In this investigation, groups of students will graph data reflecting temperature anomalies over a short period in the recorded climate history of the world or in part of the Great Lakes region. Using only their own data, they will predict how their actual temperature anomaly trend might continue. That is, with limited data, what do they conclude about the future? As all student groups assemble and observe the trend of the 130-year data set, they may conclude that having a larger data set offers more confidence in predictions. Students will learn to identify a trend in a set of graphic data, evaluate and discuss the difficulties inherent in interpreting and forecasting long- and short-term trends, and analyze data, draw conclusions about whether temperature anomalies are evidence of global warming, and defend their conclusions.