c. The amount of solar energy absorbed or radiated by Earth is modulated by the atmosphere and depends on its composition. Greenhouse gases— such as water vapor, carbon dioxide, and methane— occur naturally in small amounts and absorb and release heat energy more efficiently than abundant atmospheric gases like nitrogen and oxygen. Small increases in carbon dioxide concentration have a large effect on the climate system.

This animation depicts the carbon cycle in a fashion that is suited for younger audiences. The video discusses how carbon enters and exits the environment through both natural and human-driven ways.

In this video, students see how data from the ice core record is used to help scientists predict the future of our climate. Video features ice cores extracted from the WAIS Divide, a research station on the West Antarctic Ice Sheet.

This video examines the thawing of permafrost due to changes in climate and shows examples of the impacts that warming temperatures have on permafrost in the Arctic, including the release of the greenhouse gas methane. Dramatic results are shown, including sink holes forming on the landscape and beneath buildings, roads, and other infrastructure, causing some communities to relocate.

In this video segment, two students discuss the greenhouse effect and visit with research scientists at Biosphere 2 in Arizona, who research the effects of global climate change on organisms in a controlled facility. Their current research (as of 2002) focuses on the response to increased quantities of CO2 in a number of different model ecosystems.

This video segment demonstrates carbon dioxide's role in the greenhouse effect and explains how increasing concentrations of C02 in the atmosphere may be contributing to global warming. Video includes an unusual demonstration of C02's heat-absorbing properties, using infrared film, a researcher's face, and a stream of C02 between them.