The Carbon Budget in Soils

The global soil C reservoir, ∼1500 Gt of C (1 Gt = 10¹² kg of C), is dynamic on decadal time scales and is sensitive to climate and human disturbance. At present, as a result of land use, soil C is a source of atmospheric CO2 in the tropics and possibly part of a sink in northern latitudes. Here I review the processes responsible for maintaining the global soil C reservoir and what is known about how it responds to direct and indirect human perturbations.

“I am fire and air; my other elements I give to baser life”

     —William Shakespeare, Antony and Cleopatra