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The Environmental Downside of Biofuel Crops

A new survey reveals that biofuel crops have expanded onto millions of acres of new land, with serious consequences for the environment.
(Photo: Fabio Alcini/Shutterstock)

(Photo: Fabio Alcini/Shutterstock)

Using corn as a biofuel seems like a good idea in principle. Corn is, after all, renewable, cheap, and relatively low impact. Despite that, there's growing concern that the expansion of biofuel crops into new land areas could have significant environmental and economic drawbacks—something a new, nationwide study appears to confirm. In fact, according to the study, biofuel crops like corn and soy expanded onto seven million new acres between 2008 and 2012, much of that environmentally precious grassland.

Though the researchers behind the new study ultimately focused on the expansion of farmland into new areas, they began with a different question: How can we meet future needs for energy and food while maintaining crucial habitat and biodiversity?

The researchers faced a common dilemma, though. "There wasn't good data," says the new study's lead author, Tyler Lark, a graduate student at the University of Wisconsin-Madison. For much of its history, the United States Department of Agriculture's National Agriculture Statistics Service reported net changes in farmland, but not on where or how farmland is expanding and contracting. In other words, there wasn't enough data to say much of anything about the environmental impacts of crop expansion.

Many of the newly planted crops were on marginal-quality lands, which generally costs more to farm on than higher-quality land.

To access more useful data, Lark and colleagues turned to the USDA's cropland data layer (CDL), a detailed, satellite-based survey of U.S. land use, which began collecting data in 2008. To put any perceived trends into historical context, the team also compared the CDL with data from the U.S. Geological Survey and other sources going back two decades or more.

From 2008 until 2012, the team's analysis revealed, 7.34 million acres—an area roughly the size of Maryland—were turned into corn, soy, and other biofuel croplands, primarily in the Great Plains but also in more surprising places including forest land in the Ozark and Appalachian Mountains.

Most of that land hadn't been cultivated since at least 2001, and about three-quarters was grassland, which brings with it special problems. "Grasslands harbor one of the highest levels of species [diversity] and provide habitat to endangered species" as well, Lark says. They also trap enormous amounts of carbon dioxide in the soil. Digging up grasslands for biofuels likely released the equivalent of an additional 28 million cars on the road for a year, he says.

Beyond that, many of the newly planted crops were on marginal-quality lands, which generally costs more to farm on than higher-quality land. That, Lark says, means the expansion didn't make much sense, economically or environmentally.

While the team makes a number of policy recommendations, including further cuts to subsidies for cropland expansion, Lark says the onus is ultimately on everyday folks. "When we look toward the future, it'll become increasingly important to look at changing diets and reducing food waste," Lark says. Never mind your figure—it's time to eat less for the sake of the planet.

Quick Studies is an award-winning series that sheds light on new research and discoveries that change the way we look at the world.