2.3.16 (HL)—Methane cycle

Methane persists for roughly a decade on average, yet is a potent greenhouse gas while present; lifetime and potency are different properties.

Oxidation eventually converts methane mainly to CO₂, but the climate effect during its atmospheric lifetime matters. Cutting emissions can reduce methane forcing relatively quickly.

A short-lived methane pulse can cause strong near-term warming, while a continuous leak keeps replacing the methane removed by oxidation.

No. Compare both concentration, radiative effect and the time horizon; a continuing source prevents decline.

‘Short-lived’ does not mean ‘weak’; persistence and greenhouse potency must not be collapsed into one label.