The Permian extinction, 251 million years ago, was the worst episode the Earth has so far endured. With less oxygen dissloving into warm water, oxygen breathing water dwelling life forms faced suffocation. Warm water also expands, raising sea levels by 20 metres. The ensuing ‘'super hurricanes' would have triggered flash floods that nothing could survive.

But the biggest monster was the Methane Hydrate beneath the oceans, the same that would bring devastation to the Paleocene nearly 200 million years later, and that still lies there today.

Mark Lynas, author of ‘'Six Degrees: Our Future on a Hotter Planet', describes the release of Methane Hydrate. “"First, a small disturbance drives a gas-saturated parcel of water upwards. As it rises, bubbles begin to appear, as dissolved gas fizzles out with the reducing pressure … these bubbles make the parcel of water still more buoyant, accelerating its rise through the water. As it surges upwards, reaching explosive force, it drags surrounding water up with it. At the surface, water is shot hundreds of metres into the air as the released gas blasts into the atmosphere. Shockwaves propagate outwards in all directions,” triggering more eruptions nearby."

Unlike CO2, methane is flammable. “"Even in air-methane concentratons as low as 5%"” says Lynas, “" the mixture could ignite from lightning or some other spark and send fireballs tearing across the sky". Effectively, the atmosphere itself would become combustilbe. Methane air clouds from oceanic eruptions could destroy terrestrial life almost entirely. It has been estimated that a large eruption could release energy equivalent to 10/8 megatonnes of TNT, 100,000 times more than the world's entire stockpile of nuclear weapons.