Estimating the Value of Ecosystem Services Brook Milligan - - PowerPoint PPT Presentation

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 hectare1

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

11 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 × 1012

range: $16–54 × 1012

Most of current value outside of markets

values difficult to estimate

Global GNP: $18 × 1012

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