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 animated visualization represents a time history of atmospheric carbon dioxide in parts per million (ppm) from 1979 to 2011, and then back in time to 800,000 years before the present.

This is a video overview of the history of climate science, with the goal of debunking the idea that in the 1970s, climate scientists were predicting global cooling.

In this activity, 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.

This video features CU Boulder Professor Jeff Mitton and his research team, who study the effects of mountain pine beetle infestations on the forest ecology in the Rocky Mountains. They explain the pine beetle life cycle and how they attack trees. An outlook into the future is also provided.