Airborne fraction
The airborne fraction is a scaling factor defined as the ratio of the annual increase in atmospheric CO2| to the emissions from anthropogenic sources. It represents the proportion of human emitted that remains in the atmosphere. The fraction averages about 45%, meaning that approximately half the human-emitted is absorbed by ocean and land surfaces. There is some evidence for a recent increase in airborne fraction, which would imply a faster increase in atmospheric for a given rate of human fossil-fuel burning.
Changes in carbon sinks can affect the airborne fraction.
