Submitted to: Climate and Weather Research Workshop Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 9/15/2005
Publication Date: 11/14/2005
Citation: Adler, P.R., Del Grosso, S.J., Parton, W.J., Easterling, W.E. 2005. Determining the long-term impact of bioenergy crops on the global warming potential of energy use [abstract]. U.S. Climate Change Science Program Workshop: Climate Science in Support of Decision Making. p. 62. Interpretive Summary: An interpretive summary is not required.
Technical Abstract: As a provider of climate change information, the presenter will describe a framework to assess the impact of different bioenergy cropping systems (corn, soybeans, alfalfa, switchgrass, reed canarygrass, and hybrid poplar) on the global warming potential (GWP) of energy use and examine how the long-term impact of those predictions vary with climate change. Reducing the net GWP of energy use is a major factor driving interest in biofuels. Bioenergy cropping systems vary in contribution to the GWP due to the following: crop yield and resulting quantity of fossil fuels displaced by the biofuels produced, change in soil organic carbon and belowground biomass carbon, fossil fuels used in feedstock transport to the biorefinery, conversion to biofuel and subsequent distribution, N2O and CH4 emissions, CO2 emission from N fertilizer manufacture, and fuel used by agricultural machinery for tillage, planting, fertilizer/pesticide application, harvesting, and drying corn grain. To conduct a life cycle analysis of the GWP of bioenergy cropping systems, DAYCENT is used to model the dynamic sources and sinks of greenhouse gases (GHGs). Cropping system practices, such as tillage, plant life cycle, and N fertilizer use have a significant impact on GHG emissions. DAYCENT can integrate climate, soil properties, and land use and can dynamically evaluate the impact of cropping systems on crop production, soil C, and trace gas fluxes, factors critical to conducting a full C cycle analysis of bioenergy cropping systems. This approach to determining the GWP of bioenergy cropping systems can be used to extend evaluations from local to regional scales across the United States. By determining the optimal portfolio of bioenergy crops grown regionally, reduction in GWP can be maximized. This analysis can be expanded to include the impact of climate change on crop production and GWP. Weather data driving climate change scenarios are taken from VEMAP for the baseline scenario with no climate change and from the Canadian Centre for Climate Modeling and Analysis (CGCM1model) and Hadley Centre for Climate Prediction and Research, UK (HADCM2 model) for the climate change simulations where CO2 was assumed to double from 2004 - 2100. This modeling approach permits determination of the GWP of bioenergy cropping systems across the United States, including the effect of climate change.