This short video, the sixth in the National Academies Climate Change, Lines of Evidence series, explores the hypothesis that changes in solar energy output may be responsible for observed global surface temperature rise. Several lines of evidence, such as direct satellite observations, are reviewed.

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.