中国不同行政尺度下的碳收支时空变化特征

Characteristics of Spatiotemporal Changes in China's Carbon Budget at Different Administrative Scales

在“双碳”背景下如何科学合理指定碳减排措施已经成为当今政府与科学领域共同关注的问题,行政区划对相关政策的制定与实施有显著影响,因此准确计算我国不同尺度行政区划下的碳吸收与碳排放的时空变化特征,可为我国不同行政区今后制定合理的差异化碳减排政策提供科学依据.为此采用遥感和统计等多源数据资料,综合生态模型、统计和GIS空间分析等方法分析了我国不同行政尺度下(省、市、县)的碳排放与碳吸收的时空动态变化特征.结果表明:①2000~2021年中国植被碳吸收总量不断增加,平均值逐渐增大;不同行政尺度下的碳排放存在时空变化的差异性,小尺度下的时空变化更为明显,碳排放量呈现出明显的“北高南低,东高西低”的空间差异;②不同行政尺度下碳压力指数(CPI)时空分布与碳排放相似,总体呈现逐年增长趋势,碳排放对碳吸收的压力逐渐由东部向中西部减弱;③时空热点分析表明,碳吸收量全国冷热点空间分布总体表现为“东热西冷”的空间格局;碳排放量冷热点空间分布呈现聚集特征,省级尺度主要为振荡的热点,市级和县级尺度主要为连续热点.启示:①我国不同区域和时段的碳吸收呈现显著的变异性,特别是中、东部区域仍然有通过增加碳吸收来抵消碳排放的可能性;②同一尺度下的行政区(如不同省份)以及一个尺度下的下一级行政区(例如同一省的不同市),碳吸收和碳排放等均存在不同程度的变异性.因此,以省级行政区为例,后续在制定碳交易和减排等政策时可先考虑省内不同地市之间协调排放等,再考虑省与省之间的协调,有望能更好地推动相关政策实施.

Currently,scientifically and reasonably specifying carbon emission reduction measures in the context of“double carbon”has become a common concern worldwide.China's administrative divisions have a notable impact on the formulation and implementation of relevant policies.Therefore the carbon emissions must be calculated accurately under China's administrative divisions at different scales.The spatiotemporal change characteristics of absorption and carbon emissions can provide scientific basis for the formulation of reasonable and differentiated carbon emission reduction policies in different administrative regions in China.To this end,this study used multi-source data such as remote sensing and statistics and integrated ecological models,statistics,and GIS space analysis and other methods to analyze the spatiotemporal dynamic change characteristics of carbon emissions and carbon absorption at different administrative scales(provinces,cities,and counties)in China.The results showed that:①The total carbon absorption of vegetation in China continued to increase from 2000 to 2021 and the average value gradually increased.Differences were observed in spatiotemporal changes in carbon emissions at different administrative scales.The spatiotemporal changes at smaller scales were more evident.Carbon emissions showed obvious spatial differences of“high in the north and low in the south,high in the east and low in the west.”②The spatiotemporal distribution of CPI at the administrative scale was similar to that of carbon emissions and the overall trend was increasing annually.The pressure of carbon emissions on carbon absorption gradually weakened from the east to the central and western regions.③Spatiotemporal hotspot analysis showed that the overall spatial distribution of cold and hot spots in China's carbon absorption was as follows:In the spatial pattern of“hot in the east and cold in the west,”the spatial distribution of cold and hot spots of carbon emissions showed agglomeration characteristics.The provincial scale was primarily oscillating hotspot whereas municipal and county scales were majorly continuous hot spots.Further results revealed that:①Carbon absorption in different regions and periods in China showed significant variability,especially in the central and eastern regions.The possibility of offsetting carbon emissions by increasing carbon absorption remains.②At the same scale,administrative regions(such as different provinces)and lower-level administrative regions at another scale(such as different cities in the same province)showed varying degrees of variability in carbon absorption and carbon emissions.Therefore,taking provincial administrative regions as an example for subsequent formulation considering carbon trading,emission reduction,and other policies,we should first consider the coordination of emissions between different cities in the province and then consider the coordination between provinces,which is expected to better promote the implementation of relevant policies.