Development of a Conceptual–Operational Model of Environmental Resilience Based on the Carbon-Neutral City Approach: A Case Study of Tehran Municipality District 6

Introduction:
Climate change, increasing greenhouse gas emissions, and the growing intensity of environmental hazards have created major challenges for contemporary urban planning. Cities are both important sources of carbon emissions and highly vulnerable to the environmental consequences of climate change. Therefore, achieving carbon neutrality requires not only reducing greenhouse gas emissions but also strengthening the capacity of urban systems to adapt to environmental stresses and climatic disturbances. In this context, environmental resilience and the carbon-neutral city represent complementary approaches to sustainable urban development. Environmental resilience emphasizes the capacity of urban and ecological systems to maintain functions, adapt to changing conditions, and recover from environmental stresses, while the carbon-neutral city focuses on reducing greenhouse gas emissions and balancing emissions with carbon absorption. Integrating these approaches can create synergies, as strategies such as green infrastructure, sustainable transportation, energy efficiency, and ecological resource management can simultaneously reduce carbon emissions and strengthen environmental resilience. However, previous studies have identified related indicators in a fragmented manner, with differences in definitions, spatial scales, data requirements, and measurement approaches. Moreover, many theoretically relevant indicators cannot be operationalized at the local urban scale because of data availability and spatial measurability limitations. Consequently, a context-sensitive and spatially measurable framework is needed to translate the theoretical dimensions of environmental resilience and carbon neutrality into operational indicators. District 6 of Tehran Municipality, characterized by high building and population density, intensive urban activities, major transportation corridors, and significant environmental pressures, provides an appropriate context for developing such a framework.
The Purpose of the Research:
The purpose of this research was to develop a conceptual–operational model of environmental resilience based on the carbon-neutral city approach, with emphasis on localizing and spatially measuring indicators in District 6 of Tehran Municipality. The study sought to identify and organize indicators associated with environmental resilience and carbon-neutral cities in the international literature and subsequently determine which indicators could be operationalized within the specific spatial and data conditions of the study area. Rather than selecting indicators solely according to their frequency of occurrence in previous studies, the research considered their theoretical relevance, spatial measurability, data accessibility, compatibility with the local context, and suitability for quantitative and computational analysis. The final framework was intended to provide a spatially explicit basis for assessing environmental resilience and supporting monitoring, prioritization of interventions, and data-driven urban planning toward resilient and carbon-neutral urban development.
Methodology:
The research employed a systematic literature review combined with qualitative content analysis and descriptive analysis of the identified indicators. The review process followed the PRISMA 2020 framework to increase transparency and reproducibility. Searches were conducted in international databases using combinations of the terms “Environmental Resilience,” “Ecological Resilience,” “Carbon-Neutral City,” and “Carbon Neutral City.” Following the identification and screening stages, 56 relevant studies were ultimately selected for detailed analysis. The full texts of the selected studies were systematically examined to identify indicators related to environmental resilience and carbon-neutral cities. This process resulted in the extraction of 81 initial indicators. The indicators were subsequently organized into five dimensions: physical, environmental, economic, social, and institutional–governance. To develop an operational framework for District 6, the 81 indicators were evaluated using five criteria: theoretical repeatability and relevance, spatial and quantitative measurability, availability of data at the parcel scale, compatibility with the local context, and suitability for computational modeling. Accordingly, frequency was considered as supporting evidence rather than an independent selection threshold. After applying these criteria, 12 indicators were selected as the final operational indicators. These indicators were transformed into spatial, raster, or parcel-scale information layers within a GIS environment, allowing their application in spatial analysis of environmental resilience.
Findings and Discussion:
The findings demonstrated that environmental resilience and the carbon-neutral city are interconnected through interactions between urban pressures and ecological regulating capacities. The systematic review identified 81 indicators across five dimensions. The physical and environmental dimensions included indicators related to urban form, building density, transportation accessibility, vegetation, air pollution, water resources, climatic conditions, albedo, energy efficiency, and carbon processes, while the economic, social, and institutional dimensions incorporated indicators associated with energy consumption, population, quality of life, participation, governance, and environmental policies. The localization process resulted in 12 operational indicators structured into two groups. The first comprised urban drivers and pressure indicators, including building density, population density, accessibility to metro and bus stations, nighttime light intensity, and air pollution. Public transportation accessibility can reduce private vehicle dependence and transportation-related emissions, while nighttime light intensity serves as a proxy for urban activity and energy consumption. The second group included ecological and environmental regulating indicators, namely vegetation density, sky-view factor, land surface temperature, water resources, albedo, and annual precipitation, representing capacities that support climatic regulation and adaptation.
The selected indicators showed direct and indirect relationships. Vegetation density, water resources, annual precipitation, and albedo had positive direct effects on environmental resilience. Vegetation contributes through carbon sequestration, shading, and evapotranspiration; water resources support thermal regulation and ecological capacity; precipitation contributes to moisture and water availability; and albedo influences solar radiation reflection. Conversely, air pollution and land surface temperature act as environmental stressors with negative direct effects on resilience.
Other indicators operate through indirect or mediated relationships. Public transportation accessibility can influence resilience by changing mobility behavior and reducing private vehicle use, thereby decreasing traffic-related emissions and air pollution. Higher building and population densities can increase energy demand and urban activity, with effects reflected in nighttime light intensity. Dense development may also reduce the sky-view factor, restrict natural ventilation, and increase heat retention, contributing to urban heat island effects. These interactions indicate that environmental resilience emerges not from isolated indicators but from interconnected physical, demographic, environmental, and functional processes.
Conclusion:
The research concludes that integrating environmental resilience with the carbon-neutral city approach provides a comprehensive framework for understanding and managing urban environmental conditions. The systematic review demonstrated substantial conceptual and functional overlap between the two approaches, particularly in reducing environmental pressures, carbon emissions, and climatic vulnerability while strengthening ecological capacities. Although 81 indicators were identified from the international literature, their direct local application was constrained by differences in spatial context, data availability, and analytical requirements. The selection of 12 operational indicators therefore represents a transition from a broad theoretical framework toward a spatially measurable and context-sensitive model.
The proposed conceptual–operational model represents the relationships between urban pressures and environmental regulating capacities in District 6 of Tehran. Its main contribution is transforming theoretically identified indicators into measurable spatial variables that can be represented as GIS-based raster or parcel-scale datasets. This reduces the gap between theoretical discussions of environmental resilience and practical urban planning applications, providing a foundation for spatial monitoring, vulnerability identification, intervention prioritization, and evidence-based decision-making. Moreover, the computational compatibility of the selected indicators provides an appropriate data foundation for subsequent quantitative and machine-learning analyses. Ultimately, resilient and carbon-neutral urban development requires an integrated approach that reduces anthropogenic pressures, strengthens ecological capacities, improves environmental quality, and supports carbon reduction. The framework provides a localized methodological basis for these objectives and can be adapted to other urban contexts following appropriate local assessment and validation.