Was the Little Ice Age anything more than a local phenomenon confined to the countries that border the North Atlantic Ocean? Climate alarmists are loathe to admit that it was, because that acknowledgement would imply that the globe was a significantly warmer place prior to the Little Ice Age, perhaps even warm enough to equal or exceed the warmth that followed in its wake; and they can't have that, for it implies that our current warmth may have little or nothing to do with the historical rise in the atmosphere's CO2 concentration, which was much lower prior to the Little Ice Age than it is today, revealing that temperatures such as those of the last few decades can readily arise from causes other than anthropogenic CO2 emissions, which climate alarmists demonize on a regular basis and use as a lever to move the nations of the world ever closer to a state of subservience to a central Planetary Management Authority designed to regulate almost everything imaginable, because almost everything imaginable is inextricably linked to energy, which today is produced primarily from the burning of fossil fuels, from whence comes the CO2 that enriches earth's atmosphere. Consequently, we regularly report the results of studies that reveal the presence of the Little Ice Age in various places around the globe, and which often characterize it in relation to the warmth that preceded and followed it. In this Summary we thus review what we have learned in this regard from studies that have been conducted in Russia.
Naurzbaev and Vaganov (2000) developed a proxy temperature record based on tree-ring data obtained from the cores of 118 trees that grew near the upper timberline in Siberia over the period 212 BC to AD 1996. This record agreed well with air temperature variations reconstructed from Greenland ice core data, suggesting to them that "the tree ring chronology of [the Siberian] region can be used to analyze both regional peculiarities and global temperature variations in the Northern Hemisphere." And what did they find in this regard? They observed the presence of the Medieval Warm Period from about AD 850 to 1150, the cooling of the Little Ice Age from 1200 though 1800, and the subsequent recovery warming of the 20th century. What is more, with respect to this latter temperature increase, they report that it was "not extraordinary" and that "the warming at the border of the first and second millennia [AD 1000] was longer in time and similar in amplitude."
In the Middle Ural Mountains of Russia, Demezhko and Shchapov (2001) used borehole data to develop a temperature history that revealed the existence of a number of climatic excursions, including the "Medieval Warm Period with a culmination about 1000 years ago and Little Ice Age 200-500 years ago." They also determined that the mean temperature of the Medieval Warm Period was more elevated above the mean temperature of the past century than the mean temperature of the Little Ice Age was reduced below it.
Analyzing a much greater array of information drawn from written historical evidence, as well as glaciological, hydrological, dendrological, archaeological and palynological data, Krenke and Chernavskaya (2002) reported large differences in a number of climatic variables between the Little Ice Age and the preceding Medieval Warm Period in Russia. With respect to the annual mean temperature of northern Eurasia, for example, they report a Medieval Warm Period-to-Little Ice Age temperature drop on the order of 1.5°C. They also note that the frequency of severe winters increased from once in 33 years in the Medieval Warm Period to once in 20 years in the Little Ice Age, also noting that the abnormally severe winters of the Little Ice Age were associated with the spread of Arctic air masses over the entire Russian Plain.
The two members of the Russian Academy of Sciences note that the data they used to draw these conclusions were "not used in the reconstructions performed by Mann et al. (1999)," which perhaps explains why the Mann et al. temperature history of the past millennium does not reproduce the Little Ice Age nearly as well as does the more appropriately derived temperature history of Esper et al. (2002). And in contradiction of another of Mann et al.'s contentions, the Russian scientists unequivocally state, based on the results of their comprehensive study of the relevant scientific literature, that "the Medieval Warm Period and the Little Ice Age existed globally."
Mackay et al. (2005) analyzed paleolimnological data obtained from a sediment core taken from the south basin of Lake Baikal in an effort to reconstruct the climatic history of the surrounding area over the past millennium. Using cluster analysis, they identified three significantly different climatic eras that were coincident with the Medieval Warm Period (AD 880-1180), the Little Ice Age (1180-1840) and the Current Warm Period. Although they did not obtain actual temperature values, Mackay et al. say their diatom data support the idea "that the period known as the Medieval Warm Period in the Lake Baikal region was a relatively warm one." Following the Medieval Warm Period, diatom species shifted toward taxa indicative of colder climates, implying maximum snow depth values during the Maunder Minimum (1645-1715). Thereafter, the diatom-derived snow accumulation data indicate a warming trend that may have begun as early as 1750.
Rounding out our repertoire of Russian studies, Kalugin et al. (2005) analyzed sediment cores retrieved from Lake Teletskoye in the Altai Mountains of Southern Siberia, producing a multi-proxy climate record that revealed several distinct climatic periods over the past eight centuries. With respect to temperature, the regional climate was relatively warm with high terrestrial productivity from AD 1210 to 1380. Thereafter, however, temperatures cooled, reaching peak deterioration between 1660 and 1700, which time period, in their words, "corresponds to the age range of the well-known Maunder Minimum (1645-1715)" and is "in agreement with the timing of the Little Ice Age in Europe (1560-1850)," with prior-level warmth not recurring until the late 20th century.
With respect to moisture and precipitation, Kalugin et al. say that the period between 1210 and 1480 was more humid than it is today, while the period between 1480 and 1840 was more arid. In addition, they report the discovery of three episodes of multi-year drought (1580-1600, 1665-1690 and 1785-1810), which finding is in agreement with historical data and tree-ring records from the Mongolia-Altai region (Butvilovskii, 1993; Jacoby et al., 1996; Panyushkina et al., 2000). Hence, their study adds to the large and growing body of evidence for a global Little Ice Age, as well as a similarly widespread Medieval Warm Period with temperatures as high as, or in some cases even higher than, those of today, at a time when the atmosphere's CO2 concentration was fully 100 ppm less than it is currently.
References
Butvilovskii, V.V. 1993. Paleogeography of the Late Glacial and Holocene on Altai. Tomsk University, Tomsk.
Demezhko, D.Yu. and Shchapov, V.A. 2001. 80,000 years ground surface temperature history inferred from the temperature-depth log measured in the superdeep hole SG-4 (the Urals, Russia). Global and Planetary Change 29: 167-178.
Esper, J., Cook, E.R. and Schweingruber, F.H. 2002. Low-frequency signals in long tree-ring chronologies for reconstructing past temperature variability. Science 295: 2250-2253.
Jacoby, G.C., D'Arrigo, R.D. and Davaajatms, T. 1996. Mongolian tree rings and 20th century warming. Science 273: 771-773.
Kalugin, I., Selegei, V., Goldberg, E. and Seret, G. 2005. Rhythmic fine-grained sediment deposition in Lake Teletskoye, Altai, Siberia, in relation to regional climate change. Quaternary International 136: 5-13.
Krenke, A.N. and Chernavskaya, M.M. 2002. Climate changes in the preinstrumental period of the last millennium and their manifestations over the Russian Plain. Isvestiya, Atmospheric and Oceanic Physics 38: S59-S79.
Mackay, A.W., Ryves, D.B., Battarbee, R.W., Flower, R.J., Jewson, D., Rioual, P. and Sturm, M. 2005. 1000 years of climate variability in central Asia: assessing the evidence using Lake Baikal (Russia) diatom assemblages and the application of a diatom-inferred model of snow cover on the lake. Global and Planetary Change 46: 281-297.
Mann, M.E., Bradley, R.S. and Hughes, M.K. 1999. Northern Hemisphere temperatures duing the past millennium: Inferences, uncertainties, and limitations. Geophysical Research Letters 26: 759-762.
Naurzbaev, M.M. and Vaganov, E.A. 2000. Variation of early summer and annual temperature in east Taymir and Putoran (Siberia) over the last two millennia inferred from tree rings. Journal of Geophysical Research 105: 7317-7326.
Panyushkina, I.P., Adamenko, M.F., Ovchinnikov, D.V. 2000. Dendroclimatic net over Altai Mountains as a base for numerical paleogeographic reconstruction of climate with high time resolution. In: Problems of Climatic Reconstructions in Pliestocene and Holocene 2. Institute of Archaeology and Ethnography, Novosibirsk, pp. 413-419.
Last updated 2 November 2005