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In northern India the millennial-scale, patterns of glacier advance and
retreat correspond to patterns of monsoon variability (Scherler et al.
2010).
Groundwater signifi cantly infl uences the Himalayan river discharge
cycle for the Ganges River basin. About two-thirds of its annual
discharge comes from water travelling through groundwater reservoirs
in the eastern HKH (Andermann et al. 2012).
The greater concern is impact of climate change on the Asian monsoon
(bigger than glaciers), yet highly seasonal, with about 75% of the annual
rainfall occurring during the monsoon months (June-September); the
pressing question is how the monsoon will respond to global warming,
especially in monsoon-dominated regions, where there is a decreasing trend
in precipitation and runoff from the east to west due to the weakening of
the summer monsoon as it moves westward along the Himalayan range
(UNEP 2008, Armstrong 2010). The largest changes to the hydrological
system in future will mostly likely be because of changes in the timing,
location, and intensity of the monsoon (NAS 2012). These changes will lead
to construction of dams and water transfer systems; India and China are
planning or already implementing large interbrain schemes to transfer water
to water-scare regions (Kohler and Maselli 2009). Construction of dams for
future water security will potentially lead to confl ict due to displacement of
an estimated 50-70 million people in India, China, Bangladesh and Nepal
by 2050 (SFG 2010).
Climate change and Himalayan glaciers
One of the main concerns in relation to climate change in the HKH region
is the reduction of snow and ice. Many assessments link the receding of the
Himalaya glaciers to global warming, and state that the melting of glaciers
is a clear indicator of climate change (Xu et al. 2009). Also note that glacier
change is the most visible and obvious indicator of changing temperatures
(Armstrong 2010, Winkler 2010). Temperatures at some locations in the
Himalayan region have risen faster than the global average. From 1982
to 2006, the average annual mean temperature in the region increased
by 1.5°C with an average increase of .06°C per year, although the rate
of warming varies across seasons and ecoregions (Shrestha et al. 2012).
It stands to reason that the rising temperature in the Himalayas would
affect glacier melt (Barnett et al. 2005). Also, climate change is predicted
to lead to major changes in the strength and timing of the Asian monsoon
and winter westerlies. However, uncertainties exist about the current
state of the Himalayan glaciers (Bamber 2012, Kargel et al. 2010, UNEP
2009), because studies suggest that HKH glaciers have not responded
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