Livestock rearing as a key component of mitigation efforts for non-CO2 greenhouse gas emissions in global crop-livestock system

Non-carbon dioxide greenhouse gas (non-CO2 GHG) emissions from global crop-livestock systems, primarily driven by enteric fermentation and manure-related emissions, pose significant challenges to climate mitigation. Identifying emission hotspots and simulating future mitigation potential are crucial for achieving agricultural carbon neutrality. Constructed a comprehensive dataset spanning 138 countries (1961–2020), integrating FAO statistics, literature-derived emission factors, and socioeconomic data, this study quantified spatiotemporal emission trends and identified decoupling patterns between emissions and economic development. The Logarithmic Mean Divisia Index (LMDI) was used to decompose drivers and six scenarios (BAU (Baseline), RSA (Rearing Structure Adjustment), LMO (Livestock Management Optimization), BMPs-30% and BMPs-50% (best management practices with a manure substitution ratio of 30% or 50%), and NMA (No Manure Application)) were developed to assess mitigation potential. Results revealed that global non-CO2 GHG emissions from crop-livestock systems increased by 61.9% from 2696.5 to 4365.0 Mt CO2-eq. yr−1 from 1961 to 2020, with India, Brazil, China, and the United States accounting for about 40% of total emissions in 2020. Significant decoupling occurred in developed countries, such as the United States, around in 1985 at approximately $10,000 per-capita GDP. In developing countries like China, significant decoupling was evident around in 1990 at approximately $3000 per-capita GDP. Ambitious scenarios (BMPs-50%) could reduce global emissions by 3.2–6.7 Gt CO2-eq. yr−1 by 2060, with major contributions from India (671.3 Mt CO2-eq. yr−1), Brazil (494.2 Mt CO2-eq. yr−1), China (486.1 Mt CO2-eq. yr−1), and the USA (238.8 Mt CO2-eq. yr−1). The findings confirmed the decoupling of non-CO2GHG emissions within crop-livestock systems from economic growth in developed countries but highlight persistent challenges in developing regions. Strategic shifts toward monogastric livestock, manure recycling, and dietary transitions emerge as critical pathways for aligning food security with carbon neutrality goals.