全球碳排放空间约束条件下美国退出《巴黎协定》对中欧日碳排放空间和减排成本的影响

应用全球多部门、多区域动态可计算一般均衡（CGE）模型，采用情景分析方法，评估美国退出《巴黎协定》后，由于其碳排放路径的变化对国际气候谈判中的3个重要谈判方中国、欧盟和日本实现国家自主贡献（NDC）和2℃目标情景下碳排放空间和减排成本的影响。结果表明：在全球碳排放固定且分配方式固定的条件下，美国不同程度的退约将为自身获得较大的碳排放空间，同时挤压其他地区，包括中国、欧盟和日本实现NDC和2℃目标的碳排放空间，将推高中国、欧盟和日本实现NDC和2℃目标的碳价。2030年，2℃目标下中国碳价的升幅将达4.4~14.6美元/t，欧盟为9.7~35.4美元/t，日本为16.0~53.5美元/t。同时将增加中国、欧盟和日本等其他国家和地区的GDP损失。2030年，2℃目标下中国GDP损失的升幅将达220.0亿~711.0亿美元（相当于16.4~53.1美元/人），欧盟为93.5亿~321.4亿美元（相当于20.7~71.1美元/人），日本为41.3亿~134.5亿美元（相当于34.3~111.7美元/人）。

The Impacts of U.S. Withdrawal from the Paris Agreement on the Carbon Emission Space and Mitigation Cost of China,EU and Japan Under Constraints of Global Carbon Emission Space

Based on the computable general equilibrium (CGE) model and scenario analysis, this article assesses the impacts of the United States' (U.S.) withdrawal from the Paris Agreement on China, European Union (EU) and Japan in terms of carbon emission space and mitigation cost under Nationally Determined Contributions (NDCs) and 2℃ scenarios due to changed emission pathway of U.S. The results show that, under the condition of constant global cumulative carbon emissions and fixed burden sharing scheme among countries, the failure of the U.S. to honor its NDC commitment to different degrees will increase its carbon emission space and decrease its mitigation cost. However, the carbon emission space of other parties, including China, EU and Japan, will be reduced and their mitigation costs will be raised. In 2030, under the 2℃ target, the carbon price will increase by 4.4-14.6 US$/t in China, by 9.7-35.4 US$/t in EU, and by 16.0-53.5 US$/t in Japan. In addition, China, EU and Japan will incur additional GDP loss. Under the 2℃ target in 2030, the GDP loss of China would increase by US$ 22.0 billion-71.1 billion (equivalent to 16.4-53.1 US$ per capita), EU's GDP loss would rise by US$ 9.4 billion-32.1 billion (equivalent to 20.7-71.1 US$ per capita), and Japan's GDP loss will rise by US$ 4.1 billion-13.5 billion (equivalent to 34.3-111.6 US$ per capita).