Quantifying the Cooling Nexus of Green-Blue Infrastructure in Hyper-Arid Cities: A Spatial Ecosystem Services Approach

While many studies have investigated ecosystem services, the cooling potential of green and blue infrastructures (GBIs) for alleviating extreme heat in arid regions has been studied less frequently. The aim of this study is to measure GBI cooling potential for mitigating extreme heat in arid and semi-arid regions, using Ahvaz City (south-west Iran) as a case study. Multiple data sources were used with the InVEST urban cooling model to estimate cooling ecosystem services (CESs) by evaluating the cumulative effects of shade, evapotranspiration, and albedo. Results show: (a) spatial heterogeneity in GBI cooling effects; (b) the highest cooling capacity (Cooling Capacity Index = 0.75) is achieved along the Karun River corridor and adjacent irrigated agriculture, where land surface temperature is reduced by 2–6 °C relative to built-up areas; and (c) interconnected GBIs and high vegetation density enhance cooling. High cooling capacity (>0.6) covers only 8.3% of the city (14.2 km2), predominantly the Karun River (4.2 km2) and adjacent agriculture (10.0 km2). In contrast, built-up areas (76% of the city) exhibit low cooling capacity (<0.3). Therefore, improving GBI connectivity and integrating passive cooling strategies are essential to enhance thermal resilience and should be prioritized in urban planning to maximize CES effectiveness and reduce heat-related risks.