Keeling measure is a graph that is used to identify the varying concentrations of Carbon dioxide (CO2) in the atmosphere.

It is named after Charles David Keeling, a researcher who has been measuring the CO2 concentration since 1958 at Mauna Loa Observatory in the Big Island of Hawaii. 

The main reason for choosing the Mauna Loa to be the place for CO2 concentration is its location. Since it is far from the continents of the world, the air sample that can be derived is an acceptable average for the pacific area. Since it has a high altitude, the top of the mountain is located above the inversion where local effects are present.