This paper presents a case study conducted as part of the International Geodesign Collaboration (IGC), focusing on the central-southern region of Belo Horizonte, Brazil—a densely built urban area experiencing climate change impacts such as extreme heat and flooding. The goal was to test the IGC framework and tools provided through the Global Climate Geodesign Challenge (GC) to facilitate geodesign workshops and simulate potential CO₂ reductions resulting from proposed Climate Actions (CAs). The study describes the applied methodology and analyzes the group’s contributions, including the use of a geoportal (WMS service) and an If-then model to simulate projected future conditions for 2050 based on the negotiated final scenario.