贸易自由化与环境碳排放——基于中国加入WTO后关税冲击的量化分析

Trade Liberalization and Environmental Carbon Emissions:A Quantitative Analysis of Tariff Shocks after China’s WTO Accession

结合量化贸易模型和国际投入产出模型,将多国—多部门一般均衡模型拓展至环境分析,以中国加入WTO后的关税下降作为贸易自由化的标志性事件,量化评估贸易开放带来的环境绩效,系统审视其中的规模效应、结构效应和技术效应。研究发现,在不考虑技术进步的前提下,贸易自由化会通过规模效应和结构效应加重中国的碳排放强度,使得2005年的碳排放强度相对于2000年整体提高约1.68%—1.83%。其中对能源行业需求的增加以及能源行业降污减排技术落后是短期内碳排放增加的重要原因。但贸易规模扩张带来的“干中学”效应在行业渗透性更强的电力燃气和水供应行业中发挥了更大的技术溢出效果,极大地推动了该行业降污减排的技术进步,进而降低了经济整体的碳排放强度。从长期看,贸易自由化对污染的短期恶化效应在技术溢出中会得到有效解决。

Based on the quantitative trade model and the international input-output model,this paper extends the multi-country and multi-sector general equilibrium model to environmental analysis,takes the tariff reduction after China’s accession to the WTO as the landmark event of trade liberalization,quantifies the environmental performance brought by trade opening,and systematically examines the scale,structural effect and technological effect.It is found that trade liberalization has increased China’s carbon emission intensity through scale effect and structural effect,resulting in an overall increase of 1.68%-1.83%in carbon emission intensity in 2005 compared with that in 2000.Among them,the increasing demand for the energy industry and the backward technology of pollution reduction and emission reduction in the energy industry are important reasons for the increase of carbon emissions in the short term.However,the“learning by doing”effect brought by the expansion of trade scale has played a greater technological spillover effect in the electricity,gas and water supply industries with stronger industry penetration,which greatly promotes the technological progress of pollution reduction and emission reduction in the industry,and thus reduces the carbon emission intensity.In the long run,the short-term worsening effect of trade liberalization on pollution can be effectively solved through technology spillovers.