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. They emerged as a US Senate committee held a hearing on the new Renewable Fuels Standard’s (RFS) impact 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-NM) said as he opened the hearing.
He expressed particular concern that early-year biofuel requirements could be too aggressive, mandates for specific technologies and feedstock could be overly prescriptive, and environmental restrictions could be too narrow. Congress as well as the Bush administration continue to support biofuels. 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 in Science, the American Academy for the Advance of Science’s weekly magazine.
“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%,” the report said.
The second study, by the Nature Conservancy and the University of Minnesota, raised the issue of “carbon debts” that could result from clearing land to plant crops for biofuels. “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,” 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 Pres. 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.
Biofuels probably will remain a significant part of the US energy strategy. But questions about their benefits are growing louder.