Glacier in the upstream Manla Reservoir in the Nianchu River Basin, Tibet: shrinkage and impacts

Glaciers in the upstream Manla Reservoir in the Nianchu River Basin are crucial for agriculture and hydropower in the "One River and Two Streams" area. Rising temperature has caused widespread retreat of glaciers on the Tibetan Plateau during the last few decades. In this study, glacier variations under climate change in the Nianchu River Basin are quantified and their influence are evaluated by analyzing 1980 aerial topographic maps, 1990 Landsat TM, 2000 Landsat ETM+, and 2005 CBERS remotely sensed images. It is found that from 1980 to 2005, the debris-free glacier area shrank by 7.3% (13.42 km(2)). Glacier shrinkage will have a positive effect on agriculture, hydropower and eco-environment in the near future. However, because the large number of small glaciers (<2 km(2)) will rapidly retreat and disappear in future years, melt water will decrease, ultimately resulting in a long term water shortage. Glacial lakes exhibited rapid expansion due to accelerating glacier retreat during 1980-2005, increasing the possibility of glacial lake outburst floods.