Green roofs and green walls are effective resilient and adaptive solutions that provide multiple ecosystem services when implemented in urban environments. In the past years, research efforts have been made to understand the real value of these solutions. However, there is still a lack of comprehensive calculation of the economic merit of green roofs and walls, which have restricted the decision-making process. The objective of this study is to provide a state-of-the-art of green infrastructure economics, namely, to identify research methods, summarize range values for each green system and highlight research gaps. A systematic review with a particular focus on green roofs and walls is conducted as well as a qualitative and quantitative analysis of 79 scientific articles. Overall findings suggest that green infrastructure is preferable to traditional alternatives. Financial performance is typically low, quite often negative. However, economic evaluation improves when adding ecological and social benefits. The current weight of evidence suggests that balancing costs against benefits plays a significant role in the implementation of green infrastructure. However, this evidence is still not clear as studies have been reporting contradictory results. Firstly, the listed benefits are not always supported with empirical data, especially intangible ones, where valuation can be extremely difficult. Also, there seems to be a lack of awareness about the multiple benefits and co-benefits of green infrastructure as studies analyze just a few in-depth. Thus, the full potential of green infrastructure is not fully exploited. Secondly, results depend on the dynamic behavior of green roofs and walls. A wide range of possible values for the benefits and costs come out of different study conditions, depending on the influence of design characteristics and external factors on systems performance. Lastly, research methods are not systematically laid out. All this hampers the discussion and comparison of results and further progress. This review is expected to contribute to the body of knowledge on green infrastructure, by helping to set general guidelines to assess their value, identify research gaps and, thus, better support the decision-making process of greening the built environment. Current analyses focus primarily on the most acknowledged benefits, but also extrapolation of results from previous modeling. Future research should be inclusive and based on local studies, using a more collaborative and interdisciplinary approach.

绿色屋顶和绿色墙壁是有效的弹性和自适应解决方案，在城市环境中实施时可提供多种生态系统服务。在过去的几年中，已经进行了研究工作以了解这些解决方案的真实价值。但是，仍然缺乏对绿色屋顶和墙壁的经济价值的综合计算，这限制了决策过程。这项研究的目的是提供绿色基础设施经济学的最新技术，即确定研究方法，总结每个绿色系统的范围值并突出研究差距。系统地审查了绿色屋顶和墙壁，并对79篇科学论文进行了定性和定量分析。总体研究结果表明，绿色基础设施优于传统替代方案。财务业绩通常很低，经常是负面的。但是，当增加生态和社会效益时，经济评估会提高。当前的证据表明，平衡成本与收益在实施绿色基础设施方面发挥着重要作用。但是，由于研究一直在报告相互矛盾的结果，因此这一证据仍不清楚。首先，列出的收益并不总是得到经验数据的支持，特别是无形的经验数据，因为在这种情况下，估值非常困难。此外，由于研究仅深入分析了一些内容，因此似乎对绿色基础设施的多重收益和共同收益缺乏认识。因此，绿色基础设施的全部潜力未被充分开发。其次，结果取决于绿色屋顶和墙壁的动态行为。取决于设计特性和外部因素对系统性能的影响，不同的研究条件会产生各种可能的收益和成本值。最后，研究方法还没有系统地列出。所有这些都妨碍了对结果的讨论和比较以及进一步的进展。通过帮助制定通用准则以评估其价值，确定研究差距，从而更好地支持绿化建筑环境的决策过程，有望对绿色基础设施领域的知识体系做出贡献。当前的分析主要集中在最广为人知的收益上，而且还从以前的建模结果中推断出来。未来的研究应具有包容性，并应基于本地研究，