Permafrost, Methane and Climate Change

An short introduction to a contentious discussion

It’s difficult for most people in the climate world to talk about methane and climate change. Methane certainly has an effect on the climate. Methane is a powerful but short-lived greenhouse gas that’s both encased in and produced by thawing permafrost. Thawing permafrost releases carbon, and it also “wakes up” dormant bacteria that feed on the half-decayed organic matter, producing methane. Permafrost is like a frozen compost heap, only massively larger. The above video from PBS is good on this subject.

The problem with the methane discussion comes when we try to evaluate the seriousness of the threat. Note, for example, the video concludes that a methane catastrophe produced by melting permafrost is “likely a long way into the future.”

But note also that the video discusses only land-based permafrost thawing. The same Arctic regions contain sea-based methane as well, in the form of “methane calthrates,” methane trapped in very cold water. When the water warms, the methane is released, often producing rising underwater plumes.

Image source

The whole subject is fraught with controversy, not as to the science, but the rate at which thawing permafrost and methane calthrates will become a problem.

For now I just want to introduce the subject: land-based permafrost melt and the threat it presents. I’ll return to the larger methane discussion from time to time, perhaps producing a short series. For that, stay tuned.