Agriculture Reference
In-Depth Information
agement, poor marketing and networks (lack of market development) and
lack of entrepreneurship. Number of reports has indicated that mountain-
ous regions are noticeably impacted by climate change. The most widely
reported impact is the rapid reduction in glaciers (which has profound fu-
ture implications for downstream water resources), crop shift, decline in
productivity and nonperformance of existing crop varieties. The impacts
of climate change are superimposed on a variety of other environmental
and social stresses, many already recognized as severe (Ives and Messerli,
1989).
The Himalayan region is the source of ten of the largest rivers in Asia
(Table 19.1). The basins of these rivers are inhabited by 1.3 billion people
and contain seven megacities. Natural resources in these basins provide
the basis for a substantial part of the region's total GDP and important
environmental services, which are also of importance beyond the region
(Penland and Kulp, 2005; Macintosh, 2005;Nicholls, 1995; Sanlaville
and Prieur, 2005; She, 2004; Woodroffe et al., 2006). Continuing climate
change is predicted to lead to major change in the strength and timing of
the Asian monsoon, inner Asian high-pressure systems, and winter west-
erlies - the main systems affecting the climate of the Himalayan region.
The impacts on river flows, groundwater recharge, natural hazards, and the
ecosystem, as well as on people and their livelihoods, could be dramatic,
although not the same in terms of rate, intensity or direction in all parts
of the region. Given the current state of knowledge about climate change,
determining the diversity of impacts is a challenge for researchers, and
risk assessment is needed to guide future action.
TABLE 19.1
Principal Rivers of the Himalayan Region - Basin Statistics
River
River basin
River
Annual
mean dis-
charge m
3
/
sec
% of gla-
cier melt
in river
flow
Basin area
(km
2
)
Popula-
tion den-
sity (per/
km
2
)
Popula-
tion
×
1000
Water
availability
(m
3
/person/
year)
Amu Darya
1376
a
Not avail-
able
534,739
39
20,855
2081
Brahmaputra
21,261
a
~ 12
651,335
182
118,543
5656
Ganges
12,037
a
~ 9
1,016,124
401
407,466
932
Indus
5533
a
Up to 50
1,081,718
165
178,483
978
