So the quote which shook me is this (from the official website of the US National Park Service, but obviously not yet cleansed by CAGW types):

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“Many bits of evidence, both from North America and Europe, indicate that there was a period called the climatic optimum about 6,000 years ago when the climate was significantly warmer and drier than at present. We suspect, though there is as yet no direct proof, that the Pinedale glaciers wasted away entirely during this interval.”

http://www.cr.nps.gov/history/online_books/grte/grte_geology/sec9.htm

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They are of a previous generation of geologists, seem to have been active 1940s to 80s, and I have no idea whether more definite assessments have been made about glaciers and temps in the Rocky Mtn. West or not. The document was first published in 1959 and went through 11 editions as of the NPS website in 2007 (when or if the most interesting statement was revised since 1959 I have no idea). Could there be more evidence about temperate zone glaciers (such as in the US Rocky Mtns.) that would help to indicate whether or not there was a high “Holocene Optimum” in those areas?

It occurs to me that the quotation points to something possibly as important (or even more so) than debates about the Medieval Warm Period, i.e., if there were such a high Holocene Optimum that could also be very imporant to understanding the climate hisotry. In case there is anything here that merits further attention (and I know this is a non-scientific website but the authors do seem to be professional geologists now or formerly in Wyoming). The senior member of the pair, Dr. J.D. Love, is said to have done the first complete geologic map of Teton County (western Wyomning where many of the mountains are) and was senior geologist for the statewide geologic map of Wyoming.

Certainly I have seen discussions of the Climatic or Holocene “Optimum” but not being in a related field I had not known that there is physical evidence that the HO might be (as they assert)”significantly warmer and drier than at present.” If there were strong evidence for that claim it would seem (just as with the MWP if that is strong and not weak) to undermine the more hysterical claims about AGW. This might be a great topic for someone who has the ability to re-assess diverse geological and climate evidence that is (possibly) ignored or suppressed by contemporary climatologists. We hear how Lonnie Thompson et al are showing peril for “tropical” glaciers at high altitudes. But the climate pressures on glaciers were obvious long before the past few decades, I think? That seems obvious in many spots in N. America and the Alps, anyway. Has anyone who can rigorously assess glaciation evidence looked at what the glaciers which greatly retreated BEFORE 1950 might have to say about climate change in the past 1, 2, and many centuries?? i.e., as a traveler and mountaineer I am well aware of areas where few or only small glaciers remain, but where the glacier retreats had been far advanced long before any possible human/CO2 influence.

For instance, Glacier Bay on the Alaskan coast was the scene of a huge retreat of glaciers between the 1780s and 1880s, with dozens of miles of the bay opening up as the ice retreated (confirmed by John Muir’s visit there). Or, to take the case of the Tetons in Wyoming, glaciers there were small to non-existent by the 1950s or 60s, but of course they had once extended all over the mountain valleys there. These might be the kinds of examples at the “margin” which could show the ways in which non-human causes have been melting the glaciers in the past 1-2 centuries (and of course for much longer).

Perhaps a more specific question might be considered by CA readers knowledgeable in these areas:

Both 6-7,000 years ago and again throughout the 19th to early 20th centuries, many glaciers may have retreated or largely disappeared: how do these “natural” changes compare to recent claims of CAGW? I’m thinking of many places I have hiked and climbed in US and Canadian Rockies, the Sierra, and the Alps, where remaining glaciers are much fewer and smaller without any possible human intervention…. although of course similar examples may exist in many other places in the years since the Little Ice Age. Indeed, rather than assume that remaining ice far from the polar regions will remain as it is, my layman’s perspective is that it would not be surprising at all if many more sub-polar glaciers would be melting from natural trends.

I don’t “know” this could develop as any scientific argument, I’m simply wondering who has really looked carefully at the data, say pre-1970s, to understand what “natural” trends were already underway, either in the past 2 centures or 7,000 years ago. My hunch is that it would require more of an explanation for why sub-polar glaciers will remain indefinitely than why they might be retreating now, but I am not a scientist.

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Here is the original web source for what seems to be a booklet written for the US National Park Service many years ago (first in 1959) but which has gone through 11 editions.

[from 2007 website of US Nationl Park Service, for the Teton National Park (Wyoming)]:

http://www.cr.nps.gov/history/online_books/grte/grte_geology/sec9.htm

[emphasis added]

“…In either case, the shells indicate that the Pinedale glaciers probably existed on the floor of Jackson Hole as recently as 9,000 years ago, at a time when Indians were already living in the area. We can easily imagine the fascination with which these primitive peoples may have watched as year after year the glaciers wasted away, slowly retreating back into the canyons, then withdrawing into the sheltered recesses of the high mountains, eventually to dwindle and disappear.”

“Many bits of evidence, both from North America and Europe, indicate that there was a period called the climatic optimum about 6,000 years ago when the climate was significantly warmer and drier than at present. We suspect, though there is as yet no direct proof, that the Pinedale glaciers wasted away entirely during this interval.”

“The modern pattern of vegetation in Jackson Hole is strongly influenced by the distribution of Pinedale glacial moraines and outwash deposits. Almost without exception the moraines are heavily forested, whereas the nearby outwash deposits are covered only by a sparse growth of sagebrush. This is probably because the moraines contain large amounts of clay and silt produced by the grinding action of the glaciers. Material of this type retains water much better and, because of the greater variety of chemical elements, is more fertile than the porous quartzite gravel and sand on the outwash plains.”

Modern glaciers

“About a dozen small rapidly dwindling glaciers exist today in shaded reentrants high in the Teton Range. They are probably vestiges of ice masses built up since the climatic optimum, during the so-called “Little Ice Age.” These glaciers, while insignificant compared to those still present in many other mountain ranges, are fascinating working models of the great ice streams that shaped the Tetons during Pleistocene time.”

“The Teton Glacier (fig. 6) is one of the best known. It is an ice body about 3,500 feet long and 1,100 feet wide that lies at the head of Glacier Gulch, shaded by the encircling ridges of the Grand Teton, Mount Owen, and Mount Teewinot. Ice in the central part is moving at a rate of more than 30 feet a year….”

About the authors

J. D. Love, a native of Wyoming, received his bachelor and master of arts degrees from the University of Wyoming and his doctor of philosophy degree from Yale University. His first field season in the Teton country, in 1933, was financed by the Geological Survey of Wyoming. After 12 years of geologic work ranging from New England to Utah and Michigan to Mississippi, he returned to the Teton region. Beginning in 1945, he spent parts or all of 20 field seasons in and near the Tetons. He compiled the first geologic map of Teton County. He is the senior author of the geologic map of Wyoming, and author or co-author of more than 70 other published maps and papers on the geology of Wyoming. In 1961, the University of Wyoming awarded him an honorary doctor of laws degree for his work on uranium deposits that “led to the development of the uranium industry in Wyoming.” The Wyoming Geological Association made him an honorary life member and gave him a special award for his geologic studies of the Teton area. He is a Fellow of the Geological Society of America and is active in various other geological organizations, as well as having been president of the Wyoming Chapters of Sigma Xi (scientific honorary) and Phi Beta Kappa (scholastic honorary) societies.

John C. Reed, Jr., joined the U.S. Geological Survey in 1953 after receiving his doctor of philosophy degree from the John Hopkins University. His principal geologic work before coming to the Teton region was in Alaska and in the southern Appalachians. Beginning in 1961, he spent five field seasons studying and mapping the Precambrian rocks in Grand Teton National Park, including all the high peaks in the Teton Range. He is a noted mountaineer, a Fellow of the Geological Society of America, a member of the Arctic Institute of North America, and the American Alpine Club. His numerous publications, in addition to those on the Tetons, describe the geology of mountainous areas in Alaska, the Appalachians, and Utah.

It is conceivable that the refill event involving lakes Fryxell, Hoare, and Vanda was initiated by a global MWP forcing (Broecker, 2001).

The Helium Isotopic Chemistry of Lake Bonney, Taylor Valley, Antarctica: Timing of Late Holocene Climate Change in Antarctica. ROBERT J. POREDA1, ANDREW G. HUNT1,3, W. BERRY LYONS2,? and KATHLEEN A. WELCH2. 1Department. of Earth and Environmental Sciences, University of Rochester, Hutchison Hall, Rochester, NY 14627,USA; 2Byrd Polar Research Center, Ohio State University, 1090 Carmack Rd, Scott Hall, Columbus, Ohio 43210-1002, USA; Present address: 3US Geological Survey, Federal Center, Denver, CO 80225, USA (Received 21 November 2003; accepted 13 May 2004)

Yeah, it was important to look at nuclear dna too because the close relationship with the ABC islands brown bear could have been the indication of hybridisation with polar bears (mtdna is only passed via the female line). Highly variable microsatellite markers have confirmed the mtdna conclusions.

Paetkau, D., and C. Strobeck. 1998. Ecological genetic studies of bears using microsatellite analysis. Ursus 10:299’306.

Paetkau, D., W. Calvert, I. Stirling, and C. Strobeck. 1995. Microsatellite analysis of population structure in Canadian polar bears. Molecular Ecology 4:347” 54.

Paetkau, D., L. P. Waits, P. L. Clarkson, L. Craighead, and C. Strobeck. 1997. An empirical evaluation of genetic distance statistics using microsatellite data from bear (Ursidae) populations. Genetics 147:1943’57.

Paetkau, D., S. C. Amstrup, E. W. Born, W. Calvert, A. E. Derocher, G. W. Garner, F. Messier, I. Stirling, M. K. Taylor, “. Wiig, and C. Strobeck. 1999. Genetic structure of the world’s polar bear populations. Molecular Ecology 8:1571’84.

Mol Phylogenet Evol. 2000 May;15(2):319-26.
Phylogeography of mitochondrial DNA variation in brown bears and polar bears.

Shields GF, Adams D, Garner G, Labelle M, Pietsch J, Ramsay M, Schwartz C, Titus K, Williamson S.
Institute of Arctic Biology, University of Alaska at Fairbanks, Fairbanks, Alaska 99775-7000, USA.
We analyzed 286 nucleotides of the middle portion of the mitochondrial cytochrome b gene of 61 brown bears from three locations in Alaska and 55 polar bears from Arctic Canada and Arctic Siberia to test our earlier observations of paraphyly between polar bears and brown bears as well as to test the extreme uniqueness of mitochondrial DNA types of brown bears on Admiralty, Baranof, and Chichagof (ABC) islands of southeastern Alaska. We also investigated the phylogeography of brown bears of Alaska’s Kenai Peninsula in relation to other Alaskan brown bears because the former are being threatened by increased human development. We predicted that: (1) mtDNA paraphyly between brown bears and polar bears would be upheld, (2) the mtDNA uniqueness of brown bears of the ABC islands would be upheld, and (3) brown bears of the Kenai Peninsula would belong to either clade II or clade III of brown bears of our earlier studies of mtDNA. All of our predictions were upheld through the analysis of these additional samples.

DNA fingerprinting has to survive challenges in courts of law so it’s not surprising that the analysis has been rigorous. It’s far better tested than actual fingerprint identification, from what I’ve read.

But since nobody outside the field, including myself, really cares, we may never know.

Because no one really needs to care because the science is not being used to justify trillion dollar public policy decisions. I have been frequently frustrated by warmers who don’t seem to understand that “the way science is always done” is not good enough when huge sums of money depend on the science being right.