中国县域碳汇时空格局及影响因素

Spatiotemporal patterns and factors influencing county carbon sinks in China

以全国1300个县级行政单位作为研究对象,利用全国县域尺度土地利用数据和社会经济数据,核算了1990—2015年间中国县域碳汇总量,并结合标准差椭圆、空间自相关、冷热点分析和地理加权回归分析方法,探析中国县域碳汇的时空分异特征及影响因素,旨在为优化国土空间开发格局,实施差异化减排路径及推动生态文明建设提供参考。研究表明:(1)时空变化上,1990—2015年中国碳汇总量呈波动下降趋势,由13307.79×10^(4)t下降至13198.27×10^(4)t;林地为主要碳汇类型,其余碳汇类型比例结构基本不变;在空间分布上,中国县域碳汇呈现"西部>东北>南部>中部"的"西高东低"格局。(2)在空间分异和聚集上,碳汇空间分布中心向西南移动,分布范围呈收缩态势,西南地区对整体碳汇空间格局影响作用加强;1990—2015年中国县域碳汇总量的冷热点集聚程度呈现波动稳定特征,空间集聚程度呈现高值与低值聚集,高-低区域零星分布的特征。(3)从影响因素分析来看,2015年经济发展、产业结构、土地利用程度对碳汇产生影响并存在空间异质性。建议通过合理规划县域非建设用地的土地利用方式、差异性制定各区域内策略、控制建设用地规模等方式达到县域的低碳发展。

1300 county-level administrative units across China were considered for the study. County-level land usage data and socioeconomic data were used to calculate the total carbon sinks in China from 1990 to 2015. Combining standard deviation ellipse, spatial autocorrelation, cold-hot spot analysis, and geographic weighted regression analysis methods, the spatiotemporal differentiation characteristics and factors influencing these carbon sinks were explored. This study aims to provide a reference for optimizing China′s land development patterns to implement differentiated emission reduction paths and promote the establishment of an ecological civilization. The research shows that:(1) In terms of spatiotemporal changes, China′s carbon sinks showed a declining trend from 1990 to 2015, with a reduction in carbon from 133077900 tons to 131982700 tons. Forestland was the primary type of carbon sink, and the proportion of the remaining types were basically unchanged. In terms of spatial distribution, the carbon sinks were generally greater in the west than in the east, following a west > northeast > south > middle pattern.(2) During the research, the spatial distribution center of the carbon sinks was moving to the southwest, and the distribution range was shrinking. The influence of the southwest region on the overall spatial pattern of the carbon sinks was strengthened. From 1990 to 2015, the degree of cold and hot spot agglomeration of the carbon sinks showed a stable fluctuation. The spatial agglomeration showed clusters of high-value and low-value numbers, and sporadic distribution of high and low regions.(3) By analyzing influencing factors in 2015, economic development, industrial structure, and land usage, all demonstrated impacts on carbon sinks, indicating spatial heterogeneity. It is recommended to increase carbon sinks and reduce emissions at county-level by proper planning of land usage for non-construction land, formulating strategies for increasing carbon sinks and reducing emissions for various regions, and controlling the extent of land used for construction.