Assessing the implementation process of Ecosystem-based Adaptation in coastal urban areas

Nature-based solutions (NbS) are regarded as an umbrella concept for actions focused on nature conservation and restoration, offering a range of social, economic, and environmental benefits. When specifically dealing with climate change adaptation, the term Ecosystem-based Adaptation (EbA) is also applicable. This research investigates EbA as a strategy to tackle the escalating climate challenges faced by coastal urban areas, including changing water regimes, and more frequent and severe floods and droughts. The study develops a decision-support framework aimed at guiding local governments in successfully implementing EbA. It highlights the importance of proposing protocols to evaluate the EbA implementation process in coastal urban areas. This framework is based on three core areas: governance systems, policy framework, and sustainable funding, with a set of indicators proposed for each area.  

Within governance systems, the framework highlights the necessity of horizontal (within the same governance level) and vertical (across different administrative levels) cooperation. Political support, scientific expertise, and co-creation with local stakeholders are essential for integrating EbA into planning processes. Moreover, flexible governance structures enable institutions to adapt and ensure the sustainability of interventions. 

Under policy framework, the framework proposes incorporating EbA into climate adaptation plans, urban policies, and international agreements, enhancing its uptake. Alignment between local regulations and broader strategic objectives, such as the EU Green Deal or the UN Sustainable Development Goals, reduces conflicts and supports EbA prioritization. 

Sustainable funding is critical for scaling EbA. This study explores innovative mechanisms such as Public-Private Partnerships (PPPs), ecological fiscal transfers, and fiscal incentives. These mechanisms complement traditional funding sources, such as local budgets and EU grants, to ensure long-term viability of EbA solutions. 

The decision-support framework was tested across ten EbA initiatives of Spain and Portugal, focusing on coastal urban areas vulnerable to flooding. Examples include wetland restoration, urban farming, and green corridors in cities such as Lisbon, Barcelona, and Santander. The assessment revealed common challenges in implementing EbA measures, such as bureaucratic delays, governance misalignments, and limited fiscal incentives. However, successful cases demonstrated the importance of political support, horizontal cooperation, and stakeholder involvement. 

While EbA are increasingly recognized at the EU level, its local implementation remains limited. Addressing governance challenges, aligning policies, and securing diverse funding sources are crucial for scaling EbA interventions. The assessment conducted in this study underscores the need for adaptive governance and the inclusion of diverse stakeholders in planning and execution of EbA. In addition, the research emphasizes the importance of adopting a systemic approach to incorporate EbA into local adaptation strategies, enhancing the resilience and stability of coastal cities. This research aims to contribute to a better understanding of how EbA can foster climate adaptation and urban resilience, offering practical tools to bridge the gap between policy and practice.