目前中国的碳转移排放测算方法有很多,虽然方法不尽相同,但总的结论和计算出的变化趋势类似。造成碳转移量测算结果产生较大差异的原因主要有两方面,一是碳排放强度的测算模型不同,二是对于中国加工贸易转移碳排放的认识不同。测算避免转移排放量时,如果不考虑加工贸易的影响,在某些年份(如2002年)甚至会得到"中国是碳转移的净进口国"的结论。在出口额远大于进口额的年份,与强大的规模效应相比,几乎所有不确定性产生的误差都可以忽略,不会影响"中国是碳转移的净出口国"的最终结论。鉴于规模效应是主导原因,出口贸易量与出口碳排放份额存在一定的对应关系,对测算结果进行合理性分析的结果显示:中国1997—2007年出口贸易额占国内生产总值中的比例由19%稳步增长到37%,出口碳排放的相对份额从18%~23%增加到33%~35%是相对合理的结果。
There are lots of calculation methods of emissions embodied presently.This paper compares the input-output models,the calculation methods of carbon embodied intensity in exports,and analyzes the data processing methods and their results.The recent results show the calculation methods are different,but the general conclusions and the change trend are similar.The emission embodied in export and the emission embodied in import increased significantly in 1997-2007,and the former increased from 314~881 MtCO2 to 1 725~2 633 MtCO2,with an increase from 10%~23% to 27%~35%,accouting for total emission embodied.Deducting the emission embodied in import,the net embodied emission which transfers to China increased from 176~733 MtCO2 to 1 137~2 257 MtCO2,with an increase from 5%~20% to 17%~30%,accouting for total emission embodied.There were two main reasons that caused great differences on emissions embodied: first,the calculation methods of carbon intensity are different;second,the understanding of emissions embodied of Chinese processing trade is different.Comparing different results in 2004,when they used multi-regional input-out model,single-regional input-out model with main import-countries instead and direct calculation model,there were no significant difference.When calculating emission avoided by imports,if we do not consider improvement trade,it maybe result in an opposite conclusion,for example in 2002.However,because of high scale effect,when the export is much higher than imports,error caused by uncertainty can be ignored and will not impact the final conclusion.Based on recent research summary,we found the ratio of exports to GDP and the proportion of exports of total emissions emissions are related.So using this kind of relationship,we analyzed the reasonableness of existing research,and the results shows from 1997 to 2007,ratio of exports to GDP increased from 19.19% to 37.11% steadily,and the proportion of exports of total emissions emissions increased from 18%~23% to 33%~35%.