The water that begins it's flow from the glaciers of the Himalaya are a freshwater lifeline for nearly 20 percent of the world's population, almost 1.5 billion people. Around 18,000 glaciers store a massive 12,000 square kilometres of freshwater here. Together with snow-melt they contribute to the summer flow of the Ganges and other major life giving rivers such as the Indus, Brahmaputra, Yangtze and Yellow Rivers.
This perfect balance of climate that allows water to be stored frozen and released as melt water, is one of the key factors behind the birth and sustenance of all great Asian civilisations. As well as being the water towers for the most populated area in the world the Himalayas play a significant role in the dynamics of the Indian monsoon. Radiation from snow and ice cover provides feedback mechanisms for advection water vapour from the surrounding oceans and directly impacts the maintenance of seasonal cycles.
Studies of this massive fresh water reserve in the Himalayas show a general decline since the little ice age, but the glaciers have experienced accelerated melting in recent decades. Average temperatures in this mountainous region have increased more than the global average and the snowline is creeping higher. Increased volumes of melt water flowing down the valleys provides short-term benefits in the form of hydro power electricity generation and higher crop yields, but longer-term warming is predicted to have catastrophic consequences. People living around the Himalayas have already felt the devastating effects of climate change in the form of changing monsoon patterns, floods, erosion and severe droughts.
Another big problem is contamination. According to a recent study, all India's fourteen major river systems are heavily polluted, mostly from the 50 million cubic meters of untreated sewage discharged into them each year.