GLACIER FLUCTUATIONS ACROSS THE PAKISTAN HIMALAYA AND AFGHANISTAN PAMIR

Himalayan glaciers are thought to be sensitive to climate forcing due to the high altitude and significant debris-cover variation. Remote-sensing based studies in the eastern Himalaya reveal systematic retreat patterns for some glaciers. In the western Himalaya, glacier fluctuations are known for a limited number of glaciers, and retreat rates in Afghanistan have not been reported. Given that glacier sensitivities to climate forcing across the western Himalaya and Afghanistan Pamir are relatively unknown, our objectives were to estimate glacier retreat rates in the Nanga Parbat and Hunza Karakoram Himalaya, and Afghanistan Pamir regions. Specifically, we used satellite multi-temporal imagery and maps to compute retreat rates for different time periods ranging from 1934-2006. Results indicate significant variations in glacier fluctuations within and among the three regions. We found retreat rates ranging from 0-36 m/yr from 1976-2004 in the Pamir region. Many glaciers have significantly downwasted, and new high-altitude lakes and proglacial lakes now exist. Some of the glaciers in the Hunza Karakoram region have also retreated and downwasted, although retreat rates from 1992-2001 are relatively low. Furthermore, glacier advances, probably caused by surging have been documented. Further south, glaciers in the Nanga Parbat Himalaya were found to exhibit oscillating terminus positions, with several glaciers advancing over time, and others exhibiting relatively low retreat rates or recent acceleration of retreat. Collectively, our results indicate that glacier fluctuations in the western Himalaya are spatially and temporally complex, reflecting topography-climate multi-scale interactions. They also reveal that specific glacier ablation and mass-balance estimates/conditions should not be extrapolated to represent adjacent glacier conditions or to generate regional estimates. Our results suggest that the glaciers in the western Himalaya of Pakistan may be reacting differently to climate forcing compared to glaciers in the Wakhan Pamir region and eastern Himalaya.