Based on a simple soil carbon model and GCM output for future climate, we conducted several experiments in order to study net carbon exchanges between the terrestrial biosphere and atmosphere. The climate situation between 1901 and 2029 was simulated by NCAR CCM model. The simulated land temperature in 2029 will be 17.0℃ which is about 3.8℃ higher than the mean value during 1920~1949, but the simulated precipitation has slight increase. Thus, the GCM predicts a relation with about 5 mm increase in precip...