Warning from the highest source
Chinese scientists have recently added their voices to warnings that global warming, by melting glaciers in and around the Himalayan mountain chain, is threatening Asia's future water supplies.
Glaciers hold about 70 per cent of the world's fresh water. The Himalayas and other parts of the Tibetan Plateau have the largest concentration of these slow-moving rivers of ice, formed when snow from mountains accumulates in valleys and is then compressed. They cover an area of nearly 105,000 sq km, almost half of which is in China and somewhat less in India and Pakistan. Of all the mountain chains in the area, the Himalayas have the biggest glacier cover, amounting to nearly 35,000 sq km.
Xinhua said last month Chinese scientists had reported glaciers on the Tibetan side of Mount Everest were shrinking faster than ever. The melting point of one Everest glacier had risen around 50 metres in two years, more than twice as fast as normal, while a huge, high-altitude ice cliff seen in 2002 had apparently disappeared.
Why is this alarming? Scientists say global warming - caused by the burning of fossil fuels and the release of heat-trapping gases like carbon dioxide and methane into the atmosphere - could drive the average temperature up by between 1.4 and 5.8 degrees Celsius over the next 100 years. This would cause glaciers to retreat further and oceans to rise, swamping low-lying areas around the world.
But the melting of glaciers on the Tibetan Plateau is a special problem for much of Asia because the vast plateau is the headwaters for rivers flowing to countries home to half of humanity.
The Himalayan and other glaciers feed eight of Asia's great rivers: the Yangtze and Yellow rivers, which start in northeastern Tibet and flow across China; the Mekong, Southeast Asia's biggest river, which originates in eastern Tibet; Myanmar's two main rivers, the Irrawaddy and the Salween; and the giant rivers of northern India and Pakistan - the Ganges, Indus and Brahmaputra.
The glaciers regulate the water supply to China, South Asia and Southeast Asia, where drought and water shortages are already a serious problem in many areas.
The glaciers prevent winter flooding when snowfall is heaviest but release water used for drinking, farming and manufacturing in spring and summer, when it is needed most.
The scientists' warning that glacial melting on the Tibetan Plateau threatens the balance of global water resources is only the latest alarm bell to ring. In March, the China, India and Nepal offices of the Switzerland-based WWF issued a report saying the retreat of glaciers in the Himalayan region is accelerating as global warming increases.
They are now receding at an average rate of between 10 and 15 metres a year. In the past 40 years or more, glaciers on the Tibetan Plateau had shrunk by over 6,600 sq km, with the biggest retreat occurring since the mid-1980s.
Melting glaciers could in the short term increase flooding, landslides and soil erosion in China, South Asia and Southeast Asia before leading to water shortages for hundreds of millions of people across the region.
'The rapid melting of Himalayan glaciers will first increase the volume of water in rivers, causing widespread flooding,' said Jennifer Morgan, director of the WWF's Global Climate Change Programme.
'But in a few decades, this situation will change and the water level in rivers will decline, meaning massive economic and environmental problems for people in western China, Nepal and northern India.'
Michael Richardson is a visiting senior research fellow at the Institute of Southeast Asian Studies in Singapore. This is a personal comment
