The ecosystem structure and function of terrestrial biosphere have significant two-way feedbacks with climate. Historically, biogeographic studies have mentioned strong effects of climate onto vegetation and other ecological properties. However, the vegetation can also modify the climate. For example, in shorter timescales, biophysical properties of land surface such as albedo and evapotranspiration affect atmospheric conditions. In longer timescales, biogeochemical cycling such as carbon balance influences atmospheric concentrations of greenhouse gases, and thereby controlling radiative forcing that determines climatic conditions. Moreover, these two-way feedbacks mediated by terrestrial vegetation are strongly affected by local ecological dynamics. For instance, the rate of vegetation change due to climatic forcing depends on the stability of local ecosystem, and a time lag will arise because of the ecological memory. By coupling sSEIB, a simplified version of SEIB-DGVM, with an atmospheric general circulation model, the climate and terrestrial vegetation are simulated as an integrated system. Since sSEIB is an individual-based forest model, the model system appropriately reproduce the transient dynamics of terrestrial changes from climatic forcing.