Eisenman, Ian and Bitz, Cecilia M. and Tziperman, Eli (2009) Rain driven by receding ice sheets as a cause of past climate change. Paleoceanography, 24 . Art. No. PA4209 . ISSN 0883-8305 http://resolver.caltech.edu/CaltechAUTHORS:20091210-135025958
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The Younger Dryas cold period, which interrupted the transition from the last ice age to modern conditions in Greenland, is one of the most dramatic incidents of abrupt climate change reconstructed from paleoclimate proxy records. Changes in the Atlantic Ocean overturning circulation in response to freshwater fluxes from melting ice are frequently invoked to explain this and other past climate changes. Here we propose an alternative mechanism in which the receding glacial ice sheets cause the atmospheric circulation to enter a regime with greater net precipitation in the North Atlantic region. This leads to a significant reduction in ocean overturning circulation, causing an increase in sea ice extent and hence colder temperatures. Positive feedbacks associated with sea ice amplify the cooling. We support the proposed mechanism with the results of a state-of-the-art global climate model. Our results suggest that the atmospheric precipitation response to receding glacial ice sheets could have contributed to the Younger Dryas cooling, as well as to other past climate changes involving the ocean overturning circulation.
|Additional Information:||© 2009 American Geophysical Union. Received 6 April 2009; accepted 17 July 2009; published 10 November 2009. We are grateful for helpful conversations with Brian Farrell, Dan Schrag, Peter Huybers, Carl Wunsch, Tapio Schneider, Greg Ravizza, Lorraine Lisiecki, Chris Walker, and Dorian Abbot. Thanks to Oliver Timm for useful comments on the manuscript. We thank Bette Otto-Bliesner, Esther Brady, and Bruce Briegleb for their assistance using CCSM3 and for generously making the results of their CCSM3 simulations available to us. This work was supported by the NSF paleoclimate program grant ATM-0502482, the McDonnell foundation, a NASA Earth and Space Science Fellowship, a Prize Postdoctoral Fellowship through the California Institute of Technology Division of Geological and Planetary Sciences, and a NOAA Climate and Global Change Postdoctoral Fellowship administered by the University Corporation for Atmospheric Research.|
|Subject Keywords:||Laurentide Ice Sheet ; hydrological cycle ; Younger Dryas|
|Official Citation:||Eisenman, I., C. M. Bitz, and E. Tziperman (2009), Rain driven by receding ice sheets as a cause of past climate change, Paleoceanography, 24, PA4209, doi:10.1029/2009PA001778.|
|Usage Policy:||No commercial reproduction, distribution, display or performance rights in this work are provided.|
|Deposited By:||Tony Diaz|
|Deposited On:||05 Jan 2010 23:46|
|Last Modified:||26 Dec 2012 11:38|
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