Is Arctic Amplification dominated by regional radiative forcing and feedbacks: Perspectives from the World‐Avoided scenario

Arctic amplification (AA) is typically associated with Planck, lapse rate, and ice albedo feedbacks. However, the relative importance of poleward energy transport on AA remains uncertain. Here, we analyze integrations from a Chemistry Climate Model to investigate the impact of the Montreal Protocol on forcing, feedback, and transport contributions to AA. Two ensembles of future integrations are considered-one projecting decreasing ozone-depleting substance concentrations and stratospheric ozone recovery and another assuming that ozone-depleting substances are not regulated (the "World Avoided"). We find similar degrees of AA in both ensembles, despite a negative radiative forcing over the Arctic in the "World Avoided" from massive ozone loss. That negative radiative forcing is primarily balanced from positive atmospheric energy flux convergence and long-wave cloud feedbacks. Our results highlight the impact of inhomogeneous radiative forcing on regional differences in forcing and feedback strength and the importance of radiative forcing meridional structure on poleward energy transport. Plain Language Summary Stronger rates of surface warming in the Arctic relative to the global average, often described as Arctic amplification, are attributed to positive climate feedbacks. However, the direct influence of energy flux into the Arctic region from lower latitudes, as well as the relative importance of different regional climate forcings (such as ozone depletion or greenhouse gases), remains unclear. Here, we use output from a global climate model to investigate the impact of ozone loss on Arctic amplification. Using two ensembles of model simulations-one projecting ozone recovery and another projecting ozone loss-we find that ozone depletion in the Arctic leads to a negative climate forcing, which, if acting alone, would promote Arctic cooling. However, more positive climate feedbacks and heat transport into the Arctic contribute to Arctic amplification, even in the presence of ozone depletion.