The Paris Agreement not only shifted the course of global climate diplomacy – it catalyzed a new era of bottom-up action. At the heart of that transformation were cities, states, and regions: subnational actors that recognized climate change as both an urgent and tangible threat and an opportunity to build a better, healthier, more resilient future for their communities. This publication tells the story of how local climate ambition has moved from the margins to the mainstream.

The 10-year anniversary of the Paris Agreement is a critical milestone, offering us the opportunity to reflect on a decade of local climate leadership and signal the decisive role subnational governments must continue to play in delivering on the Paris goals – especially as countries prepare their next round of Nationally Determined Contributions (NDCs) ahead of COP30 in Belém, Brazil.