Environmental studies regularly use the net present value (NPV) to value benefits and costs of projects. However, the NPV disregards whether the stream of net benefits is steady or volatile and ignores the distribution of net benefits among different groups of people. Here we test alternatives to NPV, building on two example cases: 1) We use discounted utility (DU) to evaluate land-use projects and calculate opportunity costs for avoided deforestation. 2) We simulate decision-making on tropical deforestation, whereby we use multiple decision criteria to consider the distribution of net benefits between two groups: farmers and conservationists. Results show considerable differences in the ranking of projects between DU and NPV, when projects are not marginal. Compared to DU, NPV regularly overestimates the value of forest plantations. Moreover, NPV tends to overstate the opportunity costs of avoiding deforestation in terms of saved carbon emissions. Not accounting for the distribution of net benefits when optimizing land-use allocation leads to sub-optimal simulated deforestation scenarios. We therefore suggest that future studies should either also use DU to value economic consequences of projects or that they use the NPV as only one among several socio-economic and ecological decision criteria.

中文翻译：

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在环境研究中使用和误用净现值

环境研究经常使用净现值 (NPV) 来评估项目的收益和成本。然而，NPV 忽略了净收益流是稳定的还是波动的，而忽略了净收益在不同人群中的分布。在这里，我们基于两个示例案例测试 NPV 的替代方案：1) 我们使用贴现效用 (DU) 来评估土地使用项目并计算避免森林砍伐的机会成本。2）我们模拟热带森林砍伐的决策，我们使用多个决策标准来考虑两个群体之间的净收益分配：农民和保护主义者。结果显示，当项目不是边缘时，DU 和 NPV 之间的项目排名有很大差异。与 DU 相比，NPV 经常高估人工林的价值。而且，NPV 倾向于夸大避免森林砍伐以节省碳排放的机会成本。在优化土地利用分配时不考虑净收益的分配会导致次优的模拟毁林情景。因此，我们建议未来的研究也应该使用 DU 来评估项目的经济后果，或者将 NPV 仅用作几个社会经济和生态决策标准中的一个。