Climate change is increasingly experienced at the local level, where cities serve as both frontline responders and laboratories for innovation. This panel, Climate Sister Cities – When Urban Challenges Meet Innovative Green Solutions, brings together municipal leaders and practitioners from Québec, New York, and the greater US, to explore how cross-border collaboration is accelerating urban climate action. Through concrete case studies, panelists will highlight successful initiatives ranging from clean energy integration and resilient infrastructure to sustainable mobility 2 expansion, and community-based adaptation strategies. By examining what has worked—and why—this discussion will underscore the tangible environmental gains achieved through shared expertise and coordinated local action. The conversation will also address persistent challenges, including regulatory misalignment, financing constraints, and scaling pilot projects into long-term solutions. Emphasizing the value of knowledge exchange, the panel will identify opportunities for deeper cooperation and replication of best practices across jurisdictions. At a time when cities are under increasing pressure to deliver measurable climate outcomes, this session will demonstrate how “sister city” partnerships can move beyond symbolic ties to become engines of practical, results-driven climate solutions.