Antarctic Ice Sheet freshwater discharge drives substantial Southern Ocean changes over the 21$^{st}$ century | CU Experts

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.

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