Evolution and global trends in nature-based solutions for eco-city planning: a bibliometric analysis (2005–2025)

Nature-Based Solutions (NBS) are increasingly recognized as a strategic approach to addressing urbanization, climate change, and ecological degradation in cities. This study employs a bibliometric analysis of Scopus-indexed publications from 2005 to 2025 to examine global research trends on NBS in the context of eco-city planning. Based on a final corpus of 148 documents, the analysis identifies five major thematic clusters: green infrastructure and urban resilience; NBS and climate change adaptation; blue-green infrastructure; urban biodiversity and ecosystem services; and smart sustainable cities. The findings indicate that explicit NBS for eco-city planning most frequently include urban forests, wetlands, green roofs, permeable green spaces, ecological corridors, and blue-green infrastructure systems. China, the United Kingdom, and Norway emerged as the leading contributing countries in the screened corpus. Overall, the results show that NBS research has evolved from broad sustainability discourse toward more integrated approaches linking ecosystem services, climate adaptation, biodiversity, and urban resilience. The study highlights the growing importance of embedding explicit NBS interventions into urban planning frameworks and calls for stronger research attention to underrepresented regions, particularly in developing countries, to support sustainable urban transformation.