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.

对气候减缓成本的担忧，阻碍了为实现既定全球变暖防控目标所需的气候政策的推行。尽管成本是政策制定中需要考量的重要因素，但收益亦不容忽视。然而，气候政策协同效益（co-benefits，即规避气候变化成本之外的额外收益）的相关证据，在政策制定过程中常被忽视。诸多领域内，相关研究尚且有限，且未得到全面整合。本文旨在解决这一问题，对覆盖“协同效益”及相关术语的文献检索所得的1749条命中结果中筛选出的239篇同行评议论文进行了综述。本文旨在为政策制定者提供助力，并厘清研究空白，系统梳理、阐述、分析并整合了快速增长的气候政策协同效益相关研究成果。空气质量改善是相关文献中占比最高的协同效益类别，但覆盖广泛地理范围的研究还关注了饮食、体力活动、土壤与水质、生物多样性、经济表现以及能源安全等领域。在上述领域中，协同效益已被证实具备可观的经济价值；就空气质量而言，其效益量级通常与减排成本相当，部分情况下甚至更高。但对协同效益进行量化或货币化的研究占比仍然有限，实证证据相对不足，尤其是在空气质量与健康之外的领域。此外，相关研究成果极少被应用于政策制定，这意味着决策往往存在偏差，且过度关注成本，最终导致气候政策并非最优，乃至目标落空。显然，我们需要开展更多研究，同时优化决策流程。充分理解并运用气候政策协同效益相关知识，能够推动出台更有效的气候变化减缓政策，提升整体社会福祉。

**核心政策洞察**
气候政策协同效益在空气质量、健康等研究较为充分的领域规模可观，通常与减排成本相当，甚至更高。
尽管协同效益意义重大，但在决策过程中却极少被纳入考量，由此导致政策存在偏差，目标难以实现。
在饮食、能源安全等诸多领域，针对协同效益的研究尚且匮乏，但最新研究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。
需要优化决策流程、完善文档记录要求与评判标准，以确保政治决策者能够将协同效益纳入决策考量范畴。
气候政策协同效益在空气质量、健康等研究较为充分的领域规模可观，通常与减排成本相当，甚至更高。
尽管协同效益意义重大，但在决策过程中却极少被纳入考量，由此导致政策存在偏差，目标难以实现。
在饮食、能源安全等诸多领域，针对协同效益的研究尚且匮乏，但最新研究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。
需要优化决策流程、完善文档记录要求与评判标准，以确保政治决策者能够将协同效益纳入决策考量范畴。