Governing Urban Wetlands for Decarbonization: Integrating Policy, Infrastructure, and Biogeochemistry

Urban wetlands are increasingly promoted as nature-based solutions for climate mitigation, yet their greenhouse gas outcomes remain highly variable and, in some cases, counterproductive. While wetlands can sequester substantial amounts of carbon, methane and nitrous oxide emissions often offset these gains, particularly in urban environments where hydrology, nutrient loading, and disturbance regimes are tightly managed. This Perspective argues that carbon outcomes in urban wetlands are not determined by ecological potential alone but by governance decisions that shape design, infrastructure operation, monitoring, and institutional coordination. Rather than presenting new empirical data, we reframe existing biogeochemical knowledge through a policy science lens to identify controllable decision points that determine whether urban wetlands function as net climate assets or as liabilities. We outline four interlinked strategies: governance-informed riparian and wetland design, low-carbon operation of urban water infrastructure, adaptive monitoring and measurement-reporting and verification systems, and institutional alignment through water rights and regulatory frameworks. Together, these strategies reposition urban wetlands from passive ecosystem services to actively managed climate-friendly infrastructure. Recognizing wetlands as governable systems provides a pragmatic pathway for integrating urban wetlands into decarbonization strategies under real-world institutional and resource constraint scenarios.