Climate 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.

The 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.

The 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 now.

Increased 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 sea-level rise.

The 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.

Efforts 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 the impacts.

The 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, Surrey, Bcpc.

Baethgen, W. E. (1997). "Vulnerability of the agriculture sector of Latin America to climate change." Climate Research 9(1-2): 1-7.

Bawa, K. and A. Markham (1995). "Climate change and tropical forests." Tree 10(9): 348-349.

Beardall, 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

Becker, 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 Lank