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The Climatic Consequences of Permafrost Degradation in Boreal Peatlands
Reference
Turetsky, M.R., Wieder, R.K., Vitt, D.H., Evans, R.J. and Scott, K.D. 2007. The disappearance of relict permafrost in boreal North America: Effects on peatland carbon storage and fluxes. Global Change Biology 13: 1922-1934.

Background
The authors write that "ongoing climate change has triggered widespread degradation of localized permafrost in peatlands across continental Canada," which observation has led many a climate alarmist to become, well, alarmed -- alarmed that the large volumes of methane being released to the atmosphere by this phenomenon, from both North America and Eurasia, will significantly exacerbate global warming, as suggested, for example, by Al Gore in his 21 March 2007 testimony before the United States Senate's Environment & Public Works Committee.

What was done
As Turetsky et al. describe it, they explored "the influence of differing permafrost regimes (bogs with no surface permafrost, localized permafrost features with surface permafrost, and internal lawns representing areas of permafrost degradation) on rates of peat accumulation at the southernmost limit of permafrost in continental Canada" via a variety of techniques.

What was learned
The five American researchers found that "surface permafrost inhibits peat accumulation and that degradation of surface permafrost stimulates net carbon storage in peatlands." In fact, they report that "unfrozen bogs and internal lawns had net organic matter accumulation rates two-times faster [our italics] than rates of accumulation in localized permafrost features over the most recent 25-year horizon," when climate alarmists claim the planet warmed at a rate that was unprecedented over the past two millennia or more.

What it means
In discussing their findings, Turetsky et al. say their data suggest that "permafrost degradation within peatland environments, likely triggered by climate change, could serve as a negative feedback to net radiative forcing via enhanced carbon accumulation as peat." They note, however, that "increased methane emissions to the atmosphere will partially or even completely offset this enhanced peatland carbon sink for at least 70 years following permafrost degradation." Nevertheless, they say that because "internal lawns succeed relatively quickly (within 70 years) to more bog-like conditions and [since] bogs in continental Canada are associated with low methane emissions, the degradation of localized permafrost in peatlands is likely over the long-term [our italics] to serve as a negative feedback to radiative forcing."

Reviewed 19 December 2007