In the Arctic Circle, on the continental slope off Canada in the Beaufort Sea, the shallowest known deposit of methane hydrate has been discovered. The crystalline solid is comprised of methane molecules trapped in an ice-lattice structure.
The scientists presented their findings at the annual meeting of the Geophysical Union in San Francisco, California. The trapped gas deposit is located just 290 meters below sea level. Previously, the shallowest deposits were found in the vicinity of the Svalbard Islands, in the Gulf of Mexico, at a depth of around 400 meters.
The newly discovered deposit is of modest size, but such trapped deposits represent a large global carbon reservoir and some researchers fear that their destabilization around the world, caused by changes in sea temperature or drilling, could cause a release of methane into the environment and accelerate global warming.
Even a subtle warming makes this new deposit makes it vulnerable to decomposition, since it is at such a shallow depth. The deposit is within the “methane hydrate stability zone,” a range of pressure and temperature at which gas hydrates are stable. The stability zone begins at a depth of about 270 m in this region, above sea temperatures are too warm to ensure that the methane remains locked.
Some climate scientists fear that gas-hydrate decomposition could destabilize the sea floor, causing landslides and tsunamis. Other scientists remain skeptical, since there is no proof in the geological record that any of that has ever happened before.