Running 2,000 kilometres from east to west and comprising more than
60,000 square kilometres of ice, the Hindu Kush–Karakoram–Himalayan
glaciers are a source of water for the quarter of the global population
that lives in south Asia. Glaciers are natural stores and regulators of
water supply to rivers, which, in turn, provide water for domestic and
industrial consumption, energy generation and irrigation.
Ice cover is decreasing in this region, as
for most glaciers in the world, as a result of global warming. Between
2003 and 2009, Himalayan glaciers lost an estimated 174 gigatonnes of
water1,
and contributed to catastrophic floods of the Indus, Ganges and
Brahmaputra rivers. Pollution is accelerating the melt. An 'Asian brown
cloud', formed from the 2 million tonnes of soot and dark particles
released into the atmosphere every year, mostly from India and China,
warms the air and surface ice2.
Seasonal meltwater serves as the main source of power for an increasing number of hydroelectric dams on the rivers served by the glaciers. But hydropower faces a difficult future in south Asia because of climatic, environmental and politico-economic factors. The region is starved of energy, and power shortages of up to 20 hours a day are stunting development. Importing oil and gas from the Gulf, Iran or Tajikistan is expensive or politically difficult. So countries are turning to indigenous hydroelectric power, and to other renewable energies such as solar and wind, for cheap, sustainable energy.
Hydroelectric power must play a part in south Asia's low-carbon energy future. But to be effective, governments around the Himalayas need to work together to measure and model glacier retreat, changing river flows and their impact on hydroelectric power generation. Political obstacles to dam construction and watershed management must also be overcome.
Modelling of glacier retreat in the Himalayas is hindered by sparse data. Field, satellite and weather records confirm that 9% of the ice area present in the early 1970s had disappeared by the early 2000s (ref. 5). But there has been no comprehensive assessment of current regional mass balance — the difference between the accumulation of ice and its loss3.
An increased seasonal melt coupled with rains will bring more intense floods, such as those in 2010 caused by excessive monsoon rains that inundated one-fifth of Pakistan's land area for five weeks, killing 2,000 people and costing tens of billions of dollars in damage and economic impact. Sea level is rising at around 3.5 millimetres per year5 and the frequency of tropical cyclones is predicted to increase as a result of global warming. Because rain, rather than snow, falls on mountains in spring, river flows will peak before the main growing season. Summers will increasingly see dry streams, withered and abandoned crops, dead fish and low groundwater levels.
... From--http://www.nature.com/news/climate-change-melting-glaciers-bring-energy-uncertainty-1.14031
Seasonal meltwater serves as the main source of power for an increasing number of hydroelectric dams on the rivers served by the glaciers. But hydropower faces a difficult future in south Asia because of climatic, environmental and politico-economic factors. The region is starved of energy, and power shortages of up to 20 hours a day are stunting development. Importing oil and gas from the Gulf, Iran or Tajikistan is expensive or politically difficult. So countries are turning to indigenous hydroelectric power, and to other renewable energies such as solar and wind, for cheap, sustainable energy.
Hydroelectric power must play a part in south Asia's low-carbon energy future. But to be effective, governments around the Himalayas need to work together to measure and model glacier retreat, changing river flows and their impact on hydroelectric power generation. Political obstacles to dam construction and watershed management must also be overcome.
Glacial retreat
Glaciers feed thousands of miles of rivers in Pakistan. The largest, the river Indus, depends on glacial waters for up to half of its flow. But near the river's source, in mountains in the Indian-administered state of Jammu and Kashmir, the glaciers are thinning at an alarming rate of 0.7 metres per year3. The Ganges and Brahmaputra rivers in India and Bangladesh are similarly threatened by glacial melting in the regions of their headwaters4.Modelling of glacier retreat in the Himalayas is hindered by sparse data. Field, satellite and weather records confirm that 9% of the ice area present in the early 1970s had disappeared by the early 2000s (ref. 5). But there has been no comprehensive assessment of current regional mass balance — the difference between the accumulation of ice and its loss3.
An increased seasonal melt coupled with rains will bring more intense floods, such as those in 2010 caused by excessive monsoon rains that inundated one-fifth of Pakistan's land area for five weeks, killing 2,000 people and costing tens of billions of dollars in damage and economic impact. Sea level is rising at around 3.5 millimetres per year5 and the frequency of tropical cyclones is predicted to increase as a result of global warming. Because rain, rather than snow, falls on mountains in spring, river flows will peak before the main growing season. Summers will increasingly see dry streams, withered and abandoned crops, dead fish and low groundwater levels.
... From--http://www.nature.com/news/climate-change-melting-glaciers-bring-energy-uncertainty-1.14031
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