Revised estimates of the annual net flux of carbon to the atmosphere from changes in land use and land management 1850–2000

摘要: Recent analyses of land-use change in the US and China, together with latest estimates tropical deforestation afforestation from FAO, were used to calculate a portion annual flux carbon between terrestrial ecosystems atmosphere. The calculated includes only that resulting direct human activity. In most regions, activities included conversion natural cultivated lands pastures, including shifting cultivation, harvest wood (for timber fuel) establishment tree plantations. US, woody encroachment woodland thickening as result fire suppression also included. does not include increases or decreases storage environmental changes (e.g., increasing concentrations CO2, N deposition, climatic pollution). Globally, long-term (1850‐2000) land use management released 156 PgC atmosphere, about 60% it tropics. Average fluxes during 1980s 1990s 2.0 2.2 yr −1 , respectively, dominated by releases Outside tropics, average net attributable decreased source 0.06 sink 0.02 1990s. According summarized here, responsible for sinks North America Europe small sources other non-tropical regions. revisions large 0.3 individual regions but largely offsetting, so global estimate was changed little an earlier estimate. Uncertainties recent improvements data are reviewed, results compared evaluate extent which processes than important explaining storage.