Conceptual Model Analysis of the Influence of Temperature Feedbacks on Polar Amplification

The role of temperature feedbacks in polar amplification of climate change is examined by comparing the response of idealized high- and low-latitude atmospheric columns to greenhouse gas forcing. An analytic expression for the surface polar amplification factor is derived with a one-layer atmospheric model and compared to a more detailed column model with two radiative transfer schemes. The modeled temperature profiles result from competition between the stabilizing influences of atmospheric heat flux convergence and atmospheric solar heating (dominant at high latitudes), and the destabilizing influence of surface solar heating (dominant at low latitudes). For a stable high-latitude radiative-advective atmosphere, the lapse rate increases with greenhouse gas forcing, leading to a positive feedback, and is dependent on the nature of the forcing—pointing to limitations of the traditional forcing-feedback framework. For a low-latitude radiative-convective atmosphere, the lapse rate decreases, leading to a negative feedback.