Why is the temperature response larger for radiative forcing imposed in high latitudes than for forcing imposed in low latitudes?

Previous studies have shown that radiative forcing imposed in high latitudes causes larger global warming than similar forcing in low latitudes. In this paper, we study the causes for this using a linear forcing-feedback framework. For this we conducted different experiments by increasing the solar insolation in various latitude bands using the NCAR CAM4 model and compare the magnitudes of five major climate feedbacks (Planck, albedo, lapse rate, water vapour, and clouds) for these latitudinal radiative forcing distributions. Compared to the simulation where forcing is imposed in low latitudes, we find that the climate sensitivity is nearly twice (thrice) in the simulation where the forcing is imposed in northern (southern) hemisphere high latitudes. We show that these sensitivity differences between low and high latitude radiative forcing simulations primarily arise due to differences in all four classically defined feedbacks including albedo, lapse rate, water vapour, and cloud feedbacks, with the largest differences attributed to differences in lapse rate, water vapor, and cloud feedbacks. Albedo feedback and the Planck response also contribute to the overall differences. Our study highlights the strong dependence of climate feedbacks and sensitivity on the meridional structure of radiative forcing, which could have implications for the design of solar radiation modification options that are proposed to offset anthropogenic climate change.