Corn-based ethanol harms climate more than gasoline, says study

The U.S. Navy’s Tomahawk missiles also have been running on corn since 2020.

Ameya Paleja

| Feb 17, 2022 08:21 AM EST

Created: Feb 17, 2022 08:21 AM EST

science

An ethanol plant.BanksPhotos/iStock

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For over a decade and a half, pumps in the U.S. have been blending gasoline with ethanol produced from corn, as it was believed that the mixture was less dangerous the gasoline itself. Now a recently published study says that the environmental impact of this blending might be worse than if only gasoline were used, Reuters reported.

In 2007, the U.S. government brought into effect the Renewable Fuel Standard that permitted a partial replacement of gasoline with biofuels, such as those made from corn. The main aim of this move was to reduce the carbon emissions from burning fuel for transportation, which is the major contributor of greenhouse emissions in the U.S. Biofuels could be burnt while emitting 20 percent less carbon, which makes them an ideal replacement for gasoline. Taking it a step further, the U.S. Navy also began using corn fuel in its Tomahawk missiles.

Unanticipated adoption

According to researchers Tyler Lark and Professor Holly Gibbs at the University of Wisconsin-Madison, this shift to using corn-ethanol has contributed to an increase in emissions in the U.S. than it would have occurred had only gasoline been used as fuel.

While the U.S. Environmental Protection Agency had the right intent while effecting the Fuel Standards in 2007, it did not anticipate the sharp uptick in the adoption of corn as a commodity crop following the new legislation.

In a university press release, Lark and Gibbs said that crop prices rose significantly after 2007. Following the Enactment of the Fuel Standards, corn prices increased by as much as 30 percent, leading to an expansion in corn cultivation. While cropland usage had been declining for the previous three decades, the change in federal policy resulted in an increase of nearly nine percent as 6.9 million acres of land were brought under corn cultivation between 2008 to 2016.

The increased cultivation also meant that more fertilizers have been used each year on these lands while also contributing to water quality degradation in their wake. Nitrates from fertilizers end up contaminating the soil and drinking water, forcing municipalities to set up water treatment plants. Put together with the emissions attributable to land-use changes, the effective carbon emissions from corn-ethanol usage could be as high as 24 percent, the researchers said.

All not lost

While the study's findings are shocking, the researchers add that blending of gasoline has been helpful so far in integrating renewable fuels into gasoline. With the development of advanced biofuels such as those made from switchgrass or waste materials, we can focus on using a replacement fuel that is sourced in a more sustainable manner.

Coincidentally, the blending mandate set by Fuel Standards expires this year, providing the Environmental Protection Agency a chance to reform its policies in the light of new data.

However, the Renewable Fuels Association, a trade lobby for use of ethanol in fuel called the study "fictional" and "erroneous" while accusing the authors of cherry-picking data. The study was published in the Proceedings of the National Academy of Sciences and funded in part by the National Wildlife Federation and the U.S. Department of Energy.