长江经济带三大城市群土地利用碳排放的区域差异及空间收敛性

探讨长江经济带土地利用碳排放的区域差异及协同减排路径对实现区域可持续发展具有重要意义.首先依据土地利用碳排放估算方法,对长江经济带中长江三角洲城市群、长江中游城市群和成渝城市群2010~2020年土地利用碳排放进行了科学测算,然后利用核密度估计和空间收敛模型研究动态演化、区域差异及收敛特征.结果表明：①林地、水域、草地和未利用地的碳吸收相较于耕地和建设用地的碳排放而言较小,建设用地的碳排放量逐渐增加,而四大碳汇的碳吸收量在研究期内变化波动较小；②不同城市群的核密度曲线呈现不同的分布形态、延展性以及极化特征,但总体上逐渐趋于平衡；③长江经济带2010~2020年土地利用碳排放整体上呈现先增后减和东高西低的时空特征,三大城市群中心城市的土地利用碳排放量稳居最高层级,经济发展水平与生态环境之间还未建立起稳固的耦合机制；④长江经济带三大城市群的土地利用碳排放均存在绝对β收敛,也存在经济发展水平、城镇化水平、产业结构、人口密度和环境规制等控制变量下的条件β收敛,且条件收敛速度大于绝对收敛速度,长江三角洲城市群的收敛速度最慢.以上结论为长江经济带三大城市群协同减排路径提供支撑,从而有利于积极稳妥推进碳达峰、碳中和目标的实现.

Regional Difference and Spatial Convergence of Land Use Carbon Emissions in Three Urban Agglomerations of Yangtze River Economic Belt

It is of great significance to explore the regional differences of land use carbon emission （LUCE） in the Yangtze River Economic Belt and the path of coordinated emission reduction for regional sustainable development. Based on the LUCE estimation method, this study scientifically calculated the LUCE of the three major urban agglomerations of the Yangtze River Economic Belt （Yangtze River Delta, middle reaches of the Yangtze River, and Chengdu-Chongqing urban agglomeration） from 2010 to 2020. Kernel density estimation and the spatial convergence model were used to study the dynamic evolution, regional differences, and convergence characteristics of LUCE. The results showed that： ① The carbon absorption of forest land, water areas, grassland, and unused land were relatively small in terms of carbon emissions from cultivated land and construction land. The carbon emission of construction land increased gradually, whereas the carbon absorption of four carbon sinks fluctuated little during the study period. ② The core density curves of different urban agglomerations showed different distribution patterns, extensibility, and polarization characteristics but generally tended to be balanced. ③ From 2010 to 2020, the LUCE of the Yangtze River Economic Belt as a whole showed the spatio-temporal characteristics of increasing first and then decreasing and high in the east and low in the west. The LUCE of the central cities of the three urban agglomerations were at the highest level steadily, and stable coupling mechanisms had not been established between the economic development level and the ecological environment. ④ The LUCE of the three urban agglomerations in the Yangtze River Economic Belt all had absolute β convergence and also had conditional β convergence under the model control variables such as economic development level, urbanization level, industrial structure, population density, and environmental regulation, etc., and the conditional convergence speed was greater than the absolute convergence speed in each region. The convergence speed of the Yangtze River Delta urban agglomeration was the slowest. The above conclusions provide support for the coordinated emission reduction path of the three urban agglomerations in the Yangtze River Economic Belt and are also conducive to actively and steadily promoting the realization of the goals of carbon peak and carbon neutralization.