It’s a pretty picture, but it should strike a bit of fear once you know what it is.
Sonar image of methane plumes rising from methane hydrates on the Arctic Ocean floor; image from National Oceanography Centre, Southampton (Britain)
It’s been predicted for years, and now it’s happening. Deep in the Arctic Ocean, water warmed by climate change is forcing the release of methane from beneath the sea floor.
Over 250 plumes of gas have been discovered bubbling up from the sea floor to the west of the Svalbard archipelago, which lies north of Norway. The bubbles are mostly methane, which is a greenhouse gas much more powerful than carbon dioxide.
The methane is probably coming from reserves of methane hydrate beneath the sea bed. These hydrates, also known as clathrates, are water ice with methane molecules embedded in them.
The methane plumes were discovered by an expedition aboard the research ship James Clark Ross, led by Graham Westbrook of the University of Birmingham and Tim Minshull of the National Oceanography Centre, Southampton, both in the UK.
Fortunately, the methane is not making it out of the water — yet. The gases are absorbed before they get to the surface — but that increases ocean acidity. If, and when, the methane hits the atmosphere, it will contribute to greenhouse warming of the planet. This could create a runaway heat effect: Warmer waters cause hydrates to release methane to the atmosphere, which causes the atmosphere to warm more, faster.
Scientists have not dismissed all other possibilities, but methane hydrate melting is the most likely cause:
Cohen cautions that the Arctic methane may not be from hydrate, but could be coming from the methane’s primary source, which might be deep within the Earth.
If that was the case, the warming of the West Spitsbergen current may not be to blame.
He says that the large amounts of methane being released make this unlikely, however: “If the methane is all primary, it would be an unprecedented amount.” So the idea that the hydrates are at least partly to blame is more plausible. “It’s not definitively proven, but it’s certainly reasonable,” he says.
Posted by Ed Darrell 
