Nature-based Solutions (NbS) – What are They and What are the Barriers and Enablers to Their Use?

This rapid review examines literature around Nature-based Solutions (NbS), what are NbS, the pros and cons of NbS, design and implementation issues (including governance, indigenous knowledge), finance and the enabling environment. The breadth of NbS and the evidence base means that this rapid review only provides a snapshot of the information available, and therefore does not consider all types of NbS, nor all sectors that they have been used in. Considering this limited scope, this report highlights many issues, some of which are that Covid-19 has highlighted the importance of NbS, Pros of NbS include the low cost compared to infrastructure alternatives; the flexibility in addressing multiple climate challenges; potential co-benefits such as better water quality, improved health, cultural benefits, biodiversity conservation. The literature also notes the cons of NbS including slow adaptation or co-benefits, very context specific making effectiveness difficult to measure and many of the benefits are non-monetary and hard to measure. The literature consulted suggest a number of knowledge gaps in the evidence base for NbS effectiveness including lack of: robust and impartial assessments of current NbS experiences; site specific knowledge of field deployment of NbS; timescales over which benefits are seen and experienced; cost-effectiveness of interventions compared to or in conjunction with alternative solutions; and integrated assessments considering broader social and ecological outcomes