 The Permian mass extinction was initiated by a colossal flow of lava in an area of what is now Siberia. That was the trigger, but not the killer. The killer was under the water and under the ice, where trillions of tons of greenhouse gases, largely derived from carbon and frozen in the form of crystalline methane, lay in wait. Thus, global warming is the force behind the death of nearly everything on the planet during the Permian mass extinction.