Here is a news release from the US Geological Survey. I've copied some parts of it, but please read the entire release before commenting. http://www.usgs.gov/newsroom/article_pf.asp?ID=2326 In brief, there are lots of uncertainties and potentials for climate change to impact the role of the arctic as a CO2 sink and CH4 source. The science isn't there yet to make much of a prediction and it may be decades before we know for sure. However, what is interesting are the current CO2 sink and CH4 source numbers. Although the CH4 source is one eighth the CO2 sink (50 vs 400), since CH4 is 23 times more powerful as a greenhouse gas, the implication is that the Arctic is already providing a positive feedback to climate change. It is providing roughly effectively 3 times more greenhouse gases than it is absorbing. In other words, even if human CO2 emissions were reduced to near zero, there would still be a net positive global warming from sources/sinks inherit in the Arctic. If true, that's a huge statement because unless there are significant changes in the dynamics of the Arctic, that means climate change is probably irreversible. By irreversible, I mean even if Humans were to cease all CO2 emissions (which is highly unlikely), there would still be climate change due to the current CH4 emissions from the Arctic.