From the introduction: In this exercise, students role-play advisors to various heads of state on the subject of global warming. The web site offers a curriculum to help the students become experts on global warming. It offers lab activities, computer visualizations (using free WorldWatcher software), lots of background readings, and choose-your-own-adventure journeys through the carbon and water cycles. The unit concludes with a summit on global warming at which students give their presentations. For teachers, there is a pedagogical explanation for each activity and rubrics for the presentation and for an energy balance diagram assignment.