An examination and analysis of the climate change-induced vulnerabilities in Asia has to be undertaken against the backdrop of the physical, economic, and social environment of the countries in the region. They provide not only the benchmark against which vulnerabilities are to be assessed but also the potential for adaptation to them. Surface water and groundwater resources in Asian countries play vital roles in forestry, agriculture, fisheries, livestock production, and industrial activity. The water and agriculture sectors are likely to be most sensitive to climate change-induced impacts in Asia.
As reported in IPCC (1998), climate change in boreal Asia could have serious effects on climate-dependent sectors such as agriculture, forestry, and water resources. Climate change and human activities, for example, may influence the levels of the Caspian and Aral Seas, with implications for the vulnerability of natural and social systems (Kelly et al., 1983; Golubtsov et al., 1996; Popov and Rice, 1997). The increase in surface temperature will have favorable effects on agriculture in the northernmost regions of Asia, and a general northward shift of crop zones is expected. However, as much as a 30% decrease in cereal production from the main agriculture regions of boreal Asia by 2050 has been projected (Budyko and Menzhulin, 1996; ICRF, 1998). A decrease in agriculture productivity of about 20% also is suggested in southwestern Siberia (ICRF, 1998). Forest ecosystems in boreal Asia could suffer from floods and increased volume of runoff, as well as melting of permafrost regions. Model-based assessments suggest that significant northward shifts (up to 400 km) in natural forest zones are likely in the next 50 years (Lelyakin et al., 1997; Serebryanny and Khropov, 1997). There also is growing anxiety that significant increases in ultraviolet radiation, as observed in recent years, could have serious implications for ecosystems along the Arctic shore of Siberia (Makarov, 1999; Voskoboynikov, 1999; ACIA, 2000).
In arid and semi-arid Asia, the climate limits the portion of land that presently is available for agriculture and livestock production. Croplands in many of the countries in the region are irrigated because rainfall is low and highly variable. The agriculture sector here is potentially highly vulnerable to climate change because of degradation of the limited arable land. Almost two-thirds of domestic livestock are supported on rangelands, although in some countries a significant share of animal fodder also comes from crop residues (IPCC, 1998). The combination of elevated temperature and decreased precipitation in arid and semi-arid rangelands could cause a manifold increase in potential evapotranspiration, leading to severe water-stress conditions. Many desert organisms are near their limits of temperature tolerance. Because of the current marginality of soil-water and nutrient reserves, some ecosystems in semi-arid regions may be among the first to show the effects of climate change. Climate change has the potential to exacerbate the loss of biodiversity in this region.
The major impacts of global warming in temperate Asia will be large northward shifts of subtropical crop areas. Large increases in surface runoffleading to soil erosion and degradation, frequent waterlogging in the south, and spring droughts in the northultimately will affect agriculture productivity (Arnell, 1999). As reported in IPCC (1998), the volume of runoff from glaciers in central Asia may increase three-fold by 2050. Permafrost in northeast China is expected to disappear if temperatures increase by 2°C or more. The northern part of China would be most vulnerable to hydrological impacts of climate change; future population growth and economic development here may exacerbate seriously the existing water shortage. Deltaic coasts in China would face severe problems from sea-level rise. Sea-level rise also will expand the flood-prone area and exacerbate beach erosion in Japan.
In monsoon Asia, the issue of sensitivity of physical and natural systems to the hydrological cycle is linked to major stresses caused by projected climate change on agricultural production and increased exposure of social and economic systems to impacts of extreme events, including forest die-back and increased fire risk; typhoons and tropical storms; floods and landslide; and human disease impacts. These stresses on physical systems translate into key social vulnerabilities, particularly in combination with unsustainable utilization of resources. For example, the drawing down of groundwater resources has increased the rate of relative sea-level change for many of the major cities of coastal Asia, such as Bangkok and Shanghaithereby increasing the risk from climate change-induced sea-level rise (Jarupongsakul, 1999). Conversion of natural forests to palm oil plantations in many southeast Asian countries during recent decades (particularly Indonesia and Malaysia) increased the probability of uncontrolled forest fires and increased health and biodiversity impacts during the 1997 ENSO event (Yim, 1999; Barber and Schweithelm, 2000). The ecological security of mangroves and coral reefs may be put at risk by climate change. Sea-level rise could cause large-scale inundation along the coastline and recession of flat sandy beaches of south and southeast Asia. Monsoons in tropical Asia could become more variable if ENSO events become stronger and more frequent in a warmer atmosphere (Webster and Yang, 1992; Webster et al. 1998).
Vulnerability relates to social or natural systems and is delineated as such. The issues of social and physical vulnerability to climate change are directly related because the major sensitivities of ecological and natural systems across the regions of Asia translate into risks to socioeconomic systems. Social vulnerability is defined as the degree to which individuals or groups are susceptible to impacts; the determinants of social vulnerability are exposure to stress as a result of the impacts of climate change and the underlying social position (Adger, 1999a). On this basis, the key social vulnerabilities in the Asian context occur:
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