi River to deplete oxygen from a portion of the Gulf of Mexico called the dead zone that has, in the last few years, been the size of New Jersey.
As ethanol use pushes corn prices higher, farmers are increasingly abandoning the traditional corn-soybean rotation to what's known in farm country as corn-on-corn. High prices have encouraged farmers to plant corn year after year, an intensification that boosts fertilizer and pesticide requirements.
Water use has also become a concern as corn production expands into drier areas like Kansas, where the crop requires irrigation. The ethanol boom has sent water demands skyrocketing, putting pressure on already suffering sources like the Ogallala aquifer.
And according to a recent report by the World Resources Institute, stepped-up corn ethanol production means not only increases in soil erosion and water pollution, but increases in greenhouse-gas emissions. "If your objective is reducing greenhouse-gas emissions, you need to be aware of what's happening in the agricultural sector," says Liz Marshall, coauthor of the WRI study.
Ethanol proponents say the fuel emits up to 13 percent fewer greenhouse gases than gasoline. But an increase in emissions on the farm could cancel out benefits from emission decreases at the tailpipe.
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