Change, one of the most pervasive and truly global of all issues
affecting humanity, poses a grave and serious threat to our environment.
With the signing of multilateral environment treaties such as UNFCCC,
the world community has become more aware of the consequences of
the climate change on our Planet and started addressing issues of
climate change on ecosystem health and environmental security at
global level. The scientific reality of issue came at the forefront
as early as 1990, when the Intergovernmental Panelon Climate Change
(IPCC) reported in its first assessment report that the possibility
of global warming had to be taken seriously. Regional and national
efforts to deal with climate change are currently underway to combine
the collective experiences of science and policy.
effects of climate change are already being felt in Asia and are
likely to intensify in the years to come. Substantial elevation
shifts of ecosystems in the mountains and uplands of S/SEA are projected.
At high elevations, weedy species can be expected to displace tree
species, although the rates of change could be slow and constrained
by increased erosion in mountain areas. Changes in the distribution
patterns of monsoon forests will be complex. For instance, in Thailand,
area of tropical forests could increase from 45% to 80% of total
cover. Similarly, for Sri Lanka a decrease in tropical rainforest
of 2%-11% and an increase in tropical dry forest of 7%-8% are estimated.
More than 10% (43 million ha) of global freshwater wetlands or peatlands
are located in this humid tropical zone of Asia. Projected increases
in evapo-transpiration and rainfall are likely to have a negative
impact on the viability of peat, resulting in their shrinkage and
desiccation. Rise in sea level and increases in sea-surface temperature
are most probable major climate change related stresses on coastal
ecosystems. Coral reefs are particularly sensitive to increases
in seawater temperature and increased irradiance as this has been
shown to cause coral bleaching.
Mangroves are the other vital coastal ecosystems that would be severely
affected by climate change related increases in temperature and
sea level rise (SLR). Mangroves are extensively present in the region,
with Indonesia, alone accounting for 23% of the world's total. But
intrusion of saline water and rise in temperatures are already taking
a heavy toll on these ecosystems.
Himalayas have a critical role in the provision of water to continental
Asia. Increased temperatures and increased seasonal variability
in precipitation are expected to result in increased recession of
glaciers and increasing danger from glacial lake outbursts causing
floods. A reduction in average flow of snow-fed rivers, coupled
with an increase in peak flows and sediment yield would have major
impacts on hydropower generation, urban water supply and agriculture.
Availability of water from snow-fed rivers may increase in the short
term but decrease in the long run. Runoff from rain-fed rivers may
change in the future. A reduction in snowmelt water will put the
dry-season flow of these rivers under more stress than is the case
population and increasing demand in the agricultural, industrial
and hydropower sectors will put additional stress on water resources.
Pressure on the drier river basins and those subject to low seasonal
flows will be most acute. Hydrological changes in island and coastal
drainage basins are expected to be relatively small in comparison
to those in continental S/SEA, apart from those associated with
sensitivity of major cereal and tree crops to changes in temperature,
moisture and CO2 concentration of the magnitudes projected for the
region can severly threaten the agro-biodiversity and food security
of the region. For instance, impacts on rice yield, wheat yield
and sorghum yield suggest that any increase in production associated
with CO2 fertilisation will be more than offset by reductions in
yield from temperature or moisture changes. Although climate change
impacts could result in significant changes in crop yields, production,
storage and distribution, the net effect of the changes region wide
is uncertain because of variety differences; local differences in
growing season, crop management, etc.; the lack of inclusion of
possible diseases, pests, and micro-organisms in crop model simulations;
and the vulnerability of agricultural areas to episodic environmental
hazards, including floods, droughts and cyclones. Low-income rural
populations that depend on traditional agricultural systems or on
marginal lands are particularly vulnerable.
in the region need to focsu on assessing the vulnerabilities of
these ecosystems and advise mitigatory measures for countries to
deal with the situation. capacity building, technology transfer,
regional cooperation and effectively policy development coupled
with scientific interventions can provide useful ways of minimising
need for development of national, sub-regional and regional mitigatory
strategy is therefore a priority for the region.
Some useful links:
Atkinson, D. and British Crop Protection Council. (1993). Global
climatic change: Its implications for crop protection - proceedings
of a symposium organised by the British Crop Protection Council
held at the Brighton Metropole Hotel on November 1993. Farnham,
W. E. (1997). "Vulnerability of the agriculture sector of Latin
America to climate change." Climate Research 9(1-2): 1-7.
K. and A. Markham (1995). "Climate change and tropical forests."
Tree 10(9): 348-349.
J., S. Beer, et al. (1998). "Biodiversity of marine plants
in an era of climate change: Some predictions based on physiological
performance." Botanica Marina 41(1): 113-123
A., H. Bugmann, et al. (1997). Predicting global change impacts
on mountain hydrology and ecology : integrated catchment hydrology/altitudinal
gradient studies : workshop report : documentation resulting from
an international workshop, Kathmandu, Nepal, 30 March - 2 April
1996. Stockholm, Sweden, International Geosphere-Biosphere Programme:
A Study of Global Change International Council of Scientific Unions
For further information contact:
Regional Biodiversity Programme, Asia
IUCN-The World Conservation Union
53, Horton Place,
Colombo-7, Sri Lanka