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Within agriculture, rice represents one of the biggest opportunities for greenhouse gas emissions abatement. Grown on over 400 million acres, rice is responsible for about 10% of total agricultural emissions, predominantly due to its heavy methane emission profile. Methane is a short-lived climate pollutant, 84 times more potent than carbon dioxide over a 20-year period, so near-term reductions lead to rapid climate benefits.
Implementing water management techniques like Alternate Wetting and Drying (AWD), farmers can abate emissions up to 50% (1.5 to 5 tCO₂e per hectare per season) and reduce water use by 30%. When scaled across millions of hectares, this represents a multi-billion dollar market opportunity for carbon credits, significant water savings, and a significant new income stream for smallholder farmers.
Despite this potential, rice has been an overlooked opportunity due to historical issues with project integrity, a lack of protocol framework, transparent verification of practice changes and difficulties scaling across smallholder operations.
We've reached a critical inflection point. International agreements, standardized protocols, and corporate GHG and water use goals have aligned to create not just a viable market, but a thriving investment opportunity that's poised for growth.
Article 6 within the Paris Agreement is starting to stimulate demand for launching rice emission reduction programs by creating international markets for carbon credits that attract both public and private sector buyers. The most prominent example is Japan’s Joint Crediting Mechanism (JCM), which develops bilateral agreements with partner countries to jointly reduce emissions. The JCM just approved its first rice cultivation methodology in partnership with the Philippines, and this will likely generate more agreements with other partner countries in the coming year.
In addition to Article 6, Verra released a new protocol, VM51 (Improved Management in Rice Production Systems), which has provided the guardrails and credibility much of the voluntary carbon market needed in order to invest in scaling rice carbon programs.
Why do we need a new protocol for rice?
Rice is a unique crop.
Unlike other agricultural systems, rice thrives in flooded wetland environments. These flooded fields (paddy fields) create ideal conditions for bacteria to emit methane (hence, rice’s unique methane-dominant emissions profile) and require more nuanced water management practices in order to both manage emissions and yield. In fact, water management is the essential component of reducing rice emissions (VM51 requires it). Alternate Wetting and Drying (AWD) is a water management technique unique to rice that allows fields to dry for a period before re-irrigation that helps reduce methane emissions and water use.
A protocol is a rulebook that provides clear, consistent guidelines for implementing sustainable farming practices and measuring their environmental benefits in a way that's reliable and trustworthy. Prior to VM51, no credible protocol or “rulebook” existed to guide quantification of emissions reductions for this unique type of agriculture. Previous frameworks - like AMS-III.AU had been phased out due to a lack of standardization for methane measurement, and VM42 is more of a catch-all protocol that doesn't account for the unique methane dynamics in flooded rice systems or the specialized water management practices required.
In 2024, overcrediting issues with certain rice carbon projects highlighted the importance of having a rigorous methodology for methane measurement in rice. VM51's stricter requirements and emphasis on advanced quantification methods like the use of biogeochemical models directly address these concerns, helping to rebuild market confidence.
How to measure rice programs according to VM51
VM51 is designed specifically for methane mitigation in irrigated lowland rice - the most emissions intensive cultivation method - that represents 30% of total rice growth.
Quantification can be conducted via three pathways, depending on project scale and data maturity:
While QA2 and QA3 have their uses, process-based modeling (QA1) offers the optimal balance of scientific rigor with operational scalability. Process-based models like DNDC can track daily soil conditions, capturing methane emission dynamics and bursts of nitrous oxide fluxes that can occur under AWD that other methods might miss, while being economically viable across thousands of hectares.
How VM51 Differs from VM42
While VM51 specifically targets methane emissions reduction in rice cultivation through water management techniques, while VM42 is a more versatile methodology applicable across diverse agricultural systems with a primary focus on increasing soil organic carbon sequestration.
However, certain rice programs could still use VM42 if the rice is part of a mixed rotation. For example, in India and China where a rice-wheat rotation is common, many projects will decide to pursue VM42 to be able to quantify the SOC associated with wheat. (VM51 does not allow for SOC quantification).
That said, VM51 is a better fit for double or triple rice rotations where water management (e.g., Alternate Wetting and Drying) is the core intervention, but for projects seeking to stack SOC and CH₄ abatement benefits, you must defer to VM42.
What to Look for in Your Quantification Partner
With a new Verra framework (and more to come from Article 6 and JCM), it’s important to choose the right partner for quantifying rice emissions. The right partner should have experience delivering outcomes that pass audit to ensure timely delivery of certifiable credits with minimal uncertainty adjustments.
Here are the key areas to focus on:
A partner with a biogeochemical model that can adjust to rice systems.
Rice cultivation presents unique challenges. Methane drives the majority of GHG emissions, where emissions tend to change gradually day by day and then stop once fields dry. Alongside methane, changes in water management practices can lead to sudden “bursts” in nitrous oxide that occur over a few days. These bursts can occur as fields transition back and forth between flooded and non-flooded conditions.
While biogeochemical models are most adept at capturing the unique components of rice cultivation, not all models are created equal. Especially in wetland systems. Ensure your quantification partner is using a model with a model that’s proven, peer reviewed, and designed specifically for how rice is grown.
A quantification partner that has a calibrated and validated model across key rice growing regions.
Most project developers are thinking of operating across multiple countries - especially in Southeast Asia where double-rice is the most common crop rotation. As such, your quantification partner should use a model that is already calibrated and validated according to VM53 requirements in these key rice markets you plan to scale to in the future.
Field-Proven Audit Readiness
Your quantification partner should have a track record of successfully passing third-party verifications with minimal revision cycles. Especially under a new Verra framework, it will be important to rely on a partner that has a history of being able to navigate new policies and protocols.
Final Thoughts
Rice carbon credits are seeing a large increase in demand due to more rigor and structure under VM51 and under Article 6 of the Paris Agreement. A successful rice program should be built upon a quantification approach that is rigorous, scalable, and adapted for wetland environments to ensure the credits you generate are in demand.
As Article 6 implementation accelerates and VM51 establishes a new standard for quality, early movers who partner with experienced quantification partners will be best positioned to capture this market opportunity while delivering credible climate impact.
With decades of peer review research and current use over hundreds of thousands of hectares of rice paddies, the DNDC model is proven to deliver accurate emissions quantification in wetland environments. Its unique mechanics capture the daily methane bursts, and it’s currently calibrated and ready to deploy across Southeast Asia. Get in touch if you’d like to hear more about how the DNDC model and the Regrow team can support work in reducing rice emissions.
