The Tien Shan mountain range stretches across 2,500 kilometers of central Asia, with more than 15,000 kilometers covered by glaciers. Melting snow and glaciers from these mountains supply much-needed water to the lowlands of northwestern China, Kazakhstan, Kyrgyzstan and Uzbekistan, which form one of the world's largest irrigated zones. 

Populations in Central Asia are heavily dependent on snow and glacier melt for their water supplies. However, recent decades have seen continuous and accelerating glacier loss. This has invited attention from scientists across the world. 

CHEN Yaning, a researcher with the Xinjiang Institute of Ecology and Geography (XIEG) of the Chinese Academy of Sciences, and his collaborators are among those who paid their attention to researches on the glaciers in the Tien Shan Mountains. 

Glacier mass balance is the key determinant of the health of a glacier. Mass balance refers to the difference between accumulation and ablation. When the accumulation is less than the ablation, the glacier will retreat.  

“Glaciers in retreat will have negative mass balances, and if they do not find an equilibrium between accumulation and ablation, will eventually disappear,” said CHEN. 

Researchers analyzed the measured annual mass balances for the period 2011 to 2016, and then reconstructed the seasonal mass balances from 2004 to 2010 for the Batysh Sook Glacier located in the Kyrgyz Tien Shan. 

Analysis showed that the region's glaciers are suffering from enduring negative mass balances in the near decade. For Batysh Sook Glacier, scientists found an average annual mass balance of − 0.39 ± 0.26 m w.e. a^− 1 for the period 20004 to 2016. 

Further study indicated that glaciers at the Tien Shan Mountains show consistent variation in mass balance. Tuyuksu Glacier and Abramov Glacier, another two Tien Shan glaciers suffered even severer mass loss, meaning a more serious risk of glacier melting and retreating. 

The study was published in Cold Regions Science and Technology, entitled “Mass balance observations and reconstruction for Batysh Sook Glacier, Tien Shan, from 2004 to 2016”.