Read here. Climate models, based on the AGW alarmist theory, predict that as permafrost thaws from human CO2-induced global warming more CO2 and methane stored in permafrost will be released into the atmosphere. This new release of greenhouse gases will then also increase atmospheric temperatures, a continuous positive feedback according to the models. The latest peer-reviewed research by Blok et al. discovers there is a negative feedback that offsets the thawing and further release of gases.
When the permafrost thaws, the the accelerated expansion and growth of deciduous shrubs set off by warming, shades the the tundra and prevents further thawing - this cooling of the tundra is a negative feedback.
"Blok et al. say their results suggest that "the expected expansion of deciduous shrubs in the Arctic region, triggered by climate warming, may reduce summer permafrost thaw," and that the "increased shrub growth may thus partially offset further permafrost degradation by future temperature increases," while in further support of their conclusion, the six scientists write that (1) permafrost temperature records "do not show a general warming trend during the last decade (Brown and Romanovsky, 2008), despite large increases in surface air temperature," that (2) during the decade before that, "data from several Siberian Arctic permafrost stations do not show a discernible trend between 1991 and 2000 (IPCC, 2007)," and that (3) "a recent discovery of ancient permafrost that survived several warm geological periods suggests that vegetation cover may help protect permafrost from climate warming (Froese et al., 2008)." And last of all, they note that this phenomenon "could feedback negatively to global warming, because the lower soil temperatures in summer would slow down soil decomposition and thus the amount of carbon released to the atmosphere."" [Blok, D., Heijmans, M.M.P.D., Schaepman-Strub, G., Kononov, A.V., Maximov, T.C. and Berendse, F.]
Other climate model failures.