14 Both biofuels and bioplastics are often regarded as sustainable solutions to current environmental problems 15 such as climate change, fossil depletion and acidification. However, both have been criticized for being 16 economically costly, competing with other societally beneficial goods such as food, and offering limited 17 environmental benefits compared to their fossil counterparts. This study provides a comparative 18 environmental Life Cycle Analysis (LCA) for 100% bio-based polyethylene terephthalate (PET) bottles, 19 versus fully fossil-based and partially bio-based PET bottles. An attributional life cycle assessment (aLCA) 20 and sensitivity analysis of key assumptions is carried out to compare cradle-to-factory-gate impacts (i.e. 21 feedstock extraction, component production and product manufacturing) of twelve PET bottle production 22 scenarios. Results indicate that woody-biomass based PET bottles have 21% less global warming potential 23 and require 22% less fossil fuel than their fossil based counterparts, but perform worse in other categories 24

Corn production, and its associated inputs, is a relatively large source of greenhouse gas emissions and uses significant amounts of water and land, thus contributing to climate change, fossil fuel depletion, local air pollutants, and local water scarcity. As large consumers of this corn, corporations in the ethanol and animal protein industries are increasingly assessing and reporting sustainability impacts across their supply chains to identify, prioritize, and communicate sustainability risks and opportunities material to their operations. In doing so, many have discovered that the direct impacts of their owned operations are dwarfed by those upstream in the supply chain, requiring transparency and knowledge about environmental impacts along the supply chains. Life cycle assessments (LCAs) have been used to identify hotspots of environmental impacts at national levels, yet these provide little subnational information necessary for guiding firms' specific supply networks. In this paper, our Food System Supply-Chain Sustainability (FoodS) model connects spatial, firm-specific demand of corn purchasers with upstream corn production in the United States through a cost minimization transport model. This provides a means to link county-level corn production in the United States to firm-specific demand locations associated with downstream processing facilities. Our model substantially improves current LCA assessment efforts that are confined to broad national or state level impacts. In drilling down to subnational levels of environmental impacts that occur over heterogeneous areas and aggregating these landscape impacts by specific supply networks, targeted opportunities for improvements to the sustainability performance of supply chains are identified.

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Within the US, supply chains aggregate agricultural production and associated environmental impacts in specific downstream products and companies. This is particularly important for meat and ethanol, which consume nearly half of global crop production as feed and feedstocks. However, lack of data has thus far limited the ability to trace inputs and impacts of commodity crops through domestic supply chains. For the first time, we use a commodity-flow model to link spatially distributed water resource impacts of corn and soy to individual meat and ethanol processing facilities. This creates transparency in the supply chains, illuminating substantial variation in embedded irrigation water and water scarcity footprints among meat and ethanol processed at different facilities. By calculating unique blue water scarcity footprints for end-products, we show that beef processed in Iowa or Illinois, for example, has fewer water impacts than chicken processed in California and pork processed in Oklahoma. We find that over 75% of irrigated feed embedded in meat is consolidated in six companies and 39% of irrigated feedstock for ethanol is consolidated in five companies, with potentially negative impacts to supply costs and risk management. This subnational variation and consolidation of impacts in key supply chains creates opportunities for producers and consumers of agriculture-based products to make management, investment, and sustainability decisions about those products.

SummaryIncreasingly, organizations are working to reduce the environmental footprint of their supply chains. The use of environmentally preferable purchasing criteria is one strategy organizations use to address this goal. However, evaluating the environmental performance of these criteria (e.g., recycled content, biodegradable, renewable, and so on) has remained elusive. Life cycle assessment (LCA) can measure the impact reduction potential of sourcing strategies. However, full process-based LCAs are time-consuming and costly across multiple criteria of thousands of products and inputs purchased in an organizational setting. A streamlined "hotspot" methodology is presented using a combination of environmentally extended economic input-output (EEIO) approaches and extant literature to identify hotspots in which to constrain a parameterized process-based LCA. A case study of breakfast cereal manufacturing is developed to (1) assess the efficiencies associated with the hotspotting approach and (2) demonstrate its applicability in generating comparable decision signals of environmentally preferable sourcing criteria for procurement and supply-chain managers along the dimensions of global warming potential and water use.