Permafrost Meltdown is causing Global Warming - more permafrost melting expected

http://www.scientificamerican.com/article/permafrost-meltdown-raises-risk-of-runaway-global-warming/

Goose Lake is at the knife’s edge of climate change. Half a century ago, this region, which is 250 miles from the Arctic Circle, used to contain mostly permafrost, or perennially frozen ground. Today, the ground has partially thawed and the region is predominantly wetland.
The rapid changes have been catalyzed by climate change, which has warmed these environs by 4 degrees Fahrenheit in the past half-century. Scientists worry that, as permafrost thaws, a portion of the carbon stored in the northernmost ecosystems will be released to the atmosphere and trigger runaway global warming. The biggest threat at present is posed not by the frozen tundras of the Arctic, but by the soils of the boreal—the southern reaches of the deep freeze in Canada, Alaska and other parts of the world—like at Goose Lake, where the permafrost is thin and sporadic, the soil temperature close to melting point, and the land already disturbed by oil and gas exploration.