TOWARD CLIMATE-RESILIENT SPANISH CITIES: EVALUATING ALTERNATIVE URBAN GROWTH PATTERNS THROUGH GIS, REMOTE SENSING, AND ENVIRONMENTAL RISK MODELLING

Abstract

Urban expansion and intensifying climate pressures create challenges for balancing development, environmental protection, and population safety in Spanish cities. This study develops an integrated framework to evaluate the climate resilience implications of alternative urban growth patterns using geographic information systems (GIS), remote sensing, and environmental risk modelling. The dataset comprises 24,000 spatial grid cells across Madrid, Barcelona, Valencia, and Seville, combining satellite observations from 2015 to 2025 with land cover, surface temperature, vegetation, elevation, rainfall, drainage, population, and infrastructure indicators. Satellite imagery is processed to quantify built environment expansion, vegetation dynamics, and thermal conditions, while GIS enables spatial integration, hazard mapping, and exposure assessment. Compact development, dispersed expansion, and polycentric development scenarios are simulated for 2035 using a consistent population growth assumption. Scenario performance is evaluated through flood exposure, urban heat intensity, land consumption, green space connectivity, and population exposure. A random forest model identifies high risk locations, supported by spatially separated training, validation, and testing partitions to limit spatial leakage. The model achieves an area under the receiver operating characteristic curve of 0.91 and an F1 score of 0.86. Compared with dispersed expansion, compact development reduces additional land consumption by 28.4% and population exposure to mapped flood hazards by 16.7%; however, mean summer surface temperature increases by 0.8°C where vegetation provision remains unchanged. Polycentric development incorporating connected green infrastructure reduces the composite environmental risk index by 21.6%, improves green space connectivity by 18.9%, and lowers mean summer surface temperature by 1.2°C relative to dispersed expansion. Sensitivity analysis demonstrates that rainfall assumptions, vegetation allocation, and indicator weighting influence the relative performance of development scenarios. The findings indicate that compactness alone is insufficient to deliver climate resilience and should be complemented by coordinated drainage, vegetation, and infrastructure planning. The proposed framework supports transparent comparison of urban development alternatives and provides spatial evidence for climate sensitive planning in Spain. Its application highlights the value of integrating growth management with environmental risk assessment, while validation against observed hazard outcomes and additional climate projections remains necessary to establish transferability across diverse metropolitan settings and planning contexts.