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.

One of a suite of online climate interactive simulations, this Greenhouse Gas Simulator uses the bathtub model to demonstrate how atmospheric concentrations of CO2 will continue to rise unless they are lowered to match the amount of CO2 that can be removed through natural processes.

This video segment from 'Earth: The Operators' Manual' explores how we know that today's increased levels of CO2 are caused by humans burning fossil fuels and not by some natural process, such as volcanic out-gassing. Climate scientist Richard Alley provides a detailed step-by-step explanation that examines the physics and chemistry of different "flavors," or isotopes, of carbon in Earth's atmosphere.

This lesson covers different aspects of the major greenhouse gases - water vapor, carbon dioxide, methane, nitrous oxides and CFCs - including some of the ways in which human activities are affecting the atmospheric concentrations of these key greenhouse gases. This is lesson six in a nine-lesson module about climate change.

This activity describes the flow of carbon in the environment and focuses on how much carbon is stored in trees. It goes on to have students analyze data and make calculations about the amount of carbon stored in a set of trees at three sites in a wooded area that were to be cut down to build a college dormitory.