thermokarst

1.Thermokarst failures occur when permafrost—a layer of frozen soil in Earth's polar regions—thaws and becomes unstable, possibly releasing greenhouse gases into the atmosphere.

随着永久冻土带消溶和分崩离析，热喀斯大量出，埋藏于地下的（甲烷等）温室气体可散发到大气中。