This NOAA visualization on YouTube shows the seasonal variations in sea surface temperatures and ice cover from 1985 to 2007. The visualization is based on data collected by NOAA polar-orbiting satellites. El NiÃo and La NiÃa are easily identified, as are the trends in decreasing polar sea ice.

This National Geographic video explains the origins of the El NiÃo Southern Oscillation using animations and shows the impacts on humans, wildlife and habitat, particularly in the United States.

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.

This video features University of Wisconsin-Madison researcher John Magnuson, who studies the ecology of freshwater systems. He explains the difference between weather and climate using data on ice cover from Lake Mendota in Madison, WI. Analysis of the data indicates a long-term trend that can be connected to climate change.

This animation demonstrates the changing declination of the sun with a time-lapse animation. It shows how the shadow of a building changes over the course of a year as the declination of the sun changes.

A sequence of five short animated videos that explain the properties of carbon in relationship to global warming, narrated by Robert Krulwich from NPR.

This video is the second of a three-video series in the Sea Change project, which follows the work of Dr. Maureen Raymo, paleogeologist at Columbia University's Lamont-Doherty Earth Observatory, who travels with fellow researchers to Australia in search of evidence of sea level that was once higher than it is today.

This short cartoon video uses a simple baseball analogy (steroid use increases probability of hitting home runs) to explain how small increases in greenhouse gases can cause global temperature changes and increase the probability of extreme weather events.

In this audio slideshow, an ecologist from the University of Florida describes the radiocarbon dating technique that scientists use to determine the amount of carbon within the permafrost of the Arctic tundra. Understanding the rate of carbon released as permafrost thaws is necessary to understand how this positive feedback mechanism is contributing to climate change that may further increase global surface temperatures.

In this video, adapted from KUAC-TV and the Geophysical Institute at the University of Alaska, Fairbanks, viewers learn how one-celled organisms in permafrost may be contributing to greenhouse gas levels and global warming.

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