Using the Model for Interdisciplinary Research on Climate version 3.2 (MIROC 3.2), we investigated the physical nature of regional sea level changes due to enhanced greenhouse warming. The regional sea level changes were not spatially uniform, and their patterns were principally determined by the baroclinic component (density change) due to surface fluxes of heat, freshwater, and wind stress. Sea level changes in the barotropic circulation were mainly confined to the Southern Ocean. We decomposed the baroclinic response into vertical modes of ocean climatological stratification, considering the vertical structure of the baroclinic pressure change. The first baroclinic mode was responsible for about 78% of the variance in the baroclinic response, suggesting that the regional distribution of sea level change under global warming is mainly determined by displacement of the main pycnocline. The second and third modes were responsible for about 12% and 4% of the variance, respectively, some of which was related to subduction of the global warming signal. The decomposition of the baroclinic response mentioned above is suggestive of sea level changes due to global warming as results of region-by-region physical processes.