Global warming potential of biogenic methane

The source of carbon in biogenic methane comes from the active carbon pool. Transformation of carbon into methane, through biogenic cycling of carbon implies that the global warming (GW) contributed by biogenic methane inherits the GW of CO₂. For a precise and realistic assessment of GWP of biogenic methane and its' contribution to GW, the instantaneous radiative forcing of CO₂ should be subtracted from the instantaneous radiative forcing of biogenic methane. The correction suggested on this account will decrease the GWP of biogenic methane by 5%. The proposed correction is significant, since 80% of the global emission of methane involve biospheric carbon belonging to the active carbon pool.