Which global warming potentials must a Verra project use for methane?
100-year values from the Intergovernmental Panel on Climate Change's Fifth Assessment Report (AR5): methane 28 and nitrous oxide 265, with carbon dioxide at 1. VCS Standard v5.0 requires them for reductions on or after 1 January 2021. Earlier reductions may use the Fourth or Fifth Assessment Report.
The rule
- All reductions and removals are converted to tonnes of carbon dioxide equivalent (t CO2e) using 100-year global warming potential values.
- For reductions on or after 1 January 2021, all ex-ante estimates and ex-post calculations use AR5 values.
- For reductions on or before 31 December 2020, either the Fourth Assessment Report (AR4) or AR5 values may be used.
The values in Verra's table
- Carbon dioxide (CO2): 1.
- Methane (CH4): 28.
- Nitrous oxide (N2O): 265.
Where this bites
A wastewater digester or a rice field is mostly a methane project, and a fertiliser or nitric acid plant is a nitrous oxide project, so the choice of edition moves the total. If your company report or a buyer's form uses a different edition, the two will not match line for line. State the edition next to every CO2e figure.
Example: a digester and a process line (example quantities)
- Methane avoided: 40 tonnes (t) CH4 x 28 = 1,120 t CO2e
- Nitrous oxide avoided: 5 t N2O x 265 = 1,325 t CO2e
- Total claimed for the period: 1,120 + 1,325 = 2,445 t CO2e
Example quantities to show the sum. Use your own measured tonnes and the methodology's equations.
What Senseible does here
Senseible converts fuel and power records to CO2e with published factors, each shown with its source. Gas-by-gas project quantification under a Verra methodology is outside what Senseible does.
Sources: Verra, VCS Standard v5.0 (16 December 2025), Section 3.14.4 and Table 9
Last reviewed 2026-11-04. Section numbers are from VCS Standard v5.0 (16 December 2025); re-check them when Verra publishes a new version.