Abstract

The global significance of nature-based solutions (NbS) is increasingly emphasized, yet practical and evidence-based guidance on defining and implementing effective NbS strategies remains limited. This review synthesizes findings from twenty key empirical studies that examine the role of urban green and blue spaces (GBS) in addressing two of the IUCN’s societal challenges: (1) climate change mitigation and adaptation, with a focus on urban heat reduction, and (2) disaster risk reduction, with a focus on urban flood mitigation. Evidence across the literature shows that GBS meaningfully reduce both surface temperatures and flood risks. The effectiveness of GBS is determined not only by expanding their coverage but also by designing interconnected ecological systems with optimized spatial configuration, vegetation structure, hydrological linkages, and by ensuring that they are positioned in the urban areas most vulnerable to heat and flooding. To enhance urban climate resilience, cities should adopt scale-appropriate design and placement strategies and integrate GBS within existing infrastructure networks. Future research should develop standardized performance metrics, assess long-term outcomes under climate change scenarios, and strengthen evidence-based urban planning that positions NbS as a central component of sustainable and resilient city development.