How does ocean ventilation change under global warming?

Since the upper ocean takes up much of the heat added to the earth system by anthropogenic global warming, one would expect that global warming would lead to an increase in stratification and a decrease in the ventilation of the ocean interior. However, multiple simulations in global coupled climate...

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Bibliographic Details
Published in:Ocean Science
Main Authors: Gnanadesikan, A., Russell, J. L., Fanrong Zeng
Format: Article in Journal/Newspaper
Language:English
Published: Copernicus Publications 2007
Subjects:
Online Access:https://doi.org/10.5194/os-3-43-2007
https://noa.gwlb.de/receive/cop_mods_00032650
https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00032604/os-3-43-2007.pdf
https://os.copernicus.org/articles/3/43/2007/os-3-43-2007.pdf
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Summary:Since the upper ocean takes up much of the heat added to the earth system by anthropogenic global warming, one would expect that global warming would lead to an increase in stratification and a decrease in the ventilation of the ocean interior. However, multiple simulations in global coupled climate models using an ideal age tracer which is set to zero in the mixed layer and ages at 1 yr/yr outside this layer show that the intermediate depths in the low latitudes, Northwest Atlantic, and parts of the Arctic Ocean become younger under global warming. This paper reconciles these apparently contradictory trends, showing that the decreases result from changes in the relative contributions of old deep waters and younger surface waters. Implications for the tropical oxygen minimum zones, which play a critical role in global biogeochemical cycling are considered in detail.