Schilman et al. (2001) analyzed foraminiferal oxygen and carbon isotopes, together with the physical and geochemical properties of sediments, contained in two cores extracted from the bed of the southeastern Mediterranean Sea off the coast of Israel, where they found evidence for the MWP centered around AD 1200.  In discussing their findings, they note there is an abundance of other evidence for the existence of the MWP in the Eastern Mediterranean as well, including, in their words, "high Saharan lake levels (Schoell, 1978; Nicholson, 1980), high Dead Sea levels (Issar et al., 1989, 1991; Issar, 1990, 1998; Issar and Makover-Levin, 1996), and high levels of the Sea of Galilee (Frumkin et al., 1991; Issar and Makover-Levin, 1996)," in addition to "a precipitation maximum at the Nile headwaters (Bell and Menzel, 1972; Hassan, 1981; Ambrose and DeNiro, 1989) and in the northeastern Arabian Sea (von Rad et al., 1999)."

Further to the east, Kar et al. (2002) explored the nature of climate change preserved in the sediment profile of an outwash plain two to three km from the snout of the Gangotri Glacier in the Uttarkashi district of Uttranchal, Western Himalaya.  Between 2000 and 1700 years ago, their data reveal the existence of a relatively cool climate.  Then, from 1700 to 850 years ago, there was what they call an "amelioration of climate," during the transition from the depth of the Dark Ages Cold Period to the midst of the Medieval Warm Period.  Subsequent to that time, Kar et al.'s data indicate the climate "became much cooler," indicative of its transition to Little Ice Age conditions, while during the last 200 years there has been a rather steady warming, as shown by Esper et al. (2002a) to have been characteristic of the entire Northern Hemisphere.

At a pair of other Asian locations, Esper et al. (2002b) used more than 200,000 ring-width measurements obtained from 384 trees at 20 individual sites ranging from the lower to upper timberline in the Northwest Karakorum of Pakistan (35-37°N, 74-76°E) and the Southern Tien Shan of Kirghizia (40°10'N, 72°35'E) to reconstruct regional patterns of climatic variations in Western Central Asia since AD 618.  According to their analysis, the Medieval Warm Period was already firmly established and growing even warmer by the early 7th century; and between AD 900 and 1000, tree growth was exceptionally rapid, at rates that they say "cannot be observed during any other period of the last millennium."

Between AD 1000 and 1200, however, growing conditions deteriorated; and at about 1500, minimum tree ring-widths were reached that persisted well into the seventeenth century.  Towards the end of the twentieth century, ring-widths increased once again; but Esper et al. (2002b) report that "the twentieth-century trend does not approach the AD 1000 maximum."  In fact, there is almost no comparison between the two periods, with the Medieval Warm Period being far more conducive to good tree growth than the Modern Warm Period.  As the authors describe the situation, "growing conditions in the twentieth century exceed the long-term average, but the amplitude of this trend is not comparable to the conditions around AD 1000."

The latest contribution to Asian temperature reconstruction 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) 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 from the start of the record until about AD 1600, broad minima from 1600 to 1800, and long-term increasing trends from about 1800 to the present.  As a result, in the words of Esper et al. (2003), "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. (2002a), 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 reconstructions.  In addition, 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. (2003) 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 content, 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.

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 ultimately spell the end of the IPCC's ill-conceived rush to judgment on identifying both the nature and the cause of the post-Little Ice Age climatic amelioration.

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