Examining the policy needs for implementing nature-based solutions in cities: Findings from city-wide transdisciplinary experiences in Glasgow (UK), Genk (Belgium) and Poznan (Poland)

To advance the science and practice of implementing nature-based solutions in cities, it is important to examine the obstacles and provide means to overcome them. This paper presents a conceptual framework of policy needs for analysing the science of nature-based solutions' implementation and connect it to the practice of their implementation that advances the literature by connecting well-researched gaps to a more innovative action-oriented policy development approach that we argue is required for embedding scaled-up nature-based solutions. We conceptualise and ground the policy needs framework of skills, knowledge and partnerships theoretically in current literature of NBS policy and planning and empirically in three European case study cities: Genk in Belgium, Glasgow in UK and Poznan in Poland. The cross-case study analysis points to the knowledge needs of systems' thinking and solutions-oriented thinking as paramount for implementing nature-based solutions. Our analysis further points to the skills' needs of negotiation and collaboration for administrative silo bridging and for forging multi-sectoral partnerships essential for planning, and co-managing NBS. We conclude with three ways forward to addressing the policy needs for implementation: first, cities can invest in tailored and targeted capacity building programs, second, institutional spaces need to be established that allow for collaborative learning through and for partnerships and third, cities need to chart governance innovations that promote evidence-based policy for nature-based solutions' design and implementation.