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 short animation compares graphs of the natural variation in the sun's energy striking the upper atmosphere vs global surface temperature over a 30-year period to make the point that natural variations do not account for the rising trend line in surface temperatures.