Why are rice AWD credit volumes discounted, and why is project size limited?
Modelling rice methane is uncertain, and every method compared has limits. VM0051 v1.1 offers several routes: direct measurement, country-specific values and IPCC defaults. ICVCM sees an uncertainty deduction plus limits on project scale as a reasonable, pragmatic answer, and urges programs to move toward country-specific factors.
What drives methane from a paddy
Flooded fields keep oxygen out of the soil, which favours organisms that break down organic matter without it and release methane, mainly through the rice plants. The amount depends on the number and length of crop cycles, water management, organic and inorganic soil improvers, soil type, temperature and rice variety.
How the methodology measures it
- Direct measurements.
- Country-specific values.
- IPCC global, regional or country-specific default factors.
What the Board thinks
Research comparing models for rice methane found limits in every approach. In that setting the Board sees two safeguards as reasonable: a deduction for uncertainty and limits on project scale. It also encourages programs to promote country-specific emission factors and better modelling or direct measurement over time.
What this means for a farmer group
Expect the tonnes credited to be lower than a simple model would give, and expect rules on how large one project can be. Ask the developer to show the deduction in writing before you sign.
What Senseible does here
Senseible does not issue or verify carbon credits and is not a registry. It gives carbon credit eligibility signals from your own records and keeps those records in order for a verifier. Verified here means rule checks passed against the evidence, not third-party assurance.
Last reviewed 2026-11-04.