Glaciological and hydrological sensitivities to climate change in the Hindu-Kush Himalayas

Thursday, 18 December 2014
Joseph M Shea, International Center for Integrated Mountain Development, Kathmandu, Nepal and Wouter Immerzeel, Utrecht University, Department of Physcial Geography, Utrecht, 3584, Netherlands
The impact of climate change on glaciers will affect the timing and magnitude of water availability from high-altitude catchments in the Hindu-Kush Himalaya (HKH) region. In this study, we quantify the current sensitivity of glacier systems to climatic change and the associated sub-basin hydrological sensitivity throughout the HKH region using glacier inventory data and high-resolution dynamically downscaled climate fields. We first estimate the glaciological sensitivity, or change in glacierized area with change in equilibrium line altitude (ELA), for each sub-basin using a glacier inventory and SRTM DEM. We assign a climatic sensitivity of the ELA to temperature changes (dELA/dT) based on published values for tropical and sub-tropical glaciers and a high-resolution annual precipitation field. To assess the change in glacier meltwater contribution as a result of warming, we first estimate baseline glacier meltwater contributions using a mass balance gradient and estimated current ELA. Future climate warming scenarios of +1K and +2K are then used to examine the change in glacier meltwater contributions based on the increased ELA and ablation area. Finally, we calculate a glacier significance index that examines the relative importance of melt within each sub-basin, and discuss regional variations in glacier sensitivity and significance.