World Builders: Imagining Our Green Future is an interactive, game-based workshop using the cooperative board game Climate Cooldown to guide middle school students from climate awareness to climate agency. Rather than presenting the climate crisis as overwhelming, this workshop reframes it as an invitation — one that calls for exactly the creativity and collaboration young people are uniquely positioned to offer. Students begin by exploring Climate Cooldown's issue and solution cards, selecting the problems they care most about and the solutions they find most relevant — from indigenous land stewardship and composting to clean energy and green cities. They then play a structured mini-game matching issues to solutions, building systems thinking skills while keeping the experience playful. From there, groups move into world-building: using the ABT (And-But-Therefore) storytelling framework, they craft a short narrative imagining a future where their chosen solutions have taken hold, then illustrate that vision on a shared poster. Finally, students identify the career pathways, academic subjects, and advocacy roles they could play in making that future real — and briefly present their world to the group. Grounded in a Theory of Change centered on student values, identity, and self-efficacy, this workshop helps students build genuine confidence in their ability to participate in the change they want to see. Every activity is designed for multiple modes of engagement and culturally responsive facilitation, ensuring full access for all learners. Students leave with a story, a vision, and a sense of their place in the green future they just imagined.