Hundreds of thousands of acres of grasslands and wild habitat in the Upper Midwest have been plowed up to plant corn and soybeans in the past decade because of demand created by the government's ethanol mandate, according to a trio of academic researchers who argue that federal biofuels policy is causing more environmental harm than good.
Their study, released Thursday, found that the shift has destroyed crucial habitat for monarch butterflies and increased the use of chemical fertilizers, while causing the release of millions of tons of carbon dioxide — equal to putting about 5 million more cars on the road each year.
The study was completed in response to a 2018 report by the U.S. Environmental Protection Agency (EPA) and designed to quantify exactly how much new cropland was brought into production nationally as a direct result of the ethanol mandate. The EPA report laid out much of the potential environmental damage caused by increases in row cropping, but couldn't specify how much reflected demand for ethanol and how much reflected other market factors. Several environmental groups are pressing Congress to revise federal biofuels standards in a way that moves away from corn and soy-based ethanol.
"For years we've known that agricultural lands have been changing," said Tyler Lark, associate researcher at the University of Wisconsin, one of the study's authors. "Thanks to this new research we finally know exactly how much of that additional corn and cropland is due to the Renewable Fuel Standard."
The standard, which requires refiners to blend a certain amount of gasoline with biofuels, was created in 2007 and meant to curb greenhouse gas emissions. But the production of biofuels from environmentally friendly "advanced" sources such as grasses or plant and animal waste has lagged behind what lawmakers expected more than a decade ago. Instead, biofuels have been almost entirely produced from corn and soybeans.
The study estimates that 1.6 million acres of grass and wetlands nationally were converted to grow crops because the demand for ethanol inflated the prices of corn and soybeans. Another 1.2 million acres of existing farmland, especially in the Midwest, would have been retired to pasture or conservation lands were it not for the mandate.
Add that to the millions of acres of farmland that were switched to corn from other crops and the mandate is responsible for adding about 300,000 tons of nitrogen fertilizer a year that has been draining into waterways and causing algae blooms and dead zones, the study found.
"There is no dispute that U.S. biofuels policy is driving environmental harm," said Aaron Smith, agricultural and resource economics professor at University of California-Davis, one of the authors.
