http://www.guardian.co.uk/uk_news/story/0,3604,1035130,00.html
Melting glaciers
spell water crisis
Paul Brown
Thursday September 4, 2003
The Guardian
Temperature changes
and lack of snow are causing 90% of the world's
glaciers to retreat and some to disappear completely, with potentially
catastrophic consequences for communities that rely on the meltwater
for irrigation, hydroelectric schemes and drinking, glaciologists
agreed yesterday.
Research in Europe,
Asia, Africa and the Americas all pointed
to the same conclusion: that climate change is causing increasingly
rapid melting of the ice.
Only Scandinavian and
Alaskan glaciers are holding their own or
increasing. In both cases this is due to increased snowfall,
also caused by climate change.
Although it has been
known for some time that glaciers are
in retreat, this is the first time that such a large body of
evidence has been brought together, and with such uniform results.
The loss of ice will
increase sea levels worldwide.
In the Alps, where
summer temperatures have risen by 2.1C since
the 1970s, summer flows in glacier-fed rivers have doubled.
David Collins, professor
of physical geography at the University
of Salford, said this year glaciers were melting more than he
had
ever seen.
"Temporarily,
it might be seen as good news for summer flows,"
he said. "After all the extra water from the glaciers this
summer
has meant hydroelectric dams have been topped up so they can run
on maximum power.
"It helps to make
up for the nuclear stations that had to close
because of the heat. But in the longer term, when the glaciers
disappear, there will be no meltwater at all, and it will reduce
as the glaciers get smaller and survive only on the highest mountains."
But he emphasised that
it was not just the higher temperatures
that were causing the problem.
The increase in the
number of atmospheric high pressure systems
in the Alps in the winter had caused considerable a reduction
in snow. As a result the glaciers were not being replenished.
In contrast, the change
in track of Atlantic depressions meant
that extra rain was falling in England and more snow in Scandinavia,
so despite the fact that it was getting warmer there too, the
glaciers were growing.
Stephan Harrison of
the Oxford University school of geography
and environment said in Africa most glaciers would disappear
completely in 20 years.
A paper on the Ruwenzori
mountain range, between Uganda and Congo,
showed that the glaciers which feed the headwaters of the Nile
were now so thin that they would soon disappear.
Dr Harrison's own paper,
on the glaciers on Kazakhstan, which
provide drinking and irrigation water to the country's largest
city, Alma-Ata, show that two cubic kilometres of ice (2.6bn cubic
yards) a year have disappeared from 416 glaciers in the region
every year since 1955.
"They are retreating
so fast they are leaving piles of rocks
and debris behind that dam up the meltwater," he said.
"There is a real
danger of disastrous dam bursts hurling rocks
and debris on the settlements below."
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