Nature-based solutions for climate change adaptation: A systematic review of systematic reviews
Brian Alan Johnson, Pankaj Kumar, Naoyuki Okano, Rajarshi Dasgupta, Binaya Raj Shivakoti
Abstract
More than 90 systematic reviews have been conducted on the topic of nature-based solutions for climate change adaptation (NBS-CCA). These prior reviews, however, are scattered across more than 45 different peer-reviewed journals and gray literature sources, making it difficult to follow all of the knowledge generated and remaining research gaps. In this study, we conducted a systematic review of systematic reviews on the topic of NBS-CCA, with the objective of mapping and analyzing these prior reviews. We found that most of the prior systematic reviews had relatively narrow research focuses, typically focusing on a particular geographic context of NBS-CCA (mainly in urban and coastal areas) or on a particular aspect of NBS-CCA planning/implementation (mainly outcomes assessment and policy/governance issues). Fewer reviews focused on mountainous areas or on social and financial aspects of NBS-CCA planning/implementation. The majority reviews relied solely on peer-reviewed literature for analysis, with only 26% including gray literature, despite the large amount and variety of gray literature on NBS-CCA that exists. Notably, we found that no prior systematic reviews have yet attempted to comprehensively analyze all geographic contexts and all aspects of NBS-CCA, e.g. through a review and meta-analysis of all available peer-reviewed and gray literature on the topic. This would likely require a massive multidisciplinary effort, but could be a worthy endeavor considering the realized need to integrate NBS-CCA into national/subnational policies and various international environmental agreements pertaining to climate change (e.g., Paris Agreement) and biodiversity conservation (e.g., Post-2020 Global Biodiversity Framework).