March 4, 2010, "Huge methane leak in Arctic detected" -- http://www.globalresearch.ca/index.php?context=va&aid=20032
"This discovery reveals a large but overlooked source of methane gas escaping from permafrost underwater, rather than on land," the study said. "More widespread emissions could have dramatic effects on global warming in the future."[...] More than 80 percent of the deep water and more than half of surface water had methane levels around 8 times higher than found in normal seawater, according to the study published in the journal Science. The researchers warned that the release of even a fraction of the methane stored in the shelf could trigger abrupt climate warming.
In more detail: http://www.nsf.gov/news/news_summ.jsp?cntn_id=116532
September 2, 2011. "Russian, US scientists set to study methane release in Arctic". -- http://en.rian.ru/science/20110902/166364635.html
"This expedition was organized on a short notice by the Russian Fund of Fundamental Research and the U.S. National Science Foundation following the discovery of a dramatic increase in the leakage of methane gas from the seabed in the eastern part of the Arctic, said Professor Igor Semiletov, the head of the expedition."
(boldface emphasis mine)
I know that the media love a dramatic story, since nothing sells better than undertones of catastrophic risks, but I must say that that makes me wonder: what's going on? Is the "short notice" expedition because of something new, or is it a consequence of the 2010 Science paper (based on measurements from previous years)? After searching the web fruitlessly, in the absence of results I conclude that the "dramatic increase" mentioned is the one discussed in the 2010 Science paper, not a dramatic increase coming on top of the previous already dramatic increase... as for the "short notice", every article picks up the same quote, but none mentions anything more about it, so it must be that the scientist just happened to drop those scary words, but it does not imply anything newly ominous. In other words, the terms used reflect the style of those scientists (I think) rather than newly dire events.
In any case, these people are fantastically good at P.R. Science, Scientific American, National Geographic, and short movies on youtube: all apparently referring to that same (important) piece of research published in Science.
As I was starting to suspect after surfing the web a while, those sensationalist news are really dramatized! The realclimate contributor has a great no-nonsense commentary.