Keywords:polar amplification, vegetation, paleoclimate
Previous studies revealed that vegetation change in high latitude (e.g. from tundra to forest) in warm climate strengthen a polar amplification. This is due to lower vegetation albedo of forest then tundra, snow-albedo feedback caused by early snow melt due to forest coverage and ocean heat emission in autumn and winter. In the present study, we run a vegetation–coupled general circulation model with a slab-ocean, MIROC-LPJ, for two kinds of warming experiments. One is due to higher atmospheric CO2 concentration (2xCO2 and 4xCO2) and the other is due to the difference of the Earth’s orbit (mid-Holocene and the Last Interglacial). The result shows different mechanisms of warming amplification between CO2-induced vegetation feedback and orbit-induced vegetation feedback. We also try to apply a feedback analysis (Cai and Luo 2009; Yoshimori et al. 2014) to result of MIROC-LPJ experiments.