He and other experts said the rapid disappearance of glaciers could affect people across Asia. They spoke at a news conference to explain the impact of global warming forecasts issued by the UN Intergovernmental Panel on Climate Change (IPCC) earlier this month.

"Glaciers are vital to the national economy and peoples' livelihoods," Qin said, explaining that they were a major source of water and had a profound impact on other climate patterns.

Glaciers across the Himalayas and the Qinghai-Tibet Plateau are a major source of water for large rivers, such as the Yangtze in China, the Mekong in Indochina and the Ganges in India.

A top Indian climate expert said South Asia would also be threatened if glacier-fed rivers dry up.

"That is the region that is really the granary of South Asia," said IPCC chairman Rajendra Pachauri, referring to the northern part of the subcontinent that is fed by waters from the mountains.

He also said "we will have to use water far more efficiently than we have in the past".

The panel's report predicts that warmer average global temperatures fuelled by greenhouse gases will lead to more hunger in Africa, melting of Himalayan glaciers, more heatwaves in the United States and damage to Australia's Great Barrier Reef.

In recent days, China has released its own national assessment of climate change, which says that unless steps are taken, water scarcity and increasingly extreme weather could reduce nationwide crop production by up to 10 percent by 2030.

Fast-industrialising China could overtake the United States as the world's top emitter of human-generated greenhouse gases as early as this year, and Beijing faces rising international demands to accept mandatory caps on carbon dioxide emissions from factories, fields and vehicles.