The Clathrate Smoking Gun
Huge quantities of methane are held in ice-like structures in the cold northern bogs and the bottom of the seas. They are called clathrates (or cathrates). They are stable only in the cold or under high pressure. Methane is 24 times more potent a greenhouse gas than CO2.
The estimated amount of methane stored in these clathrates is gargantuan. They are the largest concentration of methane found on earth.
The compression of methane gas in clathrates is enormous. One cubic meter of clathrates brought to the ocean's surface releases 164 cubic meters of methane.
The possibility of violent methane degassing (or "burping") has been called the clathrate gun hypothesis. There is a suggestion that the ocean's bottom waters couldn't warm up to 8°C. If so, that would certainly set off massive clathrate destabilization. This is what turns the clathrates into a ticking time bomb.
These hydrates are already being released. Satellite photos show massive chimneys of methane bubbling off the ocean floor. They are subterranean versions of the gas field fires we saw during the first Gulf War in Kuwait.
Historically there are spikes in the methane record that may be explained by the violent degassing of clathrates. Some think that the Eocene hothouse period was caused by runaway global warming from clathrates released from the oceans.
The biggest of these catastrophes occurred at the end of the Permian period some 250 million years ago. More than 94% of all marine species in the fossil records suddenly disappeared as oxygen levels plummeted and life itself teetered on the edge of extinction. It took 20 million or more years for coral reefs to begin reestablishing themselves, and in some areas over 100 million years for ecosystems to reach their former healthy diversity.
Both were caused by temperature rises of less than 6½°C. Now these are average temperatures, but in the Siberian permafrost where much of the clathrates are buried the land is warming faster than anywhere else on earth.
None of this is reassuring, especially when we read what is happening to the permafrost boglands of Alaska and Siberia.