Des Moines Register: Biofuels producers don’t like to think of themselves as a cause of global warming, but that’s how they could be regulated under the Obama administration’s regulations on greenhouse gases. The regulations, due to take effect in January, would count as greenhouse gases the carbon dioxide that’s released when corn is fermented into motor fuel or when corn stalks, straw and other sources of biomass are burned to make electricity. That means a paperwork and financial burden for most …