Spatially Resolved Greenhouse Gas Emissions of U.S. Milk Production in 2020

Abstract

This study provides a comprehensive and spatially resolved assessment of greenhouse gas (GHG) emissions from the U.S. dairy industry, spanning from cradle to farm gate. The primary goal is to refine emission estimates for key sources, including enteric fermentation, manure, and feed production, using the latest climate science, predictive models, and updated industry data, including a broader range of dietary rations across 12 distinct dairy regions. Compared with previous studies that employed generalized models and less granular data, this approach offers greater accuracy and regional specificity. In addition to establishing the 2020 GHG emissions baseline, we compare the results to 2007 estimates to highlight trends and improvements in emission intensities and production practices. U.S. raw milk production in 2020 generated 138.88 million tonnes of CO₂e, corresponding to an average of 1.38 kg CO₂e per kg of fat- and protein-corrected milk (FPCM), with regional emissions ranging from 1.24 to 1.87 kg CO₂e/kg FPCM. Notably, the study shows that while enteric fermentation and manure emissions remain substantial contributors, their share of total emissions is less than in previous assessments. A sensitivity analysis explores the impact of key methodological choices, ensuring robust results that support mitigation strategies and inform the dairy sector’s path toward net neutrality by 2050.