The lapse-rate feedback is the dominant driver of stronger warming in
the Arctic than the Antarctic in simulations with increased CO2. While
Antarctic surface elevation has been implicated in promoting a weaker
Antarctic lapse-rate feedback, the mechanisms in which elevation impacts
the lapse-rate feedback are still unclear. Here we suggest that weaker
Antarctic warming under CO2 forcing stems from shallower, less intense
climatological inversions due to limited atmospheric heat transport
above the ice sheet elevation and elevation-induced katabatic winds. In
slab ocean model experiments with flattened Antarctic topography,
stronger climatological inversions support a stronger lapse-rate
feedback and annual-mean Antarctic warming comparable to the Arctic
under CO2 doubling. Unlike the Arctic, seasonality in warming over flat
Antarctica is mainly driven by a negative shortwave cloud feedback which
exclusively dampens summer warming, with a smaller contribution from the
winter-enhanced lapse-rate feedback.