Carbon, in various forms including CO2 and organic materials, is continually exchanged between the atmosphere, oceans, and biosphere. In the pre-industrial period, these exchanges found a natural equilibrium such that the amount of carbon in each group remained more or less constant.
YOUTUBE dwVsD9CiokY Earth's Carbon Cycle.
However, human activities have perturbed the carbon cycle. The large amount of carbon added to the atmosphere by the burning of fossil fuels has dispersed itself through the atmosphere, oceans, and biosphere.
# See also