Climate change futures: health, ecological and economic dimensions

82 | NATURAL AND MANAGED SYSTEMSCASE STUDIESIMPACT ON FISHERIESPopulation reductions have been predicted for speciesthat inhabit reefs for at least part of their life cycle orthat prey on smaller reef fish. Changes in fish abundancewould vary by species, shifting the net compositionof reef fish populations toward herbivores. Such ashift would negatively impact fishermen, as herbivoresare lower in value than other species. When bleachingis superimposed on reefs that are already overfished,reductions in overall reef fish populations wouldnot be expected, since herbivores would have dominatedthe fishery prior to the bleaching event. Impactsoccurring at small spatial or temporal scales would bemasked by fishermen changing their fishing habits andpatterns. The impacts upon fisheries may become morepronounced once the structural frame of bleachedreefs is eroded.CCF-II: SURPRISE IMPACTSWith nearly 60% of the world’s reefs threatened bybleaching, pollution and disease, it is plausible to projecta collapse of coral reefs in the next severaldecades. Just 1°C additional warming of sea surfacetemperatures could bleach the entire ring of coralreefs.Costing the loss of Earth’s oldest habitat makes littlesense. The economic valuation of about US $800 billionfor the world’s reefs may vastly underestimate theirirreplaceable role. The economic and social value ofassuring the survival of coral reefs and the ecosystemsassociated with them (that is, seagrasses, mangroves,beach and upland communities) is not possible toquantify.Potential economic impacts following the collapse ofcoral reef ecosystems are of great concern. Recoveryof damages to tourist-related structures (including shorelinehotels, losses of homes, roads and bridges) wouldrequire major financial support. Economic resourceswould be necessary to repair storm-damaged properties(homes, buildings, piers, boats), to meet elevatedlocal health care costs stemming from environmental illnesses,and also to compensate unemployed localworkers. The loss of reefs as tourist attractions and theloss of reef protection against storm surge, togetherwith sea level rise, will create socio-economic catastrophesin low-lying islands and coastlines.Tourism in the Caribbean generates over US $16 billionannually. The combination of sea level rise, coralreef destruction, more intense storms, more powerfulstorm surges, and more epidemics of vector-borne diseases(such as dengue fever) collectively pose substantialrisks for tourism, travel and allied industries.Disruption of low-lying coastal areas and island lifefrom the combination of saltwater intrusion intoaquifers, the loss of barrier and fringing reefs, andmore intense tropical storms could displace manyisland and low-lying nation populations, resulting inheightened political and economic pressures on othernations. The generation of large numbers of environmentalrefugees and internally displaced persons maypresent the greatest short-term costs to internationalsecurity and stability.SPECIFIC RECOMMENDATIONSThe full impacts of global warming may be delayedby reducing the direct anthropogenic threats to coralsurvival. Direct contact between tourists and coral,boat and anchor damage, release of debris andchemical pollutants around reefs, and unsustainableharvesting activities for recreation and commerce aredetrimental to reef resilience. Marine Protected Areasprovide the framework for preserving these vital areas.Implementation of conservation measures must be comprehensivein order to have a substantial and lastingeffect. The measures include:• Treatment of domestic sewage to tertiary breakdownlevels before release into far-offshore marine environments.• Reduced use of fertilizers and pesticides in nearshorecoastal communities.• Implementing fishing quotas, establishing ‘no-go’zones and seasons, and designating temporary noharvestingzones, to allow for replenishment andprotection of shellfish and finfish stocks.• Preserve contiguous areas of the interconnectedupland forest and watershed systems, coastal wetlands,mangrove stands and spawning lagoons.• Adhering to regulations regarding Marine ProtectedAreas and restricted access zones along coastalareas.• Banning and monitoring compliance for destructivefishing practices, for example, dynamite andcyanide used for fishing, and removal of reefs forconstruction.