A novel game that captures the central dimensions of climate change mitigation as a social dilemma is presented. Students play the role of countries sharing a global atmosphere. In each round, carbon emissions are released and accumulated in the atmosphere, making climate change consequences more severe and difficult to mitigate over time. Without mitigation, CO[subscript 2] accumulations will cause losses to all countries. During each round, countries decide on how to invest their endowments between economic development and mitigation to slow down carbon emissions causing climate change. Central to the game and the subsequent classroom discussions are implications emanating from introducing uncertainty and inequality in the game. The game is suitable for courses related to environmental economics and climate policy at undergraduate and graduate levels.