Corn-based ethanol may have worse environmental impacts than fossil fuels, according to a new study that concludes the United States biofuel program has failed to meet emissions targets while delivering negatives impacts on water quality, land used for conservation, and other ecosystem processes.
“We thought and hoped it would be a climate solution and reduce and replace our reliance on gasoline,” said Tyler Lark, a researcher with the Nelson Institute for Environmental Studies at the University of Wisconsin, Madison. But biofuel turns out to be no better for the climate than the gasoline it aims to replace, and it comes with “all kinds of other impacts,” he told Inside Climate News.
Bioenergy is an important component of many proposed pathways that limit global warming because it can displace fossil fuels. However, several factors can influence its effectiveness, including additional plant growth and changes in land use management, the study explains.
The study, published in the Proceedings of the National Academy of Sciences, looks at the effects of the U.S. Renewable Fuel Standard, which requires fuel blenders to add billions of gallons of renewable fuel to the nation’s transportation fuel supply and mandates that product must generate life-cycle emissions savings of at least 20% compared to gasoline. The policy’s regulatory analysis projected that corn ethanol would reach that target by 2022, even after allowing for emissions from land use changes, the researchers write.
Although the RFS was initially touted as an environmental victory, the study finds that it has not lived up to its potential. In addition to fuel demand continuing unabated, seven million acres of grasslands and forests have been converted into cropland each year under the RFS, causing negative environmental impacts like nitrate leaching, phosphorus runoff, and soil erosion and releasing carbon otherwise stored in natural ecosystems. As a result, corn ethanol’s fuel intensity is not less than gasoline’s, and could be at least 24% higher, reports Inside Climate.
The Renewable Fuels Association (RFA) is challenging the study’s findings. “The claims in this report simply don’t align with reality and the facts on the ground, and the paper reads more like a fantasy novel than a genuine piece of academic literature,” the lobby group writes. The RFA says cropland devoted to corn has not expanded since the standard’s onset, Inside Climate writes.
But Lark pushed back on that assumption. “What’s important is what would have happened without the RFS, without this ethanol boom,” he said.. “Without this policy, there would have been a big decrease in corn.”