(Bloomberg) -- A U.S. program requiring the use of corn-based ethanol in the nation’s gasoline supply hasn’t curbed greenhouse gas emissions, according to a study from the University of Wisconsin-Madison published Monday.

The federal Renewable Fuel Standard has spurred American farmers to escalate land use for corn plantings, leading to more pollution from increased fertilizer use and degraded water quality, according to the report. All of that contributes to carbon emissions from the biofuel that are likely at least 24% higher than gasoline, the study said. 

The study was funded in part by the National Wildlife Federation, a conservation nonprofit that has been a vocal critic of the Renewable Fuel Standard.

The Renewable Fuels Association, an industry trade group, disagreed with the findings. Chief Executive Officer Geoff Cooper called its methodology “fundamentally flawed,” citing the research team’s use of satellite imaging. A U.S. Department of Agriculture report in 2019 said greenhouse gas emissions from corn-based ethanol were 39% lower than gasoline over the entire life cycle, from initial production of raw materials to eventual combustion in vehicles.

The study comes amid a political debate between biofuel supporters on the one hand and an unlikely alliance between oil refiners and some environmentalists who support an overhaul of the federal standard on the other. The Environmental Protection Agency is expected this year to propose new biofuel targets for 2023 and beyond. 

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