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