Although the amount of atmospheric CO 2 produced from fossil fuel is relatively well known, CO 2 exchange between the biosphere and atmosphere from human activities on the land is highly uncertain.
Human activities bring about changes in land cover, land use, and land management.
More knowledge of the biosphere-atmosphere exchange is needed by scientists to balance the terrestrial C budget and by policy makers for a sound scientific basis to deal effectively with the socioeconomic implications of climate change. Research centers on integrating many kinds of data into a geographically explicit model to produce estimates and associated errors of the CO 2 exchange between the biosphere and atmosphere caused by human activities at country, regional, and global scales.