The need for well-designed learning experiences about modern, anthropogenic climate change is great. In light of this need, many scholars have looked towards museums, arguing that as trusted institutions of informal learning, museums are uniquely positioned to support public engagement with contentious, impactful issues like climate change. However, while several museum exhibits have emerged over recent years, empirical research on museum-based learning experiences remains quite limited. We take a step towards advancing understanding of museum-based climate change learning through an empirical investigation at a natural history museum in the US. This study examines learners' collaborative discourse within one exhibit about climate change, a multiplayer video game called Utah Climate Challenge (UCC). Investigating moments of failure and struggle, we analyze learners' forms of collaboration through moment-to-moment discourse analysis. Findings demonstrate the importance of scaffolding multiple types of collaboration, as well as the potential for a collaborative, museum-based videogame to support learning of important science concepts relevant to climate change.