The goal of this field and laboratory- based course is to explore the idea that humans can, or should try to ‘save the earth'. What does this mean? And who are we really trying to ‘save' when we recognize and try to modify the course of recent climate and environmental changes in the earth system? To explore this idea we need to think on two, very different scales of earth history: as a geologist and as a citizen of the earth. Here are pictures from our trip to the Florida Keys to investigate the health of the ocean.