Methane emissions from cattle manure in India: A scenario-based comprehensive study

Methane (CH₄) from cattle manure is a major contributor to agricultural greenhouse gas emissions in India. This study presents a comprehensive, micro/district-level assessment of methane emissions from cattle manure for 2012 and 2019 using IPCC Tier 2 methodology and India-specific parameters. Emissions were spatially modelled across 698 administrative districts, revealing total emissions of 27.45 Tg CO₂e/year in 2019, with notable hotspots in West Bengal, Uttar Pradesh, and Madhya Pradesh. Six manure management scenarios (S1-S6) were developed to simulate technological interventions ranging from basic practices to anaerobic digestion, biogas flaring, combined heat and power (CHP) utilization, biomethane upgrading, and digestate fractionation. Scenario 4-featuring anaerobic digestion with CHP-demonstrated the highest emission reduction potential (85.65 %), while Scenario 6 offered the highest absolute carbon savings (68,646.05 Gg CO₂e/year). Methane Conversion Factor (MCF) optimization from 10 % to 1 % further increased mitigation potential up to 153 %, indicating the significance of process control. However, results indicated that the current biogas infrastructure covers less than 4 % of the manure-based biogas potential in India. This study highlights the transformative potential of climate-smart manure management for methane abatement and decentralized energy production. The results offer actionable strategies to align cattle manure treatment with India's Nationally Determined Contributions (NDCs), Sustainable Development Goals (SDGs), and Net Zero 2070 targets through targeted investments, policy reform, and technology deployment.