Multidecadal satellite observations indicate that the Antarctic Ice Sheet (AIS) is losing mass at an accelerating rate, potentially impacting many aspects of the coupled climate system. While previous studies have demonstrated the importance of AIS freshwater discharge for regional and global climate processes using climate model experiments, many have applied unrealistic freshwater forcing. Here, we explore the potential Southern Ocean impacts of realistic AIS mass loss over the 21$^{st}$ century in the Community Earth System Model version 2 (CESM2) by applying observation-based historical and ice sheet model-based future AIS freshwater forcing. The added freshwater reduces wintertime deep convective area by 72\% while retaining 83\% more sea ice. Congruent with other studies, we find the increased freshwater discharge extensively impacts local and remote Southern Ocean surface and subsurface temperature and stratification. These results demonstrate the necessity of accounting for AIS mass loss in global climate models for projecting future climate.