Life Cycle Assessment of Greenhouse Gas Emissions Associated with Production and Consumption of Peanut Butter in the U.S.

Abstract

<abstract> <bold><sc>Abstract.</sc></bold> The U.S. produced 2.6 billion kg of peanuts during the 2012 growing season, up from 1 billion kg in 2002, a 160% increase. Over $2 billion worth of peanuts were produced in seven key states: Alabama, Georgia, Oklahoma, North Carolina, South Carolina, Texas, and Virginia. Approximately 32% of U.S. peanuts were made into peanut butter, representing $850 million in sales. The goal of this study was to quantify the greenhouse gas (GHG) emissions associated with the production, consumption, and disposal of peanut butter packaged in the U.S. A life cycle assessment (LCA) model was created in SimaPro 7.3, and a combination of sources including peer-reviewed literature, producer surveys, and experts’ opinions were used to develop and populate a comprehensive model of the peanut butter life cycle from cradle to grave. The system boundaries included peanut production on farm, shelling, blanching, roasting, peanut butter manufacture, consumer use, and package disposal. The functional unit (FU) was 1 kg of peanut butter consumed by U.S. consumers. GHG impacts were assessed using the IPCC 2007 global warming potential (GWP) methodology. A Monte Carlo analysis was performed in order to determine the 90% confidence interval of the mean GHG emissions. The Monte Carlo analysis indicated that CO₂e emissions were between 2.38 and 3.49 kg CO₂e per FU at a 90% confidence interval with a mean of 2.88. The processor subsystem contributed the greatest amount of GHG to the system (1.01 kg CO₂e), followed by consumer use and disposal (0.84 kg CO₂e) and retail (0.51 kg CO₂e).