PACIFIC IN PERIL: BIOLOGICAL, ECONOMIC AND SOCIAL IMPACTS OF CLIMATE CHANGE ON PACIFIC CORAL REEFS FIGURE 9I: TRADE AND TOURISM INDICATORS CONCLUDED Chart 52 | <strong>Pacific</strong> <strong>in</strong> <strong>Peril</strong> Chart Chart Chart
IMPACTS OF CLIMATE CHANGE ON PACIFIC COASTAL ECONOMIES INTRODUCTION Although differences between the <strong>Pacific</strong> islands are enormous, the majority of constituent populations have low <strong>in</strong>comes and their dependence on fisheries for <strong>in</strong>come and animal prote<strong>in</strong> <strong>in</strong>take is high. Frequent episodes of coral bleach<strong>in</strong>g and subsequent coral mortality due to climate change are likely to have serious socioeconomic impacts on Pacifc islands. In areas where overfish<strong>in</strong>g and overexploitation of mar<strong>in</strong>e resources are already threats, coral bleach<strong>in</strong>g could worsen these problems. Also, some fish that are available may become toxic as levels of ciguatera poison<strong>in</strong>g are likely to <strong>in</strong>crease due to coral mortality and subsequent algal growth (Hales et al, 1999). In other areas, div<strong>in</strong>g and other coastal tourism are the ma<strong>in</strong> <strong>in</strong>come-generat<strong>in</strong>g activities. In Palau, for example, a large portion of GNP stems directly and <strong>in</strong>directly from tourism revenues. Furthermore, the land area around the Indo- <strong>Pacific</strong> Ocean is prone to seasonal cyclones and coral reefs form natural barriers to protect coastl<strong>in</strong>es from erosion. Examples from other regions highlight the threat. In Sri Lanka, <strong>in</strong> the Indian Ocean, severe coastl<strong>in</strong>e erosion has already occurred <strong>in</strong> areas where the reef substrate has been heavily m<strong>in</strong>ed. Countermeasures to prevent further erosion have already cost the Sri Lankan government around $US 30 million (Berg et al, 1998). In time, coral mortality may lead to bio-erosion that could similarly deteriorate the reef substrate of <strong>Pacific</strong> reefs. Current knowledge of the biophysical and ecological processes and consequences of coral bleach<strong>in</strong>g is such that we are unable to fully ref<strong>in</strong>e some key issues <strong>in</strong>to an accurate and high-resolution understand<strong>in</strong>g of the impact of climate-<strong>in</strong>duced changes <strong>in</strong> coral reefs on human societies and welfare. It cont<strong>in</strong>ues to be very difficult to translate <strong>in</strong>creases <strong>in</strong> sea surface temperature to long-term socioeconomic impacts. With<strong>in</strong> this caveat, however, we will present such estimates for tourism, fisheries and other socioeconomic services of coral reefs and develop two edges of a “w<strong>in</strong>dow” <strong>in</strong>to the future. UNCERTAINTY AND THE FUTURE The uncerta<strong>in</strong>ty surround<strong>in</strong>g many of the relationships between coral bleach<strong>in</strong>g and mortality, on the one hand, and ecosystem services, on the other, is enormous. Besides, the recovery rate of reef areas after widespread mortality is difficult to predict and depends crucially on the frequency of bleach<strong>in</strong>g episodes and other concomitant <strong>in</strong>fluences (see discussion <strong>in</strong> section 1). Therefore, it is very difficult to draw any def<strong>in</strong>ite conclusions from current studies of coral reefs <strong>in</strong> the Indo-<strong>Pacific</strong> Ocean. Nevertheless, it is vital that we build the best possible w<strong>in</strong>dow of likelihoods to more effectively address the issues that future developments will deliver. In l<strong>in</strong>e with this and to structure th<strong>in</strong>k<strong>in</strong>g about possible future outcomes, the follow<strong>in</strong>g two reef-based scenarios are worked out for the year 2020: * Scenario 1 (A BLEAK PROSPECT): major reef damage with consequential damage to fisheries and other reef services; * Scenario 2 (LESS DRASTIC CHANGE): mild reef damage and milder impacts on fishery and tourism. With<strong>in</strong> these, we will focus on the socioeconomic impacts and potential government and bus<strong>in</strong>ess responses. Due to the different factors that affect islands with<strong>in</strong> the south <strong>Pacific</strong>, we have def<strong>in</strong>ed two broad groups of islands, which fall approximately <strong>in</strong>to the regional group<strong>in</strong>gs of Melanesia and Polynesia/Micronesia. Note: These scenarios imply that government response will play a key role <strong>in</strong> a positive outcome. This may be true at some level of human welfare ma<strong>in</strong>tenance but if, for example, 90 per cent of reefs are erased <strong>in</strong> an island state, it may not be conceivable that any government <strong>in</strong>terjection will alter the local outcome (other than reduc<strong>in</strong>g the population or relocat<strong>in</strong>g communities and resources). These scenarios can be compared to the two scenarios postulated <strong>in</strong> Wilk<strong>in</strong>son et al (1999). They describe a pessimistic scenario <strong>in</strong> l<strong>in</strong>e with Scenario 1 and an optimistic scenario roughly correspond<strong>in</strong>g to Scenario 2 of this study. In the next section, the atmospheric, biological and economic variables are placed with<strong>in</strong> the context of potential impacts of climate change. In this case, three broad categories of impact are considered: Damage to fisheries, impacts on tourism and <strong>in</strong>creased coastal erosion. DAMAGE TO FISHERIES The long-term impacts of mass coral bleach<strong>in</strong>g and associated mortality on fishery yields are very uncerta<strong>in</strong>. A recent study <strong>in</strong> Kenya by the Coral Reef Conservation Project (CRCP) has assessed the short-term impact of coral bleach<strong>in</strong>g on abundance and composition of the reef fish community structure, together with biomass and composition of <strong>in</strong>dividual fish catches (McClalahan and Pet-Soede, 2000). Data were collected <strong>in</strong>side and outside mar<strong>in</strong>e-protected areas. The pre-bleach<strong>in</strong>g study was completed <strong>in</strong> late 1997, some four months before bleach<strong>in</strong>g started <strong>in</strong> Kenya. The study was repeated 10 months after the coral bleach<strong>in</strong>g, <strong>in</strong> early 1999. Underwater visual census (UVC) data show no clear changes <strong>in</strong> fish community structure that can be solely attributed to the bleach<strong>in</strong>g and mortality (see Table 1). An exception is the <strong>in</strong>crease <strong>in</strong> abundance of acanthurids (surgeonfish). McClalahan and Pet-Soede (op cit) suggest that this <strong>in</strong>crease may be related to coral mortality, as acanthurids are grazers feed<strong>in</strong>g on dead coral surface. The data do show significant effects of management (mar<strong>in</strong>e park versus exploited reefs) on fish abundance (see also McClalahan and Arthur <strong>in</strong> press). Overall catches have decreased significantly over the period 1995 to 1999, possibly as a result of overall environmental degradation. This could imply that the effect of the recent bleach<strong>in</strong>g and coral mortality will become more evident only once the reefs have further eroded (McClalahan and Pet-Soede, op cit). 53 | <strong>Pacific</strong> <strong>in</strong> <strong>Peril</strong>
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