Greenhouse Gas Emissions and Mitigation Potential in U.S. Dairy Production: A Meta-Analysis

Dairy production is a major source of agricultural greenhouse gas (GHG) emissions in the United States, yet existing life cycle assessment (LCA) studies differ widely in methodological choices and reported emission levels. This review synthesizes 27 cradle-to-farm-gate LCA studies published between 2009 and 2025 to assess emission heterogeneity and evaluate the effectiveness of commonly reported mitigation strategies. Reported GHG intensities span a broad range from 0.76 to 2.10 kg CO2-e/kg fat- and protein-corrected milk, reflecting variation in production systems, regional conditions, and management practices. To enable consistent comparison across studies, we introduce an intra-study mitigation potential metric that standardizes emission-reduction outcomes relative to each study’s baseline scenario. Analysis of 187 scenarios shows that cattle, feed, and manure management strategies are most strongly associated with higher mitigation potential, whereas field and energy management yield smaller or more context-dependent effects. Mitigation potential increases substantially when multiple strategies are combined, highlighting the importance of integrated approaches rather than single-practice interventions. These findings suggest that policy instruments such as cost-share initiatives may achieve greater emission reductions when they promote bundled interventions and prioritize cattle and manure management. The review also identifies key gaps in current LCA research, particularly the lack of farm-level economic assessments needed to evaluate cost-effectiveness and support realistic adoption. To reflect global diversity in dairy systems, expanding comparative research across additional countries and regions will be essential for identifying mitigation strategies that are both effective and transferable across varied production contexts.