中国国际贸易隐含碳文献比较研究

A Comparative Analysis on Carbon Emissions Embodied in China' s International Trade

贸易中的隐含碳流动对中国的二氧化碳排放具有重要影响。从现有的文献来看,尽管出现了大量的针对中国贸易中隐含碳的相关研究,但由于数据及方法的不同,结果之间存在较大差异,很大程度上影响了研究结果的科学性和应用价值。本文对现有的中国国际贸易隐含碳文献进行了比较研究,结果发现:不同研究得出了相对一致的结论,但在隐含碳的具体数量上差异巨大。定性来看,中国是一个隐含碳净出口国,净出口量呈现出逐年增加的趋势。定量来看,1997-2007年,中国隐含碳出口量从3.1-8.8亿t增长到17.2-30.2亿t二氧化碳;隐含碳进口量从1.0-7.0亿t增长到5.8-16.5亿t二氧化碳;隐含碳净出口量从1.8-7.3亿t增长到11.4-22.6亿t二氧化碳;隐含碳净出口量占国内总排放量的比重由5%-20%增长到17%-30%。贸易中隐含碳核算结果的不确定性主要来自三个方面:核算方法产生的不确定性、数据融合产生的不确定性以及原始数据引入的不确定性。总体来看,多区域投入产出模型的研究结果相对稳定,可重复性较高;从数据精度和数据可获得性方面考虑,40个左右的部门分类可以取得较为理想的结果:把中国划分为多个区域研究国际贸易中的隐含碳在理论上更加可靠。国家气候变化对外谈判和国内减排目标的实现都需要对碳排放进行精确管理。在未来的研究中,应重视隐含碳核算的不确定性研究,逐步提高隐含碳核算的精度,更好地服务于国家的气候变化政策。

International trade has a very important impact on China's CO_2 emissions.In recent years,a large number of researchers have investigated carbon embodied in China's trade.However,there is a huge gap among their studies owing to different data sources and methodologies,which to a great extent constrains the applicability of these studies.This paper aims to partially fill this gap in the literature by performing a comparative analysis of several representative studies on carbon embodied in China' s international trade.Although these studies in general have consistent conclusions,their detailed numerical results of embodied carbon differ greatly from one another.From a qualitative point of view,China is a net exporter of embodied carbon,and the amount of net exports shows an increasing trend year by year.From a quantitative perspective,carbon embodied in exports grew from 0.31-0.88 billion tons in 1997 to 1.72-3.02 billion tons in 2007,and carbon embodied in imports increased from 0.1-0.7 to 0.58- 1.65 billion tons in the1997-2007 period.As a result,net exports of embodied carbon also increased from 0.18-0.73 billion tons to 1.14-2.26 billion tons during the same period.The uncertainty of accounting results originates from three sources:accounting method,data aggregation,and the original input data.Overall,estimations based on multi-regional input-output models are more consistent and have higher reliability than those based on single regional input-output model.Considering the accuracy and availability of input data,classifying sectors into approximately 40 categories is likely to generate desirable results.It is appropriate to divide China into multiple regions when estimating carbon emissions embodied in international trade.Both international climate negotiations and the achievement of domestic carbon abatement targets call for precise management of carbon emissions.Future studies should pay more attention to the uncertainty of embodied carbon accounting and gradually improve the accuracy of accounting results,which will serve as important references to China' s climate policy-making.