This is a classroom activity about the forcing mechanisms for the most recent cold period: the Little Ice Age (1350-1850). Students receive data about tree ring records, solar activity, and volcanic eruptions during this time period. By comparing and contrasting time intervals when tree growth was at a minimum, solar activity was low, and major volcanic eruptions occurred, they draw conclusions about possible natural causes of climate change and identify factors that may indicate climate change.

For this lesson, the guiding Concept Question is: What is climate change and how does climate relate to greenhouse gas concentrations over time? This activity is the second lesson in a nine-lesson module 'Visualizing and Understanding the Science of Climate Change' produced by the International Year of Chemistry project (2011).

This video features research conducted at University of Colorado's Institute of Arctic and Alpine Research, which studies isotopes of hydrogen trapped in ice cores to understand climate changes in the past.

This video is narrated by climate scientist Richard Alley. It examines studies US Air Force conducted over 50 years ago on the warming effects of CO2 in the atmosphere and how that could impact missile warfare. The video then focuses on the Franz Josef glacier in New Zealand; the glacier is used to demonstrate a glacier's formation, depth of snow fall in the past, and understand atmospheric gases and composition during the last Ice Age. Supplemental resources are available through the website.