The animation underneath shows methane readings from November 9 to 19, 2013, with each frame covering a period of 24 hours. As the animation shows, it looks like methane is predominantly entering the atmosphere at specific locations, most notably along the fault line that crosses the Arctic Ocean.
It may well be that this methane ends up all the way in Baffin Bay, to the east of Greenland. Since the Greenland ice sheet is 3 kilometers (1.9 miles) thick, this may form a natural barrier that keeps the methane there, also helped by winds rising vertically from Baffin Bay to well above Greenland's mountains.
On the other hand, it could also be that hydrates in Baffin Bay have become destabilized and that, since the ice over Baffin Bay is rather thin, methane has no problem perforating the ice and is entering the atmosphere there in huge quantities.
Either way, the end-conclusion is that the methane that is now showing up all over the Arctic Ocean, is rising from the seafloor, due to destabilization of sediments that hold huge amounts of methane in the form of free gas and hydrates. As warming in the Arctic continues to accelerate, the danger is that this will cause more methane to rise from the seafloor and that the methane itself will contribute to warming in the Arctic, in a deadly spiral set to cause abrupt climate change at a devastating scale.