An Exploratory Carbon-Benefit-Oriented Sustainability Diagnostic for Rural Human Settlements: A Case Study of Qingge Village, Fujian Province

Rural low-carbon planning requires evaluation tools that connect carbon-related performance with the ecological, socioeconomic, and infrastructure conditions of rural settlements, yet carbon inventories and conventional human-settlement assessments do not fully integrate these dimensions. This study developed an exploratory carbon-benefit-oriented sustainability diagnostic and applied it to Qingge Village, Fujian Province. Fuzzy Delphi screening retained 27 indicators across ecological, social, production, and engineering subsystems; Delphi consultation generated expert-based weights; a dimensionless ratio transformation standardized the indicator values; threshold, standardization, and weighting sensitivity analyses evaluated the stability of results across analytical specifications. The primary composite score was 0.413 compared with 0.590 under the target-achievement transformation, and both expert-weighted transformations ranked subsystem contributions as production, ecological, social, and engineering. The ecological and production subsystems performed more strongly against the selected references than the social and engineering subsystems, whereas fully equal global weights placed ecology ahead of production. The principal diagnostic priorities were household energy emissions, green agricultural upgrading, public-transport access, and recorded energy-efficient building coverage. These findings indicate that the diagnostic can organize village-scale low-carbon planning priorities and translate multidimensional performance evidence into a sequenced set of spatial improvement options. This study therefore provides a transparent and practically applicable approach for linking carbon-related indicators with rural human-settlement planning and supporting evidence-informed low-carbon revitalization.