As reported in Nature, Ryskin contends that methane from bacterial decay or from frozen methane hydrates in deep oceans began to be released. Under the enormous pressure from water above, the gas dissolved in the water at the bottom of the ocean and was trapped there as its concentration grew. Eventually, the oceans could easily have contained enough methane to explode with a force about 10,000 times greater than the world’s entire nuclear-weapons stockpile, Ryskin argues. “There would be mortality on a massive scale,” he says, if it ever exploded.

According to Ryskin, just one disturbance – a small meteorite impact or even a fast moving mammal – could then have brought the gas-saturated water closer to the surface. Here it would have bubbled out of solution under the reduced pressure. Thereafter the process would have been unstoppable: a huge overturning of the water layers would have released a vast belch of methane. Besides the Permian, such an event could have happened again in Biblical times, leading to the Flood. Genesis 7:11 relates something far more ominous than a mere raincloud, noting, “All the fountains of the great deep burst forth and the floodgates of the heavens were opened.” Such eruptions happen today as a rare but well known maritime hazard; and it could happen again in the future on a devastating planetary scale.

More of Ryskin’s thoughts on this topic are found in his article “Methane driven oceanic eruptions and mass extinctions“, published in the journal Geology.