Agriculture Reference
In-Depth Information
19.10.2 ECOSYSTEMS
Mountain ecosystems contain a series of climatically very different zones
within short distances and elevations. They display a range of microhabi-
tats with great biodiversity (Korner, 2004). Mountain ecosystems are sen-
sitive to global warming and show signs of fragmentation and degradation
(Korner, 2004; Xu and Wilkes, 2004). Species in high-elevation ecosys-
tems are projected to shift to higher altitudes, although alpine plant species
with restricted habitat availability above the tree line are projected to expe-
rience severe fragmentation, habitat loss or even extinction if they cannot
move to higher elevations (Dirnbock et al., 2003). Climate warming may
increase suitable habitats for the water hyacinth
(Eichhornia crassipes)
, a
noxious weed able to survive winter temperatures.
The impacts of climate change on forest ecosystems include shifts in
the latitude of forest boundaries and the upward movement of tree lines to
higher elevations; changes in species composition and in vegetation types;
and an increase in net primary productivity (NPP) (Ramakrishna et al.,
2003). In the eastern Himalayas, forest vegetation will expand significant-
ly; forest productivity will increase from 1 to 10 percent and it is expected
that forest fires and pests such as the North American pinewood nema-
tode
(Bursaphelenchus xylophilus)
will increase as dryness and warmth
increase (Rebetez and Dobbertin, 2004).
19.10.3 HUMAN HEALTH
The impact of climate change on health conditions can be broken into
three main categories: (1) direct impacts of for example, drought, heat
waves, and flash floods, (2) indirect effects due to climate-induced eco-
nomic dislocation, decline, conflict, crop failure and associated malnutri-
tion and hunger, and (3) indirect effects due to the spread and aggravated
intensity of infectious diseases due to changing environmental conditions
(WHO, 2005). The latter effect includes the expansion of vector-borne
diseases such as malaria and dengue and water-related diseases such as
diarrhea. Regions such as the Hindu Kush-Himalayas, located at the fringe
of the current geographic distribution of these and many other diseases are
particularity susceptible to the negative effect of rising temperatures. It is
projected that the spread of malaria, Bartonellosis, tick-borne diseases and
