# Which global warming potentials must a Verra project use for methane?

Canonical: https://senseible.earth/answers/verra-gwp-values-ar5-methane-28-nitrous-oxide-265

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.

- [Carbon credits](https://senseible.earth/carbon-credits)
- [AR5 or AR6: which to use](https://senseible.earth/answers/ar5-vs-ar6-gwp-which-to-use)
- [Rice methane credits and the CCP label](https://senseible.earth/answers/rice-methane-credits-ccp-label)

Sources: [Verra, VCS Standard v5.0 (16 December 2025), Section 3.14.4 and Table 9](https://verra.org/documents/vcs-standard-v5-0/)

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.