It looks like we've hit the tipping point for positive feedback from arctic methane clathrates:
The first evidence that millions of tons of a greenhouse gas 20 times more potent than carbon dioxide is being released into the atmosphere from beneath the Arctic seabed has been discovered by scientists.In some places the release is so large it doesn't even have time to dissolve - it just bubbles to the surface like you'd see in a fish-tank.The Independent has been passed details of preliminary findings suggesting that massive deposits of sub-sea methane are bubbling to the surface as the Arctic region becomes warmer and its ice retreats.
Underground stores of methane are important because scientists believe their sudden release has in the past been responsible for rapid increases in global temperatures, dramatic changes to the climate, and even the mass extinction of species. Scientists aboard a research ship that has sailed the entire length of Russia's northern coast have discovered intense concentrations of methane – sometimes at up to 100 times background levels – over several areas covering thousands of square miles of the Siberian continental shelf.
This is serious. Methane is a powerful greenhouse gas, and its sudden release from subsea clathrate beds can raise the temperature in an extremely short timeframe. Such releases have been implicated in two mass-extinction events: the Paleocene–Eocene Thermal Maximum 56 million years ago, and the Permian–Triassic extinction event 251 million years ago. If these releases continue, we could find ourselves living in a very different world, and without much of the ecosystem we have relied on to support us.
