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 highlights research conducted at Woods Hole on how heat absorbed by the ocean and changes of ocean chemistry from human activities could lead to a tipping point for marine life and ecosystems. Includes ice bath experiment that models the tipping point of Arctic sea ice.

This video describes the foundation Plant for the Planet, a foundation created by a 9-year-old German boy, Felix. This foundation has planted more than 500,000 trees in Germany, which he says help sequester carbon and reduce greenhouse gas emissions. The student rallies, first his community and then other children, to plant millions of trees to offset our energy-use emissions.

This short video, is the fifth in the National Academies Climate Change, Lines of Evidence series. It focuses on greenhouse gases, climate forcing (natural and human-caused), and global energy balance.

This short video describes the Hestia project - a software tool and data model that provide visualizations of localized CO2 emissions from residential, commercial, and vehicle levels, as well as day versus night comparisons, in the city of Indianapolis.

This beautifully filmed and produced video describes the changes that global warming is already bringing to Northern Canada and Greenland. Local people describe changes to ecosystems, impacts on culture and life styles, and the challenges of melting permafrost. Ship captains describe changes in navigational channels and fjords. Scientists describe changes in albedo and permafrost, as well as increased pollution transported from outside the Arctic (the Grasshopper effect).

This video describes what black carbon is, where is comes from, and how it contributes to sea ice melt and global warming.

This lesson covers different aspects of the major greenhouse gases - water vapor, carbon dioxide, methane, nitrous oxides and CFCs - including some of the ways in which human activities are affecting the atmospheric concentrations of these key greenhouse gases. This is lesson six in a nine-lesson module about climate change.

This NASA video discusses the impacts of the sun's energy, Earth's reflectance and greenhouse gases on the Earth System.

In this activity, students explore the way that human activities have changed the way that carbon is distributed in Earth's atmosphere, lithosphere, biosphere and hydrosphere.