This study investigates how climate sensitivity depends upon the spatial
pattern of radiative forcing. Sensitivity experiments using a coupled
ocean-atmosphere model were conducted by adding anomalous incoming solar
radiation over the entire globe, Northern Hemisphere mid-latitudes,
Southern Ocean, and tropics, respectively, with both positive and
negative perturbation considered. The varied forcing patterns led to
highly divergent climate sensitivities, with extratropical forcing
inducing significantly more global-mean temperature change compared to
tropical forcing. This dependence is particularly strong over the
Southern Hemisphere, where the climate is nearly twice as sensitive to
Southern Ocean forcing as tropical forcing. This dependence of climate
sensitivity on the location of radiative forcing stems from covariations
between lapse rate feedback, cloud feedback and tropospheric stability.
These results contrast with the conventional SST-pattern effect in which
tropical surface temperature changes regulate the climate sensitivity,
and has important implications for geoengineering and understanding the
mechanisms of paleoclimate change.