Economic valuation of goods and services

Gas and climate regulation

Gas and climate regulation by photosynthetic fixation of carbon dioxide is of particular socio-economic importance because of climate change. The Isles of Scilly were used as a case study to value this service. Net annual carbon photosynthetic fixation values were estimated by mapping habitats of keystone species of kelp and seagrass. Their productivity (O₂ fixation) was estimated using literature data as well as remote sensing methods. The economic value of this service was then estimated. An adjacent Atlantic Ocean comparison site was used to indicate the relative importance of island biodiversity to this marine service. The Isles of Scilly were approximately twice as productive as the Atlantic Ocean region, fixing 136,495 ton C per year with a mean net present value of €59.109.529, while that of the Atlantic Ocean region was calculated to be €28.641.727.

Disturbance prevention

The role of coastal wetlands as buffer zones against waves and storms has been quantified and valued using two sets of methods: a) a contingent valuation method (CVM) using coastal householders’ willingness to pay to conserve salt marshes and mudflats, and b) a preventative cost method focusing on the savings made in sea defence construction.

As well as obtaining an economic value for the sea-defence role of wetlands, the CVM survey provided indications of coastal householders’ preferences on sea-defence provision.