港口拥堵、内生贸易成本与中国对外贸易利益

Port Congestion,Endogenous Trade Cost and China’s Gains from International Trade

近年来,港口拥堵和海洋运费飙升已严重掣肘了中国企业参与对外贸易,2022年《政府工作报告》明确提出“加强铁路、公路、航空、海运、港口等运输保障”的工作任务。本文突破已有文献海运运费外生的假定,允许企业调整产品质量,重新测算了中国对外贸易利益;进而采用模拟矩估计方法对参数进行估计,分别模拟了在海运运输成本内生和外生情况下,关税壁垒下降对中国企业出口行为的影响。结果表明:内生运输成本对贸易的外部冲击具有“缓冲剂”作用;出口运输需求增加导致出口成本上涨和出口产品质量提升,运输成本的内生增长抵消了部分贸易自由化福利。以2006年为基准,关税下降10%内生地导致运费上涨的出口直接损失高达156亿美元,占总出口的1.7%。

In recent years,port congestion and soaring ocean freight rates have been severely hampering Chinese firms’participation in international trade.For this reason,the 2022“Government Work Report”clearly set out the task of“strengthening the construction of rail,road,air,maritime transport and port infrastructure networks,and ensuring the safety of the different transportation systems”.However,the existing literature still treats the cost of international trade as contributing exogenously.This paper instead incorporates cross-border transport bottlenecks into the framework of Eaton,Kortum and Kramarz(2011)(EKK)and re-evaluates China’s gains from international trade.Estimating the model using the simulated method of moments(SMM),it examines how the counterfactual decrease in trade barriers affects Chinese firms with endogenously and exogenously determined transportation costs.The results indicate that the endogenous cost of transportation acts as a“buffer”effect against the exogenous shock of trade;the increase in demand for export transportation,which leads to an increase in export costs and an improvement in the quality of exported products,offsets some of the gains from trade liberalisation.A fall of 10%in trade barriers also endogenously causes a direct loss of USD 156 billion due to an increase in ocean freight rates,accounting for 1.7%of total exports.