March 3, 2009

The Other Side Of The Story

Climate alarmists generally refer to current temperatures as being both unprecedented and unnatural, due to what they claim is anthropogenic-induced global warming, caused primarily by mankind's CO2 emissions. They further contend that this "unnaturalness" is most vividly expressed throughout the Arctic. We here investigate this claim within the context of the past five glacial-interglacial cycles, based on scientific studies conducted in this climatically-sensitive part of the world.

Beginning with the current interglacial or Holocene, Darby et al. (2001) developed a 10,000-year multi-parameter environmental record from a thick sequence of post-glacial sediments obtained from cores extracted from the upper continental slope off the Chukchi Sea Shelf in the Arctic Ocean. As they describe it, they uncovered evidence that revealed "previously unrecognized millennial-scale variability in Arctic Ocean circulation and climate," along with evidence that suggested that "in the recent past, the western Arctic Ocean was much warmer than it is today." More specifically, they say that "during the middle Holocene the August sea surface temperature fluctuated by 5°C and was 3-7°C warmer than it is today," and they report that their data revealed "rapid and large (1-2°C) shifts in bottom water temperature," concluding that "Holocene variability in the western Arctic is larger than any change observed in this area over the last century." And since there is no evidence the air's CO2 concentration was either higher or fluctuating wildly during this period (it was, in fact, lower and very stable) something else had to have been responsible for the significantly warmer and more variable climate of that time and place, which suggests there is no compelling reason to invoke the historical increase in the air's CO2 content as the cause of the less dramatic temperature increase of the past century.

Four years later, Miller et al. (2005) summarized the main characteristics of the glacial and climatic history of the Canadian Arctic's Baffin Island since the Last Glacial Maximum by presenting biotic and physical proxy climate data derived from six lacustrine sediment cores recovered from four sites on Baffin Island, after which the paleoenvironmental implications of the new data were combined with the findings of prior studies to develop a regional picture of climatic conditions during deglaciation, the subsequent Holocene thermal maximum, the onset of Neogolaciation and its intensification in the late Holocene. This work revealed, in their words, that (1) "glaciers throughout the Canadian Arctic show clear evidence of Little Ice Age expansion, persisting until the late 1800s, followed by variable recession over the past century," that (2) wherever the Little Ice Age advance can be compared to earlier advances, "the Little Ice Age is the most extensive Late Holocene advance," and, in fact, that (3) "some glaciers remain at their Little Ice Age maximum." And because the Little Ice Age in the Canadian Arctic spawned the region's most extensive glacial advances of the entire Holocene, and because many of the resulting glaciers persisted into the late 1800s, with some still remaining at their maximum Little Ice Age extensions, it is only to be expected that the region should be experiencing a significant warming as the planet recovers from the global chill of this coldest phase of the entire Holocene, independent of whatever the air's CO2 concentration may be doing concurrently, since the atmosphere's CO2 concentration had absolutely nothing whatsoever to do with the planet's descent into this coldest of its Holocene climatic phases.

Two years later still, and also working with sediment cores recovered from three mid-Arctic lakes on the Cumberland Peninsula of eastern Baffin Island in the Canadian Arctic, Frechette et al. (2006) employed radiocarbon dating of macrofossils they contained, together with luminescence dating, to isolate and study the portions of the cores pertaining to the interglacial that proceeded the Holocene, which occurred approximately 117,000-130,000 years ago, reconstructing the past vegetation and climate of the region during this period based on pollen spectra derived from the cores. This work revealed that "in each core," as they describe it "last interglacial sediments yielded remarkably high pollen concentrations, and included far greater percentages of shrub (Betula and Alnus) pollen grains than did overlying Holocene sediments." And they say that "from applications of both correspondence analysis regression and best modern analogue methodologies, we infer July air temperatures of the last interglacial to have been 4 to 5°C warmer than present [our italics] on eastern Baffin Island," which warmth was greater than that of any interval within the Holocene. Giving even more weight to their results, they say their temperature reconstruction is "directly comparable to both earlier qualitative estimates (LIGA Members, 1991; Bennike and Bocher, 1994), as well as more recent quantifications from ice core (NGRIP Members, 2004) and pollen (Andreev et al., 2004) analyses."

In a companion study, Francis et al. (2006) analyzed midge remains found in cores recovered from two of the same Baffin Island lakes (Fog Lake and Brother of Fog Lake) for which Frechette et al. analyzed pollen spectra, reconstructing lake water temperatures and mean July air temperatures for both the Holocene and the prior interglacial period. This work also revealed, in their words, that "reconstructions at both [lake] sites indicate that summer temperatures during the last interglacial were higher than at any time in the Holocene, and 5 to 10°C higher than present [our italics]."

Last of all, the 25 authors of a major review paper (CAPE-Last Interglacial Project Members, 2006) present, in their words, "quantitative estimates of circum-Arctic Last Interglaciation (LIG) summer air and sea-surface temperatures reconstructed from proxy records preserved in terrestrial and marine archives," including beach morphology, beetles, benthic foraminifera, chironomids, coccoliths, δD, δ18O, dinocysts, insects, invertebrates, Mg/Ca ratio, mollusks, nanofossils, needles, ostracodes, planktic foraminifera, plant microfossils, pollen, soils, spores, tephra, and treeline position. And they report that "quantitative reconstructions of LIG summer temperatures suggest that much of the Arctic was 5°C warmer during the LIG than at present [our italics]." With respect to the impacts of this warmth, they say that Arctic summers of the LIG "were warm enough to melt all glaciers below 5 km elevation except the Greenland Ice Sheet, which was reduced by ca 20-50% (Cuffey and Marshall, 2000; Otto-Bliesner et al., 2006)." In addition, they note that "the margins of permanent Arctic Ocean sea ice retracted well into the Arctic Ocean basin and boreal forests advanced to the Arctic Ocean coast across vast regions of the Arctic currently occupied by tundra."

Clearly, if there is anything strange or unusual about current Arctic temperatures -- as the world's climate alarmists are fond of claiming when spinning their biosphere-threatening global warming scenarios -- it is that they are so much lower than what they were during the maximum warmth of the current interglacial and, even more so, the prior interglacial. And if the Arctic behaves anything like the Antarctic in this regard, one can extend this comparison back in time through three more interglacials, all of which were also warmer than the current one (Petit et al., 1999; Augustin et al., 2004.).

Given this vast perspective, it is truly amazing that with so much more CO2 currently in the air (40-50% more), it is currently so much colder than it was during the peak warmth of the current interglacial and the four interglacials that proceeded it. Furthermore, it should be evident to everyone that all of the planet's many current life forms had to have fared just fine during these much warmer interglacials ... else, of course, they wouldn't be here today!

Complete Original Article From Co2 Science

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