Global warming is seriously
threatening water resources in the Himalayan region, and the
subsistence of 1.3 milliards people is in question, according to
experts who met together in Stockholm for the International Water
Week. During recent years the mountainous region of the Himalayas,
which contains the largest part of the world covered with glaciers
and the largest zone of permafrost outside the polar regions, has
seen a rapid melting of the ice zones and spectacular changes in
rainfall. Mats Eriksson, responsible for water management at the
International Centre for the Integrated Development of Mountains,
said “the glaciers of the Himalayas are melting more rapidly than
anywhere else in the world. The shrinking back of the glaciers is
enormous, up to 70 metres per year.”
The high altitudes of the Himalayas,
their distance and the difficulties in co-operation between the
countries in this region, complicate study of the understanding of
the phenomenon.
Xu Jianchu, Director of
the Centre for Study of the Mountain Ecosystem in China, has also
said that climate change is devastating the Himalayan region,
underlining the example of temperatures on the Tibetan plateau that
have increased by 0.3 degrees every decade – double that of the
world average. It is difficult to quantify the repercussions on water
availability, but the impact is very real in the region where
glaciers and snow contribute to 50% of the water that runs down the
mountains and feeds the nine largest rivers in Asia. The mountain
chain constitutes an important water source for one of the most
densely populated regions on the planet, i.e., 1.3 milliards of
people in the Himalayan basin. “Snow and ice form a very important
contribution to water supply, for irrigation, energy and human water
consumption”, explained Mr. Xu. In the long term, the disappearance
of the glaciers will reduce the water available downstream.
Parallel to the glaciers
melting, scientists have noted that heavy rainfalls in numerous
regions of the Himalayas bring more rain in the monsoon periods and
less in periods of drought. The western part of the Himalayas is
that most affected by drought. Besides uncertain weather conditions
for harvests, which has provoked the migration of people looking for
alternative means of subsistence, farmers are faced with a growing
number of natural disasters such as sudden floods and the overflowing
of lakes.
Mr Eriksson said that he
imagined that in the past the region suffered floods maybe once a
season, and people adapted to it. “But if there are three, four or
even five sudden floods, it is too much. The question is knowing how
many floods the people can tolerate, without losing the basis of
their subsistence.”