This short video, adapted from NOVA, explains how Earth's position relative to the Sun might be responsible for the dramatic shift in the climate of what is now the Saharan nation of Djibouti.

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.

This video segment, from the 'Earth: The Operators' Manual' featuring climate expert Richard Alley, shows how ice cores stored at the National Ice Core Lab provide evidence that ancient ice contains records of Earth's past climate - specifically carbon dioxide and temperature.

This video segment describes climate data collection from Greenland ice cores that indicate Earth's climate can change abruptly over a single decade rather than over thousands of years. The narrator describes how Earth has undergone dramatic climate shifts in relatively short spans of time prior to 8000 years ago. The video and accompanying essay provide explanations of the differences between weather and climate and how the climate itself had been unstable in the past, with wide variations in temperature occurring over decadal timescales.

This video describes why tropical ice cores are important and provide different information than polar ice cores, why getting them now is important (they are disappearing), and how scientists get them. The work of glaciologist Lonnie Thompson is featured, with a focus on his work collecting cores of ice from high mountain glaciers that contain significant data about past climate change.

In this activity, students are introduced to tree rings by examining a cross section of a tree, also known as a 'tree cookie.' They discover how tree age can be determined by studying the rings and how ring thickness can be used to deduce times of optimal growing conditions. Next, they investigate simulated tree rings applying the scientific method to explore how climatic conditions varied over time.

In this activity, students calculate temperatures during a time in the geologic record when rapid warming occurred using a well known method called 'leaf-margin analysis.' Students determine the percentage of the species that have leaves with smooth edges, as opposed to toothed, or jagged, edges. Facsimiles of fossil leaves from two collection sites are examined, categorized, and the data is plugged into an equation to provide an estimate of paleotemperature for two sites in the Bighorn Basin. It also introduces students to a Smithsonian scientist who worked on the excavation sites and did the analysis.

This video documents how scientists, using marine algae, can study climate change in the past to help understand potential effects of climate change in the future.

This static graph of changes in CO2 concentrations is going back 400,000 years, showing the dramatic spike in recent years.

This visualization graphically displays temperature and CO2 concentration in the atmosphere as derived from ice core data from 400,000 years ago to 1950. The data originates from UNEP GRID Arendal's graphic library of CO2 levels from Vostok ice core.