Estimating land-use change effects associated with supplying a billion-ton U.S. bioeconomy

Background/Question/Methods: How much biomass can be supplied sustainably in the US to support our needs for food, feed, fiber, materials and energy? What are the implications for US ecosystems and land management under scenarios to produce over 1 billion dry metric tonnes of biomass per year? This study aims to answer these questions with a focus on the potential consequences of land-use change (LUC) under projected supply scenarios that were developed by the federal government in the 2016 Billion-Ton Report: Advancing Domestic Resources for a Thriving Bioeconomy (DOE 2016). Methods: the sources of projected supplies and land allocations from 2015 to 2040 under three scenarios (business as usual, base case, and high yield) are analyzed to examine how land allocations differ among cases and to estimate key ecological risks and implications associated with LUC.

Results/Conclusions: The analysis identifies where potential concerns and opportunities arise associated with the different biomass supply simulations. For example, the primary type of LUC associated with supply scenarios involves changes in agricultural land management practices: the area managed as perennial cover in 2040 is 10 million hectares greater under base case biomass supply simulations than under business as usual. Additional changes occur to improve management through fencing and rotation on about 15 million hectares of pasture under biomass supply simulations. This study puts these changes into the context of the overall US agricultural landscape. Potential ecological implications of exotic species and displacing diverse unimproved pasture with monoculture crops are also discussed. Sensitivities and uncertainties associated with the analysis are reviewed including the important role of how parameters for the reference case (business is usual) are defined. Because biomass markets can interact with drivers of LUC in different ways, the potential effects on global deforestation and food security are described. The analysis illustrates how inconsistent use of terms and parameters can lead to widely divergent results when estimating LUC. We conclude with recommendations describing science-based approaches to address the LUC analysis challenge. For more information including research team members, see https://bioenergykdf.net/billionton2016/overview