This video segment from 'Earth: The Operators' Manual' explores how we know that today's increased levels of CO2 are caused by humans burning fossil fuels and not by some natural process, such as volcanic out-gassing. Climate scientist Richard Alley provides a detailed step-by-step explanation that examines the physics and chemistry of different "flavors," or isotopes, of carbon in Earth's atmosphere.

This video is one of a seven, Climate Change: Lines of Evidence series, produced by the the National Research Council. It outlines and explains what evidence currently exists in support of humans playing a role in contributing to the rise in atmospheric carbon dioxide levels.

This is a multi-media teaching tool to learn about climate change. The tool is comprised of stills, video clips, graphic representations, and explanatory text about climate science. Acclaimed photographer James Balog and his Extreme Ice team put this teaching tool together.

This video reviews the benefits and drawbacks associated with growing corn to make ethanol.

This video features changes in the land, sea, and animals that are being observed by the residents of Sachs Harbour, Northwest Territories, Canada â many of whom hunt, trap, and fishâbecause of their long-standing and intimate connection with their ecosystem. Scientists interview the residents and record their observations in order to deepen our understanding of climate change in the polar region. Background essay and discussion questions are included.

This video highlights a variety of climate change research initiatives from scientists at the University of Colorado, Boulder. It describes the changing dynamics of Antarctic ice sheets and the impacts of reduced Arctic sea ice. The video illustrates the excitement of this research through interviews and video clips of scientists in the field.

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 video features CU Boulder Professor Jeff Mitton and his research team, who study the effects of mountain pine beetle infestations on the forest ecology in the Rocky Mountains. They explain the pine beetle life cycle and how they attack trees. An outlook into the future is also provided.

This is a figure from the 2007 IPCC Assessment Report 4 on atmospheric concentrations of carbon dioxide, methane and nitrous oxide over the last 10,000 years (large panels) and since 1750 (inset panels).

This short animated video provides a general overview of the atmosphere, carbon dioxide, and the greenhouse effect.