Carbon dioxide can exist in the atmosphere for long periods of time (100 years or more) and is a big contributor to the greenhouse effect.
(1) List some of the ways by which carbon dioxide can enter the atmosphere naturally.
(2) Now suggest some of the man-made processes that allow carbon dioxide to enter the atmosphere.
(3) What attempts have humans made—and continue to make—to reduce the increase in atmospheric carbon dioxide that has been observed over the past two hundred years or so.
(4) How is carbon dioxide removed from the atmosphere?
(5) How would an increase in carbon dioxide concentrations in the atmosphere affect the greenhouse effect?