According to Romanovsky et al. (2002), who examined a 1924-2001 history of mean annual temperatures for Barrow, Alaska, at soil depths of 0.08 m (the "active layer"), 0.5 m, and 1.0 m (about 60 cm below the permafrost table), permafrost temperatures were "very similar during the 1940s and 1990s (except for unprecedented warm extremes of 1998 and 1999)."  However, even including these "unprecedented warm extremes," it can easily be determined from the authors' Figure 3 that the mean temperature about 60 cm into the permafrost (-9.15°C), over what climate alarmists call the warmest period of the past millennium, i.e., 1990 and onward, was no warmer than, or possibly even cooler than, the temperature of the 16-year period 1937-1952 (-9.06°C).  Thus, in spite of all the hype about recent dramatic warming in the permafrost regions of Alaska, real-world data demonstrate -- at least for Barrow -- that it is no warmer there now than it was half a century ago, and the area's permafrost is in no more danger of melting today that it was seven decades ago.  Furthermore, the authors note that degradation of permafrost does not proceed as rapidly as climate alarmists would have one believe.  As they describe it, "degradation of permafrost is a slow process," and "if recent trends continue, it will take several centuries to millennia [our italics] for permafrost in the present discontinuous zone to disappear completely in the areas where it is actively warming and thawing."

A similar non-catastrophic view of late 20th century permafrost degradation is presented by Jorgenson et al. (2001).  Using a combination of methods that included repeat aerial photography (1949, 1978, 1998), radiocarbon dating of organic material, and tree-ring analyses, they examined the history of permafrost degradation in the Tanana River valley lowlands of central Alaska over the past 300 years.  This diverse suite of evidence led them to conclude that "nearly all the permafrost degradation has occurred since 1750 and that 83% of the degradation occurred before 1949," which certainly does not suggest an accelerated warming in recent years.

Going all the way back to the prior interglacial, Muhs et al. (2001) present an even more expansive perspective on permafrost degradation in central Alaska.  Their analysis and synthesis of various proxy climate data reveals "a region with warmer-than-present summers, an absence of permafrost in the interior, and probably greater precipitation in the interior."  How much warmer was it?  Based upon the expanded boreal forest ranges in this area, the authors estimate that summer temperatures were at least 1-2°C warmer than they are presently, and that in some locations summer temperatures may have been as much as 3-5°C higher than they are now.  Thus, even a complete melting of permafrost in central Alaska would fall well within the bounds of natural variability and need not be construed as unprecedented or catastrophic as climate alarmists are wont to do.  If it has happened before in the natural course of events, it can clearly happen again in the natural course of events, independent of any change in earth's atmospheric CO2 concentration.

More evidence that the current status of the planet's permafrost is within normal natural bounds comes from the study of Zhuo et al. (1998), who reviewed what we know about climatic conditions in China during the Holocene Climatic Optimum approximately 5,000-10,000 years ago.  Temperatures during that period, according to them, were 2-6°C warmer than they have been recently, and the southern permafrost limit was located 100 km north of its current location.

More evidence against the presumption of an unprecedented permafrost decline in the late 20th century comes from Kasper and Allard (2001), who examined soil deformations due to ice wedge activity over the past 4000 years near Salluit in northern Quebéc.  Their analysis indicated that ice wedge activity was generally present up to about 140 A.D., reflecting cold climatic conditions.  Between 140 and 1030 A.D., however, this activity generally declined, reflective of warmer conditions.  Then, from 1030 to 1500 A.D., conditions cooled; and from 1500 to 1900 A.D., ice wedge activity was at its peak, when the Little Ice Age ruled, suggesting that this climatic interval exhibited the coldest conditions of the past 4000 years.  A warm period prevailed thereafter, from about 1900 to 1946, followed by a return to cold conditions during the last five decades of the 20th century, during which time over 90% of the ice wedges studied reactivated and grew upwards by 20-30 cm.  Such resurgence of ice wedge activity in the latter half of the 20th century is certainly not consistent with climate-alarmist predictions of unprecedented concomitant CO2-induced global warming.

In addition to permafrost data being used to help reconstruct histories of past climate change, future permafrost melting as a consequence of putative CO2-induced global warming has been predicted to turn boreal and tundra biomes into carbon sources extraordinaire.  According to this hypothesis, higher soil temperatures will lead to the thawing of extensive regions of permafrost and the exposure and subsequent decay of vast stores of organic matter, thereby releasing long-sequestered carbon back to the atmosphere as CO2.  Improved soil drainage and increased aridity have also been envisioned to help this process along, possibly freeing enough carbon at a sufficiently rapid rate to rival in aggregate the yearly amount of carbon released to the atmosphere as CO2 by all anthropogenic sources combined.  The end result of this hypothetical scenario is a tremendous positive feedback to the ongoing rise in the air's CO2 content, which is envisioned to lead to catastrophic global warming. Like many other aspects of the global warming hypothesis, however, evidence for the validity of this scenario is nowhere to be found in the real world of nature.

One of the first cracks in the seemingly sound hypothesis appeared in the work of Oechel et al. (2000), when long-term measurements of net ecosystem CO2 exchange in wet-sedge and moist-tussock tundra communities of the Alaskan Arctic began to indicate these ecosystems were gradually shifting from being carbon sources to becoming carbon sinks.  The ultimate transition occurred between 1992 and 1996, at the apex of a regional warming trend that culminated with the local climate experiencing the highest average summer temperature and surface water deficit of the previous four decades.

How did it happen? ... this dramatic and unexpected biological transformation?  The answer of the scientists who observed and documented the phenomenon is that it was really nothing special -- no more, as they put it, than "a previously undemonstrated capacity for ecosystems to metabolically adjust to long-term changes in climate."  And this simple ecological acclimation process is only one of several newly-recognized phenomena that have caused scientists to radically revise the way they think about global change in Arctic regions.

The most recent of the still-evolving new work in this area comes from Camill et al. (2001), who studied (1) changes in peat accumulation across a regional gradient of mean annual temperature in Manitoba, Canada, (2) net aboveground primary production and decomposition within the major functional plant groups of the region, and (3) soil cores from several frozen and thawed bog sites that were used to determine long-term changes in organic matter accumulation following the thawing of boreal peatlands.

In direct contradiction of most earlier thinking on the subject, but in confirmation of the more recent findings of Camill (1999a,b), the authors of the new study discovered that aboveground biomass and decomposition "were more strongly controlled by local succession than regional climate."  In other words, they determined that over a period of several years, natural changes in plant community composition generally "have stronger effects on carbon sequestration than do simple increases in temperature and aridity."  In fact, the authors' assessments of peat accumulation over the past two centuries showed that rates of biological carbon sequestration can almost double following the melting of permafrost, in harmony with the findings of Robinson and Moore (2000) and Turetsky et al. (2000), who found rates of organic matter accumulation in other recently-thawed peatlands to rise by 60-72%.

As seems to be happening in so many other areas of research designed to increase our knowledge of the hypothetical global warming threat, this evidence from the carbon sequestration front turns the old gloom-and-doom hypothesis on its head.  Rather than adding to the atmosphere's burden of carbon dioxide, the warming of earth's permafrost regions would likely end up removing carbon from the air, which would tend to stabilize surface air temperatures and not push them higher.

References
Camill, P.  1999a.  Patterns of boreal permafrost peatland vegetation across environmental gradients sensitive to climate warming.  Canadian Journal of Botany 77: 721-733.

Camill, P.  1999b.  Peat accumulation and succession following permafrost thaw in the boreal peatlands of Manitoba, Canada.  Ecoscience 6: 592-602.

Camill, P., Lynch, J.A., Clark, J.S., Adams, J.B. and Jordan, B.  2001.  Changes in biomass, aboveground net primary production, and peat accumulation following permafrost thaw in the boreal peatlands of Manitoba, Canada.  Ecosystems 4: 461-478.

Jorgenson, M.T., Racine, C.H., Walters, J.C. and Osterkamp, T.E.  2001.  Permafrost degradation and ecological changes associated with a warming climate in central Alaska.  Climatic Change 48: 551-579.

Kasper, J.N. and Allard, M.  2001.  Late-Holocene climatic changes as detected by the growth and decay of ice wedges on the southern shore of Hudson Strait, northern Québec, Canada.  The Holocene 11: 563-577.

Muhs, D.R., Ager, T.A. and Begét, J.E.  2001.  Vegetation and paleoclimate of the last interglacial period, central Alaska.  Quaternary Science Reviews 20: 41-61.

Oechel, W.C., Vourlitis, G.L., Hastings, S.J., Zulueta, R.C., Hinzman, L. and Kane, D.  2000.  Acclimation of ecosystem CO2 exchange in the Alaskan Arctic in response to decadal climate warming.  Nature 406: 978-981.

Robinson, S.D. and Moore, T.R.  2000.  The influence of permafrost and fire upon carbon accumulation in high boreal peatlands, Northwest Territories, Canada.  Arctic, Antarctic and Alpine Research 32: 155-166.

Romanovsky, V., Burgess, M., Smith, S., Yoshikawa, K. and Brown, J.  2002.  Permafrost temperature records: Indicators of climate change.  EOS, Transactions, American Geophysical Union 83: 589, 593-594.

Turetsky, M.R., Wieder, R.K., Williams, C.J, and Vitt, D.H.  2000.  Organic matter accumulation, peat chemistry, and permafrost melting in peatlands of boreal Alberta.  Ecoscience 7: 379-392.

Zhuo, Z., Baoyin, Y. and Petit-Marie, N.  1998.  Paleoenvironments in China during the Last Glacial Maximum and the Holocene Optimum.  Episodes 21: 152-158.