The cooling effect of urban green spaces as nature-based solutions for mitigating urban heat: insights from a decade-long systematic review

Urban green spaces (UGS) are increasingly recognized as effective nature-based solutions (NBS) to mitigate urban heat through cooling mechanisms such as shading, evapotranspiration, and enhanced albedo. This systematic review analyzes research conducted over the past decade (2014–2024) to assess the cooling benefits of UGS, particularly in hot and arid climates. The study synthesizes findings from 84 peer-reviewed articles, examining key mechanisms including shading, evapotranspiration, and spatial configuration, while also addressing the obstacles faced in implementing UGS. It identifies critical factors, such as vegetation density, species selection, spatial patterns, and urban morphology, which influence the cooling effect. Extracted from individual studies, these results highlight that UGS can lower temperatures by 1–7 °C, with cooling intensity influenced by vegetation type, spatial configuration, and urban morphology. The study also highlights challenges in UGS planning and implementation, particularly in hot and arid climates, where water scarcity and urban density pose significant constraints. Key findings emphasize the importance of optimizing UGS design to maximize cooling benefits, integrating strategies such as spatial connectivity, species diversity, and innovative water management systems. By addressing knowledge gaps and issues, this review provides actionable insights for urban planners and policymakers to enhance the effectiveness of UGS in reducing urban heat island (UHI) effects, with a particular focus on climate-adaptive and context-specific strategies.