Spatial Identification of Carbon Stock Hotspots for Urban Climate Mitigation Planning: Remote Sensing Analysis of Malang City, Indonesia

Abstract

Urban expansion in tropical cities threatens carbon storage through vegetation-to-built conversion. Malang City, Indonesia, experiences accelerating vegetation loss due to urban sprawl. Here, spatially detailed assessments linking vegetation conversion to carbon dynamics remain absent, limiting evidence-based climate governance. This study thus employs high-resolution remote sensing integrated with spatial analysis to quantify carbon stock dynamics and identify priority intervention zones in a rapidly urbanizing tropical city context. Understanding carbon loss magnitude and geographic concentration is essential for targeted interventions. Google Dynamic World satellite data were processed through Google Earth Engine and validated against ground truth. Carbon stocks were estimated with international standard and reclassified according to national greenhouse gas mitigation guidelines. Linear regression characterized temporal trends; spatial analysis identified carbon release hotspots and sequestration opportunity areas. Results show that Malang City experienced significant annual carbon stock decline, representing a considerable overall loss. Carbon release hotspots concentrated in southern and southeastern urban-fringe zones due to vegetation-to-built conversion, while sequestration areas remained in fragmented northern and eastern patches. Hotspot permanence classification identified areas requiring urgent protection and areas retaining restoration potential. Spatially-explicit hotspot identification provides municipalities with an actionable framework for climate-responsive planning and targeted mitigation. This study demonstrates method applicability to other tropical cities seeking evidence-based urban carbon policy.