Global Outlook for Ice & Snow

The water towers of Asia

While mountains traditionally have been considered the major water sources of the region, there is great diversity in the hydro- logical significance of mountains and glaciers for downstream water supply, particularly between the dry north-western region and the monsoon-influenced south-eastern regions 76 . In spite of the vast water supply, seasonal water scarcity is a major issue 77 . Projections of glacier retreat in the region (based on IPCC sce- narios) suggest that increases in the mean annual temperature for High Asia in the range of 1.0°C to 6.0°C (low to high estimate) by 2100 are likely to result in a decline in the current coverage of glaciers by 43 to 81 per cent 78 . The Tien Shan and Qinling Shan are likely to become entirely devoid of glaciers, and glacial cover-

The Himalayas–Hindu Kush, Kunlun Shan, Pamir and Tien Shan mountain ranges (Figure 6B.10) function as water towers, provid- ing water to people through much of Asia. The glacier-fed rivers originating from the mountain ranges surrounding the Tibetan Plateau comprise the largest river run-off from any single location in the world 74,75 . While the mountains are homes to some 170 million people, the rivers that drain these mountains influence the lives of about 40 per cent of the world’s population 74 . The riv- ers provide household water, food, fisheries, power, jobs and are at the heart of cultural traditions. The rivers shape the landscape and ecosystems and are important in terms of biodiversity.

A L T A Y M O U N T A I N S

S y r D a r y a

Uzbekistan

Glaciers

Turkmenistan

Kazakhstan

M o n g o l i a

Kyrgyzstan

T I E N S H A N

Tajikistan

A m u D a r y a

T a r i m

P A M I R S

Afghanistan

K U N L U N S H A N

H I N D U K U S H

C h i n a

H u a n g h e

K A R A K O R A M R A N G E

TIBETAN PLATEAU

Pakistan

I n d u s

H E N G D U A N S H A N

S a l w e e n

Y a n g t z e

M e k o n g

B r a h m a p u t r a

H I M A L A Y A S

Nepal

Bhutan

G a n g e s

I r r a w a d d y

Bangladesh

Myanmar

I n d i a

Figure 6B.10: The Himalayas-Hindu Kush-Tien Shan-Tibet region.

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GLOBAL OUTLOOK FOR ICE AND SNOW