Title: The Role of Soils in Climate Change

Abstract: The world's soils are major absorbers, depositories, and transmitters
of organic carbon. They contain some 2400 Gt of C, while terrestrial biota
contain about 560 Gt. In contrast, the amount of carbon in the atmosphere is
estimate to total 750 Gt. The quantity of soil carbon in each location is
temporally and spatially variable, depending on the balance of inputs versus
outputs over time. Clearing of vegetation and cultivation generally spur
decomposition of the soil's organic matter reserve while depriving it of
replenishment. Though agricultural soils have acted in the past as
significant sources of atmospheric CO2, their present deficits offer an
opportunity to absorb CO2 from the atmosphere and store it as added organic
matter in future decades. Appropriate policies and practices must be devised
to accomplish that potential.