• If estimates derived by different methods are combined, is there the potential for double counting? What steps have been taken to avoid double counting?

Uncertainty

  • What are the primary sources of scientific uncertainty affecting the valuation estimates?

    • What are the possible scenarios or outcomes?

    • Can probabilities be estimated and with what degree of confidence?

  • What methods (such as sensitivity analysis and Monte Carlo simulation) will be used to address uncertainty?

    • Can the results of the valuation exercise be used to calculate not only point estimates but also estimates of the range of values?

    • Do the value estimates capture risk aversion?

  • If benefits or values extend over time, are there important irreversibilities?

    • Is it likely that significant learning will occur?

    • Is the value of being able to respond to new information (flexibility) adequately reflected in the valuation estimates?

OVERARCHING RECOMMENDATIONS

The committee recognizes that there are policy contexts in which decisions regarding ecosystem protection, preservation, or restoration will not consider the trade-offs implied by these decisions. For example, decisions may be based on rights-based decision rules, either explicitly or implicitly, where the protection of certain rights is the primary policy goal. In such contexts, valuation of ecosystem services will not play an essential role. However, when policymakers are concerned about trade-offs, then the valuation of services provided by ecosystems can inform the policy debate and lead to improved decision-making. Based on the information provided in this report, the committee has identified a number of overarching recommendations regarding the valuation of ecosystem services in such contexts. These recommendations are based on and in some cases build upon the more specific recommendations presented in the body and summaries of the six previous chapters. Two types of overarching recommendations are included: (1) recommendations for conducting ecosystem valuation and (2) research needs, which imply recommendations regarding future research funding.



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