The importance of the cryosphere in the Tien Shan as a »water tower« for Central Asia:
In relation to the population, the five Central Asian states are among the 15 largest water consumers in the world. Main user of the water resources is the agricultural sector. In the Tien Shan, snow and glacier melt contribute substantially to river runoff in the spring and summer months and thus supply water at a time convenient for agriculture. In warm and dry years, they may compensate precipitation minima and provide a stable base flow.
The continuous retreat of glacierization may result in an increased but later decreasing contribution of glacier melt to total river runoff. This depends upon the state of the glacier, in particular if it has reached the tipping point, beyond which the increasing glacier melt cannot compensate the shrinking of the glacierized area in terms of the runoff rate anymore.
In the future, summer runoff is expected to decrease due to the reduced glacier storage, and the interannual variability is expected to increase. This may have a negative impact on agriculture and the hydropower sector, and may also increase flood risk. For Central Asia, the most effective adaptation measure would be to increase water use efficiency and to adapt land use to the renewable water resources available in the long-term.