Students from around the world calculated their class mean and standard deviations for their footprints and posted them on our world map.
Do you see differences across the globe? If so, why do you think those differences exist?
Did you use the calculator to try to reduce your footprint down to the average from a citizen of another country? What changes would you have to make to lower your footprint in this way? Are you going to try and take some of these actions in your daily life?
Student Footprints >
How does the oxygen cycle relate to the greenhouse and global warming?
According to the Smithsonian, not much. "Models of past eras show that oxygen can influence global temperature and humidity as its concentration changes." Over time, the oxygen levels seem to be correlated with global temperatures, but "The planet’s climate is changing today because levels of greenhouse gases such as carbon dioxide and methane are rising dramatically—oxygen isn’t a factor." Basically, the levels change together over really long periods of time, but the oxygen doesn't have a quick or significant affect on global warming. Great question, I had to look this one up 
Smithsonian article: http://www.smithsonianmag.com/science-n … 72/?no-ist