Carbon Cycle

How Much Carbon Is in the Atmosphere?

Climate scientist Charles Keeling measured atmospheric carbon dioxide levels between 1958-2005 at the Mauna Loa Observatory on the northern slopes of Earth’s largest volcano in Hawaii. His data, shown below, show the steady increase of carbon dioxide levels in the atmosphere.

The red regular wobbles in the data reflect the seasonal growth of trees and plants in the Northern hemisphere. During the spring and summer, trees and plants absorb carbon when they undergo photosynthesis, reducing the amount of carbon in the atmosphere. During the fall and winter, they decay, releasing carbon back into the atmosphere. This famous data display is known as the Keeling curve.

The measurements shown in this curve represent the world’s longest continuous record of atmospheric carbon dioxide. This data was the first to confirm the rise of carbon dioxide in the atmosphere caused by the burning of fossil fuels.