The processes countries use to revise their Nationally Determined Contributions (NDCs) under the UNFCCC’s Paris Agreement will be key to ensure that their pledges lead to effective climate change...
The Coalition is funding research to explore how the alternate wetting and drying (AWD) irrigation technique can be applied in Vietnam to reduce methane emissions from rice production, in line with its NDC.
The findings will help to inform decisions about designing, financing and implementing the expansion of the AWD technique throughout the country.
Project activities completed to date include:
Suitability mapping

CCAC partners assessed the suitability for AWD application in the An Giang province. The AWD suitability analysis consisted of 4 steps:
- Climatic Suitability Maps: The planted area of rice was mapped based on statistic data, rice calendars and remote sensing images. Climatic factors including rainfall, potential evapotranspiration and soil percolation rate of rice land were then used to assess the water balance.
- Adoption Capacity Maps: Factors that influence the adoption capacity for AWD were evaluated. Factors and their influences were identified through discussions with key personnel from local agencies under the Department of Agriculture and Rural Development (DARD) and researchers from national research institutes. Five influencing factors were taken into account, including: topography of the area, canal irrigation infrastructure, drainage capability, farmer awareness of the technology, and cooperative authority (below).
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Overall AWD Suitability Maps: Seasonal climatic-suitability maps and adoption capacity maps were combined to generate overall suitability maps.
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Participatory Verification: Overall AWD suitability maps were verified through a participatory feedback process conducted with participation of provincial and district officials of Vietnam’s Ministry of Agriculture and Rural Development.
To date, these maps are the best reference to support AWD implementation plans in An Giang province. The suitability mapping process can now be applied to other provinces in Vietnam as well as in other countries.
Cost Benefit Analysis (CBA)
As part of the CGIAR Research Program on Climate Change, Agriculture and Food Security (CCAFS), the CCAC supported the review of Vietnam’s NDC.
Research applying the marginal abatement cost curve (MACC) method was used to compare different technologies based on mitigation potential and cost effectiveness. Mitigation options were ranked according to their potential cost effectiveness and clearly showed AWD as a strategy that is both cost effective and has high mitigation potential.
With the support of the CCAC, IRRI contributed to this research through the study on “ Reviewing Vietnam’s Nationally Determined Contribution: A New Perspective using the Marginal Cost Abatement”. Study findings show that AWD in the Mekong Delta has a mitigation potential of 25.27 MtCO2 eq at a marginal benefit of about USD23.7/tCO2 eq. In the Red River Delta, the mitigation potential of AWD is comparable but the marginal benefit is USD17.6/tCO2eq. The fees applied to irrigation water affect the overall cost- effectiveness of AWD. If higher fees make water costly, AWD is more cost-effective which increases the likelihood of adoption among farmers.
Emissions calculations
The Source-selective and Emission-adjusted GHG Calculator (SECTOR) tool for Cropland, developed by IRRI through funding from the CCAC, has been used to assess greenouse gas emissions for Thailand's rice NAMA.
MRV- Measurement, Reporting and Verification
The CCAC and IRRI will begin development of a normative Monitoring, Reporting and Verification (MRV) framework and support tools to help countries meet the reporting requirements for NAMAs.
This framework will contribute to Vietnam’s MRV system. This entails working with the national and local governments and implementing agencies to develop an MRV system that meets the following objectives: improve the basis of information and the monitoring of rice-related mitigation actions, coordinate individual mitigation activities (such as bottom-up actions / policies, top-down goals), and track emission reductions.

Investment plan
Building on the tools for suitability mapping of mitigation options, CBA, the Coalition supported IRRI to develop an investment plan which identifies potential sources to finance the NDC activities for Vietnam’s Ministry of Agriculture and Rural Development. The investment plan identifies the different cost items for AWD outscaling.