This classroom resource is a combination of 3 visualizations and accompanying text that illustrate how 3 key natural phenomena - cyclical changes in solar energy output, major volcanic eruptions over the last century, and El Nino/Nina cycles - are insufficient to explain recent global warming.

This activity engages learners to investigate the impact of Earth's tilt and the angle of solar insolation as the reason for seasons by doing a series of hands-on activities that include scale models. Students plot the path of the Sun's apparent movement across the sky on two days separated by three months of time.

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 short video, is the fifth in the National Academies Climate Change, Lines of Evidence series. It focuses on greenhouse gases, climate forcing (natural and human-caused), and global energy balance.

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.

In this activity, students use authentic Arctic climate data to unravel some causes and effects related to the seasonal melting of the snowpack and to further understand albedo.

In this video, a team of paleontologists, paleobotanists, soil scientists, and other researchers take to the field in Wyoming's Bighorn Basin to document how the climate, plants, and animals there changed during the Paleocene- Eocene Thermal Maximum (PETM). During this time a sudden, enormous influx of carbon flooded the ocean and atmosphere for reasons that are still unclear to scientists. The PETM is used as an analog to the current warming. The scientists' research may help inform our understanding of current increases in carbon in the atmosphere and ocean and the resulting impact on ecosystems.

In this activity, students are guided through graphs of surface air temperature anomaly data and Vostok ice core data to illustrate how scientists use these data to develop the basis for modeling how climate is likely to change in the future.

In this video from the Polaris Project Website, American and Siberian university students describe their research on permafrost.

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.