Go all out to decarbonise rice production
Paul Singh Sidhu and Gurdev S. Khush
CLIMATE change-induced adverse weather events have become more frequent and alarming worldwide. These events have drawn attention to greenhouse gas (GHG) emissions from industry, agriculture, transport and other sectors. Carbon dioxide (CO2) is the main planet-warming gas responsible for climate change, followed by methane and nitrous oxide. These heat-trapping gases form a blanket around the earth, making the planet warmer.
The average global temperature has risen by at least 1°C compared to pre-industrial levels. Rich countries have been historical contributors to this rise over the past 150 years. The Paris Agreement (2015) called for capping global warming at 1.5°C, which would limit climate impacts to manageable levels. Under the agreement, many developed countries have committed to attain net-zero emissions by 2050, China by 2060, and India by 2070. Net-zero means reducing GHG emissions to as close to zero as possible by removing from the atmosphere at least as much planet-warming gases as its operations emit. Meeting these targets requires 25-50 per cent reduction in GHGs by 2030.
Meeting net-zero targets requires a shift from dirty energy (coal and hydrocarbon power plants) to clean energy (biofuels, solar and wind power) and reduced emphasis on high-emission manufacturing sectors such as steel, cement and chemicals. High costs of these transitions and complexities of international trade will result in loss of price competitiveness. One way of reducing emissions is to sequester CO2 by increasing the area under forests and restoring mangroves within the borders of a country. This is not feasible for some countries due to unavailability of land and climatic constraints. Under the Paris Agreement, such countries (and companies) can buy carbon credits to offset emissions. This allows them to decarbonise and reduce emissions in a cost-effective way. Each carbon credit represents one metric tonne (MT) of carbon dioxide removed from the atmosphere or prevented from being emitted. Carbon credits can be created through projects that reduce, avoid, destroy or capture GHG emissions. Depending on the demand-supply dynamics, the price of one carbon credit is in the range of $40-80.
As an example, for attaining net-zero emissions by 2050, Singapore has set a target of reducing CO2 emissions to 60 million MT by 2030. Since the island nation cannot rely solely on what it can do within its borders, it is in the process of signing an agreement with Ghana to implement bilateral carbon trade. Under this pact, Singapore will invest in a forest conservation project in Ghana, which would be otherwise under risk of deforestation. The CO2 emissions prevented by the conservation of forests in Ghana will be counted towards Singapore’s climate targets. Similarly, agricultural practices which reduce GHG emissions in developing countries qualify for carbon credits purchased by industrialised countries and private companies.
In the agriculture sector, the contribution of rice production to GHG emissions is the highest after livestock and all croplands combined. This is due to the release of methane (21 times more potent than CO2) from the ponding of water in paddy fields, CO2 from burning of rice straw and use of coal-fired plants to produce electricity for irrigating fields, and release of nitrous oxide gas (314 times more potent than CO2) from the application of urea fertiliser. Relative GHG emission mitigation potential for rice (36%) is, however, much higher than that for livestock (9%) and croplands (3%).
Methane has 80 times the warming impact of CO2, but the effect decreases as it converts to CO2 within 12 years. Tackling methane is critical to achieve rapid reduction in global warming. Under the United Nations Framework Convention on Climate Change, methane emission reduction through alternate wetting and drying (AWD) of rice fields (1-2 drainages lasting more than three days) qualifies for carbon credits. In one certified project, about 250 farmer groups in Maharashtra are adopting AWD on 16,250 hectares of rice fields to generate carbon credits. Each year, the project is estimated to offset about the equivalent of 60,000 MT CO2 — roughly what humans emits in a minute by burning fossil fuels.
Due to the narrow interval between paddy harvesting and wheat sowing, farmers in Punjab, Haryana and UP burn rice straw. They are reluctant to adopt soil incorporation of rice straw due to additional costs. Bailing and transport of rice straw, another option to prevent burning, also involve incremental costs. On an average, about 6 MT of rice straw is produced from one hectare. Open burning of this straw produces about 7 MT of CO2. In addition to releasing planet-warming GHGs, air quality deterioration is a health and traffic hazard. Soil incorporation and physical removal of rice straw prevent/reduce GHG emissions by open burning. By developing robust methodologies and certification protocols, carbon credits can be tapped to incentivise farmers to avoid burning of rice straw.
High electricity demand for irrigating rice from July to September necessitates continuous operation of coal-guzzling thermal plants, which meet 50 per cent of the power requirement for irrigating paddy fields in Punjab. The adoption of practices such as AWD and direct seeded rice save electricity, conserve dwindling groundwater and reduce the CO2 footprint of rice. Robust, independently verifiable consumption baseline and the reduction in power consumption resulting from the adoption of these practices will not only lower CO2 emissions from thermal power plants but also help in meeting India’s net-zero climate targets by 2070.
The medium-term goals should be to produce high-quality low-carbon rice by adopting AWD, direct seeded rice and soil incorporation of rice straw; reduce the use of pesticides, fertilisers, water and energy while optimising productivity; and strengthen the rice value chain, right from producers, through processors and exporters, to importers.
Consumers in industrialised nations are willing to reward ‘climate change conscious’ producers by paying a higher price for products which shrink the carbon footprint. Vietnam, the world’s second-largest rice exporter (after India), is bringing one million hectares under low-carbon rice to enhance farmers’ income using carbon finance and carbon trade.
Sidhu is former Senior
Agriculturist, World Bank, South Asia Region; Khush is former Head, Plant Breeding, Genetics and Biotechnology, International Rice Research Institute, Philippines
