The Clathrate Gun could be the cliff, though I think he was just using a weak metaphor. There could be enough trapped methane in the Arctic to trigger a major w

The Clathrate Gun could be the cliff, though I think he was just using a weak metaphor. There could be enough trapped methane in the Arctic to trigger a major warming event if we break a certain warming threshold. This also may have happened before eons ago. https://en.m.wikipedia.org/wiki/Clathrate_gun_hypothesis https://en.m.wikipedia.org/wiki/Clathrate_gun_hypothesis