Students examine data from Mauna Loa to learn about CO2 in the atmosphere. The students also examine how atmospheric CO2 changes through the seasonal cycle, by location on Earth, and over about 40 years and more specifically over 15 years. Students graph data in both the Northern and Southern Hemisphere and draw conclusions about hemispherical differences in CO2 release and uptake.

This is a laboratory activity in which students will compare the amount of carbon dioxide in four different sources of gas and determine the carbon dioxide contribution from automobiles. They test ambient air, human exhalation, automobile exhaust, and nearly pure carbon dioxide from a vinegar/baking soda mixture.