THE Himalayan cryosphere is very sensitive to sustained changes in atmospheric temperature and humidity. The intergovernmental panel on climate change (IPCC) recognizes glaciers as best terrestrial indicator of climate change, due both to their sensitivity to climate variations and clear visibility of glacier growth and shrinkage to the public. The scientific consensus is that the climate change by global and regional factors is the main cause of shrinking glaciers and seasonal snow cover. Unfortunately, no detailed studies on glaciers and snow cover have taken place in different climate setting of Himalaya. Baseline studies are lacking for most climate zones, and there has been little or no long-term monitoring of climate variables, mass balance, snow cover extent and runoff from ice-covered basins. Most models and predictions for high-altitude areas (above 4000 meters above sea level) are dependent upon extrapolation from climate and stream gauging stations at low altitudes and assumptions based on other, better studied parts of the world.
The Hindu Kush – Himalaya range spans for more than 2500 kms east to west and include diverse cultures of five countries (India, Afganistan, Pakistan,Nepal and Bhutan) and range of ecosystem with rich biodiversity. The glaciers reduced considerably in both thickness and length from dimensions attained as a result of the cool and wet climatic conditions prevailing during the little Ice Age. For example, north-flowing glaciers are debris free with ice velocities ranging between 60 and 220 m per year and these glaciers dynamically adjust to climate variations and thus respond by retreat to atmospheric warming than local decay. Whereas south-flowing glaciers are debris covered. Their tongues appear to be stagnant and ice velocities ranges between 20 to 40 m per year. Reduced ice flux support the development of differential melt and low speed enhance the accumulation of debris on glacier surface. Blocks of glacier ice decoupled from the dynamics of upper glacier parts slowly decay with time. Declining volumes of glacier ice imply that precipitation levels have been insufficient to replenish mass lost to runoff through many warm decades, and that runoff from glacierised basins have been augmented by de-stocking ice, a process which can not continue indefinitely.
It is predicted by various studies that under warming scenario of +0.060C per year by the global emissions and +0.060C per year by regional atmospheric brown clouds, the impacts of declining glacier area on river flow will be huge in glaciated basins in both western and eastern Himalaya. Flow for most glaciated catchments will attain peaks of 150 and 170 % of initial flow by around 2050 in the west, and 2070 in the east, before declining until the glaciers disappear.
The glacier research throughout the world is conducted through a series of benchmark glaciers and the attributes of benchmark glaciers are well established by international bodies dealing with cryosphere. These glaciers are studied intensively for long-term for mass balance processes, meteorological environments and water runoff. The next level of surveillance is to measure several glaciers in each region for seasonal mass balance. This will help in understanding processes at glacier measured in detail to other glaciers in the region. Satellite remote sensing and models could be tested on the glacier measured in detail. Another major issue which is important in the Hindu Kush-Himalaya is the logistics to work in high altitude remote terrain. Glaciers are located between 4000 and 6000 meters and to reach them and work for needs supporting staff having advanced mountaineering skills. Therefore, to reach there and collect data in the accumulation zone is not easy and all scientists should have proper mountaineering skills to work and collect field data.
The down wasting of Indian glaciers in the southern Himalaya will bear heavily on the region's drinking water supply and on irrigation and power for agricultural production. For an energy-constrained economy like India, the prospect of diminishing river flows in the future and the possibility that energy potential from hydropower may not be achieved, will have far-reaching economic consequences. Another reason of immediate concern is the danger of Glacier Lake Outburst Flood (GLOF), which causes catastrophic discharges from the failure of temporary glacial lakes dammed by loose earth (moraines) materials formed by rapidly melting glacier ice. Observations indicate that the frequency of GLOFs in the eastern Himalaya including Nepal, Sikkim, Bhutan has increased during the last decade of 20th century and threatening the very existence of many hydropower plants constructed recently on Himalayan rivers.
In Jammu and Kashmir, TERI has selected Kolhai glacier, west Liddar valley, as one of the benchmark/ index glaciers for long-term monitoring. Liddar valley covers an area of 1282.55 km2 and it sustains about 48 glaciers covering an ice covered area of 39 km2. It is important to establish an index glacier in this region for assessing the water resources availability to the communities in the valley. An expedition was organized to the Kolhai glacier in November 2008 in collaboration with the University of Kashmir, Srinagar. The region is characterized by the frontal activities of westerly winds in winter and by dry sub-tropical climate in summer. Kolhai has two accumulation zones separated by Kolhai peak and two distinct ablation zones descending down and joining each other before forming a common snout. We have also made digital elevation model based on 1965 topographic map and we will revisit the glacier for measurements of mass balance stakes inserted during 2008.
Prof. Syed Iqbal Hasnain
(The Energy Resources Institute (TERI), New Delhi)