How Asymmetries Between Arctic and Antarctic Climate Sensitivity Are Modified by the Ocean

Date

2018

Authors

Singh, H. A.
Garuba, O. A.
Rasch, P. J.

Journal Title

Journal ISSN

Volume Title

Publisher

Geophysical Research Letters

Abstract

We investigate how the ocean response to CO2 forcing affects hemispheric asymmetries in polar climate sensitivity. Intermodel comparison of Phase 5 of the Coupled Model Intercomparison Project CO2 quadrupling experiments shows that even in models where hemispheric ocean heat uptake differences are small, Arctic warming still exceeds Antarctic warming. The polar climate impact of this evolving ocean response to CO2 forcing is then isolated using slab ocean experiments in a state‐of‐the‐art climate model. Overall, feedbacks over the Southern Hemisphere more effectively dissipate top‐of‐atmosphere anomalies than those over the Northern Hemisphere. Furthermore, a poleward shift in ocean heat convergence in both hemispheres amplifies destabilizing ice albedo and lapse rate feedbacks over the Arctic much more so than over the Antarctic. These results suggest that the Arctic is intrinsically more sensitive to both CO2 and oceanic forcings than the Antarctic and that ocean‐driven climate sensitivity asymmetry arises from feedback destabilization over the Arctic rather than feedback stabilization over the Antarctic.

Description

Keywords

polar climate, Arctic, Antarctic, climate sensitivity, ocean dynamics, radiative feedbacks

Citation

Singh, H. A., Garuba, O. A., & Rasch, P. J. (2018). How Asymmetries Between Arctic and Antarctic Climate Sensitivity Are Modified by the Ocean. Geophysical Research Letters, 45(23), 13,031-13,040. https://doi.org/10.1029/2018GL079023.