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Although many resource systems and populations exhibit high degrees of resilience and adaptive capacity, there is a significant risk that critical thresholds may be breached as a result of climate change, undermining this resilience. The environmental risks in a region could vary significantly for different sectors, depending on the degree of warming. To develop a risk profile for precautionary management of climate change, it is necessary to assess the critical climate threshold for a region for each of the relevant priority sectors, such as water and agriculture. For instance, a small degree of surface warming could be beneficial for agriculture in Russia but may be detrimental in India or Bangladesh. Increased glacier melt in the Himalayas may cause serious floods in Nepal, India, and Bangladesh. The potential environmental risks to water and marine resources in marginal seas of Asia such as the Sea of Japan, Bohai Bay, and the Yellow Sea also will depend on the degree of climate changewhich could differ significantly in these regions. For many countries in Asia, there is sparse scientific research on the evaluation of sector-specific critical climatic thresholds. The response of driving forces such as economic growth, population increase, and technological progress in each country or region also should be included in the determination of thresholds for precautionary risk management as an adaptation strategy to climate change.
Rapid demographic transition accompanying significant economic growth is likely in many Asian countries in the 21st century. These trends exacerbate pressures on resource use, the climate system, and the natural environment. Population growth and varying economic and technological conditions in Asia are likely to affect some societies and resources more than changes in climate per se. Moreover, socioeconomic and technological developments will interact with many vulnerable sectors. However, predicting population growth rates and future economic conditions is as uncertain an exercise as predicting the future climate. Institutional and legal structures may change and will co-evolve with climatic risks. GHG emission scenarios are especially important, but future emission trends will depend on population growth and prevailing economic and technological conditions. There have been limited studies that simultaneously take into account climate change and other human-induced stresses. For vulnerability and adaptation to be addressed comprehensively, they must be considered in a context of multiple stresses caused by climate change and other anthropogenic activities.
Table 11-11 summarizes the vulnerability of key sectors, from food and fiber through settlements, for subregions of Asia. This summary is derived from a synthesis of available scientific research reviewed in this chapter; it represents a consensus view of the authors. Levels of confidence assigned to vulnerability also are shown in Table 11-11, again based on iterative assessment of the available scientific evidence. Currently available research synthesized in this table reveals a wide range of vulnerability, as well as a wide range of uncertainties in the assessment of these vulnerabilities. Geographical resolution as well as integration and scaling of basic physical and biological responses are the key factors contributing to these uncertainties. The limited database also makes it difficult to aggregate various responses with only a few sample or spot assessments. Nevertheless, some key trends emerge from the synthesis. A consistent message is the vulnerability of south and southeast Asia across many sectors, as well as a high degree of confidence about this assertion. Across virtually all subregions, water resources and natural ecosystems are appraised as highly vulnerable to climate change, although the level of confidence varies for some regions because of lack of data or greater complexity in the resource systems. There may be some minor benefits to boreal Asia, making it more resilient to potential impacts, but natural ecosystems clearly are under threat in this subregion.
|Table 11-11: Vulnerability of key sectors to impacts of climate change for select subregions in Asia. Vulnerability scale is as follows: highly vulnerable (-2), moderately vulnerable (-1), slightly or not vulnerable (0), slightly resilient (+1), and most resilient (+2). Confidence levels abbreviated to VH (very high), H (high), M (medium), L (low), and VL (very low).|
|Regions||Food and Fiber||Biodiversity||Water Resources||Coastal Ecosystems||Human Health||Settlements|
|Boreal Asia||+1 / H||-2 / M||+1 / M||+1 / L||-1 / L||0 / M|
|Arid and Semi-Arid Asia|
|- Central Asia||-2 / H||-1 / L||-2 / H||-1 / L||-1 / M||-1 / M|
|- Tibetan Plateau||0 / L||-2 / M||-1 / L||Not applicable||No information||No information|
|Temperate Asia||-2 / H||-1 / M||-2 / H||-2 / H||-2 / M||-2 / H|
|- South Asia||-2 / H||-2 / M||-2 / H||-2 / H||-1 / M||-2 / M|
|- Southeast Asia||-2 / H||-2 / M||-2 / H||-2 / H||-1 / M||-2 / M|
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