[Rut Roe] Another Global Warming Theory Discredited

Low-Frequency Signals in Long Tree-Ring Chronologies Reveal the Existence of Multi-Centennial-Scale Temperature Trends of the Past Millennium*

If the Medieval Warm Period of a thousand years ago was truly warmer than, or merely as warm as, the Modern Warm Period in which we currently live, there is simply no basis for claiming that any of the warming that brought us out of the Little Ice Age was caused by the concomitant historical rise in the air's CO2 content (Idso, 1988). This is the reason why proponents of legislation to reduce anthropogenic CO2 emissions are so incensed by the appearance of scientific papers challenging the IPCC-inspired conclusion that recent temperatures have been the warmest of the past millennium; for if it was as warm as it is today a thousand years ago, when the atmosphere's CO2 concentration was nearly 100 ppm less than it is currently, whatever made it that warm then could well be making it that warm now. Consequently, appropriately-derived temperature reconstructions of the past thousand years are of critical importance in helping to resolve this issue. The latest contribution to this important quest is the study of Esper et al. (2003), who processed several extremely long juniper ring width chronologies for the Alai Range of the western Tien Shan in Kirghizia in such a way as to preserve multi-centennial growth trends that are typically "lost during the processes of tree ring data standardization and chronology building (Cook and Kairiukstis, 1990; Fritts, 1976)." In doing so, they used two techniques that maintain low frequency signals: long-term mean standardization (LTM) and regional curve standardization (RCS), as well as the more conventional spline standardization (SPL) technique that obscures (actually removes) such long-term trends.

Carried back in time a full thousand years, the SPL chronologies depict significant inter-decadal variations but no longer-term trends. The LTM and RCS chronologies, on the other hand, show long-term decreasing trends until about AD 1600, broad minima from 1600 to 1800, and long-term increasing trends from about 1800. As a result, in the words of Esper et al., "the main feature of the LTM and RCS Alai Range chronologies is a multi-centennial wave with high values towards both ends."

This grand result has essentially the same form as the Northern Hemisphere extratropic temperature history of Esper et al. (2002), which is vastly different from the notorious hockeystick temperature history of Mann et al. (1998, 1999) and Mann and Jones (2003), in that it depicts the existence of both the Little Ice Age and preceding Medieval Warm Period, which are nowhere to be found in the Mann and Company reconstruction. And the new result - especially the LTM chronology, which has a much smaller variance than the RCS chronology - depicts several periods in the first half of the last millennium that were warmer than any part of the last century. These periods include much of the latter half of the Medieval Warm Period and a good part of the first half of the 15th century, which has also been found to have been warmer than it is currently by McIntyre and McKitrick (2003) and by Loehle (2004), as described in our Editorial of 28 Jan 2004.

In commenting on their important findings, Esper et al. remark that "if the tree ring reconstruction had been developed using 'standard' detrending procedures only, it would have been limited to inter-decadal scale variation and would have missed some of the common low frequency signal." We would also remark, with respect to the upward trend of their data since 1800, that a goodly portion of that trend may well have been due to the aerial fertilization effect of the concomitantly increasing atmospheric CO2 concentration, which is known to greatly stimulate the growth of trees [see Long-Term Studies (Woody Plants) in our Subject Index]. Properly accounting for this very real effect would make the warmer-than-present temperatures of the first half of the past millennium even warmer, relative to those of the past century, than what they appear to be in Esper et al.'s LTM and RCS reconstructions. Last of all, we find it extremely gratifying that Donald Graybill appears as a coauthor of the Esper et al. paper, over a decade after his untimely death in 1993, the very same year he published another important paper on this specific subject (Graybill and Idso, 1993).

In conclusion, as ever more data continue to accumulate, and as more correct procedures are employed to analyze them, the world's true temperature history is becoming ever more clear … and what's beginning to take shape will shortly spell the end of the sorry centerpiece of the IPCC's ill-conceived rush to judgment on both the nature and cause of post-Little Ice Age climate change.

Evidence of ancient El Niños found
"The full sediment record indicates that 15,000 years ago severe El Niño-like storms occurred at least about every 15 years, and that they have since occurred with progressively increasing frequency. Over the past 5,000 years, storms from El Niño-like climate fluctuations have occurred about every two to eight and one-half years, possibly due to enhanced trade winds," said the study's lead author, Donald T. Rodbell of Union College, in Schenectady, N.Y.
El Niño Secrets in Old Egypt
Early Nile Records Valuable to Scientists
by Randolph E. Schmid
Researchers Elfatih A.B. Eltahir and Guiling Wang looked at Nile flood records dating back to A.D. 650 to develop an estimate of past El Niños. They have discovered a period, just over 1,000 years ago, that had relatively frequent El Niños, similar to the pattern of the past 20 year. When an El Niño is under way, rain is reduced over the sources of the Nile. Studies have found that about 30 percent of the change in water flow on the Nile at Aswan can be attributed to El Niño. The paper shows frequent El Niños between about 750 and 1000 with a reduction after that, and then an increase again in the latter years of this century.
Evolution in Your Face
by Patrick Huyghe
Lake Victoria, Africa's largest lake, is home to more than 300 species of cichlids. These fish, which are popular in aquariums, are deep-bodied and have one nostril, rather than the usual two, on each side of the head. Seismic profiles and cores of the lake taken by a team headed by Thomas C. Johnson of the University of Minnesota, reveal that the lake dried up completely about 12,400 years ago. This means that the rate of speciation of cichlid fishes has been extremely rapid: something on average of one new species every 40 years!

and, from the topmost following title, pp 208-216:

"On June 23, 1988, climatologist James Hansen testified before a hearing of the Senate Energy and Natural Resources Committee on a day when the temperature in Washington D.C. reached a sweltering 38C... Hansen had impressive data from 2,000 weather stations... which documented not only a century-long warming trend but a sharp resumption of warming after the early 1970s... Hansen flatly proclaimed that the earth was warming on a permanent basis because of humanity's promiscuous use of fossil fuels [sic]... Recently, James Hansen and a group of his colleagues have argued that the rapid warming of recent decades has in fact been driven by non-CO2 gases such as chlorofluorocarbons. Fossil fuel [sic] burning CO2 and aerosols have both positive and negative climatic forcing effects, which tend to cancel each other out. Hansen and his team point out that the growth rate of non-CO2 gases has declined over the past decade and could be reduced even further. This, combined with a slowing of black carbon and CO2 emissions, could lead to a decline in the rate of global warming. Much more research is needed to confirm this hypothesis."

In other words, in 1988 Hansen warned Congress that CO2 would raise world temperatures. About ten years went by, after which Hansen claimed that CO2 doesn't have any net impact at all. So much for his data. Mind you, this came from the book shown below, which is egregiously in advocacy of the notion of "global warming".

The Little Ice Age:
How Climate Made History 1300-1850
by Brian M. Fagan
Paperback

Floods, Famines, and Emperors:
El Nino and the Fate of Civilizations
by Brian M. Fagan

The Skeptical Environmentalist:
Measuring the Real State of the World
by Bjorn Lomborg

Junk Science Judo:
Self-Defense Against
Health Scares and Scams
by Steven J. Milloy


GGG managers are SunkenCiv, StayAt HomeMother & Ernest_at_the_Beach	join list or digest view topics view or post blog bookmark post a topic subscribe

Just to the catalog, not sending a general distribution. Evolution in Your Face by Patrick Huyghe Omni Lake Victoria, Africa's largest lake, is home to more than 300 species of cichlids. These fish, which are popular in aquariums, are deep-bodied and have one nostril, rather than the usual two, on each side of the head. Seismic profiles and cores of the lake taken by a team headed by Thomas C. Johnson of the University of Minnesota, reveal that the lake dried up completely about 12,400 years ago. This means that the rate of speciation of cichlid fishes has been extremely rapid: something on average of one new species every 40 years! 12,400 years ago? Hydrologic cycle came to a screeching whoa for some reason, hmm, what could it have been? To all -- please ping me to other topics which are appropriate for the GGG list.

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	The Little Ice Age: How Climate Made History 1300-1850 by Brian M. Fagan Paperback
	Floods, Famines, and Emperors: El Nino and the Fate of Civilizations by Brian M. Fagan
	The Skeptical Environmentalist: Measuring the Real State of the World by Bjorn Lomborg
	Junk Science Judo: Self-Defense Against Health Scares and Scams by Steven J. Milloy