Students explore the increase in atmospheric carbon dioxide over the past 40 years with an interactive online model. They use the model and observations to estimate present emission rates and emission growth rates. The model is then used to estimate future levels of carbon dioxide using different future emission scenarios. These different scenarios are then linked by students to climate model predictions also used by the Intergovernmental Panel on Climate Change.

In this activity, students compare carbon dioxide data from Mauna Loa Observatory, Barrow, Alaska, and the South Pole over the past 40 years. Students use the data to learn about what causes short-term and long-term changes in atmospheric carbon dioxide. This activity makes extensive use of Excel.

Climate has varied in the past, but today's climate change rate is much more drastic due to human activity. Students explore past climate cycle graphs and compare the cycles with the current rate of change.