In the interplay of the soil and the atmosphere, the soil can be both a contributor to and a recipient of the impacts of climate change. In the past, land management has generally resulted in considerable depletion of soil organic matter and the release into the atmosphere of such radiatively active gases as carbon dioxide, methane, and nitrous oxide. Global climate change, to the extent that it occurs, will strongly impact all soil processes. At this time, the task of soil management should be to restore soil organic carbon in order to enhance soil structure and fertility and to help counter the atmospheric greenhouse effect. Widely varying estimates of the soil's organic carbon content and of the potential for soil carbon sequestration point to the need to conduct a comprehensive inventory of this important property.