后INDC时期全球1.5℃合作减排方案

Global carbon abatement schemes for the 1.5℃ warming limitation in the post-INDC period

《巴黎协议》提出要将全球地表升温努力维持在低于较工业化前提高1.5℃的水平下,然而当前各国提交的国家自主贡献(INDCs)甚至无法实现成本最低的2℃温控目标,后INDC时期全球减排将面临严峻的形势。本文针对全程和终期两种1.5℃温控目标实现标准,基于不同的减排原则设置了三种全球合作减排方案,使用集成评估模型CIECIA对其气候有效性和经济可行性进行评价。研究结果显示:若要实现全程1.5℃升温控制目标,则各国必须在INDC目标年后立即实现净零排放;终期1.5℃温控目标可以使各国在INDC目标年后有一个到净零排放的缓冲期,但是由此带来的地表温度上升反而有损经济发展;方案3对因产业和地理因素在其他方案下经济受损的俄罗斯和高发展国家实行宽松减排措施,在满足终期1.5℃目标前提下实现了所有减排参与国经济利益的帕累托改进,是可行有效的国际减排合作方案;方案3显示中国和美国在减排过程中的经济联系更加紧密,而与俄罗斯和高发展国家存在竞争关系,因此可进一步加强与美国的减排合作,并注意协调与俄罗斯和高发展国家的利益关系。

The Paris Agreement recommended efforts to limit the temperature increase to 1.5℃above pre-industrial levels. However, the current intended nationally determined contributions（INDCs） fall short of 2 ℃ scenarios, and the post-INDC period will bring severe challenges.This study details the 1.5 ℃ warming in terms of two types of restrictions. The first restriction conforms with the requirement of the Paris Agreement and requires an overall 1.5 ℃ warming restriction throughout the simulation. In the second restriction, the terminal 1.5 ℃ control relaxes the temperature restriction during the simulation and requires a 1.5 ℃ warming restriction only at the end of the simulation. Using the two restrictions, this study proposes three global cooperating abatement schemes according to different principles. Next, the study assesses the climatic effectiveness and economic feasibility of these three schemes using CIECIA, an economic-climatic integrated assessment model. The results indicate that the carbon emissions of countries should be net zero immediately following the INDC target year to meet the overall 1.5 ℃ goal in Scheme 1, and countries suffer great economic losses at the beginning of post-INDC period. In Scheme 2, the terminal 1.5 ℃ restriction allows a buffer period from INDC target years to the net zero emission period that starts in 2041. Throughout this period, approximately 52 Gt C of carbon emissions are permitted. In this scheme, the economic shock around 2030 is less significant. However, by 2100 the countries suffer more cumulative utility losses than those in Scheme 1 due to warmer global temperatures during the late period. Of the three schemes, the Pareto improvement scheme permits looser carbon limits for Russia, and the high development countries（HDC） suffer more in the other schemes for industrial and geographic reasons. This scheme meets both the terminal 1.5 ℃ target and the Pareto improvement in the economies of all countries participating in global carbon abatement.Thus, it is economically feasible and climatically effective. Scheme 3 shows a link between the economies of China and the United States during carbon abatement, but it also shows that these countries are in competition with Russia and the HDC. Therefore, China could strengthen its abatement cooperation with the United States and pay attention to balance its gains with the gains of Russia and the HDC.