Enhanced mass loss of the Antarctic ice sheet yields ocean surface freshening, cooling and sea ice expansion, which ought to drive change in the atmosphere. Using the Southern Ocean Freshwater Input from Antarctica (SOFIA) multi-model ensemble, we study the atmospheric response to a 100-year idealized freshwater release of 0.1 Sv. All models simulate consistently surface-intensified tropospheric cooling and lower-stratospheric warming south of 35˚S. Tropospheric cooling is attributed to sea ice expansion and hence albedo increase in winter and a colder sea surface in summer. This cooling yields a downward displacement of the tropopause, reduced stratospheric water vapor content and ultimately warming around 200 hPa. An enhanced southward eddy heat flux explains warming at 10-100 hPa during austral winter. Despite a temporally (and spatially) uniform prescribed freshwater flux, a prominent sea ice seasonal cycle and atmosphere dynamics result in a distinct seasonal pattern in the occurrence and magnitude of the responses.