Ecosystem Services: Response

C. Obst 'et al'. provide a welcome opportunity to clarify the difference between environmental-economic cost-benefit analyses (such as ours) and environmental accounting exercises [such as the UN-SEEA initiative]. Accounting studies attempt to assess the total value of goods related to ecosystem services in a manner comparable to that used for market-priced goods in national accounts. A decline in the ecosystem services account over time signals a potential need to invest in underlying natural capital. However, such accounts do not indicate the most cost-effective form of that investment. Environmental economic analyses such as ours typically consider changes in value from the status quo that alternative investments provide, and identify those that yield higher value for money. The two approaches are complements rather than substitutes and serve differing but highly compatible elements of the decision-making process.