Himalayan meltwidth="600"

As glaciers succumb to global warming, a number of glacial lakes in Nepal and Bhutan could burst their banks and kill thousands of people, a UN report warns

NEW DELHI - The giant glaciers of the Himalayas are melting so quickly that within five years, dozens of glacial lakes could burst their banks and kill tens of thousands in their path, a United Nations report has warned.

Average temperature in the Himalayas has risen by 1 deg C since the 1970s.

The UN Environment Programme's regional glacier specialist, Mr Surendra Shrestha, told a press conference: 'Our findings indicate that 20 glacial lakes in Nepal and 24 in Bhutan have become potentially dangerous as a result of climate change.'

He warned that unless urgent action is initiated one of these could burst its banks in five to 10 years with potentially catastrophic results for people and property hundreds of kilometres width="600"stream.

The UNEP's findings are based on a two-year study of old and new maps, aerial and satellite photographs and the evidence of sherpas who saw tiny lakes in their childhood becoming large ponds in two generations.

The Raphstreng Tsho glacial lake in Bhutan, for example, was 1.6 km long, 0.96 km wide and 80 m deep in 1986. Nine years later, it was 1.94 km long, 1.13 km wide and 27 m deeper.

Mr Shrestha said: 'These are the ones we know about. Who knows how many others, elsewhere in the Himalayas and across the world, are in a similarly critical state?'

The Tsho Rolpa lake in the Dolakha district of Nepal covered 0.23 sq km in the late 1950s. But today, with the melting of a nearby glacier, it has swollen to six times the size, a UNEP press release said.

According to Mr Pradeep Mool, a remote sensing expert with the International Centre for Integrated Mountain Development, a flood from this lake could cause serious damage width="600" to the village of Tribeni, 108 km width="600"stream, threatening about 10,000 human lives, thousands of livestock, agricultural land, bridges and other infrastructure.

The warnings add a new dimension to the understanding of the multiple environmental hazards posed by climate change.

UNEP executive director Klaus Toepfer said: 'It is not just the risk to human lives, agriculture and property that worry us. Mountains are the world's water towers, feeding the rivers and lakes upon which all life depends.

'If the glaciers continue to retreat at the rates being seen in places such as the Himalayas, many rivers and fresh-water systems could run dry, threatening drinking water supplies as well as fisheries and wildlife.'

This makes it another compelling reason to act to reduce emissions of carbon dioxide and other greenhouse gases, he said.

Mr Shrestha said: 'Solving this problem is going to be costly because glacial lakes are situated in remote areas which are difficult to reach.'