This video discusses carbon dioxide concentrations in the atmosphere that have increased due to the burning of fossil fuels in electricity generation, transportation, and industrial processes. Video includes history of Keeling and his research, as well as the seasonal fluctuations in CO2.

This is an interactive graph that involves records of ice cover in two Wisconsin lakes - Lake Mendota and Lake Monona - from 1855-2010.

In this 6-part activity, students learn about climate change during the Cenozoic and the abrupt changes at the Cretaceous/Paleogene boundary (65.5 million years ago), the Eocene/Oligocene boundary (33.9 million years ago), and the Paleocene/Eocene boundary (55.8 million years ago).

This applet is an ocean acidification grapher that allows user to plot changes in atmospheric C02 against ocean pH, from 1988 to 2009, in the central North Pacific.

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.

This interactive displays how climate variables are changing over time (temperature, CO2, Arctic sea ice, sun's energy, sea level, etc.) in graphical form. Students can easily examine over 50+ years of archived data.

This interactive map allows students to experiment with decadal average temperature projections. Overall temperatures are expected to rise throughout the century and this tool demonstrates those projected measurements.

In this activity, students review techniques used by scientists as they analyze a 50-year temperature time series dataset. The exercise helps students understand that data typically has considerable variability from year to year and to predict trends, one needs to consider long-term data.

In this activity, students make a model sea floor sediment core using two types of buttons to represent fossil diatoms. They then compare the numbers of diatom fossils in the sediment at different depths to determine whether the seas were free of ice while the diatoms were alive.

In this activity, students examine images of alpine glaciers to develop an understanding of how glaciers respond to climate change. They record, discuss, and interpret their observations. They consider explanations for changes in the size and position of glaciers from around the world. They develop an understanding that the melting (retreat) of glaciers is occurring simultaneously on different continents around the world, and, thus, they represent evidence of global climate change.