Future abrupt reductions in the summer Arctic sea ice

We examine the trajectory of Arctic summer sea ice in seven projections from the Community Climate System Model and find that abrupt reductions are a common feature of these 21st century simulations. These events have decreasing September ice extent trends that are typically 4 times larger than comp...

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Bibliographic Details
Published in:Geophysical Research Letters
Other Authors: Holland, Marika (author), Bitz, Cecelia (author), Tremblay, Bruno (author)
Format: Article in Journal/Newspaper
Language:English
Published: American Geophysical Union 2006
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Online Access:http://nldr.library.ucar.edu/repository/collections/OSGC-000-000-004-535
https://doi.org/10.1029/2006GL028024
Description
Summary:We examine the trajectory of Arctic summer sea ice in seven projections from the Community Climate System Model and find that abrupt reductions are a common feature of these 21st century simulations. These events have decreasing September ice extent trends that are typically 4 times larger than comparable observed trends. One event exhibits a decrease from 6 million km² to 2 million km² in a decade, reaching near ice-free September conditions by 2040. In the simulations, ice retreat accelerates as thinning increases the open water formation efficiency for a given melt rate and the ice-albedo feedback increases shortwave absorption. The retreat is abrupt when ocean heat transport to the Arctic is rapidly increasing. Analysis from multiple climate models and three forcing scenarios indicates that abrupt reductions occur in simulations from over 50% of the models and suggests that reductions in future greenhouse gas emissions moderate the likelihood of these events.