Mitigating carbon loss in China's arid and semi-arid regions through optimization and management under CMIP6 scenarios

Carbon storage (CS) in arid and semi-arid regions (ASR) constitutes a key part of the global terrestrial carbon pool but remains highly sensitive to climate change. Optimizing the spatial distribution of carbon sink services is essential for maximizing their sequestration potential. Using arid and semi-arid regions of China (CASR) as a case study, we applied the InVEST model to quantify CS patterns in 2020 and 2030 under CMIP6 scenarios, examined the contributions of environmental drivers, and optimized spatial distribution with a Bayesian belief (BBN). Results show that CS decreases from east to west, with grasslands contributing over 50% of the total CS. Unused land stores more carbon than forestland and should not be overlooked. Under SSP126 scenario, carbon sink potential is projected to increase, while under SSP245 and SSP585 scenarios, CS is expected to decline by 1.41×10⁷ t and 2.84×10⁷ t, respectively. CS is primarily influenced by precipitation and elevation, but the influence weight of socioeconomic factors gradually increases under the SSP245 and SSP585 scenarios. The region was divided into four optimized subsets based on carbon sink potential—ecological conservation, ecological restoration, cropland optimization, and desert optimization—with zoned management recommended for their carbon pools. After optimization, the ecological conservation subset was projected to cover 4531×10⁴ ha, 4223×10⁴ ha, and 4132×10⁴ ha under SSP126, SSP245, and SSP585, respectively, thereby enhancing carbon sink potential. This study offers scientific insights into carbon sink management in ASR.干旱半干旱区（Arid and Semi-Arid Regions，ASR）的碳储量（Carbon Storage，CS）是全球陆地碳库的核心组成部分，但其对气候变化高度敏感。优化碳汇服务的空间布局，是最大化其固碳潜力的关键举措。本研究以中国干旱半干旱区（CASR）为研究案例，采用InVEST模型量化了CMIP6情景下2020年与2030年的碳储量格局，解析了环境驱动因子的贡献度，并通过贝叶斯信念网络（Bayesian Belief Network，BBN）优化了空间布局。研究结果表明，碳储量自东向西逐渐降低，其中草地贡献了总碳储量的50%以上。未利用地的碳储存量高于林地，不容忽视。在SSP126情景下，碳汇潜力预计将有所提升；而在SSP245与SSP585情景下，碳储量预计将分别减少1.41×10⁷吨与2.84×10⁷吨。碳储量主要受降水量与海拔高度的影响，但在SSP245和SSP585情景下，社会经济因子的影响权重逐渐升高。本研究基于碳汇潜力将研究区划分为4个优化子集，分别为生态保育区、生态修复区、耕地优化区与荒漠优化区，并建议针对各碳库实施分区管理。优化后，在SSP126、SSP245与SSP585情景下，生态保育子集的面积预计分别达到4531×10⁴公顷、4223×10⁴公顷与4132×10⁴公顷，进而提升区域碳汇潜力。本研究可为干旱半干旱区的碳汇管理提供科学参考。