Investing in Nature-based Solutions (NbS) is a smart action to back one of the most effective, inclusive and future-proof forms of adaptation we have. By harnessing natural processes, we can protect lives and assets, reduce losses, embed community participation and generate new opportunities for growth.  

Evidence increasingly shows that nature-based solutions deliver strong economic returns while enhancing resilience. GCA analyses across Africa and Bangladesh indicate benefit–cost ratios of 2:1 to 4:1, yet NbS remain under-financed as critical ecosystem services—such as flood regulation and improved biodiversity—are rarely monetized. New research by GCA and the University of Oxford demonstrates that targeted NbS investments of USD 3.6 billion across Africa could avert USD 7.6 billion in losses by 2100, with benefit–cost ratios rising to up to 8:1 when applied strategically at corridor, catchment or landscape scale.  

If we are to close the adaptation finance gap, then unlocking the full potential of NbS is not just desirable—it is indispensable. 

This Adaptation Insights builds on GCA technical assistance to integrate green adaptation measures into large-scale infrastructure investment programs under the Africa Adaptation Acceleration Program. It further draws on advanced research conducted by the Environmental Change Institute at the University of Oxford, in partnership with GCA, on the application of spatial analytics and financial frameworks to scale nature-based solutions for transport infrastructure resilience globally (Scaling Investments for NbS: GCA portal). The observations presented reflect cumulative evidence and experience derived from collaboration with multilateral development banks and implementation partners engaged in mainstreaming climate adaptation within infrastructure planning and finance.