Environmental Impacts of Continental Scale Biofuel Production.

The Energy Independence and Security Act (EISA) of 2007 mandates increased production of biofuels to reduce dependency on foreign energy and increase energy sustainability. Millions of acres will be converted to biofuel production to produce the large quantities of biofuels mandated by EISA, potentially changing the regional climate. To investigate the effects of such a change we modeled the effects of switchgrass production in 2022 in sufficient quantities to meet the 2022 mandate for advanced biofuels. Climatology was modeling using WRF, the Weather Research and Forecasting model, with the 1979-2004 North American Regional Reanalysis (NARR) and 1992-1993 NOAH land cover used as a baseline. To simulate biofuel production, county switchgrass acreage estimates for 2022 were drawn from the POLYSYS model and used to alter NOAH land cover. The WRF model output was then used to drive the Iowa Daily Erosion Project and an Upper Mississippi River Basin SWAT models to estimate environmental impacts. Most switchgrass production is predicted to occur in Oklahoma and Kansas, where an increase in evapotranspiration is predicted to lower soil moisture and drive a slight increase in storm intensity and total precipitation in the Midwest. Relatively little switchgrass is expected to be produced in the Upper Mississippi River Basin, resulting in similar estimates for water quality, water quantity, and soil erosion under the baseline and switchgrass production scenarios for most of the basin, however the southern regions of the basin did show a small signal. Lower soil moisture levels and increased residue cover are likely to decrease runoff and water erosion in areas of biofuel production.