中国粮食种植业碳效应时空演化及碳排放公平性

农业低碳转型背景下,准确把握粮食种植业碳效应时空演化及碳排放公平性特征对实现地区生态正义具有重要意义。基于2000-2021年省域面板数据,采用碳排放因子法测算中国30个省区的粮食种植业碳效应,利用核密度估计方法探析时空演化,运用Dagum基尼系数法刻画并解构全国粮食种植业碳排放公平性。研究表明:(1) 从时空特征看,粮食种植业碳效应呈现波动上升的净碳汇特征,具体表现为"东强西弱,北高南低"的空间格局,且伴随明显的"马太效应"。在碳效应结构上,秸秆燃烧与玉米种植分别是粮食种植业最主要的碳源与碳汇。(2) 从演化趋势来看,全国粮食种植业碳效应的非均衡性呈扩大趋势;在三大主粮中,水稻碳效应非均衡性有所减弱,小麦与玉米碳效应非均衡性均持续上升。(3) 从碳排放公平性来看,区域间碳排放差异已成为影响公平性的最主要因素,基尼系数呈"快速上升-波动震荡-缓慢回落"特征,全国粮食种植业碳排放始终处于较公平区间,整体公平性呈改善态势;在三大主粮中,水稻碳排放公平性最低,玉米碳排放公平性最高。最后,提出了采取差异化固碳减排策略、构建低碳发展跨区协作机制、完善碳排放责任分摊机制、探索粮食碳汇交易试点等建议,以期推动我国粮食种植业实现低碳转型发展。

Spatial and temporal evolution of carbon effect and carbon equity of grain planting industry in China

In the context of low-carbon transformation in agriculture, accurately understanding the spatio-temporal evolution of carbon effects and the characteristics of carbon equity in grain cultivation is crucial for achieving regional ecological justice. Based on provincial panel data from 2000 to 2021, the carbon emission factor method was used to measure and analyze the spatial and temporal characteristics of carbon effects in food cultivation across 30 provinces, municipalities, and regions in China. At the same time, the kernel density estimation method was applied to explore the dynamic evolution of carbon effects. Furthermore, this paper employed the Dagum Gini coefficient method to characterize and deconstruct the equity of net carbon sinks in nationwide food cultivation based on the net carbon sink intensity index. The following key findings are revealed: (1) From the perspective of spatial and temporal characteristics, the total net carbon sink of the grain farming industry fluctuated and rose during the investigation period. Notably, it exhibited a spatial pattern of "low in the west and high in the east, low in the south and high in the north", accompanied by the obvious "Matthew effect". Additionally, straw burning and corn gradually emerged as the primary carbon source and carbon sink. (2) From the perspective of the evolution trend, the spatial non-equilibrium of the carbon effect of the national grain cultivation industry had been expanding. Among them, the non-equilibrium in carbon effects of main rice-producing areas was decreasing, while wheat and maize exhibited a continuous increase in non-equilibrium. (3) From the perspective of carbon emission equity, inter-regional difference had become the primary factor affecting equity, with the contribution rate of 35.250% in 2021. In addition, Gini coefficient was characterized by "rapid growth-fluctuation shock-slow decrease", and the carbon emission of the national grain farming industry remained within a relatively equitable range during the examination period, with the overall equity improving. Among the main production areas of the three major staple grains, the main maize producing area demonstrated the highest degree of fairness, while the main rice producing area showed the least fairness. Finally, suggestions such as adopting differentiated carbon sequestration and emission reduction strategies for the grain farming industry, building a cross-regional collaboration mechanism for low-carbon development of the grain farming industry, perfecting the carbon emission responsibility-sharing mechanism, and exploring grain carbon sink trading pilots were proposed with a view to boosting China''s grain farming industry to realize low-carbon transformation.