Melting mountains

Published : Dec 07, 2007 00:00 IST

Will global warming dry up the Ganga, which supports 500 million people?

in Gangotri, UttarakhandThe snout of

The path to Gaumukh crackles with expectation. Each step over the boulders brings you closer to the glacier the source of the mighty Ganga. Pilgrims who cannot walk make their way on horses. Hikers and tourists move about enamoured of the mysticism in the mountains. A sprinkling of sadhus whets their curiosity and spices up the trail.

In the valley below, the Bhagirathi gushes past pine and deodar trees. As you approach the glacier, the landscape becomes sparse. There are only rocks and boulders. But even here, tiny mandirs (temples) and dhabas have colonised a few corners. In India, not even the holy Mother Ganga can escape land grab.

Gaumukh, at 4,000 metres, is the source of the Bhagirathi, which joins the Alaknanda at Devprayag to form the Ganga. When you finally reach the glacier, you realise it is not a huge sheet of white ice it is just a bunch of rocks covered in ice; a mountain face that is melting. The anticipation fizzles.

The Gangotri glacier is receding. Along the trail, ominous rocks are like tombstones marking its retreat. Gangotri in 1891... Gangotri in 1961 Gangotri in 1991. Its shrinking length is recorded on the rocks that once were part of the glacier.

What will remain of the Ganga? Will global warming dry up a river that supports 500 million people? The impact of the melting glaciers is still unclear. The Himalayan glaciers form the largest body of ice outside the polar caps. They are the source of seven major river systems including the Yamuna, the Brahmaputra and the Indus.

The United Nations Intergovernmental Panel on Climate Change (IPCC), which collates research about climate change from scientific work across the world, has a dire warning.

A Sivalinga put

Glaciers in the Himalayas 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 and perhaps sooner is very high if the earth keeps warming at the current rate. Its total area will likely shrink from the present 500,000 km{+2} [square kilometres] to 100,000 km{+2} by the year 2035, says the IPCCs Fourth Assessment Report, released this year.

The current trends of glacial melts suggest that the Ganga, Indus, Brahmaputra and other rivers that criss-cross the northern Indian plain could likely become seasonal rivers in the near future as a consequence of climate change.

But scientists studying the Gangotri glacier feel this prediction is alarmist. There is no doubt that the glaciers are retreating, but they are not going to disappear. Nor are the rivers, says Milap Sharma, glacial geomorphologist at Jawaharlal Nehru University, New Delhi. In recent times, glaciers have been retreating since the 19th century the end of the Little Ice Age. Our findings show that in 1966-71, the retreat was the highest (30.4 m per year), which has reduced to 19.2 m in the last few years (see table).

The pace of glacier melting is slowing down, which suggests that the rate of temperature rise is also declining, says A.K. Tangri, a glaciologist at the Remote Sensing Application Centre in Lucknow. No studies on temperature change in the Himalayas exist. In fact, proper temperature records over decades for the upper Himalayas are difficult to find. Scientists need data for more than 30-40 years to establish any clear trend. Only seven years ago, a few automated weather stations were set up.

In the rest of India (except the Himalayas), studies show that annual air temperature rose by 0.42Celsius to 0.57C per 100 years. The earth has warmed by 0.74C, according to the IPCC report.

Himalayan glaciers are not melting at an abnormal rate, says C. Sangewar from the Geological Survey of India, which is monitoring Indian glaciers.

The rate of recession in different climatic zones varies in different years. It can fluctuate due to several factors such as micro and macroclimate, mountain geography, size of the glacier, nature of nourishment, and so on.

It is still unclear how the melting of the Gangotri glacier is affecting the Ganga. Reports that the Ganga will disappear are exaggerated. Yes, the glaciers are melting due to climate change, but not at such a catastrophic rate, says Manohar Arora, glaciologist at the National Institute of Hydrology, Rourkee. After studying the glacier for eight years, we have found that the total water discharged into the river has not changed much. But, eight years is too short a period to establish any clear trend.

Snow cover in the Bhagirathi basin has been diminishing since the 1980s, which means that less snow is feeding the river. The difference between peak accumulation (after winter) and peak ablation (after melting in summer) snow cover is declining, so less melt water from the watershed area is being discharged into the Bhagirathi river, says Tangri.

The Ganga is not totally dependent on glaciers for its water. Most of the rivers catchment area up to West Bengal is rain-fed. Only 20,000 sq km (7 per cent) of the river basin up to Devprayag is fed by the glacier, says Arora. Snow and glacier melt contribute only 48 per cent to the annual flow at Gangotri and 29 per cent at Devprayag, where the Bhagirathi meets the Alaknanda to form the Ganga river. The rest is from rain water.

In the last few years, we have noticed that one major river channel, Raktwarn, is flowing on the surface of the glacier. This is unusual. It indicates that the melting may be quickening. Earlier, water was flowing from inside the glacier, says Arora. As warming continues, the entire agricultural pattern may change and our dam design parameters and flood control measures will have to be altered.

If viewed over a geological timescale, the glaciers retreat is not unusual, says Sharma, who has been studying the glaciers movement. Around 3,900 years back, it was at Gangotri, and has retreated just 8 km since then. The glacier has been retreating at different rates. In the intervening period, it also advanced a bit during the Little Ice Age in the 16th to 18th century. These are natural processes. The glacier will remain because it will be constantly fed by precipitation and because it is at such a high altitude.

After Siachen (73 km long), Gangotri (28.5 km long) is the second largest of the 9,575 glaciers in the Indian Himalayas. It is a sacred spot because it was here that the Ganga (the stream of God) is believed to have touched the earth for the first time. According to mythology, goddess Ganga (the daughter of Heaven) came down to the earth in the form of a river to absolve the sins of King Bhagiraths predecessors and help them attain moksha (salvation). Bhagirath had been in severe penance for several centuries. A stone plinth in Gangotri town is supposed to be the site where he meditated. That is why the Ganga is called Bhagirathi at its source. Siva received the Ganga in his matted locks to lighten the impact of its fall.

A Gorkha commander, Amar Singh Thapa, built the Gangotri temple in the early 18th century. In winter, the idol of goddess Ganga is taken to Mukhba, her winter abode downstream, since Gangotri is covered with snow. The entire town is deserted in the winter but is packed with pilgrims in the summer. Every year, more than 50,000 people trek to Gaumukh to bathe in the pure water at the glacier. The hike from Gangotri (a tiny tourist town at 3,000 m) to Gaumukh is 18 km.

Gangotri town itself is a tourist trap unplanned with dingy hotels and shops springing up in tiny corners of the landscape. Though the Gangotri National Park is a protected area where cars are not allowed, tourist traffic has destroyed the forest. The trail is littered with biscuit wrappers and water bottles. In the Shravan month, in July, Gaumukh has the most number of visitors. Bhojvasa, the base camp where trekkers and pilgrims halt for the night, was named after the bhoj (birch) forests here. It is believed that the Mahabharata was written on the bark of bhoj trees. Now, Bhojvasa is bare. It is difficult to find a bhoj tree there. The local dhabas have cut them down for firewood.

If there is one thing on which all scientists and local environmentalists agree, it is that tourism here has to be stopped or strictly regulated. Tourists should not be allowed beyond Gangotri. Right now, it is a free-for-all. People bathe in the water, cook, litter the place, leave their clothes, walk on top of the glacier. It is harming the environment, says Arora.

All the sewage is dumped straight into the river without treatment. This year, 12,000 chappals were left on the path to the glacier. Plastic bags are dumped without a thought, says S.S. Tariyal of the Clean Ganga Campaign. It is believed that the Gangas waters remain pure for decades, but it is being polluted at the source itself. Gangotri is far from the pure, spiritual place it is supposed to be.

The Pala Maneri and Lohari Nag Pala dams are being built just 90 km from Gangotri. The blasting and tunnelling has damaged houses in this earthquake-prone area. In 1991, an earthquake in Uttarkashi killed 769 people, and there are still frequent tremors and landslides. Dams only increase the risk of earthquakes, and there are already two major dam projects on the Ganga Maneri Bali (phase 1 and 2) and Tehri. The new dams will submerge acres of forest and agricultural and grazing lands. Already, the Tehri dam has caused widespread damage. And the government has not yet provided adequate resettlement to those ousted by the dam since the 1970s.

Pilgrims at Gaumukh

Still, the Uttarakhand government is on a dam-building spree, with almost a hundred projects planned across the State. Instead of developing water conservation projects, the government just keeps building dams, which disturb this fragile ecology. Most dams do not even work in the winter because there isnt enough water, so there are power cuts, says Harshvanti Bisht of the Clean Ganga Campaign.

Smaller sources of water such as springs and glacierets are drying up because snowfall has reduced not only in Gangotri but all over the Himalayas. Smaller glaciers are receding faster than the larger ones.

The glacier area in the Chenab, Parbati and Baspa basins in Himachal Pradesh shrunk by one-fifth during 1962 to 2006, according to a study of 466 glaciers by Anil Kulkarni and his colleagues at the Space Application Centre, Indian Space Research Organisation. They found that the number of glaciers has increased owing to fragmentation. Glacierets and ice fields melted more quickly, retreating by 38 per cent.

What is ice today will be bare stone tomorrow. The rocks on the trail to Gaumukh were once part of the glacier. As it pulls back further, no one knows how it will change the Ganga. For now, the river rolls on.

(The article is based on research under a grant from The Ashoka Trust for Ecology and Environment.)

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