Written By: Dr M. F. Khokhar and Lokhaiz Ali
Many glaciers and snowpacks around the world are receding. The rates and timing of glacial wasting, the volume of ice melt that causes a net loss of glacier volume, vary and the causes are complex. In most instances there are multiple influences that interact in complicated ways. Glaciers are retreating at different pace in different parts of the world and there are concerns about the consequences for available water supplies. The glaciers of the Hindu Kush-Himalayan (HKH) region are among the largest and most spectacular in the world. Although there is little scientific knowledge and information about the state of the glaciers of the HKH region, with repercussion for future water supplies, there is also significant uncertainty. Concern has been heightened by several highly visible decrees which upon examination proved to be highly qualitative, local in scale and/or to lack any credible scientific basis.
The Hindu Kush-Himalayan (HKH) region extends over 2,000 km from east to west across the Asian continent spanning several countries: Afghanistan, Bangladesh, Bhutan, China, India, Nepal, and Pakistan. This region is the source of numerous large Asian river systems, including the Indus, the Ganges, and the Brahmaputra, which provide water for over a billion people. The surface water of these rivers and associated groundwater constitute a significant strategic resource for all of Asia. Many of the countries in this region are already experiencing physical water scarcity. Existing water stress and projections of population growth have led to concern over possibilities of negative impacts from changes in the availability of water supplies in the coming decades. Water managers across the Himalayan region will confront a host of overlapping socioeconomic, environmental, and policy challenges as they strive to fulfil their societies' future water needs. In many of the great rivers that rise in the Hindu Kush-Himalayan mountains – the Amu Darya, Ganges, Indus, Yellow – total withdrawals nearly equal or even exceed long-term flow balances. Hundreds of millions of people today reside in basins that are essentially “closed.” All of their waters are already being used to meet various human demands and maintain vital ecosystems with little to no spare capacity left over.
The Hindu Kush-Himalayan region, including the Tibetan plateau, also functions as a complex interaction of “atmospheric, cryospheric, hydrological, geological and environmental processes that bear special significance for the Earth's biodiversity, climate and water cycles.” For example, the region plays a prominent role in generating the Asian monsoon system that sustains one of the largest populations on earth. These ecosystem services from the
Himalayan river basins also form the basis for a substantial portion of the region's total GDP (UNEP, 2012). Many studies state that the melting of glaciers is a clear indicator of climate change and note that glacier change is the most visible and obvious indicator of changing temperatures. Temperatures at some locations in the Himalayan region have risen faster than the global average. From 1982 to 2006, the average annual mean temperature in the region increased by 1.5 °C with an average increase of 0.06 °C per year, although the rate of warming varies across seasons and ecoregions. It stands to reason that the rising temperature in the Himalayas would affect glacier melt. However, uncertainty about the current state of Himalayan glaciers and the future state of the climate, as well as an incomplete understanding of the processes affecting Himalayan glaciers under the current climate, make any projections of climate change's impact on glaciers uncertain.
Despite inconsistencies in the published research, there is overall agreement that scenarios indicate a general decrease in ice volumes with retreats occurred mostly in the east, while in the west, the glaciers’ responses are complex, especially around the Karakoram region. Since the 1990s, expansion of some larger glaciers has been observed in the central Karakoram; and some have advanced and thickened indicating an apparently atypical climatic response. The current behaviour of Karakoram glaciers prevents drawing conclusions about how the glaciers will continue to respond in the Karakoram region in the future.
While data are lacking for a good understanding of the patterns of change in the glaciers of the Himalayas, there are some generalizations that can be made about the different regions of this vast area. Zone 1: Mainly in Afghanistan, this area has relatively stable or very slowly retreating glaciers. Zone 2: The Northwestern Himalayas including the Karakoram have highly varied glacier behaviour, with many surge glaciers, many advancing, stable, and retreating snouts and comparatively few large lakes. Glaciers in the Pamir Mountains of Tajikistan are generally retreating while further south, behaviour of the Karakoram glaciers is mixed, but lacking wholesale, rapid disintegration of glacier tongues and rampant lake growth. Zone 3: Mainly in India, southwestern Tibet and western Nepal, this area has mainly stagnating, retreating snouts and time variability with periods of slower retreat for some glaciers during parts of the 20th and 21st centuries. There are fewer lakes than in the eastern Himalayas, but large lakes may be a growing phenomenon as glaciers thin down and tend to stagnate.
Zone 4: Mainly Nepal, Bhutan, Sikkim and southeastern Tibet, this area has many large glacier lakes, especially since the 1960s. Many glaciers are rapidly disintegrating as they stagnate and thin down. Glaciers on the south side generally have more debris cover than they do on the north side. A widely cited estimate shows considerable variation in the contribution of melt water across the river basins fed by Himalayan glaciers, although this varies seasonally and spatially. The importance of melted water contribution also varies by basin: it is extremely important to the Indus Basin, important for the Brahmaputra Basin, but plays modest roles for the Ganges, Yangtze and Yellow Rivers. By region, meltwater contributes 30 % to the total water flow in the eastern Himalayas, 50 % in the central and western Himalayas and 80 % in Karakoram.
There is another unique feature of Himalayan glaciers; Siachen Glacier, the highest battleground on earth, where India and Pakistan have fought intermittently since April 13, 1984. Both countries maintain permanent military presence in the region at a height of over 6,000 metres (20,000 ft). More than 2000 people have died in this inhospitable terrain, mostly due to weather extremes and the natural hazards of mountain warfare. India is controlling most part of the glacier, to include: 70 km long Siachen Glacier and all of its tributary glaciers, as well as the three main passes of the Saltoro Ridge immediately west of the Glacier – Sia La, Bilafond La, and Gyong La. Pakistan controls the glacial valleys immediately west of the Saltoro Ridge.
Indian military operations are not only causing the physical damage (digging trenches, clearing glaciers for settlements and roads for logistic purposes), but their activities have resulted into spewing substantial amount of green house gases and soot particles in such high altitude region of Siachen. This may consequent in further warmer temperature, glacial lake formation and finally accelerating the glacier mass depletion rate. A recent study by Rasull et al., (2008) observed rise in temperature of 4°C over the time period of 1991-2004 and attributed this increase to the presence of army, large vehicular movement and allied activities to setup infrastructure for settlement and logistic purposes (e.g. Rohtang Tunnel etc.) in the area of Siachen Glacier. They further elaborated that human presence in the region has resulted in the thinning of ice and retreat of glacial extent at an alarming rate.
The decay estimates calculated by remote sensing techniques suggests that Siachen Glacier has reduced by 1.9 km in longitudinal extent from 1989 to 2006 along with 17 % thinning of the glacier mass. Additionally, it has resulted in increased number of avalanches in the region. For instance, on 7 April 2012, an avalanche hit a Pakistani military headquarters in the area, burying over 140 Pakistani soldiers and civilian contractors. Beside the frequent natural hazards, the military intervention at Siachen Glacier has also been affecting the neighbouring glaciers such as Gangotri, Miyar, Milan and Janapa which feed huge mass of population downstream on both Indian and Pakistan sides.
In the current scenario of climate change impacts on glaciers; the military withdrawal from Siachen region is mandatory to avoid the foreseen threats of human causalities and Himalayan glaciers retreat. After Gayari incident (avalanche) of April 2012, the then COAS, Gen Kayani offered India to demilitarize Siachen on bilateral basis. Apart from that, Indian military preparedness regarding Siachen Glacier clearly indicates that there is absolutely no sign from the Indian side to withdraw from world's highest battlefield and relocate them according to the 1989 agreement. India needs to think on these lines and plan to vacate the glaciated area as offered by Pakistan. Indians should stop causing environmental havoc to the region. The earlier, the better!