Traditionally, the emphasis has been on engineering responses to coastal erosion and protection against flooding, with action often being triggered in response to an extreme event. Now the range of options has expanded to include nonstructural adaptation consisting primarily of zoning, building codes, land-use regulation, and flood-damage insurance, with more emphasis on a precautionary approach. Two different approaches to adaptation to anticipated climate change are discussed in Box 9-4. IPCC CZMS (1990) has identified the environmental, economic, cultural, legal, and institutional implications of the three response strategies. Vulnerability assessments have since made clear that the extreme options of retreat and full protection highlight the negative effects and overestimate the potential costs and losses from climate change and sea-level rise. Yet adaptation options in low-lying island states (e.g., the Marshall Islands, the Maldives) and for nations with large deltaic areas

(e.g., Bangladesh, Nigeria, Egypt, China), which have been identified as especially vulnerable, are problematic because the options have not been fully evaluated but appear limited and potentially very costly. Even without climate change and associated sea-level rise, these nations will continue to experience rapidly increasing vulnerability to natural coastal hazards due to high rates of population growth, increased demands, continued unsustainable exploitation of resources in the coastal zone, and development in upstream catchment areas. Continued natural and possible anthropogenic subsidence (relative sea-level rise) of large river deltas will increase the risk from storm surges. Strategies must be devised to reduce the economic damages and social hazards well before climate change and associated sea-level rise become a significant factor (Han et al., 1995b; Boesch et al., 1994). For these situations, conventional adaptation options will have to be enacted as a first step. while innovative or radical solutions-for example, controlled

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flooding and sedimentation to harness the natural capability of a delta to respond to sea-level rise-are examined for their effectiveness, environmental impact, social acceptability, and economic efficiency.

Heavily populated areas are primary candidates for structural protection measures such as dikes, sea walls, breakwaters, and beach groins. Because these are expensive options, the use of economic evaluation principles-especially risk assessment and benefit-cost analysis can provide useful tools in deciding whether to protect or retreat, as well as where such infrastructure investments ought to be placed in order to maximize national or regional social and economic welfare (Carter et al., 1994).

Some of the more detailed recent studies of response strategies to sea-level rise have been accomplished for coastal urban areas. In all instances, the problems of sea-level rise are considered to be serious. Many examples can be found in Frassetto (1991) and Nicholls and Leatherman (1995a), including Venice, Hamburg, London, Osaka, St. Petersburg, Shanghai, Hong Kong, Lagos, Alexandria, Recife, and Tianjin. However, Devine (1992) has argued that the shantytown areas found in many coastal cities may be particularly vulnerable to climate change, and adaptation options are uncertain. Chapter 12 further discusses impacts of and adaptation options to climate change in human settlements, including coastal cities.

Kitajima et al. (1993) have undertaken a comprehensive analysis of the range of likely structural measures that would be required to respond to a 1-m sea-level rise at 1,100 Japanese ports, harbors, and neighboring areas, as well as their estimated costs. The cumulative undiscounted costs have been estimated at $92 billion. Of that sum, about $63 billion is for raising port facilities and $29 billion is for adjoining shore protection structures (e.g., breakwaters, jetties, embankments). This cost estimate covers about 25% of Japan's coastline; other residential areas would also have to be protected, if that were the most costeffective option. Further costs would be incurred to maintain existing standards of protection for populated areas as sea level rises (Mimura et al., 1994). For a rise of 1 m, total costs would exceed $150 million. Further, natural shores could be largely lost from Japan's coast. It should be noted that, on an average annual basis, the costs constitute a small fraction of the GNP.

Adaptation can exploit the fact that coastal infrastructure is not static. There is a turnover of many coastal facilities through major rehabilitation, construction, and technological changes in ports, harbors, and urbanized areas, averaging roughly 25-30 years. Therefore, there will be recurring opportunities to adapt to sea-level rise, especially if the rate is relatively slow and construction and maintenance plans can be taken into account in land-use planning, management, and engineering design criteria (Stakhiv et al., 1991; Yim, 1995). Moreover, experience with allowances for accelerated sea-level rise is limited but growing (e.g., Nicholls and Leatherman, 1995b). The interaction of different aspects of climate change should be considered. For instance, given the likelihood of both sealevel rise and a decrease in the return period of intense rainfall

Coastal Zones and Small Islands

events (see Section 9.3), more consideration of future drainage capacity requirements in low-lying coastal areas may be prudent (Titus et al., 1987; Nicholls et al., 1995).

Some structural examples of proactive adaptation include:

In the early 1990s, design standards for new seawalls in The Netherlands and eastern England were raised 66 cm and 25 cm, respectively, to allow for accelerated sea-level rise. This has been in response to the IPCC90 best estimate for future sea-level rise; the different magnitudes reflect a 100-year and 50-year planning horizon, respectively.

The Massachusetts Water Resources Authority has included an additional 46 cm of height in the Deer Island sewage treatment plant. This is a safety factor to maintain gravity-based flows under higher sea levels without the additional costs of pumping.

• In Hong Kong, the West Kowloon reclamation is being built 80 cm above earlier design levels to allow for sea-level rise and/or unanticipated subsidence (Yim, 1995). In this case, costs have increased by less than 1%; future reclamations are expected to be similarly raised, and existing reclamations may be raised as part of the redevelopment cycle.

Enlarged setbacks to allow for expected shoreline recession, most notably in some states in Australia (Caton and Eliot, 1993), would enable planned retreat to accommodate climate change impacts. A variant on fixed setbacks is presumed mobility-whereby coastal residents are allowed to live at the shore but give up their right to protect the shore if it retreats in response to climate change or other causes (Titus, 1991). To counter the coastal squeeze of wetlands and maintain their habitat and floodbuffering functions, managed retreat on estuarine shorelines is increasingly favored in the United Kingdom (Burd, 1995). This involves setting back the line of actively maintained defense to a new line inland of the original and promoting the creation of intertidal habitat on the land between the old and new defenses.

To date, the assessment of possible response strategies has focused mainly on protection. There is a need to better identify the full range of options within the adaptive response strategies: protect, accommodate, and retreat. Identifying the most appropriate options and their relative costs and implementing these options while taking into account contemporary conditions as well as future problems such as climate change and sea-level rise will be a great challenge in both developing and industrialized countries. The range of options will vary among and within countries, and different socioeconomic sectors may prefer competing adaptation options for the same areas. Experience shows that intersectoral conflicts are a major barrier to improved coastal management (WCC'93, 1994). In the present context, they could also be a major barrier to adaptation to climate change. An appropriate mechanism for coastal

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The applicability of any option must be evaluated against (among other things) a background of a country's technology and human resources capability, financial resources, cultural and social acceptability, and the political and legal framework. This is not to suggest that these constraints are insurmountable but that decisionmakers must be realistic when considering the range of options available to them.

9.6.3.1. Technology and Human Resources Capability

For many countries, scarcity of (or lack of access to) appropriate technology and trained personnel will impose limits on the adaptation options realistically available. For example, the design, implementation, and maintenance of "state-of-the-art" civil works may be beyond the immediate reach of many developing nations unless there is technical assistance to provide the required technology and human skills. This is highlighted in vulnerability assessments for a number of countries, such as Tonga (Fifita et al., 1994), Bangladesh (Khan et al., 1994), and Belize (Pernetta and Elder, 1993).

Specifically in the case of protection and accommodation, there will be a need for ongoing maintenance and periodic replacement and upgrade. These activities will also require access to the relevant technology and skills to remain effective.

9.6.3.2. Financial Limitations

The implementation of any adaptation option-whether retreat, accommodate, or protect-will necessitate certain financial commitments from governments, although the level of required funding may vary widely from one option to another. In the case of planned retreat, substantial infrastructure would have to be rebuilt and settlements relocated to less vulnerable areas, at high reinvestment costs. Adjustment strategies might entail acceptance of less-than-ideal circumstances, while simultaneously increasing the costs of reducing flood risks. Protection strategies almost always involve "hard" engineering structures, which are costly both to construct and to maintain. In the Maldives, for example, the present costs of shoreline protection are close to $13,000 per m; in Senegal, Benin, Antigua, Egypt, Guyana, the Marshall Islands, St. KittsNevis, and Uruguay, maintenance of the existing shoreline against a 1-m rise in sea level could require substantial funding compared with the nation's GNP (Nicholls, 1995). However, it should be noted that national responses to climate change will more likely comprise a variable combination of planned retreat, accommodation, and protection; hence, lower-cost responses probably are available in some areas (e.g., Turner er al., 1995a; Volonté and Nicholls, 1995).

Clearly, any combination of response strategies will be largely influenced by monetary considerations, necessitating both short-term investment and a commitment to longer-term maintenance and replacement costs. Many developing countries will find it especially difficult to meet such costs and will

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increasingly have to turn to donor countries and international agencies for assistance. In Kiribati, for instance, it has been demonstrated that implementation of protection measures especially will almost certainly require external assistance (Abete, 1993). Lack of adequate financial resources will also circumscribe a country's capacity to "purchase" appropriate technology and human skills required for the implementation of various options. Countries should therefore consider designing efficient, least-cost response plans, based on some realistic assessment of what their economies will be able to sustain (WCC'93, 1994).

Although certain options may be technically and financially possible in a given set of circumstances, they may, at the same time, be culturally and socially disruptive. In some societies, resettlement, for example, would lead to dislocation of social and cultural groups and might even involve the loss of cultural norms and values and the assimilation of new ones. Additionally, an option involving planned retreat could mean the loss of access to communally owned resources and land entitlements, which might undermine the entire economic, social, and cultural base of some communities. Other adaptive measures, such as the construction of "hard" engineering structures, could cause the partial or total elimination of access to traditional fishing, hunting, and culturally important sites.

The extent to which a given response strategy can be successfully employed may well be influenced by political and legal considerations (Freestone and Pethick, 1990). Retreat options, for example, might prove infeasible given the policy and legal structures of the "receiving" area. Where international resettlement is indicated, these issues can become even more complex-as demonstrated by the plight of refugees worldwide. Further, some options will be incompatible with existing systems of land tenure and ownership and in some societies would necessitate a fundamental change in arrangements prior to implementation to avoid violating certain rights. Failing this, governments could be called upon to provide substantial compensation to communities for loss of property and resource-use rights.

Coastal Zones and Small Islands

together coastal experts and policymakers to identify actions that can be taken to strengthen capabilities for progressive sustainable development and integrated coastal zone management. The conference participants acknowledged that there is an urgent need for coastal states to strengthen their capabilities, in particular with regard to the exchange of information, education and training; the development of concepts and tools; research, monitoring, and evaluation; and funding (WCC'93, 1993). The following are examples of measures that could improve capabilities for developing, implementing, and strengthening national programs for ICZM (WCC'93, 1993):

Multidisciplinary studies and assessments to determine the potential importance of the coastal zone and its vulnerabilities, particularly those that limit its ability to achieve sustainable development

An institutional body or mechanism to investigate the need and potential benefits and costs of developing an ICZM program

A long-term and effective body or mechanism to prepare, recommend, and coordinate the implementation of a permanent ICZM program

A continuing monitoring and assessment program to collect data, assess results, and identify the need for change or improvement

An ongoing research program, including an investigation of the potential effects of global climate change, to improve the analytical foundation for the decisionmaking process

Although much has been achieved since the IPCC First Assessment in 1990, this chapter shows that the understanding of the likely consequences of climate change and sealevel rise is still imperfect. This situation can be improved only through a sustained research and monitoring effort, requiring a major commitment of resources at the national, regional, and global levels. The potential problems of small islands, deltas, coastal wetlands, and developed sandy coasts deserve particular attention as part of these efforts. Coastal zones and small islands illustrate the fundamental need for better coupling of research and models from the natural sciences and the social sciences to provide improved analytical capability and information to decisionmakers. An emphasis on understanding the impacts of climate change at the local and regional scales is essential.

Active support for local initiatives, exchange of | practical and indigenous experiences, and enhancement of public participation

Education, training, and public-awareness efforts to increase the constituency for ICZM

Coordination of financial support for relevant activities and investigation of innovative sources for additional support.

Effective ICZM can be achieved by coordination among national, regional, and international organizations and institutions. This will help to avoid unnecessary duplication and develop the concepts, tools, and networks needed to facilitate the development and implementation of national programs, which is a complex process that can be accelerated and enhanced through international cooperation. Regional approaches can complement and strengthen activities at the national and international levels.

Various international initiatives have been undertaken to encourage and facilitate coordination and cooperation in both policy and research. Several United Nations organizations and other international governmental and nongovernmental organizations have developed programs aimed at strengthening ICZM capabilities at different levels. An overview of these activities is presented in WCC'93 (1994). In 1993, the IGBP

research and monitoring, as initiated by IPCC CZMS (1990, 1992), that should be continued over the next few years to enable better decisionmaking concerning the possible impacts of climate change in coastal zones and small islands:

Development of improved biogeophysical classifications and frameworks of coastal types for climatechange analysis, including the influence of human activities (IGBP-LOICZ has taken an important step in this direction)

Investigations of geomorphological and biological responses of coastal types and critical ecosystems to climate change and sea-level rise, with specific attention to the response of seagrass to climate change as well as potential changes in sediment budgets Improved methodologies for incorporating existing. high-quality historical and geological coastal-change data into response models for climate change Improved coastal-processes data (especially in developing countries), based on instrumentation (tide gauges, current meters, wave recorders, etc.), as well as improved capacity to interpret and analyze the data Improved databases for vulnerability assessment and adaptation planning on coastal socioeconomic trends, such as population changes and resource utilization and valuation, taking into consideration differences in sociocultural characteristics of countries