Potential Impacts of Climate Changes on Asia and Small Island States

1. 台大環衛上課講義05/15/95 Potential Impacts of Climate Changes on Asia and Small Island States

2. Impacts on Asia (1) • GCMs suggest that under the combined influence of greenhouse gas and sulfate aerosols, surface warming would be restricted to about 2.5°C in the 2050s and about 4°C in the 2080s • In general, projected warming over Asia is higher during Northern Hemisphere (NH) winter than during summer for both time periods. • The rise in surface air temperature is likely to be most pronounced over boreal Asia in all seasons

3. Impacts on Asia (2) • relatively more pronounced increases in minimum temperature than in maximum temperature over Asia on an annual mean basis, as well as during winter, hence a decrease in diurnal temperature range (DTR) • During summer, an increase in DTR is projected, suggesting that the maximum temperature would have more pronounced increases relative to the minimum temperature • The summertime increase in DTR over central Asia is likely to be significantly higher relative to that in other regions

4. Impacts on Asia (3) • In general, all GCMs simulate an enhanced hydrological cycle and an increase in area-averaged annual mean rainfall over Asia • Under the combined influence of greenhouse gases and sulfate aerosols,the projected increase in precipitation is limited to about 3% and 7% in the 2050s and 2080s, respectively • The projected increase in precipitation is greatest during NH winter for both time periods

5. Impacts on Asia (4) • The increase in annual and winter mean precipitation is projected to be highest in boreal Asia • a decline in summer precipitation is likely over the central parts of arid and semi-arid Asia, resulting in expansion of deserts • high uncertainty in future projections of winter and summer precipitation over south Asia • Because much of tropical Asia is intrinsically linked with the annual monsoon cycle, a better understanding of the future behavior of the monsoon and its variability is warranted

6. Impacts on Asia (5) • The socioeconomic environment of many countries in Asia is characterized by high population density and relatively low rates of economic growth • The following risks linked to changes in climate and its variability for Asia are identified: ( *: “very low confidence” to *****: “very high confidence”) • The dangerous processes of permafrost degradation resulting from global warming would increase the vulnerability of many climate-dependent sectors affecting the economy in boreal Asia. ***

7. Impacts on Asia (6) • Surface runoff increases during spring and summer periods would be pronounced in boreal Asia. *** • The frequency of forest fires is expected to increase in boreal Asia. *** • The large deltas and coastal low-lying areas of Asia could be inundated by sea-level rise. **** • The developing countries of temperate and tropical Asia already are quite vulnerable to extreme climate events such as droughts and floods; climate change and its variability could exacerbate these vulnerabilities. ****

8. Impacts on Asia (7) • Increased precipitation intensity, particularly during the summer monsoon, could increase flood-prone areas in temperate and tropical Asia. There is a potential for drier conditions in arid and semi-arid Asia during summer, which could lead to more severe droughts. *** • Freshwater availability is expected to be highly vulnerable to anticipated climate change. **** • Tropical cyclones could become more intense. Combined with sea-level rise, this impact would result in enhanced risk of loss of life and properties in coastal low-lying areas of cyclone-prone countries of Asia. ***

9. Impacts on Asia (8) • Crop production and aquaculture would be threatened by a combination of thermal and water stresses, sea level rise, increased flooding, and strong winds associated with intense tropical cyclones. **** • Warmer and wetter conditions would increase the potential for a higher incidence of heat-related and infectious diseases in tropical and temperate Asia. *** • Climate change would exacerbate threats to biodiversity resulting from land-use/cover change and population pressure in Asia.***

10. Strategies on Adaptation (1) • The first is a macro strategy that involves rapid development. Sustainable and equitable development will increase income levels, education, and technical skills and improve public food distribution, disaster preparedness and management, and health care systems in developing countries of Asia. All of these changes could substantially enhance social capital and reduce the vulnerability of these countries to climate change

11. Strategies on Adaptation (2) • The second strategy is a micro strategy that involves modifying the management of sectors that are most sensitive to climate change. This approach entails developing new institutions or modifying existing institutions related to these sectors that promote rather than discourage adaptation to climate change. It also involves modifying climate-sensitive infrastructures that are already planned or implemented or other long-term decisions that are sensitive to climate to incorporate the risks of climate change

12. Potential Adaptation Options for Tropical Asia (1) • Agriculture: • Adjust cropping calendar and crop rotation • develop and promote use of high-yielding varieties and sustainable technological applications • Water Resources: • Develop flood- and drought-control management systems • reduce future developments in floodplains • use appropriate measures for protection against soil erosion • conserve groundwater supply, water impoundments, and efficient water resource systems

13. Potential Adaptation Options for Tropical Asia (2) • Ecosystems and Biodiversity: • Assess risks to endemic species and ecosystems • Introduce integrated ecosystem planning and management • Reduce habitat fragmentation and promote development of migration corridors and buffer zones • Prevent deforestation and conserve natural habitats in climatic transition zones inhabited by genetic biodiversity of potential for ecosystem restoration

14. Potential Adaptation Options for Tropical Asia (3) • Coastal Resources: • Protect wetlands and allow for migration • prepare contingency plans for migration in response to sea level rise • improve emergency preparedness for weather extremes (e.g., cyclones and storm surges) • evaluate coastal subsidence rates in sensitive coastal regions • Common Adaptation: Implement coastal zone management; protect marine resources

15. Potential Adaptation Options for Tropical Asia (4) • Human Health: • Build heat-resistant urban infrastructures and take additional measures to reduce air and water pollution • Adapt technological/engineering solutions to prevent vector-borne diseases/epidemics • Improve health care system, including surveillance, monitoring, and information dissemination • Improve public education and literacy rate in various communities • Increase infrastructure for waste disposal • Improve sanitation facilities in developing countries

16. Potential Adaptation Options for Tropical Asia (5) • Cross-Cutting Issues • Continue monitoring and analysis of variability and trends in key climatic elements • Improve weather forecasting systems in the region • Improve and implement reforms on land-use planning • Apply new techniques for confident projection of regional climate change and its variability, including extreme events • Improve coordination of climate change adaptation activities among countries in the region • Keep the nongovernmental organization (NGO) community and the public aware of developments on risks of climate change and involve them in planning, adaptation, and mitigation strategies • Take advantage of traditional knowledge in planning for the future

17. Impacts on Small Island States (1) • The small island states considered here are located mainly in the tropics and the subtropics • These island states span the ocean regions of the Pacific, Indian, and Atlantic, as well as the Caribbean and Mediterranean Seas • Because of the very nature of these states, the ocean exerts a major influence on their physical, natural, and socioeconomic infrastructure and activities

18. Impacts on Small Island States (2) • Small island states share many common features that serve to increase their vulnerability to projected impacts of climate change • These characteristics include their small physical size and the fact that they are surrounded by large expanses of ocean; limited natural resources; proneness to natural disasters and extreme events; relative isolation; extreme openness of their economies, which are highly sensitive to external shocks; large populations with high growth rates and densities; poorly developed infrastructure; and limited funds, human resources, and skills • These characteristics limit the capacity of small island states to mitigate and adapt to future climate and sea-level change

19. Impacts on Small Island States (3) • The most significant and immediate consequences for small island states are likely to be related to changes in sea levels, rainfall regimes, soil moisture budgets, and prevailing winds (speed and direction) and short-term variations in regional and local patterns of wave action • Owing to their coastal location, the majority of socioeconomic activities and infrastructure and the population are likely to be highly vulnerable to the impacts of climate change and sea-level rise

20. Impacts on Small Island States (4) • temperatures have been increasing by as much as 0.1°C per decade, and sea level has risen by 2 mm yr-1 in regions in which small island states are located • Analysis suggests that increases in surface air temperatures have been greater than global rates of warming (e.g., in the Pacific Ocean and the Caribbean Sea regions) • for some small islands it is difficult to establish clear trends of sea-level change because of limitations of observational records, especially geodetic-controlled tide gauge records

21. Impacts on Small Island States (5) • Observational evidence also suggests that much of the variability in the rainfall record of Caribbean and Pacific islands appears to be closely related to the onset of El Niño-Southern Oscillation (ENSO). However, part of the variability in these areas also may be attributable to the influence of the Inter-Tropical Convergence Zone (ITCZ) and the South Pacific Convergence Zone (SPCZ) • models indicate general increases in surface air temperature for the 2050s and 2080s and an increase in rainfall of about 0.3% for the 2050s and 0.7% for the 2080s for the Pacific region • The diurnal temperature range is projected to decrease marginally for the regions of the small island states for both time horizons

22. Impacts on Small Island States (6) • With respect to extreme events, by the 2050s and 2080s, there will be increased thermal stress during summer, as well as more frequent droughts and floods in all four tropical ocean regions • This projection implies that in the future these regions are likely to experience floods during wet seasons and droughts during dry seasons • Furthermore, warming in some regions (e.g., the Pacific Ocean) is likened to an El Niño pattern, suggesting that climate variability associated with the ENSO phenomenon will continue on a seasonal and decadal time scale. It is probable that such an association may dominate over any effects attributable to global warming

23. Development, sustainability, and equity issues • The small island states account for less than 1% of global greenhouse gas (GHG) emissions but are among the most vulnerable of all locations to the potential adverse effects of climate change and sea-level rise • Economic development and alleviation of poverty constitute the single most critical concern of many small island states. Thus, with limited resources and low adaptive capacity, these islands face the considerable challenge of meeting the social and economic needs of their populations in a manner that is sustainable. At the same time, they are forced to implement appropriate strategies to adapt to increasing threats resulting from greenhouse gas forcing of the climate system, to which they contribute little

24. Sea-level rise • it is projected that sea level will rise by as much as 5 mm yr-1 over the next 100 years as a result of GHG-induced global warming. This change in sea level will have serious consequences for the social and economic development of many small island states • For some islands, the most serious consideration will be whether they will have adequate potential to adapt to sea-level rise within their own national boundaries

25. Beach and coastal changes • Most coastal changes currently experienced in the small island states are attributable to human activity. With the projected increase in sea level over the next 50–100 years superimposed on further shoreline development, however, the coastal assets of these states will be further stressed • This added stress, in turn, will increase the vulnerability of coastal environments by reducing natural resilience, while increasing the economic and social “costs” of adaptation

26. Biological systems (1) • Coral reefs, mangroves, and seagrass beds, which provide the economic foundation for many small islands, often rely on “stable” coastal environments to sustain themselves • Although it is acknowledged that human-induced stresses are contributing to their degradation, these systems will be adversely affected by rising air temperature and sea levels • In most small islands, coral reefs already are undergoing great stress from episodic warming of the sea surface, causing widespread bleaching

27. Biological systems (2) • Mangroves—which are common on low-energy, nutrient/sedimentrich coasts and embayments in the tropics—have been altered by human activities. Changes in sea levels are likely to affect landward and longshore migration of remnants of mangrove forests, which provide some protection for the coasts and backshore infrastructure • It is projected that changes in the availability of sediment supply, coupled with increases in temperature and water depth as a consequence of sea-level rise, will adversely impact the productivity and physiological functions of seagrasses • Consequently, this would have a negative downstream effect on fish populations that feed on these communities

28. Biodiversity • It is estimated that 33% of known threatened plants are island endemics, and 23% of bird species found on islands also are threatened • Although there is still some uncertainty about precisely how and to what extent biodiversity and wildlife in small islands will be affected, available projections suggest that climate change and sea-level rise will cause unfavorable shifts in biotic composition and adversely affect competition among some species

29. Water resources, agriculture, and fisheries (1) • The availability of water resources and food remain critical concerns in island communities • In many countries, water already is in short supply because islands (many of which are drought-prone) rely heavily on rainwater from small catchments or limited freshwater lenses • Arable land for crop agriculture often is in short supply; thus, the likely prospect of land loss and soil salinization as a consequence of climate change and sea-level rise will threaten the sustainability of both subsistence and commercial agriculture in these islands

30. Water resources, agriculture, and fisheries (2) • Because water resources and agriculture are so climate sensitive, it is expected that these sectors also will be adversely affected by future climate and sea-level change • Although climate change is not expected to have a significant impact on world fisheries output, it is projected to have a severe impact on the abundance and distribution of reef fish population on the islands

31. Human health, settlement and infrastructure, and tourism (1) • Human health is a major concern in many tropical islands, which currently are experiencing a high incidence of vectorand water-borne diseases • This is attributable partly to changes in temperature and rainfall, which may be linked to the ENSO phenomenon, and partly to changes in the patterns of droughts and floods • Climate extremes also place a huge burden on human welfare; this burden is likely to increase in the future • Almost all settlements, socioeconomic infrastructure, and activities such as tourism in many island states are located at or near coastal areas. Their location alone renders them highly vulnerable to future climate change and sea-level rise

32. Human health, settlement and infrastructure, and tourism (2) • Tourism is a major revenue earner and generates significant employment in many small islands. Changes in temperature and rainfall regimes, as well as loss of beaches, could be devastating for the economies that rely on this sector • Because climate change and sea-level rise are inevitable in the future, it is vital that beach and coastal assets in the small island states are managed wisely • Integrated coastal management has been identified and proposed as an effective framework for accomplishing this goal

33. Sociocultural and traditional assets • Other island assets, such as know-how and traditional skills (technologies), are under threat from climate change and sea-level rise • In some societies, community structures and assets such as important traditional sites of worship, ritual, and ceremony—particularly those at or near the coasts—could be adversely affected by future climate change and sea-level rise

34. Needs for Adaptation (1) • global assessments have consistently identified the small island states as one of the most high-risk areas, irrespective of methodology employed. This evidently robust finding must be of considerable concern to these states • It is further established that climate change is inevitable as a result of past GHG emissions and that small islands are likely to suffer disproportionately from the enhanced effects of climate change and sea-level rise • Hence, identification and implementation of effective adaptation measures and avoidance of maladaptation ( i.e., measures that increase exposure rather than decrease vulnerability) are critical for small islands, even if there is swift implementation of any global agreement to reduce future emissions

35. Needs for Adaptation (2) • For most small islands, the reality of climate change is just one of many serious challenges with which they are confronted. Such pressing socioeconomic concerns as poverty alleviation; high unemployment; and the improvement of housing, education, and health care facilities all compete for the slender resources available to these countries • In these circumstances, progress in adaptation to climate change almost certainly will require integration of appropriate risk reduction strategies with other sectoral policy initiatives in areas such as sustainable development planning, disaster prevention and management, integrated coastal management, and health care planning

36. Understanding El Niño Can Help Adaptation to Climate Change (1) • There is evidence of an association between El Niño and epidemics of vector-borne diseases such as malaria and dengue in some areas where El Niño affects the climate (Kovats et al., 1999) • Malaria transmission in unstable areas is particularly sensitive to changes in climate conditions, such as warming or heavy rainfall (Akhtar and McMichael, 1996; Gupta, 1996; Najera et al., 1998) • In Venezuela and Colombia, malaria morbidity and mortality increases in the year following the onset of El Niño (Bouma and Dye, 1997; Bouma et al., 1997b; Poveda et al., 2000)

37. Understanding El Niño Can Help Adaptation to Climate Change (2) • ENSO also has been shown to affect dengue transmission in some Pacific islands (Hales et al., 1999b), though not in Thailand (Hay et al., 2000) • However, in many of the studies that have found a relationship between El Niño and disease, the specific climate drivers or mechanisms have not been determined • There also are other climate oscillations that are less well studied • Furthermore, there are other important explanations of cyclic epidemics, such as changes in herd immunity (Hay et al., 2000)

38. Understanding El Niño Can Help Adaptation to Climate Change (3) • The ENSO phenomenon provides opportunities for early warning of extreme weather, which could improve epidemic preparedness in the future • Seasonal forecasting methods and information have the potential to be used to far greater effect by the health sector (IRI, 1999; Kovats et al., 1999) • In addition to these direct applications, attention to the impacts of interannual climate variability associated with the ENSO phenomenon would help countries develop the necessary capacity and preparedness to address longer term impacts associated with global climate change (Hales et al., 2000). On the other hand, there are limitations to using ENSO interannual climate variability to assess potential impacts of long-term climate change