Dynamics in the Water Towers of the Pamir and Downstream Consequences

Abstract Changes in water delivery from the Pamir Water Towers to streams affect poor regions of Central Asia. We used a 20-yr remotely sensed climate record to assess water source dynamics in the sparsely monitored region. Varying spatial and temporal patterns of rain and snowfall occurred throughout the region. Temperatures increased across the east-central Panj and eastern Vakhsh basins. Warmer temperatures in central Panj and Wakhan corridor coupled with minor declines in snow water will induce water stress during dry years. In contrast, stable temperatures at lower elevations together with increasing precipitation, especially in spring, will benefit agriculture and community water supplies. Seasonal temperature increases, particularly in December, occurred in glaciated areas; however, December temperatures were <-20°C. In the Fedchenko and lower Panj glacier sectors, increasing spring snowfall offsets temperature increases causing little glacier mass change. The Wakhan corridor is at highest risk of glacier mass loss due to declining snow in early spring and increasing temperature in late winter and early spring. Interannual snowfall variability poses the largest uncertainty for water supplies. Permafrost thaw may contribute a small, but timely, source of runoff. Because of high interannual and spatial variability of precipitation, regional climate change scenarios cannot inform adaptation measures for mountain communities, thus, more granular-scale data are needed.