Reliable, corroborated records of climate fluctuations before and since the industrial revolution are essential to the early detection of global climate change and its attribution to specific causes. We report a valuable and underutilized source of such information - six very small glaciers in the Polar Urals (FIG. 1, 2). Such small glaciers respond to climate changes on decadal time scales, directly relevant to human concerns. In addition to being valuable records in their own right, they provide an opportunity for comparison with other, completely independent, natural archives of climate variability. These glaciers, each of whose area is no more than 1 km2, so far survived the increased temperatures of the 20th century. They were discovered in the 1930's, intensively monitored from 1953-1981 and visited most recently in 1999-2000s (Troitsky, 1961, Voloshina, 1981, Tsvetkov, Tiuflin, 1981, Solomina et al., 2000, Nosenko et al.in press). The Holocene climate and treeline variations in the area were reconstructed using pollen (Surova et al., 1971, 1975) and tree-ring analysis (Shiyatov, 1981, 2000, 2003; Hantemirov, 2000).
The modern area of Polar Urals glaciers is 20-50% smaller than it was at the "Little Ice Age" maximum. The terminal moraines located below the modern glaciers bear witness to repeated glacier advances of approximately identical amplitude. Six major advances of the last millennium were identified by lichenometry. Using a combination of direct measurements and control points, we estimated the growth rate of Rhizocarpon geographicum as approximately 0.25 mm/year for the first hundred years (TABLE 1), which is close to (although a little slower than) to the growth rates of these lichens in Northern Sweden (0.29 mm/year) (Denton, Karlen, 1973) (see FIG.3). According to the preliminary growth curve, the age of the moraines is estimated as AD1880's (24-26 mm), AD1850's-1830's (38-44 mm), AD1800's (50-51 mm), AD1750's-1730's (63, 66 mm), AD1600 (?) (87 mm) and in the 13th century (?) (120 mm). These dates correspond to well-known Northern Hemisphere glacier advances (Grove, 1988), and most of them (with the exception of the oldest one) agree with a tree-ring temperature reconstruction from this region (Briffa et al., 1995). Being very small and having a short time of reaction to climatic changes, the Polar Urals glaciers seem to be a very convenient source of proxy data. In the long run their variations are in agreement with the regional expression of global climatic trends during the last millennium.
Table 1. Control points for Rhizocarpon geographicum growth curve in Polar Urals Name of the site Year of studies Age of surface stabilization /exposion Number of measured lichens Maximum diameter, mm Average of 5 maximum diameters, mm Standard deviation, mm Paipudina valley, 490 m asl., dump and entrance to the gallery 1999 1940's-beginnig of 1950's. 62 12 11,80 0,45 Second dump at the same location 1999 1940's-beginnig of 1950's. 14 9 7,00 1,41 Road leading to Khanmey, 240 m asl., open mines 1999 until the beginning of 1950's 107 15 14,20 0,45 Nemur-Egan mine, cores 1999 1959-1962 53 8 7,20 0,45 Kharbey village, molibdenum mine 1999 until the beginning of 1950's 88 14 12,40 1,14 130 m asl., 37 km of Balanankov' road, quarry 1999 beginning of 1980's none none none none Anuchina glacier, ablation moraine 1999 1960's 103 9 8,20 0,45 Obrucheva glacier, ablation moraine 1999 1953-1966 34 10 9,00 1,00
Hantemirov, R. M. (2000). Climate changes and polar timberline dynamics in the nothrwest Siberian plain during last 6000 years reconstructed using supra-long tree-ring chronology. International Conference on Dendrochronology for the Third Millennium, Mendoza, Argentina, 2-7 April, 2000.
Shiyatov, S., Tchehklov, O. (2001). Spatio-temporal dymanics of forest-tundra ecosystems under climate change in the Polar Ural Mountains. Tree-rings and people, Davos, Switherland.
Shiyatov, S. G. (1981). Cliamate-triggered changes of forest vegetationat the upper and polar tree limits. Klimatogenniye cmeni lesnoy rastitel'nosti na verkhnem i poliarnom predelakh ee proizrastaniya. Sverdlovsk: 57.
Shiyatov, S. G. (2000). Climate dependent dynamics of the upper treeline and forest-tundra ecosystems during the last 1350 years in the Polar Ural Mountains, Russia. Int. Conf. on Dendrochronology for the Third Millennium. 2-7April, 2000. Mendoza, Argentina.
Shiyatov, S. G. (2003). "Rates of changes in the upper treeline ecotone in the Polar Ural Mountains." PAGES News 11(1): 8-10.
Solomina, O. N. (2003). "Dynamics of subpolar glaciation over 2000 years by lichenometric data." Data of glaciological studies 94: 17-30.
Solomina, O. N., Filatov, E.S. (1998). "Changes in mountain glaciers in Northeast Russia from the Little Ice age to the mid-20th century." Polar Geography 22: 65-78.
Solomina, O. N., Zhidkov, V.A., Moskalevsky, M.Yu. (2000). "New data on the lichenometry of moraines of the Polar Urals No." Data of Glaciological Studies 90: 57-68.
Surova, T. G., Troitsky, L.S. (1971). About the dinamics of vegetation< climate and glaciers in Polar Urals in Holocene. O dinamike rastitel'nogo pokrova, klimata i oledeneniya na Poliarnom Urale v golotsene. Palynology of Holocene Palinologiya Golotsena. M. I. Neishtadt. Moscow: 121-135.
Surova, T. G., Troitsky, L.S., Punning, Ya.-M.K. (1975). "Paleogeography and absolute chronology of Holocene of Polar Urals. Paleogeografiya i absoliutnaya khrolologiya golotsena Poliarnogo Urala." Procedings of Academy of Sciences of Estonian Soviet Republic. Chemistry, Geology. Izvestiya Akademii Nauk Estonskoi SSR. Khimiya, geologiya. 24(2): 152-159.
Troitsky, L. S. (1961). "Some features of modern glaciation of Polar Urals. Nekotoriye osobennosti sovremennogo oledeneniya Poliarnogo Urala." Glaciological studies Gliatsiologicheskiye issledovaniya 6: 70-85.
Tsvetkov, D. G., Tiuflin, A.S. (1981). "Catastrofic degradation of MGU glacier in the Polar Urals.Katastroficheskaya degradatsiya lednika MGU na Poliarnom Urale." Data of glaciological studies Materiali gliatsiologicheskikh issledovanii 41: 162-172.
Voloshina, A. P. (1988). "Nekotoriye itogi issledovanii balansa massi lednikov Poliarnogo Urala. Some results the studies of the mass balance of the glacier of Polar Urals." Data of Glaciological Studies. Materialy Gliatsiologicheskikh Issledovanii. 61: 44-51.
IGAN Glacier. Photo by G. Nosenko
Fig. 3 Obrucheva Glacier. Photo by G. Nosenko