Narrator: This is Science Today. The "Keeling Curve" is a famous, historical graph depicting the rise of carbon dioxide in the atmosphere. It was started in 1958 by the late Charles David Keeling of the University of California, San Diego's Scripps Institution of Oceanography. Ralph Keeling, an atmospheric geochemist at Scripps, has contributed to his father's work by showing that levels of oxygen in the atmosphere are decreasing along with the rise in carbon dioxide.

Keeling: These changes are really tiny, so they don't comprise an environmental problem per se....everyone is fond of oxygen! (laughter) People get a little worried that it's decreasing, but actually at the present rate of loss we run out of something like 50 thousand years and we run out of fossil fuels long before then

Narrator: But scientists can learn more about the rise of carbon dioxide by studying oxygen levels.

Keeling: It's been helpful in establishing, for example, the amounts of carbon dioxide that are being removed by the ocean and by land plants and account for that fraction that isn't remaining in the air.

Narrator: For Science Today, I'm Larissa Branin.