|WAGNER, MELISSA - Arizona State University|
|WANG, MENG - Arizona State University|
|MIGUEZ-MACHO, GONAZALO - Universidad De Santiago De Compostela|
|MILLER, JESSE - University Of Illinois|
|VANLOOCKE, ANDY - Iowa State University|
|BAGLEY, JUSTIN - Lawrence Berkeley National Laboratory|
|GEORGESCU, MATEI - Arizona State University|
Submitted to: Global Change Biology Bioenergy
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/6/2016
Publication Date: 6/1/2017
Citation: Wagner, M., Wang, M., Miguez-Macho, G., Miller, J., VanLoocke, A., Bagley, J., Bernacchi, C.J., Georgescu, M. 2017. A realistic meteorological assessment of perennial biofuel crop deployment: a southern Great Plains perspective. Global Change Biology Bioenergy. 9(6):1024-1041.
Interpretive Summary: The Earth’s surface is tightly linked with weather patterns. Changes in the land surface, such as increasing the amount of land devoted to crops used specifically for producing energy, can have a large impact on weather and climate. This research coupled plant growth models, ecosystem models, and climate models to determine how the change in land use can impact climate and weather patterns. Perennial bioenergy crops are shown to have a net cooling effect driven by the amount of light being reflected from the plant canopies compared with the traditional crops being replaced. Simulating this effect during a drought showed similar results, but to a much lesser extent. This research outlines the importance of considering how changing vegetation can influence weather, precipitation, and climate events as land use decisions are made.
Technical Abstract: Utility of perennial bioenergy crops (e.g., switchgrass and miscanthus) offer unique opportunities to transition toward a more sustainable energy pathway due to their reduced carbon footprint, averted competition with food crops, and ability to grow on abandoned and degraded farmlands. Studies that have examined the biogeophysical impacts of these crops noted a positive feedback between near-surface cooling and enhanced evapotranspiration (ET), but also potential unintended consequences of soil moisture and groundwater depletion. To better understand hydro-meteorological effects of perennial bioenergy crop expansion, this study conducted high resolution (2 km grid spacing) simulations with a state-of-the-art atmospheric model (Weather Research and Forecasting system) dynamically coupled to a land surface model. We applied the modeling system over the Southern Plains of the U.S. during a normal precipitation year (2007) and a drought year (2011). By focusing deployment of bioenergy cropping systems on marginal and abandoned farmland areas (to reduce potential conflict with food systems), the research presented here is the first realistic examination of hydro-meteorological impacts associated with perennial bioenergy crop expansion. Our results illustrate that deployment of perennial bioenergy crops lead to widespread cooling (1-2 oC) that are largely driven by enhanced reflection of shortwave radiation and secondarily due to enhanced ET. Bioenergy crop deployment was shown to reduce impacts of drought through simultaneous moistening and cooling of the near-surface environment. However, simulated impacts on near-surface cooling and moistening were reduced during the drought relative to normal precipitation year, revealing differential effects based on background environmental conditions. This study serves as a key step towards assessment of hydroclimatic sustainability associated with perennial bioenergy crop expansion under diverse hydrometeorological conditions by highlighting the driving mechanisms and processes associated with this energy pathway.