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A 1500-Year Climate History of Northern Eurasia
Volume 9, Number 23: 7 June 2006

In a special issue of Palaeogeography, Palaeoclimatology, Palaeoecology, Solomina and Alverson (2004) review and synthesize the findings of a number of papers presented at a conference held in Moscow in May of 2002, which brought together more than 100 local paleoenvironmental researchers from Bellarussia, Estonia, Georgia, Kyrgyzstan, Russia, Ukraine and Uzbekistan, plus another 30 scientists from 18 additional countries. The two researchers report the meeting's overall findings for five distinct regions: The Arctic and Sub-Arctic, The Russian Plain and Caucasus, Central Asia and the Caspian Region, Eastern and Southern Siberia, and The Far East. We here summarize their conclusions, mostly in their own words.

The Arctic and Sub-Arctic. "The 9th-14th centuries were relatively warm, though at least two colder periods probably occurred in the 11th and 13th centuries," after which "the 15th-early 20th centuries were generally cold," while "subsequent warming is recorded with almost all proxies."

The Russian Plain and Caucasus. "The climate of the Russian plain was relatively warm from the 11th to 14th centuries, with the exception of the late 12th-early 13th centuries, and colder from the 15th to 19th centuries, except for a warm interval in the first half of the 16th century." In the Central Caucasus, they also report the existence of a "relatively warm climate around the end of the first to the beginning of the second millennium AD," followed by "numerous glacier advances...during the 14th-19th centuries," the timing of which correlates well with those in the European Alps.

Central Asia and the Caspian Region. "A milder, less continental climate with more precipitation approximately from the 9th to 12th centuries" was indicated by most of the available data, while "cold conditions dominated from the 13th to 19th centuries, though interrupted by a brief warm period from the end of the 14th-early 15th century," after which "the coldest conditions were probably in the 17th and 19th centuries, when glaciers advanced several times, lake level was high, and permafrost depth increased."

Eastern and Southern Siberia. "Two periods of warmer and drier climate can be roughly identified in this huge area as having occurred from the 9th to 11th centuries and in the 14th century," while "the 15th-19th centuries were clearly cold and the 20th century has seen a return to warm conditions."

The Far East. "There is some evidence suggesting moderately warm conditions in the North Pacific region from the end of the first to the beginning of the second millennium," with "a subsequent cooling after the 14th century."

In summarizing their findings for the bulk of the Northern Eurasia region, Solomina and Alverson say "a number of records allow one to distinguish the climatic pattern of the 9th-13th centuries [i.e., the Medieval Warm Period] from earlier and later colder conditions [i.e., the Dark Ages Cold Period and Little Ice Age, respectively]." They also say "the spatial pattern of temperature anomalies ca. 1000 years ago is similar to the earlier mid-Holocene 'optimum'." Last of all, they remark that "the warming of the 14th century in several regions, including the Russian plain, Altai and Central Asia, was at least as intense as the earlier one at ca. 1000 years before present or even warmer [our italics]." This latter widely-detected event might possibly correspond to what we have called the Little Medieval Warm Period. Just as easily, it may well be what we have called "the 'last hurrah' of the Medieval Warm Period before it relinquished control of earth's climate to the Little Ice Age," as stated in the conclusion of our Little Medieval Warm Period summary.

Taken together, the many observations summarized by Solomina and Alverson bear strong testimony to the reality of the natural, as opposed to anthropogenic-induced, millennial-scale oscillation of earth's climate that has most recently resulted in the development of the Current Warm Period.

Sherwood, Keith and Craig Idso

Reference
Solomina, O. and Alverson, K. 2004. High latitude Eurasian paleoenvironments: introduction and synthesis. Palaeogeography, Palaeoclimatology, Palaeoecology 209: 1-18.