IVL Swedish Environmental Research Institute

Across the globe, water security is under threat. Climate change and watershed degradation are driving up costs and increasing the frequency of disruptions for water users—impacts that are hitting the world’s most vulnerable communities hardest. These same forces are contributing to unprecedented habitat destruction and biodiversity collapse. Nature-Based Solutions (NbS) are proven to help address these acute water challenges as they deliver resilient, lower-cost water and sanitation services, extend the service life of traditional grey infrastructure and support thriving biodiversity and communities.

The good news is that investments in NbS for water are gaining important momentum. In fact, investments doubled over the past decade, reaching USD 49 billion in 2023.3 But while some countries and regions appear to be embracing the approach, uptake remains remarkably uneven. This disparity in uptake raises a number of questions for decision makers, including: what is the role of policy in mainstreaming investments in NbS at a watershed scale? And what enabling conditions are necessary to succeed? The Power of Policy aims to answer these questions and, in doing so, help policy makers deliver targeted reforms that will accelerate NbS delivery for the benefit of people and nature.

This research distils insights from existing literature, 17 original country case studies, and over 75 expert interviews. The selection of case studies captures the wide range of political, legal, and economic contexts in which NbS for water investment are delivered today. The findings of the case studies underscore the fact that policies driving investment in water security are embedded in political, legal, financial, and social systems—each offering a unique set of opportunities and barriers for NbS deployment. As such, the study doesn’t propose a one-size-fits-all set of reforms for policy makers to adopt. Rather, for the first time, it captures a comprehensive set of enabling conditions based on real-world experience and distils these findings into an analytical framework. This framework is a tool to support policy makers in understanding where policies are enabling or inhibiting NbS adoption where they work, and with insights from case studies and broader findings, design actionable and locally targeted reforms to enable investment in NbS.