Transient simulation of last deglaciation with a new mechanism for Bølling-Allerød Warming

• Published in: Science
• Other Authors: Liu, Z. (author), Otto-Bliesner, Bette (author), He, F. (author), Brady, Esther (author), Tomas, Robert (author), Clark, P. (author), Carlson, A. (author), Lynch-Stieglitz, J. (author), Curry, W. (author), Brook, E. (author), Erickson, D. (author), Jacob, R. (author), Kutzbach, J. (author), Cheng, J. (author)
• Format: Article in Journal/Newspaper
• Language: English
• Published: American Association for the Advancement of Science 2009
• Subjects: North Atlantic
• Online Access: http://nldr.library.ucar.edu/repository/collections/OSGC-000-000-002-287; https://doi.org/10.1126/science.1171041

We conducted the first synchronously coupled atmosphere-ocean general circulation model simulation from the Last Glacial Maximum to the Bølling-Allerød (BA) warming. Our model reproduces several major features of the deglacial climate evolution, suggesting a good agreement in climate sensitivity between the model and observations. In particular, our model simulates the abrupt BA warming as a transient response of the Atlantic meridional overturning circulation (AMOC) to a sudden termination of freshwater discharge to the North Atlantic before the BA. In contrast to previous mechanisms that invoke AMOC multiple equilibrium and Southern Hemisphere climate forcing, we propose that the BA transition is caused by the superposition of climatic responses to the transient CO₂ forcing, the AMOC recovery from Heinrich Event 1, and an AMOC overshoot.