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.

Video introduces wind energy research at the National Renewable Energy Lab (NREL) and provides an overview of the NREL Wind Technology Center near Boulder, Colorado.

In this interactive, students can investigate a typical hydrogen fuel cell prototype car from its fuel cell stacks to its ultracapacitor, a kind of supplementary power source.

The limited-production vehicle seen in this feature is a Honda 2005 FCX, which is typical of the kinds of hydrogen fuel cell cars that some major automakers are now researching and developing.

In this video segment from NOVA's Saved By the Sun hour-long video, students learn about photovoltaics and see how two families are using solar technologies in their homes. The video introduces the ideas of state incentives and net metering benefits.

The figure summarizes some of the key variations amongst the six illustrative scenarios used by the Intergovernmental Panel on Climate Change (IPCC) in considering possible future emissions of greenhouse gases during the 21st century.

This video segment from What's Up in the Environment shares how an entire home can be constructed using green energy sources (solar and geothermal energy). Video is narrated by young boy whose father is the chief engineer on the project.

This simulation allows the user to project CO2 sources and sinks by adjusting the points on a graph and then running the simulation to see projections for the impact on atmospheric CO2 and global temperatures.

Citizen scientist Anya, an indigenous Siberian girl, witnesses the changes in her community as a result of climate change after working with Woods Hole scientist Max Holmes' research team aboard her father's ship. She gets involved in collecting water samples to learn, and teach her schoolmates about, global warming.

This video is a segment from the Switch Energy Project focusing on energy security. Switch Energy Project is a multi-pronged effort designed to build a balanced national understanding of energy.

This is a photo essay linked to a New York Times story about climate-related stressors on forests -- including mountain pine beetles, forest fires, forest clearance, and ice storms -- and the importance of protecting forests as an important carbon sink.