The glaciers in the Tien Shan mountain range, which stretches 2,500 km across the heart of Central Asia, have lost more than 25% of their total mass over the past 50 years, according to a study published online in Nature Geoscience. This glacier mass loss is about four times greater than the global average over this time period.

Snow and glacier melt from the Tien Shan provides water to populations in Kazakhstan, Kyrgyzstan, Uzbekistan, Turkmenistan and the Xinjiang Uyghur Autonomous Region of China. However, despite the implications of this dwindling water supply and the growth of the populations dependent on it, information about the conditions of individual glaciers in the Tien Shan is sparse and estimates of glacier change across the region have been limited to the past decade.

Daniel Farinotti and colleagues combined satellite data, field observations and glaciological models to reconstruct changes in the masses of individual glaciers across the Tien Shan region from 1961 to 2012. Although mass changes vary from year to year as well as between glaciers, the authors find that overall the region has lost over 25% of its total glacier ice over the past half century ? a decline that they link to increased summer melting.

Climate models project that summer temperatures will continue to rise in the coming decades, suggesting that the glaciers in the Tien Shan will become increasingly vulnerable. Although more detailed projections are needed, the authors estimate that half of the glacier ice volume remaining in the Tien Shan could be lost by 2050.