TEMPE, Ariz. A team of researchers from Arizona State University, Stanford University and Carnegie Institution for Science has found that converting large swaths of land to bioenergy crops could have a wide range of effects on regional climate.
In an effort to help wean itself off fossil fuels, the U.S. has mandated significant increases in renewable fuels, with more than one-third of the domestic corn harvest to be used for conversion to ethanol by 2018. But concerns about effects of corn ethanol on food prices and deforestation had led to research suggesting that ethanol be derived from perennial crops, like the giant grasses Miscanthus and switchgrass. Nearly all of this research, though, has focused on the effects of ethanol on carbon dioxide emissions, which drive global warming.
"Almost all of the work performed to date has focused on the carbon effects," said Matei Georgescu, a climate modeler working in ASU's Center for Environmental Fluid Dynamics. "We've tried to expand our perspective to look at a more complete picture. What we've shown is that it's not all about greenhouse gases, and that modifying the landscape can be just as important."
Georgescu and his colleagues report their findings in the early online edition (Feb. 28, 2011) of the Proceedings of the National Academy of Sciences. Co-authors are David Lobell of Stanford University and Christopher Field of the Carnegie Institution for Science, both located in Stanford, Calif.
In their study, the researchers simulated an entire growing season with a state-of-the-art regional climate model. They ran two sets of experiments one with an annual crop representation over the central U.S. and one with an extended growing season to represent perennial grasses. In the model, the perennial plants pumped more water from the soil to the atmosphere, leading to large local cooling.
"We've shown that planting perennial bioenergy crops can lower surfa
|Contact: Skip Derra|
Arizona State University