It said global warming had pushed up the temperature of the Himalayas by up to 0.6 degrees Celsius in the past 30 years.

"It is extremely serious," said Surendra Shrestha, regional director at the United Nations Environment Programme for Asia and the Pacific. "It is going to change fundamentally the way we live."

"If the temperature continues to rise as it is, there will be no snow and ice in the Himalayas in 50 years."

Thousands of glaciers in the Himalayas are the source of water for nine major Asian rivers whose basins are home to 1.3 billion people from Pakistan to Myanmar, including parts of India and China, conference delegates said.

Andreas Schild, ICIMOD's director general, said the disappearance of glaciers meant a reduction in the mountains' natural water storage capacity.

"It means that the flow of water will be more erratic," he said.

Melting glaciers will have an adverse impact on biodiversity, hydropower, industries and agriculture and make the region dangerous to live in.

The melting also causes lakes to form at the base of glaciers, lakes which can subsequently burst their banks as temperatures continue to rise. This can have devastating effects downstream, delegates said.

"If there is a small earthquake all that water is going to come down," Shrestha told reporters in the sidelines of the conference. "Because of the altitude it will pick up debris and speed... it is like a big bulldozer that wipes everything out."

"It is a silent tsunami," he added.

Officials estimate that there are more than 3,200 glaciers in Nepal -- 14 of which have lakes which are at risk of bursting.