中国耕地低碳利用绩效测算与时空分异

推进耕地利用低碳转型是应对气候暖化威胁的有效途径。在核算耕地利用碳排放、碳吸收基础上,应用GB-US-S-SBM模型测算2000—2019年中国30个省（市、自治区）的耕地低碳利用绩效,进而分析绩效时空特征及收敛性。研究发现：（1）中国耕地利用碳排放、碳吸收、净碳汇强度依次为1.980 t?hm^-2、5.624 t?hm^-2、3.644 t?hm^-2,各省份耕地利用系统均呈碳盈余状态。 （2）全国耕地低碳利用绩效历经剧烈起伏、缓慢上升、波动不定、高速增长四个阶段。根据初始绩效和变化率,可将省域划分为低效高潜型（北京等15地）、低效平稳型（江苏等4地）、高效平稳型（重庆等3地）、高效低潜型（湖北等3地）、高效高潜型（吉林等5地）。期初,高、低效省份分别聚集于西南、西北;期末,高效省份主要位于西北、东北,低效省份集中分布于长江中游地区。（3）全国、中部、东部的绩效不存在σ收敛,东北和西部的绩效遵循σ收敛。全国及四大区域绩效均呈β收敛,省份间存在追赶趋势。本文可为制定区域差异化耕地利用低碳转型策略提供依据。

Estimation and spatio-temporal divergence of the low-carbon performance of cropland use in China

The low-carbon transition of cropland use can help to mitigate climate change to a certain extent. Based on carbon emissions accounting and sequestration of cropland use, this paper attempted to develop a theoretical framework for analyzing the low-carbon performance of cropland use. Then, the GB-US-S-SBM was applied to assess the performance in China's 30 provincial-level regions (hereafter provinces) from 2000 to 2019, and to examine the spatiotemporal characteristics. The study found that: (1) Overall, the intensities of carbon emissions, sequestration and net sequestration were 1.980 t?hm^-2, 5.624 t?hm^-2, and 3.644 t?hm^-2, respectively, indicating that the cropland use system was a major carbon sink. (2) Nationwide, the low-carbon performance of cropland use went through four stages, namely, ups and downs, slow growth, fluctuation, and fast growth. According to the initial performance and growth rate, the provinces were classified into five types, namely, low performance with high potential (15 provinces such as Beijing), low performance with stable trend (4 provinces such as Jiangsu), high stable performance (3 provinces such as Chongqing), high performance with low potential (3 provinces such as Hubei), and high performance with high potential (5 provinces such as Jilin). At the early stage, provinces with high performance were clustered in the southwest, while those with low performance were agglomerated in the northwest. High-performance provinces were mainly located in the northwest and northeast, and low-performance provinces were distributed in the middle reaches of the Yangtze River. (3) σ convergence was not observed in the performance of the whole country, central region, or eastern region, while the performance of northeastern and western region strictly followed σ convergence. Both China and its four regions exhibited β convergence, indicating that provinces tended to chase each other in performance. This paper may provide a basis for the differentiated low-carbon transition of regional cropland use.