The services of ecological systems and the natural capital stocks that produce them are critical to the functioning of the Earth's life-support system. They contribute to human welfare, both directly and indirectly, and therefore represent part of the total economic value of the planet. p253

• Estimated value of ecosystem services in the biosphere: US$16-54 trillion per year (average US$33 trillion per year), as a minimum estimate because of the uncertainty involved (compared to a global gross national product (GNP) total of US$18 trillion per year)

• Ecosystem services are not often adequately accounted for in policy decisions as they are not entirely captured by commercial markets or quantified

  The economies of the Earth would grind to a halt without the services of ecological life-support systems, so in one sense their total value to the economy is infinite p253

• It is vital to estimate the value of ecosystem services, despite the problems in doing so, to:

  • Make the range of potential values of ecosystem services more apparent
  • To approximate the relative magnitude of global ecosystem service value
  • To encourage their further analysis, research and debate, and highlight where research is most needed

  and since making decisions about ecosystems (cost-benefit analysis) implies valuations: we have a choice about whether to explicitly value ecosystems

• The minimum ecosystem service value would increase with:

  • Greater effort in valuing ecosystem services
  • Incorporating more realistic representations of ecosystems
  • Greater scarcity of ecosystems and ecosystem services

• Ecosystem goods/services definition: "the benefits human populations derive, directly or indirectly, from ecosystem functions" p253

  • Ecosystem functions definition: "the habitat, biological or system properties or processes of ecosystems" p253
  • Ecosystem services and ecosystem functions do not necessarily have a one-to-one relation
  • Human welfare is produced by the combination of ecosystem services (flows of material, energy and information from natural capital stocks) with human capital services
    • ⇒ natural capital is then essential to human welfare, as human capital depends on natural capital (e.g. the resources for construction of human systems)
    • Ecosystem services are vital to maintaining human welfare

Biosphere I (the Earth) is a very efficient, least-cost provider of human life-support services. p255

• Practical uses of these estimates of the value of ecosystem services:
  • Modifying pricing systems to reflect the value of ecosystem services/natural capital not currently accounted for in global price systems
  • Project appraisal processes to weigh lost ecosystem services against the benefits of a project more appropriately (as ecosystem services are often outside of markets, uncertain, ignored and undervalued)