A study by the University of Wisconsin says carbon emissions increase when land is converted into crops for ethanol. The study released this week says the carbon emissions increase since the ethanol mandate in 2007 is equivalent to 20 million new cars driving on America’s roadways every year.

The Milwaukee Journal Sentinel reports the study underscores the unintended consequences of a federal policy meant to reduce America’s reliance on fossil fuels. While adding ethanol means burning fewer fossil fuels, the study found that the benefits were lost as even greater amounts of carbon held in the soil were released into the atmosphere in newly cultivated farm fields.

The study noted major land changes between 2008 and 2012, and the shifting of more than seven million acres into cropland.

The Renewable Fuels Association responded to the study, saying the results were “grossly overstated.” The association pointed out that corn production has fallen more than three percent between 2007 and 2017, while production per-acre increased by 16 percent over that time.

From the National Association of Farm Broadcasting News Service.