Climate change futures: health, ecological and economic dimensions

There are many questions concerning this cost-benefitaccounting methodology, especially the true nature ofthe benefits (for example, medicines derived from reefdwellingorganisms, which can generate billions ofdollars in revenue), and the connected costs and multipleintangibles included in the cost-benefit analyses. Inaddition, benefits can accrue over time and alter thevalue of natural assets. It is questionable if these figuresaccurately portray the full evaluation of a thresholdevent, such as the collapse of reefs worldwide.SOCIO-ECONOMICS OF THE 1997-98CORAL REEF BLEACHING EPISODEIN THE INDIAN OCEANIn the short term, the most dramatic socio-economicimpacts from the 1997-98 mass bleaching event wereestimated losses to reef-dependent tourism. These losseswere developed for the diving destinations atPalau, El Nido, Palawan, the Philippines and othersites in the Indian Ocean region.Table 2.5 Losses from 1997-98 Bleaching (US $Millions)Country Total LossesZanzibar 7.4Mombasa 35.1Maldivas 22.0Sri Lanka 2.2Philippines 29.6Palau 0.4Source: Westmacott et al. 2000The manifestation of the losses shown in the tableabove is multidimensional and includes: a) impacts ontourist destination choice, which results in lost visitationand therefore a total loss of tourism revenue; b)impacts on choice of activities pursued, which maycause reduced coral reef-related revenue; and c)reductions in tourist satisfaction with the diving experienceas a result of degraded reef conditions.The implication is that impacts of coral bleaching ontourism depend upon whether diving destinations canmaintain their status and reputation, even in the face ofreef degradation, through promotion of other underwaterattractions. Impacts upon the diving industry mightbe reduced by diverting diver attention to other interests,such as shipwrecks or even the documentation ofcoral bleaching per se. However, such tactics may berisky and non-sustaining. For example, resorts in ElNido shifted market segments away from divers tohoneymooners in response to reef degradation, resultingin a significant loss of US $1.5 million annually.Studies undertaken in the Indian Ocean region inresponse to the 1997-98 bleaching event provide empiricaldocumentation and estimates of the impact of a singlecatastrophic episode of coral reef bleaching. Theupper end of the cost estimate is US $8 billion, dependingon the ability of the reefs to ultimately recover.THE FUTURECCF-I: ESCALATING IMPACTSGlobal warming, with inadequate winter cooling, willcontinue to heat sea surfaces, especially across the tropics.The full impact of such temperature increases on thevitality of coral reef ecosystems will depend upon thenature of other human-induced changes and the cumulativestresses placed upon reef ecosystems. Overall, theprojected warm seasonal disruption of symbiosis in reefbuildingcorals will reduce the growth in mass of theinorganic reef frame.With weakened frames, the susceptibility of coral reefsto physical damage during storms increases, while thecapacity for self-repair diminishes. Thermal stress andbleaching also disrupts food production and energeticswithin reef-building corals, retarding the generation ofmature gametes for sexual reproduction and reducingthe coral’s abilities to resist predation. With time, reefsbecome fragile and less able to protect shores againststorm surges.Global warming, meanwhile, would stimulate proliferation,colonization, random mutation and host invasion ofmarine microbes. The coral’s already compromiseddefenses against predation would be further challengedby an invigorated assortment of micro-predators with limitlessstrategies for penetrating coral tissues.81 | NATURAL AND MANAGED SYSTEMSCASE STUDIES