UN:Forty per cent of the world's population could be affected by loss of snow and glaciers on the Himalayas and other Asian mountain ranges as a result of global warming, according to a new report by the UN Environment Programme (UNEP).
Released to coincide with World Environment Day today, the Global Outlook for Ice and Snow report says that similar challenges are facing countries, communities, farmers and electricity-generators from the Andes to the Alps and the Pyrenees.
"Hundreds of millions of people across the world will be affected by declines in snow cover, sea ice, glaciers, permafrost and lake ice," it says. "Impacts are likely to include significant changes in the availability of water supplies for drinking and agriculture.
"Melting ice and snow are also likely to increase hazards, including avalanches and floods, from the build-up of potentially unstable glacial lakes. These can burst their ice and soil dams, sending walls of water down valleys at speeds close to that of a modern anti-tank missile."
The report, which ties in with UNEP's theme for 2007 - "Melting Ice: A Hot Topic?" - also suggests that thawing permafrost (frozen land) is triggering the expansion of existing waterbodies in places like Siberia and even creating new ones.
"These are bubbling methane into the atmosphere with emissions so forceful they can keep holes open on the lakes' icy surfaces even during sub-zero winter months," it says, adding that methane is also a "powerful global warming gas".
Meanwhile, less snow and sea ice is leading to more of the sun's heat being absorbed by the land and the polar oceans, which in turn could speed up global climate change, according to the report.
Some communities are already adapting to climate change, it notes. Hunters in Greenland are abandoning dog sleds in favour of skiffs as a result of less predictable sea ice, while a key railway line in China built on permafrost has special cooling technology.
However, the report acknowledges that many indigenous peoples lack the financial resources and technology needed to adapt, while many parts of the world currently remain ill-prepared for the likely pace of change caused by global warming.
UNEP executive director Achim Steiner said that some people might see the report as addressing issues in faraway places. "But the fate of the world's snowy and icy places . . . should be cause for concern in every ministry, boardroom and livingroom across the world," he declared.
"Indeed, the findings are as relevant to people living in the tropics and temperate climates - and in cities from Berlin to Brasilia and Beijing to Boston - as they are for the people living in Arctic or in ice-capped mountain regions."
Noting that the cost of offsetting the worst effects may be less than 0.1 per cent of global GDP a year, Mr Steiner said: "Overcoming the climate change challenge is the bargain of the century."