This PBS video shows how Klaus Lackner, a geophysicist at Columbia University, is trying to tackle the problem of rising atmospheric CO2 levels by using an idea inspired by his daughter's 8th-grade science fair project. The video examines the idea of pulling CO2 out of the atmosphere via a passive chemical process.

In this activity, students explore past examples of climate variability in three locations: the Peruvian and Bolivian Andes, Central America, and coastal Greenland, and consider differences between climate variability and climate change.

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