Two separate scientific studies released on Feb. 7 asked if converting forests to farm land for ethanol crops will do more environmental harm than good. The studies emerged as a US Senate committee held a hearing on impacts of the new Renewable Fuels Standard on energy markets.
"Homegrown biofuels are good energy policy, good environmental policy and good national security policy. However, there is some concern that the RFS as enacted risks taking the biofuels industry backward rather than pushing it ahead," Senate Energy and Natural Resources Committee Chairman Jeff Bingaman (D-N.M.) said as he opened the hearing.
"I am particularly concerned about three aspects of the RFS: first, early-year biofuel requirements could be too aggressive; second, mandates for specific technologies and feedstock could prove to be overly prescriptive; finally, the environmental restrictions may be too narrow," he continued.
The Bush administration and Congress continue to support biofuels. "The Department [of Energy] actively supports biofuels production, from the most basic science research activities to efforts toward the integration of advanced biofuels into the national energy supply," Alexander Karsner, DOE's assistant secretary for energy efficiency and renewable energy, said in his written testimony.
But the studies, which came out after the hearing, questioned the assumption that substituting biofuels for gasoline will reduce greenhouse gases.
Land conversion impacts
"Most prior studies . . . have failed to count the carbon emissions that occur as farmers worldwide respond to higher prices and convert forest and grassland to new cropland to replace the grain (or cropland) diverted to biofuels," said the first report, published in the online edition of Science, the American Academy for the Advance of Science's weekly magazine.
Timothy Searchinger, a visiting research scholar in the science, technology and environmental program at Princeton University's Woodrow Wilson School of Public and International Affairs, was the report's lead author. Researchers from Iowa State University's Center for Agricultural and Rural Development, the Woods Hole Research Center in Falmouth, Mass., and Agricultural Research Economics in Laurel, Md., also contributed.
"Using a worldwide agricultural model to estimate emissions from land use change, we found that corn-based ethanol, instead of producing a 20% savings, nearly doubles greenhouse emissions over 30 years and increases greenhouse gases for 167 years. Biofuels from switchgrass, if grown on US corn lands, increase emissions by 50%. This result raises concerns about large biofuel mandates and highlights the value of using waste products," they said.
The second study, by the Nature Conservancy and the University of Minnesota, raised the issue of "carbon debts" which could result from clearing land to plant crops for biofuels. It suggested that converting rain forests, peat lands, savannas or grasslands to produce biofuels in Brazil, Southeast Asia and the United States could release 17 to 420 times more carbon dioxide than the fossil fuels they replace. "Soybean biodiesel produced on converted Amazonian rainforest would incur a biofuel carbon debt that would require approximately 320 years to repay," it said.
"Analysis suggests that biofuels produced on converted lands could, for long periods of time, be greater net emitters of greenhouse gases than the fossil fuels they typically displace. For current or developing biofuels technologies, any strategy to reduce greenhouse gas emissions that causes land conversion from native ecosystems is likely to be counterproductive," the study continued.
'Ignores key factors'
One leading biofuels advocate responded promptly. "Assigning the blame for rain forest deforestation and grassland conversion to agriculture production solely to the renewable fuels industry ignores key factors that play a greater role," Renewable Fuels Association President Bob Dinneen said of the report in Science.
"The continued growth of the global population, surging global demand for food from expanding middle classes in China and India, and continued expansion of development and urban sprawl are all factors contributing to the demand for arable acres," he suggested.
Without biofuels and increased fuel economy, more petroleum will be needed to meet growing liquid fuels demand worldwide, Dinneen continued. "As the 'easy' sources of oil decline, development of exotic resources, like tar sands in Canada, is being pursued. Tar sands, by comparison, release some 300% more greenhouse gas emissions than traditional petroleum recovery," he said.
National Petrochemical and Refiners Association President Charles T. Drevna said that the studies prove that hasty political action can sometimes have the opposite effect of what was intended. "Calling the studies simplistic, as biofuel interests have, doesn't eliminate the inconvenient truth or change the facts about ethanol and greenhouse gases," he said.
Biofuels probably will remain a significant part of the US energy strategy. But questions about their benefits are growing louder.
Contact Nick Snow at [email protected].
