Estimating the Value of Ecosystem Services Brook Milligan Department of Biology New Mexico State University Las Cruces, New Mexico 88003 brook@nmsu.edu Fall 2009 Brook Milligan Estimating the Value of Ecosystem Services
How Valuable are Ecosystem Services? Biodiversity contributes to ecosystem services One component of the value of biodiversity is through its contribution to ecosystem services What type of value is that offered by ecosystem services? If a goal of conservation biologists is to quantify the value of biodiversity, it is important to quantify the value of ecosystem services Brook Milligan Estimating the Value of Ecosystem Services
Ecosystem Services and Functions Brook Milligan Estimating the Value of Ecosystem Services
General Approach to Quantifying the Value of Ecosystem Identify a set of relevant ecosystem services Division of world into ecosystem types total land area per ecosystem type Valuation of each service in each ecosystem type per hectare 1 unit value of service Total value of service per ecosystem type = land area of ecosystem type × unit value of service Total value of service = sum of total value of service per ecosystem type Total value = sum of total value of each service 1 1 hectare = 100 m × 100 m = 2.471 acre Brook Milligan Estimating the Value of Ecosystem Services
Average Global Value of Annual Ecosystem Services Brook Milligan Estimating the Value of Ecosystem Services
Estimated Global Value of Annual Ecosystem Services Total value: $33 . 268 × 10 12 range: $16–54 × 10 12 Most of current value outside of markets values difficult to estimate Global GNP: $18 × 10 12 1/1.8 × ecosystem service value Brook Milligan Estimating the Value of Ecosystem Services
Geographic Distribution of Value of Annual Ecosystem Services Brook Milligan Estimating the Value of Ecosystem Services
Difficulties Assessment of supply-demand curve Identification of market value for non-marketed or partially marketed goods Market prices based on ill-informed participants and an unsustainable economy Extrapolation from small-scale estimates to global properties may not scale correctly Intra-currency comparisons based on relative GNP may be inaccurate Brook Milligan Estimating the Value of Ecosystem Services
Supply and Demand Curves Brook Milligan Estimating the Value of Ecosystem Services
Implications Mere replacement of freely obtained ecosystem services requires tripling the world GNP! Yet no net gain in standard of living! Modify system of national accounting to reflect value of ecosystem services and natural capital Such accounting shows a different picture of economy than GNP Leveling of global welfare since 1970, although GNP continues to rise Project appraisal: how does value of ecosystem services lost compare with value of a project Brook Milligan Estimating the Value of Ecosystem Services
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