Do nature-based solutions deliver climate adaptation equally? Comparing mangroves and seawalls in the Global South

Coastal communities in the Global South face growing risks from climate change. While grey infrastructure remains dominant in climate change adaptation approaches, its limitations have driven interest in nature-based solutions. This study compares the impacts of a mangrove restoration and a tide embankment project on social, physical, human, natural, and financial capitals in Tacloban City in the Philippines using the Sustainable Livelihoods Framework. Through a mixed-methods approach, we combined household surveys, interviews, and focus group discussions to evaluate how these two infrastructure types differ in delivering climate adaptation outcomes. Results showed that differences emerged primarily in physical capital, where the seawall was associated with higher perceived infrastructure protection, durability, and housing safety. In contrast, qualitative data revealed that mangroves contributed more to natural capital, supporting biodiversity and ecosystems. Impacts on social and financial capital were similar across projects. While both projects enhanced human capital through improved perceived safety, seawall communities had higher rates of displacement but also expressed greater pride in the final infrastructure as a symbol of identity. Findings reveal that while seawalls are perceived to offer greater durability, they are associated with significantly higher rates of community displacement and estimated construction costs that are several hundred times higher than mangrove restoration per meter of coastline. These results suggest that nature-based solutions offer a more equitable and cost-effective pathway to resilience by delivering superior natural capital and community stewardship at a fraction of the investment required for grey infrastructure.