Low-Methane Rice: How Alternate Wetting and Drying Can Cut Emissions From Paddy Fields
A recent analysis pointed out that rice feeds more than half of the world's people, but its flooded fields are a major source of methane, a strong heat-trapping gas.
Rice paddies give out about 7,870 kg of CO2-equivalent (CO2e, a common unit that converts all greenhouse gases into "how much carbon dioxide would cause the same warming") per hectare each year.
Rice is linked to about 1.5% of all greenhouse gas emissions in the world, about 48% of emissions from cropland and about 10% of global methane emissions.
The suggested fix is low-methane rice farming, mainly through Alternate Wetting and Drying (AWD): the field is flooded, then allowed to dry until water drops below the soil surface, then flooded again.
A private pilot project started in 2022 with about 6,000 farmers on nearly 10,400 hectares reported about 23% lower greenhouse gas emissions, 40% better water-use efficiency, 5% higher yields and 5% higher farmer profit.
The results are to be presented during the World Bank and International Monetary Fund (IMF) meetings in Bangkok, with the aim of building rewards and incentives for farmers who shift to sustainable rice.
Alternate Wetting and Drying (AWD): Technique, Benefits, and Climate Relevance
Alternate Wetting and Drying, or AWD, is a way of watering rice fields. Instead of keeping the field under standing water all season, the farmer floods it, lets the water slowly go down until it is below the soil surface, and only then floods it again. This "wet, then dry, then wet" cycle saves water and sharply cuts the methane gas that flooded rice fields give out, usually without lowering the harvest.
The news describes AWD as the core of low-methane rice farming. A pilot with about 6,000 farmers reported 23% lower emissions and 40% better water-use efficiency while yields rose by 5%. This shows the main promise of AWD: farmers can grow as much rice with less water and less methane, if they get the training and incentives to switch.
Global Methane Pledge (2021)
The Global Methane Pledge is a promise made by a group of countries to reduce the world's methane emissions caused by human activity by at least 30% from 2020 levels by 2030. It was launched at the COP26 climate summit in Glasgow (United Kingdom) in November 2021, led by the United States and the European Union. It is a voluntary promise, not a legally binding treaty. India has not joined it.
Rice causes about 10% of global methane, so low-methane rice is one of the main farm-side tools for the goals behind the Global Methane Pledge. India has not joined the pledge because of farmers' livelihoods and food security, but methods like AWD let it cut methane while also saving water and keeping yields steady. Rewarding farmers for such methods is the kind of incentive the news says is being discussed.
Climate-Resilient Agriculture in India
Climate-resilient agriculture means farming in a way that can survive and recover from heat waves, droughts, floods and irregular rain. It uses better seeds, smart water use, healthy soils and new methods so that yields and incomes do not collapse when the weather turns bad. In India, it is led by ICAR's National Innovations in Climate Resilient Agriculture (NICRA) project, started in 2011, and the National Mission for Sustainable Agriculture (NMSA) under the National Action Plan on Climate Change.
The farmers in the news who switched to AWD saved water and inputs while keeping strong yields. This is a clear example of climate-resilient farming: it protects the farmer against water shortage and also reduces the farm's climate footprint.
- Rice feeds more than half of the world's population
- Rice paddies: about 7,870 kg CO2e per hectare per year
- Rice: about 1.5% of global greenhouse gas emissions, about 48% of cropland emissions, about 10% of global methane emissions
- Methane GWP over 100 years: about 27 to 30 times carbon dioxide (IPCC AR6)
- Pilot (from 2022): about 6,000 farmers, about 10,400 hectares; emissions down about 23%, water-use efficiency up 40%, yields up 5%, profit up 5%
- Safe AWD: re-flood when water is about 15 cm below the soil surface
- IPCC default: multiple drainage cuts paddy methane by about 48% compared with continuous flooding
- Global Methane Pledge: 30% cut from 2020 levels by 2030, launched at COP26 (2021); India not a member
- India rice production 2024-25: about 149 million tonnes; India the largest rice exporter since 2012