Assessing barriers to ecosystem-based adaptation: Application to tropical islands.

Barriers to ecosystem-based adaptation (EbA), which is part of the broader nature-based solutions (NbS) category, remain poorly understood and assessed. This article addresses this research gap, by proposing a structured analytical framework to understand barriers and applying it to 24 coastal EbA projects deployed in French tropical island territories. This framework considers four dimensions of barriers: categories, origins, impacts on the adaptation process, and temporalities. The findings highlight three main barriers relating to institutions, governance, politics, laws and regulations (35%); awareness, knowledge and technical resources (20%); and finance (15%). Most barriers are objective (80%), contextual (51.7%) and not adaptation specific (63.3%). Prevalent adaptation-specific barriers are the lack of or weakness of EbA-oriented policy and tools (59.5%) and lack of a future-oriented risk- and solution-based approach (27.0%). Most barriers (56.7%) affect two stages of the adaptation process (readiness and implementation) and were not overcome over the lifetime of the projects (53.3%). Thirteen solutions to barriers were implemented, with information, knowledge and awareness sharing or strengthening and increased coordination efforts being the most utilised and successful. This study highlights the benefits of including a barrier-oriented analysis in the evaluation of adaptation projects and proposes an operational and transferable framework to do so.