Atmospheric Carbon Dioxide Records from Mauna Loa, Hawaii (1958–2000)

Carbon dioxide in the atmosphere traps heat and warms the earth’s surface. (Other greenhouse gases also trap heat, as do clouds.) This graph presents measurements of carbon dioxide concentration in the atmosphere over the last half of the twentieth century.

These measurements represent continuous air samples taken at a lava field near Hawaii’s lofty Mauna Loa volcano. Mauna Loa’s remoteness makes it an exceptionally good spot to take such measurements, because influences of vegetation or human activity on the amount of carbon dioxide are minimal. Additionally, any atmospheric change due to volcanic eruptions can be measured and subtracted from the observations. And the time carbon dioxide stays in the atmosphere (around one hundred years) allows winds to mix the air from sources worldwide. That’s why these measurements are considered a reliable index of carbon dioxide concentration in the mid-atmosphere.

These measurements break down one million units of sampled air into the portions that do and do not contain carbon dioxide. The graph shows a 17% increase in carbon dioxide concentrations from 1959 ( about 316 parts per million by volume) to 2000 (about 369 ppmv).