This visualization, from the US Geological Survey, provides a simple schematic of the various pathways that water can take as it cycles through ocean, lakes, atmosphere, surface and ground.

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.

This animation presents the characteristics of wind power as a source of clean energy. The force of moving air generates electricity, by rotating blades around a rotor. The motion of the rotor turns a driveshaft that drives an electric generator.

In this interactive simulation, students can explore global CO2 emissions displayed by different continents/countries and plotted based on the GDP. A map view is also accessible.

In this activity, students learn how carbon cycles through the Earth system by playing an online game.

This NASA animation of the Five-Year Average Global Temperature Anomalies from 1881 to 2009 shows how temperature anomalies have varied in the last 130 years. The color-coded map displays a long-term progression of changing global surface temperatures from 1881 to 2009. Dark red indicates the greatest warming and dark blue indicates the greatest cooling.

This NBC Learn video features climate scientists doing their research on Mt. Kilimanjaro to study the climate of the past. The scientists put the recently observed changes on the glacier into perspective by comparing past climate fluctuations, stressing that the current observed rate of change is unprecedented.

This NASA animation depicts thermohaline circulation in the ocean and how it relates to salinity and water density. It illustrates the sinking of water in the cold, dense ocean near Iceland and Greenland. The surface of the ocean then fades away and the animation pulls back to show the global thermohaline circulation system.

This video illustrates the advantages of woody biomass as a renewable, carbon-neutral energy source. Woody biomass is underutilized and often overlooked as a renewable fuel, and it can be harvested sustainably and burned cleanly.

This gallery of ten temperature graphs shows global temperatures on different timescales from decades (recently measured temperatures) to centuries (reconstructed) to millions of years (modeled from ice cores).