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

Area of Science:

• Agricultural Science
• Environmental Science
• Climate Change Mitigation

Background:

• Methane (CH4) from cattle manure is a significant source of agricultural greenhouse gas emissions in India.
• Accurate, district-level data on these emissions are crucial for effective mitigation strategies.

Purpose of the Study:

• To conduct a micro/district-level assessment of methane emissions from cattle manure in India for 2012 and 2019.
• To evaluate the potential of six different manure management scenarios for emission reduction and carbon savings.
• To explore the impact of optimizing the Methane Conversion Factor (MCF) on mitigation potential.

Main Methods:

• Utilized the IPCC Tier 2 methodology with India-specific parameters for emission calculations.
• Spatially modelled methane emissions across 698 administrative districts.
• Simulated six manure management scenarios, including anaerobic digestion, biogas flaring, and combined heat and power (CHP) utilization.

Main Results:

• Total methane emissions were estimated at 27.45 Tg CO2e/year in 2019, with hotspots identified in West Bengal, Uttar Pradesh, and Madhya Pradesh.
• Scenario 4 (anaerobic digestion with CHP) showed the highest emission reduction potential (85.65%), while Scenario 6 achieved the greatest absolute carbon savings.
• Optimizing the Methane Conversion Factor (MCF) from 10% to 1% enhanced mitigation potential by up to 153%.

Conclusions:

• Climate-smart manure management offers transformative potential for methane abatement and decentralized energy production in India.
• Current biogas infrastructure utilization is significantly below the national potential.
• The study provides actionable strategies to align manure management with India's climate goals, including NDCs, SDGs, and Net Zero 2070 targets.