Himalayan glaciers ? alarm grows
 

The anticipated effects of  global climate change become more perturbing by the month.  The chains of reaction are especially alarming when scenarios are projected forward fifty years.  The likely effects of deglaciation on the Himalayan watersheds and on the major rivers which irrigate the Indian sub continent give cause for particular concern. Could even the Ganges become a seasonal river? The following was adapted from India's leading environmental campaigning publication "Down to Earth" and based on papers for the International Commission for Snow and Ice (ICSI)  meeting to be held in July 1999.  Use with acknowledgement.  Get more information from "Down to Earth" - web addresses at the end.
 
 A moraine-dammed glacial lake, DigTsho, burst in the Khumbu Himal area of Nepal on August 4,1985.  The whole lake took only four to six hours to empty into Lagmoche valley, one of the tributary valleys of the river Bhote Kosi, which flows past many Sherpa settlements. For more than 90 km, the flood waters—10 to 15 metres high—surged through the valley in the form of a huge "black" mass of debris.

Trees and boulders were dragged and tossed around, causing landslides of varying sizes. Entire trails and the nearly complete Namche Small Hydel Project, 14 bridges and numerous houses that dotted the river margins disappeared in a few hours.

Two Swiss scientists, Daniel Vuichard and Marcus Zimmermann, studied the catastrophe in detail. They concluded that the incident was one of several possible disasters resulting from the thinning and receding of glaciers. They  warned about the frequency of such outbursts in the Himalaya in the future.

"Glaciers in the Himalaya are receding faster than in any other part of the world and, if the present rate continues, the likelihood of them disappearing by the year 2035 is very high," says the International Commission for Snow and Ice (ICSI) in its recent study on Asian glaciers. "but if the Earth keeps getting warmer at the current rate, it might happen much sooner" says Syed Iqbal Hasnain of the School of Environmental Sciences, Jawaharlal Nehru University, New Delhi. Hasnain is also the chairperson of the Working Group on Himalayan Glaciology (WGHG), constituted in 1995 by the ICSI.

"The glaciers will be decaying at rapid, catastrophic rates. Total area will shrink from the present 500,000 to 100,000 square km by the year 2035," says former ICSI president V M Kotlyakov in the report Variations of snow and ice in the past and present on a global and regional scale.

With the end of the Little Ice Age ( 1430 to 1850), glaciers have been retreating with the rise in atmospheric temperatures. "In the last 100 years alone, the global mean temperature has increased by about 0.5 to 1°C... and the rapid receding of glaciers, to a major extent, is a consequence of global warming," says Jagdish Bahadur, a leading glaciologist and former joint advisor at the Department of Science and Technology, New Delhi.

Snowblind

In geological terms, the Dig Tsho lake burst was a very recent event. But, despite warnings and several reports of receding glaciers in India, there has been no attempt to study the glaciers that dot the northern and eastern part of the country.

Himalayan glaciers cover about three million hectares or 17 per cent of the mountain area as compared to 2.2 per cent in the Swiss Alps. They form the largest body of ice outside the Polar caps. The 15,000-odd Himalayan glaciers form a unique reservoir which supports mighty perennial rivers such as the Indus, Ganga and Brahmaputra which, in turn, are the lifeline of millions of people. The Gangetic basin alone is home to 500 million people, about 10 per cent of the total human population.

But whenever disaster strikes in the form of floods or landslides, no one thinks beyond the immediate damage control and rescue operation. The tragedy is forgotten by the end of the monsoons. Another year, another string of tragedies follow. There is no effort to study the problem in detail. And policymakers are yet to comprehend the gravity of the problems caused by receding glaciers.

This not only means more Dig Tsho-like tragedies in the near future. It means more water in the rivers. "But, in the long run, the melting of glaciers also means the drying up of rivers," says Hasnain. "Most of the rivers in northern India originate from glaciers. About 70 to 80 per cent of the water in these rivers come from snow and glacial melts, and the rest from monsoonal rains." Does this mean that the Ganga, Indus, Brahmaputra and the innumerable rivers that crisscross the entire northern Indian plain will become seasonal rivers in the near future? "This is not unlikely," warns Hasnain.
 

Melting into Thin Air

Between 40 and 50 million years ago, the Indian subcontinent collided with the rest of the Asian landmass. This collision caused the Earth's crust to buckle and rise forming the Himalaya. The uplift of the Himalaya was a gradual process over a long period. As the elevation of the mountains rose above the permanent snowline, it was transformed into "the abode of eternal snow and ice" forming the glaciers. For over two million years, these glaciers have sculpted the Himalayan landscape and influenced the course of human history.

"Himalayan glacial snowfields store about 12,000 cubic kilometres of freshwater and have a significant cooling effect in the entire region," says Bahadur. "The moisture-laden environment acts as a coolant for the region, thus creating an area of mega-biodiversity in flora and fauna."

"These glaciers are, in turn, affected by various factors such as changes in the energy output from the Sun and anthropogenic (or human-induced) changes," says Bahadur. But the receding and thinning of glaciers can be blamed primarily on the increase in emission of greenhouse gases.

Scientists had expected the five-kilometre-long Dokriani Bamak glacier in Himachal Pradesh to grow after a severe winter in 1997. Instead, it retreated by 20 m in 1998, compared to an annual average of  16.5m over the past five years. "This is a phenomenal melt rate," says Joseph Gergan, a geologist at the government-run Wadia Institute of Himalayan Geology (WIHG) at Dehradun.
 

But Dokriani Bamak is just one of several glaciers that feed the Ganga. The Gangotri glacier, too, has been receding alarmingly in recent years, says Bahadur. "From observations dating back to 1842, the rate of recession of the snout - the point at which the glacier ice ends-has been found to have increased every year. Between 1842 and 1935, the glacier was receding at an average of 7.3m every year, whereas between 1935 and 1990, the rate of recession had gone up to 18 m a year. "The increase can be ascribed in part to the phenomenon of global warming and also to the environmental impact of increasing human activities in the Himalaya," he says. All these affect precipitation which is the source of nourishment for the glaciers, says Hasnain.

The glaciers in the Western Himalaya are fed by winter and summer precipitation. But those in the eastern and central Himalaya get their nourishment only from summer precipitation. "With only the summer precipitation to depend on, the glaciers in the eastern and central Himalaya have the dual problem of receding snowline and decreased precipitation due to global warming," says Hasnain. "Besides, accumulation and melting of snow takes place at the same time in these glaciers."

Hasnain has another dimension to add, "The recession is also the highest in the central and eastern Himalayan glaciers because, compared to the rest of the world, the population density near these glaciers is very high." Most of the people living in this area are economically backward and the consequent deforestation has adversely affected the glaciers, adds Bahadur.

It is important to understand that, in summer, there is a higher probability of precipitation resulting in rain than in winter, explains Hasnain. In cases where temperatures are higher than normal years, there are three negative effects on glaciers: increased proportion of rain in the precipitation which reduces accumulation by snowfall; higher temperatures increase melting; and decreased albedo due to decrease of snowfall.

The WGHG, of which Hasnain is chairperson will submit its final report to ICSI in July 1999. "Ironically, we have very little information on India because, apart from the possible causes of recession, we do not have many weather monitoring stations near glaciers to collect information and create a database," says Hasnain. "The glaciers in Nepal are better monitored. Our government is totally blind to the urgency of the problem. Just one glacier monitoring station has been set up and that stopped functioning within two months," he says.

Hasnain is also a member of the Flow Regime for International Experimental and Network Data (FRIEND), an organisation recently launched by Nepal, Bhutan, Pakistan, China and Bangladesh to study the glaciers. "Strangely, India is not participating in this very important regional activity supported by UNESCO," says Hasnain. "It is beyond my comprehension why the government is ignoring these initiatives, though the Himalayan waters are the lifeblood of millions of Indians."

Ends

Other articles in the same issue of "Down to Earth" deal  with the drying out of Ladakh, glacial recession in Sikkim, and the increased threat and size of natural hazards over the whole Himalaya.

"Down to Earth" is a fortnightly published in New Dehli by the Centre for Science and Environment (CSE) < www.cseindia.org> and edited by India's leading environmentalist Anil Agarwal.

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P.B. Stone on mountains under pressure (general overeview of so-called Mountain problematique

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