The glaciers in this gigantic mountain range hold the third largest body of freshwater ice in the world. Together with snow melt they contribute to the summer flow of Ganges and other major life giving rivers such as the Indus, Brahmaputra, Yangtze and Yellow rivers. This perfect balance of climate allowing water to be stored frozen as ice and released as melt water, is the key factor behind the birth and sustenance of all great Asian civilisations. The mountains themselves have profoundly sculpted the culture and religions in Asia, as well as shaping the weather and climate on earth. Causing the Monsoon in India and drought in the High Plateau deserts of Tibet and China, agriculture and populations are dependent on the Himalayas.
The water that flows from the Himalayas and Tibetan plateau is a freshwater lifeline for nearly 20 percent of the Worlds population, almost 1.5 billion people. There are around 18,000 glaciers storing a massive 12,000 square kilometres of freshwater.
It is debated how quickly climate change is tipping the balance of this unique freshwater storage. If the glaciers continue to melt, and even disappear, it will have major impacts on the water availability and food production for people living in these densely populated areas downstream. As the air temperature rises it will lead to a continuous shift of the snow line toward higher altitudes. Shift in snowline will result in less input to glacier mass balance. Higher atmosphere temperature and more liquid precipitation at higher altitude in the Himalayas will lead to rapid retreat of glaciers and downstream flooding in the coming future.
A study released in June 2010 shows a predicted decrease of 70 million people that can be sustained by the five main rivers with mountain glacial sources by 2050. Regions where water supply is dominated by melting snow or ice are predicted to suffer severe consequences in a warming climate. The average melting rate from mountain glaciers has doubled since the millennium in comparison with the already accelerated rates observed in the two decades before. In 2004 and 2006 the loss was almost twice as high as the previous 1998 record.
There are other anthropogenic causes of climate change in the Himalayas besides the emission of greenhouse gases. With India and China on its borders it comes as no surprise that the glaciers are also suffering from the impacts of increased pollution. Carbon and black soot from industry is turning the white snow black, contributing to the rate of melting as dark surfaces keep heat, while white reflects.
The consequences of ice disappearance in these high mountain areas will be felt regionally, while changes in the water cycle will affect continental scale water supply, and on a global scale, sea levels.
400 million people live along the course of the river Ganges and are dependent on water originating from the Gangotri glacier. According to a world glacier inventory created by NASA, the United S...