Future Sustainability Challenges in Hindu Kush-Himalaya - Impact of Global Changes on Mountains: Responses and Adaptation - page 250

in HKH region is most likely to be decades to centuries (Armstrong 2010).
This has the potential to have serious implications in the future on water
availability and the situation could worsen if the melting is expected in
decades to come.
Filling the knowledge gaps: an urgent need
Studies on glacial melt contributing to the basin's hydrology lack direct
evidence and sometimes appear to be inconsistent (Kaser et al. 2010). This
has raised doubts that melting glaciers provide a key source of water in
downstream areas across the entire Himalayan region (UNEP 2012a). Due
to uncertainty about the future state of the climate, as well as a lack of long-
term comprehensive in situ monitoring of glacial melt contributing to the
Himalayan basins, some projections of their future have serious implication
on water resources (NAS 2012, Bolch et al. 2012). Understanding the future
implications of climate change to the Himalayan basins is urgently required
because more than 1.4 billion people depend on water from the Indus,
Ganges, Brahmaputra, Yangtze and Yellow Rivers (Immerzeel et al. 2010).
Their dependency on these water resources underpins environmental
sustainability, food security and livelihoods of the Himalayan community.
Indus Case study 3: Future implication Indus Basin— Fig. 10.20
The Indus River Basin covers an area of about 1 million sq. km and touches
four countries (China, India, Afghanistan, Pakistan). It has one of the
world's largest irrigation networks and the most depleted basins in the
world (Sharma et al. 2010), is Pakistan's primary source of freshwater and
can been seen as its lifeline. The Indus River irrigates 80% of Pakistan's
21.5 million ha of agricultural land and is critical for Pakistan's 160 million
people (Rizvi 2001, CIA 2006). About 90% of Pakistan's agriculture depends
on the river and much of the world's cotton comes from the Indus River
Valley. On average, about 737 billion gallons of water are being withdrawn
from the Indus River annually to grow cotton (enough water to supply
Delhi residents for more than two years). In addition, the river is used for
hydropower generation in Pakistan and India. In India, about 60 million
live in the basin. The drainage 321,289 sq km of the Indus River basin
encompasses nearly 10% of the total geographical area of India. Five% of 9.6
million hectares of cropland of India, of which 30% is irrigated (Rosegrant
et al. 2002). Glacial melt contributes as much as half of the region's fl ow
(Wheeler 2011, Winiger et al. 2005). Also, meltwater is crucial for upstream
reservoirs to store and release water to downstream areas when most
needed. The Indus Basin Irrigation System gets its water supply from the
Tarbela dam on the Indus River and the Mangla dam on the Jhelum River;
both are located in the upper Indus basin and are fed largely by glacier