Valuation of Biodiversity Benefits (OECD)

cost-benefit studies. Finally, the carbon value is estimated in terms of the sequestration of carbon bythe mangrove. Overall, some two-thirds of the economic value of the mangrove comes from coastalprotection, and a further 9 per cent from carbon sequestration. Local values amount to just one quarterof the total. In terms of the local/global distinction, the estimates still omit many of the linkagesdiscussed above. Nonetheless, the estimates are illustrative of the importance of indirect use values.Table 2.4 Economic value of mangrove functions: Surat Thani, ThailandType of economic value Net return per rai, US$ As % of totalreturnsLocal use value 169 23Indirect use value:off-shore fisherycoastal protectioncarbon sequestration*1349868Total economic value 748 100Source: Sathirathai, 1998.Note: * Sathirathai uses a value of US$ 5.67 per tonne of carbon which is too low – see Annex B.We have multiplied this value by a factor of 5 here.2679Global non-use valuesFinally, we turn to global non-use values. There are very few studies which seek to elicit thecross-border willingness to pay to conserve resources. There are many more that focus on the ‘local’willingness to pay to conserve species and habitats. Kramer and Mercer (1997) sought the WTP of USresidents to conserve 5 per cent of the world’s tropical forests, and Swanson et al. (1998) estimate UKresidents WTP for the conservation of the black rhinoceros in Africa. The results were that USresidents were WTP US$ 21-31 per household for rainforest conservation via a rainforest ‘tax’ orfund. Aggregated over all US households this would be some US$ 1.9 to 2.8 billion. In the rhinoceroscase, UK residents were WTP US$ 20-24 per person (say US$ 50 per household) for rhinocerosconservation in Namibia, the lower value relating to an option which included trophy hunting (aimedat raising revenues).Pearce (1996) looks at the available WTP studies, the ‘implicit’ WTP of Westernconservationists for developing country biodiversity via debt-for-nature swaps, and the funding of theGlobal Environment facility. He concludes that ‘world’ WTP for conservation of biodiversity mightnot exceed a few billions of dollars each year.ConclusionsThis brief overview raises several questions about the economic value of biodiversity.First, it is not clear that the many willingness to pay studies of biological resources such aswetlands, forests, endangered species, etc. are also studies of biological diversity. Studies tend to focuson individual ecosystem services, a given ecosystem, or particular species. While people may bevaluing these resources because they ‘represent’ diversity, we cannot be sure.Second, we currently have only the most limited idea of the economic value of diversity as astore of genetic information for agriculture. We have a far better idea of the value of diversity for39