A spatially explicit greenhouse gas footprint of beef production supply chains in the United States

Miller, Anona Leigh (2022) A spatially explicit greenhouse gas footprint of beef production supply chains in the United States. Masters thesis, Northern Arizona University.

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Abstract

Across all food products, beef has consistently been reported as having one of the largest greenhouse gas (GHG) footprints. In order to reduce the amount of GHGs emitted as a result of beef production, a better understanding of the GHG emissions linked to the complexities of the beef supply chain is critical. Here we estimate the GHG footprint attributed to domestic beef consumption in major U.S. metropolitan areas and non-metro regions using a spatially and temporally explicit model of the U.S. beef production supply chain network which tracks the flow of feed, cattle, and beef from origin to destination. The beef production network was created for the year 2012 using commodity flow data from the Commodity Flow Survey and Freight Analysis Framework, commodity production data, and leverage network principles. A life-cycle assessment based on the resulting beef production network is conducted using GHG emission factors and energy consumption data obtained through a comprehensive literature review and established GHG accounting protocols. We estimate a U.S. average GHG footprint of 8.7 ± 3 kg CO2e/lb retail beef. Cattle production contributes the vast majority (75%) of GHG emissions related to beef production with enteric-fermentation alone contributing 66%. Across all domestic beef destinations (except Alaska and Hawaii), the proportional contribution of GHG emissions from each step of the supply chain to the total supply chain GHG footprint was relatively consistent. Though transport as a emissions source showed the greatest range in emissions relative to other sources in individual beef supply chains, at the national level transportation only accounts for 4% of beef supply chain emissions. This underscores the importance of addressing feed and cattle production practices, particularly enteric fermentation as the largest emissions source, as opposed to focusing only on reducing vehicle miles traveled within the supply chain. Unlike previous work that focuses on calculating GHG emissions for either one individual region or generalized across the U.S., this study developed a hybrid life cycle assessment - urban metabolism approach combined with regional-level commodity flow data to track GHG emissions for individual beef supply chains in a manner that is inclusive of and comparable across each metro- and non-metropolitan area.

Item Type:	Thesis (Masters)
Publisher’s Statement:	© Copyright is held by the author. Digital access to this material is made possible by the Cline Library, Northern Arizona University. Further transmission, reproduction or presentation of protected items is prohibited except with permission of the author.
Keywords:	beef; food systems; footprint; Greenhouse gas emissions; life cycle assessment; mitigation
Subjects:	S Agriculture > SF Animal culture
NAU Depositing Author Academic Status:	Student
Department/Unit:	Graduate College > Theses and Dissertations College of the Environment, Forestry, and Natural Sciences > School of Earth Sciences and Environmental Sustainability
Date Deposited:	06 Jun 2023 17:22
Last Modified:	18 Aug 2023 08:30
URI:	https://openknowledge.nau.edu/id/eprint/5968

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