Greenhouse Gas (GHG) Emissions from Rice Cultivation
Context
- A recent study has identified India’s irrigated rice fields as a significant source of methane emissions, releasing nearly 3.9 million tonnes of methane annually, making the country one of the world’s major agricultural emission hotspots.
- The assessment analysed greenhouse gas emissions from global rice cultivation between 1961 and 2020, focusing on methane (CH₄), nitrous oxide (N₂O), and changes in soil carbon stocks.
Key Findings
Rising Emissions
- Greenhouse gas emissions from rice cultivation have more than doubled over the past six decades, reaching nearly 1.1 billion tonnes of CO₂ equivalent each year.
Major Emission Hotspots
- Asia continues to account for the largest share of emissions, mainly because of intensive rice cultivation and widespread incorporation of crop residues.
- Africa has emerged as a rapidly growing hotspot following a nearly seven fold increase in rice cultivation area.
- Within India, the Indo Gangetic Plain, Odisha, and several eastern coastal regions record particularly high emission levels due to extensive irrigated paddy farming.
Factors Driving Emissions
- Expansion of Rice Area: Growth in paddy cultivation has converted more than one-third of rice fields from acting as carbon sinks to becoming net carbon sources.
- Higher Agricultural Inputs: Greater use of crop residues and nitrogen based fertilisers rising by around 76% since 2000 has intensified microbial activity, resulting in increased methane and nitrous oxide emissions.
Mitigation Measures
- Alternate Wetting and Drying (AWD) irrigation can substantially reduce methane emissions while maintaining crop productivity.
- Improving nitrogen fertiliser efficiency and limiting excessive incorporation of crop residues can further lower emissions.
- Adoption of these climate smart practices can reduce paddy related greenhouse gas emissions by about 10% without affecting rice yields.