长江经济带土地城镇化、人口城镇化与城市生态效率提升——基于108个地级及以上城市面板数据的实证分析

Economy and society Land Urbanization,Population Urbanization and Urban Ecological Efficiency Improvement in Yangtze River Economic Belt Empirical : analysis based on panel data of 108 cities at prefecture level and above

基于2007-2018年中国长江经济带11省市108个地级及以上城市的土地城镇化和人口城镇化数据,运用包含非期望产出的SBM-DEA模型测算各城市的生态效率水平,并选取城市商品房销售价格作为控制城镇化建设反向因果效应内生性的工具变量,在两阶段最小二乘法和三阶段最小二乘法的框架内实证分析城镇化建设对城市生态效率的影响及其传导机制。研究发现,土地城镇化和人口城镇化对城市生态效率具有非线性的"U"型影响,且现阶段均已跨过拐点,能显著提高城市的生态效率水平;产业结构优化和人力资本积累是城镇化影响长江经济带各城市生态效率的两个重要传导渠道;商品房销售价格的适度提高能有效促进人口和土地城镇化建设,进而提升城市生态效率;人口城镇化建设对城市生态效率改善的促进作用明显大于土地城镇化。

Based on the data of urbanization(land urbanization and population urbanization)of 108 cities at prefecture level and above in 11 provinces of China’s Yangtze River economic belt from 2007 to 2018,this paper uses the SBM-DEA model including unexpected output to measure the urban ecological efficiency,and innovatively selects the consumer sales price of urban commercial housing as an instrumental variable to control the endogenousness of the reverse causal effects of urbanization.Then,In the framework of 2 SLS and 3 SLS,this paper empirically analyzes the impact of urbanization on urban ecological efficiency and its transmission mechanism.It is found that both land urbanization and population urbanization can significantly improve the level of urban ecological efficiency.The optimization of industrial structure and the accumulation of human capital are two important channels through which urbanization affects the ecological efficiency of cities in the Yangtze River economic belt.A moderate increase in the sale price of commercial housing can effectively promote urbanization construction and thus improve urban ecological efficiency.The promotion effect of population urbanization on urban ecological efficiency improvement is obviously greater than that of land urbanization.