This unit allows students to investigate past changes in Earth's climate. Students first explore relationships in climate data such as temperature, solar radiation, carbon dioxide, and biodiversity. They then investigate solar radiation in more depth to learn about changes over time such as seasonal shifts. Students then learn about mechanisms for exploring past changes in Earth's climate such as ice cores, tree rings, fossil records, etc. Finally, students tie all these together by considering the feedbacks throughout the Earth system and reviewing an article on a past mass extinction event.

Climate has varied in the past, but today's climate change rate is much more drastic due to human activity. Students explore past climate cycle graphs and compare the cycles with the current rate of change.

This activity has students examine the misconception that there is no scientific consensus on climate change. Students explore temperature data and report their conclusions to the class. Then students examine techniques of science denial and examine a claim about scientific consensus.

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.