Agriculture Reference
In-Depth Information
TABLE 8.1
Renewable Freshwater Resources of South Asian Countries
Estimates of Renewable Freshwater (km
3
/year)
Country
UN (2010)
Engelman and LeRoy (1993)
Afghanistan
65
50
Bangladesh
1210
2357
Bhutan
73
95
Nepal
210
170
India
1869
2085
Pakistan
234
468
Sri Lanka
50
43
Source:
United Nations. 2011. Environment statistics—Country snapshots:
India. United Nations Statistics Division.
http://unstats.un.org/unsd
20, 2012); Engelman, R., and P. LeRoy. 1993.
Sustaining Water
. 56.
Washington, DC: Population Action International.
exacerbated by the climate change. The projected warmer climate implies acceleration
of the hydrologic cycle with severe impacts on groundwater depletion and reduction
in stream flow because of the general reduction in runoff (Saleth 2011) partly caused
by changes in rainfall amount and distribution (Mall et al. 2006). Increase in evapora-
tion may accentuate water scarcity by reducing the net recharge of the groundwater
and aquifer. Vulnerability to the impact of climate change on renewable groundwater
resources may be a serious constraint to achieving food security and maintaining
economic growth (Döll 2009). There has also been a significant increasing trend in
the frequency and magnitude of extreme rain events corresponding with a decreasing
trend in the frequency of moderate events (Goswami et al. 2006). Thus, variation in
water availability is a major source of risk for agricultural productivity decline and
food insecurity in South Asia (Li et al. 2011). Whereas rainfed cropping systems by
small landholders are the most vulnerable to drought stress, reduction in runoff and
depletion of groundwater also adversely influence irrigated agriculture. Rapid melting
of the Himalayan glaciers may increase water scarcity in the Indo-Gangetic plains.
8.4 CLIMATE CHANGE AND THE HIMALAYAN GLACIERS
There are marked trends of increasing temperature since early 1980 in India, but
with significant variations in these trends during different seasons and over differ-
ent regions (Dash and Hunt 2007). Trends of increased temperatures in Pakistan
correspond to an increase in growing degree days and a decrease in growing sea-
son lengths (Hussain and Mudasser 2007). The projected climate change may
reduce the total and per capita availability of renewable freshwater resources in
South Asia (Table 8.2). The Greater Himalayas, also called the Third Pole, hold the
largest mass of ice outside of the polar regions. The Himalayan glaciers are the
