Field-level analysis of cropland changes across the United States between 2008 and 2012, combined with satellite data on changes in land cover, shows that the biofuel boom makes a significant contribution to global carbon pollution, according to a paper in the journal Environmental Research Letters.
“The estimated greenhouse gas emissions from land converted to corn and soy alone were equivalent to a year’s release from 34 coal-fired power plants or an additional 28 million cars on the road,” says lead author Tyler Lark of the University of Wisconsin-Madison. “That’s comparable to over a 10% increase in the amount of U.S. vehicles and their emissions.”
Across all farm products, “7.3 million acres of land—an area the size of Maryland—were converted to crop production,” Lark reports. Much of the conversion involved grasslands and marginal land, and “the environmental impacts and economic costs of new croplands are likely to be greater than already-existing croplands.”
The study points to the Dakotas, southern Iowa, and the western parts of Kansas, Oklahoma, and the Texas panhandle as “local hot spots” where more than 10% of the land was converted to crop production during the study period, Environmental Research Web reports. Lark and his colleagues are calling for changes to the U.S. Renewable Fuels Standard to bar biofuel feedstocks from being planted on lands cleared since 2007.