Past and future glacier changes in the indus river basin

Glacier meltwater contributes significantly to the runoff of the Indus River, especially during summer months when precipitation in large areas of the basin is very low. This chapter reviews the current knowledge on the measured past and projected future changes in glaciers in the Indus Basin, which covers large parts of the Hindu Kush, Karakoram, and Western Himalaya. Glaciers have been retreating and shrinking since the end of the Little Ice Age. Glacier changes, however, have been heterogeneous. More recently, some glaciers have shown irregular behavior via frequent surges, especially in the Karakoram. Glacier mass losses were relatively small in the Karakoram over past decades, whereas since about 2000 mass losses of glaciers in the Western Himalaya were among the highest in all of High Mountain Asia. The average mass loss of the glaciers in the Indus Basin was approximately 0.2 m w.e. a^{- 1} during the past decade. Projections of future glacier changes reveal an average ice loss of about 50% by 2100. However, results of the different studies deviate from one another, and the uncertainties are significant. The glacier mass loss will lead first to an increase in runoff, but the glacier melt contribution will probably decrease after the middle of this century.