Abstract

Nature-based solutions (NbS) use nature and natural processes to address societal challenges and protect ecosystems. More specifically, they provide physical risk reduction benefits, they create or maintain habitat and biodiversity, and they provide social and equity benefits to the communities that interact with and maintain them.

This report summarizes the state of knowledge of this topic in the context of coastal climate adaptation in the United States and identifies numerous challenges and opportunities. Findings are useful for practitioners, nongovernmental organizations (NGOs), climate service providers, state regulators, federal agencies, and myriad institutions and researchers engaged with NbS. We address two main Action Areas for NbS implementation: understanding and evaluating effectiveness, and identifying the challenges that can be overcome to accelerate coastal adaptation with NbS.

We identified three specific bottlenecks where action is constricted and can be facilitated with specific and actionable measures:

1. First, GOVERNANCE is the most critical opportunity for accelerating applications of NbS. Practitioners need governance structures that meet ongoing systemic needs and address historical, current, and future contexts. This includes supporting Indigenous knowledges and practices, and moving planning from preserving a past baseline to flexibly managing for an adaptive future. Systems-based approaches can support adaptive management, but are only possible where regulations and institutions support them.
    
2. Second, we cannot address governance without better COMMUNICATION and COLLABORATION. Collaboration is frequently the unpaid and invisible labor of NbS—it is a critical ingredient for success and lack of collaboration is often cited as a significant limitation to progress.
    
3. Finally, EQUITY is at the heart of effective NbS, and using an equity lens to evaluate effectiveness provides important framing to ask effectiveness for whom (or what), at what cost to whom? Naming and valuing the co-benefits of NbS and hybrid projects are critical to advancing equity in this space.