Global warming triggers glacial lakes flood threat.

• Position: International Year of Mountains

We are halfway through the International Year of Mountains and the International Year of Ecotourism, intended to highlight the fragility and threats to these vital ecosystems from global warming, unsustainable tourism, pollution and other impacts, and to galvanize Governments, industry, non-governmental organizations and the public to act and protect.

The observances of the Year come as scientists with the United Nations Environment Programme (UNEP) and the International Centre for Integrated Mountain Development (ICIMOD) have reported the finding of at least 44 glacial lakes in the Himalayas that are filling so rapidly they could burst their banks in as little as five years' time, sending millions of gallons of deadly floodwaters swirling down valleys and putting tens of thousands of lives at risk. The lakes are rapidly filling with icy water as rising temperatures in the region accelerate the melting of glaciers and snowfields that feed them.

Pradeep Mool, a remote sensing expert with ICIMOD, said work is under way to lower the water levels of one critical glacial lake pinpointed by on-the-ground surveys and new satellite images. This is the Tsho Rolpa Lake that feeds the Rolwaling and Tama Koshi valleys in the Dolakha District of Nepal. Researchers have found that, as a result of the melting of a nearby glacier, the lake has grown sixfold, from an area of 0.23 square kilometres in the late 1950s to one of 1.4 square kilometres now. "A flood from this lake could cause serious damage down to the village of Tribeni, which is 108 km downstream, threatening about 10,000 human lives, thousands of livestock, agricultural land, bridges and other infrastructure", said Mr. Mool.

In Nepal, for example, data from 49 monitoring stations reveal a clear increase in temperature since the mid- 1970s, with highest temperatures found at higher altitudes. On average, air temperatures here are one degree Celsius higher than in the 1970s, rising by 0.06 degrees per year. It is no lust people who are at risk but many millions of dollars' worth of property, tourism facilities, trekking trails, roads, bridges and hydroelectric plants, which are the economic lifeblood of many countries in the region. Surendra Shrestha, Regional Coordinator in Asia for the UNEP Division of Early Warning and Assessment, observed that any one of twenty potentially dangerous glacial lakes in Nepal and 24 in Bhutan could burst its banks in five to ten years' time with catastrophic...