南京市土地利用结构碳排放效率增长及其空间相关性

采用南京市11个区2005-2014年的相关数据,首先对不同类型土地的碳排放量进行核算,进一步将其作为非期望产出引入DEA模型并采用Hicks-Moorsteen指数对南京市各区的土地利用结构碳排放效率增长进行估算、比较和分析。研究结果表明：① 碳排放的主要来源是建设用地的间接碳排放,研究期内的土地利用碳排放量呈现出持续增长的发展态势。② 全要素碳排放效率增长及其分解要素均低于传统全要素生产率增长,即不考虑碳排放约束的全要素生产率增长高估了实际的土地利用效率增长水平。全要素碳排放效率增长在研究期内表现出收敛态势和区域之间均衡性的发展特征,源于“低碳和高效”发展理念的深入人心,单位GDP能耗不断降低。③ 南京市各区的技术效率值较低,“技术追赶”效应不明显,开始出现土地利用的规模经济效应,但是范围经济效应不显著。④ 全要素碳排放效率增长在南京市范围内具有空间正相关性,且表现出空间集聚特征。基于此,提出了一些有益的建议。

Carbon emission efficiency growth of land use structure and its spatial correlation: A case study of Nanjing city

The increase of carbon emissions has a direct impact on extreme weather disasters and global warming. Therefore, controlling and reducing carbon emissions is one of the important ways to promote ecological balance and regional sustainable development. The difference in urban land use patterns and the different speeds and levels of urban economic development will, of no doubt, lead to the differences in carbon emissions. The amount of carbon emissions from different land use structures and the levels of its efficiency will directly affect the sustainable development of the urban economy, which has aroused the attention of academics. This paper estimated the quantities of carbon emissions of different land types by using the land use structure data from 11 districts in Nanjing from 2005 to 2014, and further introduced the estimated carbon emissions into the DEA model as an undesirable output variable to estimate, compare and analyze the total factor carbon emissions productivity growth of land use structure in Nanjing by using the Hicks-Moorsteen index method. The major results were shown as follows. First, the main sources of carbon emissions for land use structure in Nanjing were the indirect carbon emissions from the construction lands. During the study period, the carbon emissions of land use structure showed a continuous growth trend and certain degree of spatial heterogeneity in the districts of Nanjing city. The severe emission areas were mainly concentrated in the central regions and there was a tendency to shift to the northern regions. Second, the total factor carbon emission productivity growth and its decomposition factors were lower than the traditional total factor productivity (TFP) growth, which means that the traditional TFP growth without considering the constraints of carbon emissions overestimated the actual productivity growth level of land use structure. The total factor carbon emission productivity growth showed a convergence trend with the characteristic of equilibrium development between regions during 2006-2014, due to the fact that the development concept of "low carbon and high efficiency" were deeply rooted in people's mind and the energy consumption per unit of GDP was continuously decreasing. The calculation results of model 2 showed that the total factor carbon emission productivity growth level of Jiangning district was the highest and that of Yuhuatai district was the lowest. Third, the decomposition results of total factor carbon emission productivity growth indicated that the technical efficiencies of all the districts in Nanjing were relatively low, the "technology catch-up" effects were not obvious, and the scale economy effects of land use began to appear, but the scope economy effects were not very significant. Fourth, total factor carbon emission productivity growth presented a positive spatial correlation and the characteristics of spatial agglomeration in all the districts of Nanjing. The districts of high and high (HH) agglomeration were increasing and the districts of low and low (LL) agglomeration were decreasing. Finally, some suggestions were put forward.