The Himalayas have the largest concentration of glaciers outside the polar region. provide the headwaters for nine major river systems in Asia. These freshwater reserve are a lifeline for almost one-third of humanity. There is clear evidence that Himalayan glaciers have been melting at an unprecedented rate in recent decades. This has causes major changes in freshwater flow regimes and is likely to have a dramatic impact on drinking water supplies, biodiversity, hydropower, industry, agriculture and others, with far-reaching implications for the people of the region and the earth’s environment.
One result of glacial retreat has been an increase in the number and size of glacial lakes forming at the new terminal ends behind the exposed end moraines. These in turn have caused an increase in the potential threat of floods occurring due to glacial lake outbursts. Such disasters often cross national boundaries with the water from a lake in one country threatening the lives and properties of people in another.
The International Centre for Integrated Mountain Development (ICIMOD) in partnership with UNEP and the Asia Pacific Network have documented baseline information on the Himalayan glaciers, glacial lakes, and GLOFs identifying some 200 potentially dangerous glacial lakes in the Himalayas. The publication provides an account of glacier retreat and growth of glacial lakes in two selected river sub-basins, one in Nepal and one in Bhutan.