ISEN-ASTC-L is a service of the Association of Science-Technology Centers
Incorporated, a worldwide network of science museums and related institutions.
*****************************************************************************
Millions face glacier catastrophe
Global warming hits Himalayas
Robin McKie, science editor
Sunday November 20 2005
The Observer
Nawa Jigtar was working in the village of Ghat, in Nepal, when the
sound of crashing sent him rushing out of his home. He emerged to see
his herd of cattle being swept away by a wall of water.
Jigtar and his fellow villagers were able to scramble to safety. They
were lucky: 'If it had come at night, none of us would have survived.'
Ghat was destroyed when a lake, high in the Himalayas, burst its banks.
Swollen with glacier meltwaters, its walls of rock and ice had suddenly
disintegrated. Several million cubic metres of water crashed down the
mountain.
When Ghat was destroyed, in 1985, such incidents were rare - but not
any more. Last week, scientists revealed that there has been a tenfold
jump in such catastrophes in the past two decades, the result of global
warming. Himalayan glacier lakes are filling up with more and more
melted ice and 24 of them are now poised to burst their banks in
Bhutan, with a similar number at risk in Nepal.
But that is just the beginning, a report in Nature said last week.
Future disasters around the Himalayas will include 'floods, droughts,
land erosion, biodiversity loss and changes in rainfall and the
monsoon'.
The roof of the world is changing, as can be seen by Nepal's Khumbu
glacier, where Hillary and Tenzing began their 1953 Everest expedition.
It has retreated three miles since their ascent. Almost 95 per cent of
Himalayan glaciers are also shrinking - and that kind of ice loss has
profound implications, not just for Nepal and Bhutan, but for
surrounding nations, including China, India and Pakistan.
Eventually, the Himalayan glaciers will shrink so much their meltwaters
will dry up, say scientists. Catastrophes like Ghat will die out. At
the same time, rivers fed by these melted glaciers - such as the Indus,
Yellow River and Mekong - will turn to trickles. Drinking and
irrigation water will disappear. Hundreds of millions of people will be
affected.
'There is a short-term danger of too much water coming out the
Himalayas and a greater long-term danger of there not being enough,'
said Dr Phil Porter, of the University of Hertfordshire. 'Either way,
it is easy to pinpoint the cause: global warming.'
According to Nature, temperatures in the region have increased by more
than 1C recently and are set to rise by a further 1.2C by 2050, and by
3C by the end of the century. This heating has already caused 24 of
Bhutan's glacial lakes to reach 'potentially dangerous' status,
according to government officials. Nepal is similarly affected.
'A glacier lake catastrophe happened once in a decade 50 years ago,'
said UK geologist John Reynolds, whose company advises Nepal. 'Five
years ago, they were happening every three years. By 2010, a glacial
lake catastrophe will happen every year.'
An example of the impact is provided by Luggye Tsho, in Bhutan, which
burst its banks in 1994, sweeping 10 million cubic metres of water down
the mountain. It struck Panukha, 50 miles away, killing 21 people.
Now a nearby lake, below the Thorthormi glacier, is in imminent danger
of bursting. That could release 50 million cubic metres of water, a
flood reaching to northern India 150 miles downstream.
'Mountains were once considered indomitable, unchanging and
impregnable,' said Klaus Tipfer, of the United Nations Environment
Programme. 'We are learning they are as vulnerable to environmental
threats as oceans, grasslands and forest.'
Not only villages are under threat: Nepal has built an array of
hydro-electric plants and is now selling electricity to India and other
countries. But these could be destroyed in coming years, warned
Reynolds. 'A similar lake burst near Machu Picchu in Peru recently
destroyed an entire hydro-electric plant. The same thing is waiting to
happen in Nepal.'
Even worse, when Nepal's glaciers melt, there could be no water to
drive the plants. 'The region faces losing its most dependable source
of fresh water,' said Mike Hambrey, of the University of Wales.
A Greenpeace report last month suggested that the region is already
experiencing serious loss of vegetation. In the long term, starvation
is a real threat.
'The man in the street in Britain still isn't sure about the dangers
posed by global warming,' said Porter. 'But people living in the
Himalayas know about it now. They are having to deal with its
consequences every day.'
· Additional reporting: Amelia Gentleman and Felix Lowe
Copyright Guardian Newspapers Limited
***********************************************************************
More information about the Informal Science Education Network and the
Association of Science-Technology Centers may be found at http://www.astc.org.
To remove your e-mail address from the ISEN-ASTC-L list, send the
message SIGNOFF ISEN-ASTC-L in the BODY of a message to
[log in to unmask]
|
