Late-twentieth century changes in glacier extent in the Ak-shirak Range, Central Asia, determined from historical data and ASTER imagery

Global analysis of glacier regimes reveals widespread wastage since the late 1970s, with a marked acceleration in the late 1980s. We investigate changes in the heavily glacierized Ak‐shirak Range, central Tien Shan plateau (43°N, 75°E) using air photo mapping surveys (1943 and 1977), an ASTER imagery (2001), and long term glaciological and meteorological observations. The wasting of the Ak‐shirak glacier system features a decrease in average glacier size, and an increase in the area of outcrops. A small shrinkage during 1943–1977 was followed by a greater than 20% reduction during 1977–2001 in response to increases in summer and annual air temperature and decreases in annual precipitation.