Contradictory mandates covering the biofuels sector, "could slow or halt the growth of some parts of the biofuels industry", according to Iowa State University Biofuels Economist Dr. Robert Wisner.  Wisner's comments, made in a recent article on the Agricultural Marketing Resource Center website, specifically focussed on the actions of the US Environmental Protection Agency (EPA) and the California Air Resources Board (CARB) which, he said, are moving too fast in relying on unproven "indirect land use emissions impacts." He writes that instead of downgrading the environmental benefits of US corn-based ethanol based on possible conversion of pasture and forests to cropland in other countries, "Much more research is needed on these issues to accurately measure indirect land use impacts."

EPA and CARB programs for reducing greenhouse gas emissions could make both soy-based biodiesel and corn-based ethanol uncompetitive. As a result, investors could pull back from building biodiesel and ethanol plants. That pull back in turn could undermine the biofuel industry's ability to meet the federal Energy Independence & Security Act's requirement for increasing biofuels use.

 Wisner notes that EPA's indirect land use calculations ignore the fact that agriculture is constantly changing. He writes that "direct emissions from biofuels refineries are being reduced over time through technological advances. . . Longer-term technological changes that bring increased crop yields per acre, changes in livestock and poultry feed conversion efficiency that reduce feed needs per animal, the amount of crop residue left on soils, and other factors will affect indirect land use emissions." He adds that proposed CARB rules present the greatest threat since "California is the largest potential market in the US for biofuels and at least 13 other states are considering adoption of its standards."

Wisner's article, "Biofuels and Greenhouse Gas Emissions on a Collision Course" can be read in full here .