Interactions Between Land-Use Change and Climate-Carbon Cycle Feedbacks

Interactions between land-use change and climate-carbon cycle feedbacks include biological processes, such as CO2-enhanced productivity of lands managed for food, energy, or wood; an increased terrestrial carbon sink as a consequence of an expanded area of secondary forests; and the effects of land cover on biophysical properties affecting climate (e.g., albedo, roughness, evapotranspiration). Interactions also result at a conceptual level because of the methods used to evaluate terrestrial terms in the global carbon budget. For example, net carbon emissions from land-use change help define the airborne fraction, as well as the magnitude of the residual terrestrial carbon sink. And the lost additional sink capacity (LASC) determined with dynamic global vegetation models (DGVMs) reveals an indirect long-termconsequence of land-use change: the loss of a carbon sink as a result of converting forests to open lands. Three different terrestrial carbon fluxes are important for understanding perturbations to the global carbon cycle: the net annual emissions from land-use change, the residual terrestrial carbon sink, and the LASC.