Climate policy co-benefits: a review

Concern over mitigation costs impedes the adoption of the climate policies needed to achieve agreed global warming targets. While costs are important to consider, so are benefits. However, the evidence for climate policy co-benefits, that is, the benefits in addition to avoided climate change costs, is commonly overlooked in policy-making. In many areas, the research is limited and not comprehensively synthesised. This article counters that problem and reviews 239 peer-reviewed articles, selected from 1,749 hits from a literature search covering ‘co-benefits’ and related terms. Aiming to aid policy-makers and to identify research gaps, we structure, describe, analyse and synthesize the rapidly expanding knowledge on climate policy co-benefits. Improved air quality is the co-benefit category dominating the literature, but studies covering a broad geographic range also focus on diet, physical activity, soil and water quality, biodiversity, economic performance, and energy security. In these areas, co-benefits are shown to be of substantial economic value, regarding air quality often of the same order of magnitude as mitigation costs, in some instances even larger. However, the share of studies quantifying or monetizing co-benefits is limited, and the empirical evidence is small, in particular for areas besides air quality and health. Furthermore, the knowledge is seldom used in policy-making, meaning that decision-making is often biased and overly concerned with costs, leading to suboptimal climate policies and goal failures. Evidently, more research is needed, as well as improved decision-making. Understanding and acting on climate policy co-benefits can promote policies that better mitigate climate change and improve overall welfare. <b>Key policy insights</b>Climate policy co-benefits in well-researched fields such as air quality and health are large, often equalling or exceeding mitigation costs.Despite their significance, co-benefits are seldom considered in decision-making, leading to biased policies and goal failures.In several areas, such as diet and energy security, co-benefits are sparsely researched, but emerging evidence points to high values.More research is needed, including on how to describe the total value of different co-benefits.Improved processes, documentation requirements and criteria in decision-making are needed, in order to ensure that political decision-makers consider co-benefits. Climate policy co-benefits in well-researched fields such as air quality and health are large, often equalling or exceeding mitigation costs. Despite their significance, co-benefits are seldom considered in decision-making, leading to biased policies and goal failures. In several areas, such as diet and energy security, co-benefits are sparsely researched, but emerging evidence points to high values. More research is needed, including on how to describe the total value of different co-benefits. Improved processes, documentation requirements and criteria in decision-making are needed, in order to ensure that political decision-makers consider co-benefits.

对减排成本的顾虑阻碍了为实现既定全球变暖目标所需的气候政策的推行。尽管成本是重要的考量因素，但收益同样不容忽视。然而，气候政策协同效益（climate policy co-benefits）——即规避气候变化成本之外的额外收益——的相关证据，在政策制定中常被忽视。诸多领域的相关研究均较为有限，且未得到全面的综合梳理。本文旨在解决这一问题，针对以“协同效益”及相关术语为关键词的文献检索所得到的1749条结果，筛选出239篇同行评议论文并进行综述。本文旨在为政策制定者提供帮助，并识别研究空白，因此对快速增长的气候政策协同效益相关知识进行了结构化梳理、描述、分析与综合。现有文献中占主导的协同效益类别为空气质量改善，但覆盖广泛地理范围的研究还涉及饮食、体力活动、水土质量、生物多样性、经济表现与能源安全等领域。上述领域的协同效益已被证实具有可观的经济价值；就空气质量而言，其价值通常与减排成本处于同一量级，部分场景下甚至更高。但对协同效益进行量化或货币化的研究占比仍然有限，实证证据较为匮乏，尤其是在空气质量与健康之外的领域。此外，相关研究成果极少应用于政策制定中，这意味着决策往往存在偏向性，过度关注成本，进而导致气候政策次优、既定目标无法实现。显然，我们需要开展更多研究，并改进决策流程。理解并合理运用气候政策协同效益，能够推动更有效的气候变化减缓政策，同时提升整体社会福祉。**核心政策洞察**：在空气质量、健康等研究较为充分的领域，气候政策协同效益规模可观，通常等同于甚至超过减排成本。尽管协同效益意义重大，但在决策制定中极少被纳入考量，这导致政策存在偏向性，既定目标难以实现。在饮食、能源安全等诸多领域，协同效益的相关研究较为匮乏，但新兴证据显示其价值颇高。我们需要开展更多研究，包括如何量化不同协同效益的总价值。同时，需要改进决策流程、完善文档记录要求与决策标准，以确保政治决策者能够考虑到协同效益。在空气质量、健康等研究较为充分的领域，气候政策协同效益规模可观，通常等同于甚至超过减排成本。尽管协同效益意义重大，但在决策制定中极少被纳入考量，这导致政策存在偏向性，既定目标难以实现。在饮食、能源安全等诸多领域，协同效益的相关研究较为匮乏，但新兴证据显示其价值颇高。我们需要开展更多研究，包括如何量化不同协同效益的总价值。同时，需要改进决策流程、完善文档记录要求与决策标准，以确保政治决策者能够考虑到协同效益。