CLIMATE CHANGE AND GLACIER FLUCTUATION DURING THE LAST 1,000 YEARS IN THE SOUTHERN MOUNTAINS OF THE USSR

The last thousand years of glacier fluctuations and glacier-climate responses have been studied in the Tien Shan mountain region of southern USSR. Several hundred glacial moraines have been dated, using lichenometry and dendrochronology in conjunction with radiocarbon dating, studies of lake-level changes, and archeological and historical data. Comparisons are made with data from the Caucasus, the Alps, and other mountain regions. Broad conclusions of importance to the International Geosphere-Biosphere Program are given and areas where additional research is needed are identified. Many Tien Shan glaciers show evidence of advances that predate the conventional time span of the Little Ice Age; many advances and recessions have occurred synchronously, although the magnitude of such trends varied significantly between regions and within the same region; fluctuations in equilibrium-line altitudes were more pronounced in the outer, or more maritime, areas and became progressively less prominent toward the interior where the climate is more continental. While it may be claimed that glacier-climate analysis has been developed to the point where climate forecasting is feasible, the recent anthropogenic impacts on the atmosphere and their potential for climate change cannot yet be incorporated into such forecasting. This is because the complex relationships between natural variations in precipitation and temperature are not sufficiently well understood and because the record of glacier fluctuation is by no means fully systematic. Nevertheless, if the pattern of the last thousand years in the Tien Shan persists, one can expect pseudo-cyclic oscillations of summer temperature with an amplitude of about 2-degrees-C and a periodicity of 30-50 years.