Biofuels made from the leftovers of harvested corn plants are worse than gasoline for  global warming in the short term, a new study shows, challenging the Obama administration's  conclusions that they are a much cleaner oil alternative and will help combat climate change. A $500,000 study – paid for by the federal government and released Sunday in the peer-reviewed  journal Nature Climate Change – concludes that biofuels made with corn residue release 7% more
 greenhouse gases in the early years compared with conventional gasoline.
The biofuel industry and administration officials immediately criticised the research as flawed.  They said it was too simplistic in its analysis of carbon loss from soil, which can vary over a  single field, and vastly overestimated how much residue farmers actually would remove once the market gets underway.
http://www.theguardian.com/environment/2014/apr/20/corn-biofuels-gasoline-global-warming