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Sophie Szopa coauthored the IPCC assessment chapter on short-lived climate forcers. Its treatment of methane separates an atmospheric burden's chemical removal time from the relaxation time of a methane perturbation.

Additional methane can change the abundance of the hydroxyl radical that removes it. This chemical feedback makes the perturbation lifetime a coupled-system property rather than a simple fixed loss constant.^[ref]

A local or box-model balance between hydroxyl-radical production and effective losses. For fixed production $P$ and pseudo-first-order total loss frequency $K$, $[\mathrm{OH}]=P/K$. Additional hydrogen, carbon monoxide or methane consumption can lower hydroxyl radical if production and other terms stay fixed; radical recycling and spatial transport can alter that simple result.