The clathrate gun hypothesis is the popular name given to the hypothesis that increases in sea temperatures (and/or falls in sea level) can trigger the sudden release of methane from methane clathrate compounds buried in seabeds and permafrost which, because the methane itself is a powerful greenhouse gas, leads to further temperature rise and further methane clathrate destabilization – in effect initiating a runaway process as irreversible, once started, as the firing of a gun.In its original form, the hypothesis proposed that the "clathrate gun" could cause abrupt runaway warming on a timescale less than a human lifetime, and was responsible for warming events in and at the end of the last glacial maximum.