Challenges and Opportunities in the Use of Nature-Based Solutions for Urban Adaptation

The concept of nature-based solutions (NbS) has been endorsed by multiple international organizations as one of the priority approaches to address climate-related challenges. These solutions are versatile, and can simultaneously address challenges such as climate impacts, public health, inequality, and the biodiversity crisis, being uniquely suited for urban adaptation. NbS are particularly relevant in the developing world, where strategies should be as self-reliant as possible, reducing the need for technological processes that require expensive and complex maintenance. NbS can also promote political, societal, cultural, and ultimately, systems change. The purpose of this paper is to present a literature review on the use of NbS for urban adaptation, identifying the main opportunities, challenges, and, most specifically, knowledge gaps, which can be addressed in subsequent research. The present paper identifies four types of knowledge gaps that are particularly relevant for the use of NbS for urban adaptation: future climate uncertainty, lack of site-specific technical design criteria, governance strategies, and effectiveness assessment evaluation. To overcome local governments’ limitations, specific implementation strategies and structures should be considered, centered on knowledge transfer within a transdisciplinary and participatory framework. These should be developed in partnership with urban planning entities, seeking to consolidate these approaches in policies that support social resilience and institutional capacity. Therefore, urban adaptation should be initiated with pilot projects to simultaneously address the urgency for implementation, while allowing urban planning practices the time to adjust, building capacity at the local level, and filling knowledge gaps through the assessment of effectiveness. The climate-resilience of urban tree species adequate to the future climate was identified as a relevant knowledge gap for the implementation of NbS.