U.S. and European mandates for subsidies of cellulosic ethanol production and use have uncertain environmental consequences according to an international group of scientists which includes researchers from the University of Oklahoma and Oklahoma State University.
The 23-member group co-authored an article on the need for a science-based policy to address this global issue for the Oct. 3 issue of Science magazine. Linda Wallace, OU botany professor, and Michael Palmer, OSU botany professor, believe biodiversity in biofuels production may contribute to its long-term success.
Wallace was the first to introduce the idea of a symposium on this topic to the Ecological Society. She urged the society to address the ecological sustainability of biofuels production before more problems were created than solved. The society gave Wallace the green light in 2007 to organize a symposium on the subject.
At the second symposium held earlier this year, Wallace and Palmer co-chaired a working group on biodiversity and biofuels. Both researchers agree that multiple species contribute to the stability of a system needed to sustain an environmentally and economically viable biofuels industry.
"We know ethanol produced from corn has both environmental and economical challenges. And, we are studying the downside of the more popular switchgrass species even though funding for its use is already in place," says Wallace.
Switchgrass may not be the best species for ethanol production, but it is much better than corn which is used in many food products. However, native grasses are much more viable than the alternatives. Where feedstock production is planned, there are also species-rich native prairies. Native grassland, especially the tallgrass prairie, is highly endangered.
Palmer proposes hay meadows as an option for the production of cellulosic ethanol. "In Oklahoma, we have a century-old tradition of hay meadows where we've cut the grasslands for hay and have had continuous yields all that time," Palmer said. "These grasslands can be extremely diverse and really good for wildlife."
Wallace believes we should let native grasses grow and then harvest them after the first frost. Using a gasification process developed at OSU, the grasses can be used for ethanol production. Wallace says we should not limit our options to just one species though.
Palmer agrees citing several "unintended consequences" as the potential result of pursuing a narrow range of feedstocks for ethanol production. These include the introduction of invasive species, increased soil erosion and the release of additional nitrous oxide—a powerful greenhouse gas.
Rather than react to the energy crisis with another potential crisis, both researchers suggest collecting the right kind of data now to find out if cellulosic ethanol production is sustainable. Ecological research supports stability in cultures with multiple species, but both Wallace and Palmer say we need to more thoroughly examine the options.
"We have to think long term," says Wallace. "Our future depends on it."
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Science