It’s the release of CO2 from the permafrost that worries me much more than the CH4 — the CO2 sticks around forever in human terms, so even a fairly low rate of release means a big problem. By contrast, a CH4 release can end up being not terribly meaningful so long as it is gradual.
Not so permanent now, eh frost?
We just call it “frost” now. We also call Glaciologists “unemployed”.