Asia-Pacific, Environment, Headlines

ENVIRONMENT-HIMALAYAS: Rising Glacial Lakes Threaten Catastrophe

Samanta Sen

LONDON, Apr 16 2002 (IPS) - Hundreds of glacial lakes building up across the Himalaya mountains are moving towards a catastrophic collapse, a new study warns.

Glaciers are melting at an alarming rate following a one degree Celsius rise in temperature across the Himalayas since the seventies, according to the study carried out by the United Nations Environment Programme (UNEP). The melting glaciers are forming new lakes that their surroundings cannot sustain. The highest temperatures are being found at higher altitudes.

The study carried out in two Himalayan countries, Nepal and Bhutan, has identified 20 such lakes in Nepal and 24 in Bhutan that are in danger of collapsing within the next five years. These lakes “could burst their banks sending millions of gallons of deadly waters swirling down valleys, putting at risk tens of thousands of lives,” UNEP scientists warn.

But these 44 lakes are only the ones the UNEP knows about. “Who knows How many others, elsewhere in the Himalayas and across the world, are in a similar critical state,” says Surendra Shreshtha, regional co-ordinator in Asia for UNEP.

The UNEP survey does not cover India which has much of the Himalayas. “UNEP scientists were denied access to India because these lakes are located in India’s sensitive border regions with Pakistan and Kashmir,” Surendra Shreshtha told media representatives at the launch of the report in London.

The new research begun in 1999 is based on topographic maps, aerial photographs and satellite images. The survey has identified 3,252 glaciers and 2,323 glacial lakes in Nepal, and 677 glaciers and 2,674 glacial lakes in Bhutan. Across the Himalayas there will be tens of thousands of such lakes and glaciers, and at least hundreds are believed to be dangerous already.

Himalayan lakes are the source of all major river systems in Asia, says Shreshtha. “The life support systems of two billion people depend on this,” he says. “These lakes are not able to hold their water any more, and as a lake comes down it will be like an enormous bulldozer that cuts everything in its way.”

There have been 12 such Glacial Lake Outburst Floods (GLOFs) in the Himalayas since 1935, the report says. The most devastating of these came from the Sangwang Cho glacial lake in Tibet in 1954. That GLOF brought 300 million cubic metres of water bursting into the valley below, damaging the cities of Gyangze 120 km downstream and Xigaze 200 km away. It caused a 40-metre high flood in the Nyang Qu River.

In August 1985 a burst from the Dig Tsho glacial lake in Nepal destroyed 14 bridges and damaged the Namche hydropower plant. Another GLOF in 1981 in Tibet caused damage 50 km downstream, destroying three concrete bridges Along the way. What used to happen once in a while is now set to become more frequent under the threat of global warming, the report says.

The UNEP proposes to counter the threat by working with countries to set up a combination of early warning systems and systems to drain the lakes. It has a long way to go. Draining measures have been launched for just one lake in Nepal.

This glacial lake, the Tsho Rolpa, used to cover an area of just 0.23 square kilometres in the late 1950s but has grown six-fold to 1.4 square kilometres now. The level of this lake has been reduced by three metres, but there are at least 20 more metres to go before the lake can be declared safe.

A flood from this lake could cause serious damage to the village of Tribeni 108 km downstream, threatening about 10,000 human lives, says Pradeep Mool, a remote sensing expert working in the region. A high-tech system of sensors and sirens has been linked from the lake to the villages below.

Experts say money is needed urgently to carry out similar work on hundreds of other lakes if catastrophes are to be averted. Some donor governments are backing the effort but much more aid is needed, the experts say. “Solving this problem is going to be costly because glacial lakes are situated in remote areas which are difficult to reach,” says Shreshtha. The Tsho Rolpa lake where work is being carried out is seven days walk from the nearest road.

But alarming reports coming in from all over the region. “Local people are telling us that many lakes have grown enormously, and others have formed where there were none before,” says Mool. The report says: “It is not just people who are at risk but many millions of dollars of property, tourism facilities, trekking trails, roads, bridges and hydro-electric plants which are the economic life-blood of many countries in the region.”

Mountains were once considered indomitable, unchanging and impregnable, says Klaus Toepfer, executive director of UNEP. “But we are learning that they are as vulnerable as the world’s oceans, grasslands and forests to environmental threats, and insensitive, unfettered development…we now have another compelling reason to act to reduce emissions of carbon dioxide and other greenhouse gases.”

Toepfer is due to visit Pakistan this week to launch urgent arrangements for study of these glacial lakes. He is due to sign a survey agreement in China in early May. The new survey will also cover the Hindukush mountains In the Central Asian Republics to the west of the Himalayas.

The report was released on the eve of the meeting of the Intergovernmental Panel on Climate Change (IPCC) in Geneva. The IPCC is the scientific body that advises the UN and governments on global warming. The findings come in what the UN is observing as the International Year of the Mountains.

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