Tackling climate change and improving ecosystems and the services that ecosystems provide for people are quintessentially global challenges given that nature doesn’t respect political boundaries. However, in addition to the policy, regulatory and macro-financial levers that are certainly necessary at the national and international level, these challenges also require more intimate and contextually attuned place-based action. Nature-based solutions that are designed to tackle these challenges are demonstrably more effective at the city level, especially when cities work together to share knowledge and know-how within a range of national and international policy frameworks. Developing and implementing policies, strategies, and actions on this basis require monitoring and evaluation to ensure that impacts are optimized and in order for such sharing to take place.