At the start of an integrated Algebra I and Environmental Science class, students were presented with the following challenge: "How much carbon is stored in the Normanskill Preserve?" They were told they had one month to investigate and present their results, and asked, "What do you need to begin?" This hook served to introduce the next project in the author's 100% project-based curriculum. It addresses both the New York State Learning Standards and the National Science Education Standards. This article describes the project in more detail and what students learned along the way. (Contains 1 figure and 7 online resources.)