Department of Business Management, Public University of Navarra, Spain.
Sci Total Environ. 2011 Mar 1;409(7):1305-14. doi: 10.1016/j.scitotenv.2010.12.004. Epub 2011 Jan 16.
Cost-benefit analysis is a standard methodological platform for public investment evaluation. In high environmental impact projects, with a long-term effect on future generations, the choice of discount rate and time horizon is of particular relevance, because it can lead to very different profitability assessments. This paper describes some recent approaches to environmental discounting and applies them, together with a number of classical procedures, to the economic evaluation of a plant for the desalination of irrigation return water from intensive farming, aimed at halting the degradation of an area of great ecological value, the Mar Menor, in South Eastern Spain. A Monte Carlo procedure is used in four CBA approaches and three time horizons to carry out a probabilistic sensitivity analysis designed to integrate the views of an international panel of experts in environmental discounting with the uncertainty affecting the market price of the project's main output, i.e., irrigation water for a water-deprived area. The results show which discounting scenarios most accurately estimate the socio-environmental profitability of the project while also considering the risk associated with these two key parameters. The analysis also provides some methodological findings regarding ways of assessing financial and environmental profitability in decisions concerning public investment in the environment.
成本效益分析是公共投资评估的标准方法平台。在对后代有长期影响的高环境影响项目中，贴现率和时间范围的选择特别重要，因为它可能导致非常不同的盈利性评估。本文描述了一些环境贴现的最新方法，并将其与一些经典方法一起应用于对一个用于淡化集约化农业灌溉回流水的工厂的经济评估，旨在阻止西班牙东南部具有重要生态价值的马略卡湖地区的退化。在四种 CBA 方法和三个时间范围内使用蒙特卡罗程序进行概率敏感性分析，旨在将国际环境贴现专家小组的观点与影响项目主要产出（即缺水地区的灌溉用水）市场价格的不确定性结合起来。结果表明，在考虑与这两个关键参数相关的风险的同时，哪些贴现情景最能准确估计项目的社会环境盈利性。该分析还提供了一些关于在环境公共投资决策中评估财务和环境盈利性的方法的发现。
