Methane is 72 times more potent than CO2 over a 20 year period

While the 23-times figure of Methane’s CO2  equivalence is still widely cited, this figure is not reflective of methane’s true global warming potency, as it is based on a 100-year activity window.

However due to methane’s short half-life, a 20-year window is more appropriate.

In the IPCC’s 2007 assessment report, the recalculated figure for methane was shown to be 72 times higher than CO2 over 20 years.

This also implies that methane reduction would offer a much more realistic and efficacious reduction strategy than CO2 reduction.

Source: IPCC 2007 Assessment Report – Changes in Atmospheric Constituents and in Radiative Forcing (P. 212) (PDF)

Date: 2007

Source: Beyond Kyoto: Why Climate Policy Needs to Adopt the 20-year Impact of Methane (PDF) – EcoCycle Position Memo

Date: 17 March 2008