Amplified North Atlantic warming in the late Pliocene by changes in Arctic gateways

Under previous reconstructions of late Pliocene boundary conditions, climate models have failed to reproduce the warm sea surface temperatures reconstructed in the North Atlantic. Using a reconstruction of mid‐Piacenzian paleogeography that has the Bering Strait and Canadian Arctic Archipelago Strai...

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Bibliographic Details
Published in:Geophysical research letters 2017-01, Vol.44 (2), p.957-964
Main Authors: Otto‐Bliesner, Bette L., Jahn, Alexandra, Feng, Ran, Brady, Esther C., Hu, Aixue, Löfverström, Marcus
Format: Article
Language:English
Subjects:
Amplification
Archipelagoes
Arctic
Arctic Ocean
Atlantic Meridional Overturning Circulation (AMOC)
Boundary conditions
Circulation
Climate
climate modeling
Climate models
Climate system
Closures
Communities
Computer simulation
Freshwater
Freshwaters
Inland water environment
Marine
Ocean circulation
Ocean currents
Ocean temperature
Paleogeography
Pliocene
Reconstruction
Sea surface
Sea surface temperature
Simulation
Straits
Surface temperature
Temperature (air-sea)
Transport
Transportation models
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Summary:Under previous reconstructions of late Pliocene boundary conditions, climate models have failed to reproduce the warm sea surface temperatures reconstructed in the North Atlantic. Using a reconstruction of mid‐Piacenzian paleogeography that has the Bering Strait and Canadian Arctic Archipelago Straits closed, however, improves the simulation of the proxy‐indicated warm sea surface temperatures in the North Atlantic in the Community Climate System Model. We find that the closure of these small Arctic gateways strengthens the Atlantic Meridional Overturning Circulation, by inhibiting freshwater transport from the Pacific to the Arctic Ocean and from the Arctic Ocean to the Labrador Sea, leading to warmer sea surface temperatures in the North Atlantic. This indicates that the state of the Arctic gateways may influence the sensitivity of the North Atlantic climate in complex ways, and better understanding of the state of these Arctic gateways for past time periods is needed. Key Points Closure of Arctic gateways in a new reconstruction of mid‐Piacenzian paleogeography reduces simulated Arctic freshwater exports to the North Atlantic and enhances the AMOC Simulated regional patterns of temperature show better correspondence with proxy‐indicated warm sea surface temperatures in the North Atlantic The climatic response to the closure of Arctic gateways is not a linear combination to the closure of the individual straits
ISSN:0094-8276
1944-8007
DOI:10.1002/2016GL071805