The Himalayan glaciers feed seven of Asia’s greatest rivers (see chart). The glaciers ensure a year-round supply of water to hundreds of millions of people in China and the Indian subcontinent.

The Worldwide Fund for Nature (WWF) said the Himalayan glaciers are receding 10 to 15 metres per year on average and that the rate is accelerating as global warming increases.In India, the Gangotri glacier is receding at an average rate of 23 metres per year, the study said.“The Himalayan glaciers are among the fastest retreating glaciers globally due to the effects of global warming,” the WWF said in Geneva.

“This will eventually result in water shortages for hundreds of millions of people who rely on glacier-dependent rivers in China, India and Nepal,” it said.“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 levels in rivers will decline, meaning massive economic and environmental problems for people in western China, Nepal and northern India,” she said.

The WWF released the study before a two-day ministerial roundtable in London this week of the 20 greatest energy-consuming countries, to be followed by a G8 meeting focusing on climate change in Africa. Such meetings have assumed an added significance against the backdrop of the tsunami that ravaged several countries in December.The WWF called for work towards reducing carbon dioxide emissions — blamed for global warming — plus increasing the use of renewable energy and energy-saving measures.

The countries participating in the Energy and Environment Ministerial Roundtable include Canada, France, Germany, Italy, Japan, Russia, the UK and the US plus non-G8 countries like India, China, Australia and Brazil.“It is a fact that the Himalayan glaciers are receding at a very fast rate. Even the working group of Inter Governmental Panel on Climate Change has recognised the phenomenon sometime back,” Suruchi Bhadwal, an Indian researcher working on the impact of climate change, told The Telegraph.

Sugato Hazra, a scientist from the oceanography department of Jadavpur University, said the findings of a study with which he is associated support the WWF warning.“We have been mainly working in the Sunderbans area to trace the environmental impact of climate change and our findings show that both the temperature at the sea surface as well as the sea levels are consistently rising,” Hazra said.“The temperature at sea surface is increasing 0.019 degree every year — about one degree over 50 years — while the sea level is gaining a height of 3.14 millimetre a year,” the scientist added.