经济增长路径中的最优环境政策设计

Design of the Optimal Environmental Policy for a Growing Economy

一国的最优污染物排放量取决于该国的经济发展阶段,这已基本成为人们的共识,现实中观察到的"环境库兹涅茨曲线(EKC)"印证了这一命题。但另一个重要且尚无明确答案的问题是,最优环境政策是否也取决于经济发展阶段?本文对这一问题进行了深入探讨并得到了重要发现,即最优环境政策确实具有阶段性:在经济发展的初级阶段,侧重价格管理的庇古税是更有效率的政策手段;而当经济发展到一定阶段,特别是跨过EKC的拐点后,侧重数量管理的可交易排污权将成为更有效率的政策手段,并且其比较优势会随着经济继续增长而进一步强化。基于欧盟数据的实证分析也证实了这一发现。本文的政策建议是:随着中国经济规模的不断扩大,政府应及时加大环境治理力度,并更多地采用可交易排污权这一环境政策手段。

It＇s well agreed in literature that the optimal level of pollutant released in a country depends on its income level. The existence of Environmental Kuznets Curve （EKC） supports the above statement, however, another important open question lies in whether the optimal environmental policy of a country also depends on its income level？ We design a model based on Stokey （1998） in order to answer the question, and we find indeed the optimal environmental policy is income-dependent. In specific, at the early stage of development when the income level is low, the Pigou taxes are more efficient regulatory instrument, while as the income level increases, especially when it goes beyond the threshold level specified by the EKC, the tradable pollution rights （vouchers） become more efficient policy choice. As the income level further increases, the efficiency advantage of tradable pollution rights over Pigou taxes is strengthened. Our empirical analysis using EU data also supports this relationship. Therefore, we suggest the Chinese government to strengthen environment regulation in general, and to rely more on vouchers to achieve the goal more efficiently.