Glaciers worldwide are retreating in the face of accelerating global warming, as human activities cause steadily increasing concentrations of greenhouse gases in the atmosphere: their melting is an important indicator of climate change. By one forecast, up to a quarter of the global mountain glacier mass could disappear by 2050, and up to half could be lost by 2100. Changes in temperature are more pronounced at higher altitudes, and several studies have revealed that the Himalayan glaciers have been melting at an unprecedented rate in recent decades. This will cause major changes in freshwater flow regimes and thus have dramatic impacts on drinking water
supply, biodiversity, hydropower, industry, agriculture and livelihoods.
