Climate Progress quote: "NSF issues world a wake-up call: “Release of even a fraction of the methane stored in the shelf could trigger abrupt climate warming.”
Science 5 March 2010: Vol. 327 no. 5970 pp. 1246-1250 DOI: 10.1126/science.1182221 Report Extensive Methane Venting to the Atmosphere from Sediments of the East Siberian Arctic Shelf
http://www.sciencemag.org/content/327/5970/1246.abstract
Climate Action: http://thinkprogress.org/romm/2010/03/04/205600/science-nsf-tundra-permafrost-methane-east-siberian-arctic-shelf-venting/