Turner et al. (1995) assert that relationships between the physical impacts of climate change and socioeconomic implications in the coastal zone have not been fully encompassed in recent work. This statement remains valid to date. Some attempts have been made to express the value of coastal features that are normally regarded as nonmarket goods (Costanza et al., 1997; Alexander et al., 1998). Several assessments of mangrove and reef ecosystems have highlighted their economic value on the basis of ecosystem goods and services, as well as natural capital value (e.g., Moberg and Folke, 1999).
Estimates of the monetary value of wetlands and information about attitudes toward wetland conservation can be used in policy decisions (e.g., Söderqvist, 2000). "Use" and "non-use" values may be determined (Stein et al., 2000). For example, Rönnbäck (1999) suggests that mangrove systems alone account for US$800-16,000 ha-1 in seafood production. Streever et al. (1998) sought public attitudes and values for wetland conservation in New South Wales, Australia, and found that a conservative estimate of the aggregate value of these wetlands, based on willingness-to-pay criteria, was US$30 million yr-1 for the next 5 years. They also refer to an earlier study on the value of marketable fish in mangrove habitats of Moreton Bay, Queensland, estimated at more than US$6,000 ha-1 yr-1 (Marton, 1990). Stein et al. (2000) have developed a framework for crediting and debiting wetland values that they suggest provides an ecologically effective and economically efficient means to fulfill compensatory mitigation requirements for impacts to aquatic resources.
Climate change impacts on natural systems can have profound effects on socioeconomic systems (Harvey et al., 1999). One example cited by Wilkinson et al. (1999) is the 1998 coral bleaching event in the Indian Ocean. This event was unprecedented in severity; mortality rates reached as high as 90% in many shallow reefs, such as in the Maldives and the Seychelles. Such severe impacts are expected to have long-term socioeconomic consequences as a result of changed fish species mix and decreased fish stocks and negative effects on tourism as a result of degraded reefs. Degradation of reefs also will lead to diminished natural protection of coastal infrastructure against high waves and storm surges on low-lying atolls. Wilkinson et al. (1999) estimate the costs of the 1998 bleaching event to be between US$706 million (optimistic) and US$8,190 million (pessimistic) over the next 20 years. The Maldives and the Seychelles are identified as particularly affected, because of their heavy reliance on tourism and fishery.
Some economic impacts of marine diseases and harmful algal blooms influenced by climate variations have been evaluated since the SAR. An outbreak in 1997 of the toxic dinoflagellate Pfiesteria piscida, which has been associated with increased nutrients and SSTs, caused large fish kills on the U.S. Atlantic coast that resulted in public avoidance and economic losses estimated at US$60 million (CHGE, 1999). A persistent brown tide bloom in the Peconic Estuary system of New York blocked light and depleted oxygen in the water column, severely affecting seagrass beds and reducing the value of the Peconic Bay scallop fishery by approximately 80% (CHGE, 1999). Harmful algal blooms associated with increased SST and the influx of nutrients into an estuary can result in economic harm through shellfish closures, impacts on tourism, reduction of estuarine primary productivity, deterioration of fishery habitat (e.g., seagrass beds), and mortality of fish and shellfish.
In some coastal societies, the significance of cultural values is equal to or even greater than that of economic values. Thus, some methodologies have been developed that include traditional social characteristics, traditional knowledge, subsistence economy, close ties of people to customary land tenure, and the fact that these factors are intrinsic components of the coastal zone (e.g., Kay and Hay, 1993). As such, they must be taken into account in certain contexts, including many South Pacific island countries (e.g., Yamada et al., 1995; Solomon and Forbes, 1999) and indigenous communities in northern high latitudes (e.g., Peters, 1999), among other examples.
Patterns of human development and social organization in a community are important determinants of the vulnerability of people and social institutions to sea-level rise and other coastal hazards. This observation does not mean that all people in a community share equal vulnerability; pre-event social factors determine how certain categories of people will be affected (Heinz Center, 1999). Poverty is directly correlated with the incidence of disease outbreaks (CHGE, 1999) and the vulnerability of coastal residents to coastal hazards (Heinz Center, 1999).
Examples of inequitable vulnerability to coastal hazards include population shifts in Pacific island nations such as Tonga and Kiribati. In Tonga, people moving from outer islands to the main island of Tongatapu were forced to settle in low-lying areas, including the old dumping site, where they were proportionally more vulnerable to flooding and disease (Fifita et al., 1992). Storm-surge flooding in Bangladesh has caused very high mortality in the coastal population (e.g., at least 225,000 in November 1970 and 138,000 in April 1991), with the highest mortality among the old and weak (Burton et al., 1993). Land that is subject to floodingat least 15% of the Bangladesh land areais disproportionately occupied by people living a marginal existence with few options or resources for adaptation.
El-Raey et al. (1997, 1999) studied the effects of a 0.5-m sea-level rise on the Nile delta. In addition to economic costs from loss of agricultural land and date palms, they identify social and cultural impacts. Under a no-protection policy, El-Raey et al. (1997) predict that the population would suffer from the loss of residential shelter (32% of urban areas flooded) and employment (33.7% of jobs lost). In addition, a substantial number of monuments and historic sites would be lost (52%).
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