Background
The authors write that a thawing of permafrost in sensitive ecosystems will "increase the vulnerability of soil organic matter (SOM) to rapid microbial decomposition that was previously stabilized by freezing temperatures." And they say that "this process might increase the release of CO2 to the atmosphere," which would enhance the warming that was responsible for its release, thereby repeating the cycle and leading to still more warming, which is one of Al Gore's favorite fairy tales.

What was done
In exploring how this simplistic concept may - or may not - work in the real world, Zollinger et al. studied soils (both with and without permafrost) of two areas above the timberline and one below the timberline in south-eastern Switzerland.

What was learned
The nine researchers report that carbon stocks (down to the C horizon or rock surface) "did not show a significant difference between permafrost and non-permafrost soils and were in the same range of 10-15 kg/m² in alpine (grassland) and subalpine (forest) sites."

What it means
In light of this finding, Zollinger et al. remark that it is "questionable whether a thawing of permafrost really would lead to an accelerated and increased carbon loss in these soils." For example, as they continue, "several scenarios of global change are predicting ascending vegetation zones, with the subalpine coniferous forest and Ericaceous shrubs becoming able to colonize meadows at higher altitudes (Ozenda and Borel, 1991)." And they suggest that these "changes in plant species and a potential increase in vegetation growth will enhance the aboveground carbon storage capacity that might offset initial carbon losses."

Reference
Ozenda, P. and Borel, J.L. 1991. Les consequences ecologiques possibles des changements climatiques dans l'Arc alpin. Rapport Futuralp, Volume 1. ICALPE, Le Bourget-du-Lac, France.