Question about Thermohaline Circulation

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Discussion Overview

The discussion revolves around the relationship between Thermohaline Circulation and Quaternary Glaciation, particularly in the context of an assignment on glaciation. Participants explore various factors that may influence glaciation, including ocean currents, atmospheric conditions, and freshwater inputs.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant notes the uncertainty surrounding the cause of Northern Hemisphere glaciation and suggests that enhanced thermohaline circulation could have increased moisture supply to high latitudes, potentially affecting ice growth.
  • Another participant mentions that abrupt climate changes during the last glaciation may have originated from alterations in the Atlantic thermohaline circulation due to changes in the hydrological cycle.
  • It is proposed that multiple factors, such as astronomical cycles, atmospheric composition, plate tectonics, and ocean currents, may simultaneously contribute to glaciation, with no single satisfactory theory currently available.
  • A participant highlights the role of CO2 levels in Antarctic glaciation, suggesting that lower pCO2 levels may have facilitated the expansion of ice sheets.
  • One contributor emphasizes that ocean currents are density-driven, with cold temperatures and increased salinity affecting water density, which in turn influences deep water formation and movement.
  • References to historical figures and studies, such as Wallace Broecker's conveyor belt concept, are made to provide context for the discussion.

Areas of Agreement / Disagreement

Participants express various viewpoints and hypotheses regarding the factors influencing glaciation and the role of Thermohaline Circulation, indicating that multiple competing views remain without a clear consensus.

Contextual Notes

The discussion includes references to several external articles and studies, but limitations such as missing assumptions and unresolved mathematical steps are present, contributing to the complexity of the topic.

EthanWM
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Hey guys,

I have an assignment to do on Glaciation for university but I'm a bit lost with an aspect of the question and was wondering could anyone help.

The aspect is how the Thermohaline Circulation is linked to the Quaternary Glaciation. I can't find any published articles about it from researchers or anything. Could anyone help by pointing me in the right direction?

Thanking you,

Ethan
 
Earth sciences news on Phys.org
http://geology.rutgers.edu/~jdwright/MarGeol/Old%20Marine%20Geol%20folder/Driscoll.pdf[/URL]

[QUOTE]The cause of Northern Hemisphere glaciation about 3 million years ago remains
uncertain. Closing the Panamanian Isthmus increased thermohaline circulation
and enhanced moisture supply to high latitudes, but the accompanying heat
would have inhibited ice growth. One possible solution is that enhanced moisture
transported to Eurasia also enhanced freshwater delivery to the Arctic via
Siberian rivers. Freshwater input to the Arctic would facilitate sea ice formation,
increase the albedo, and isolate the high heat capacity of the ocean from the
atmosphere. It would also act as a negative feedback on the effciency of the
"conveyor belt" heat pump.[/QUOTE]

[URL]http://www.nature.com/nature/journal/v415/n6874/full/415863a.html[/URL]

[QUOTE]Data and models both suggest that abrupt climate change during the last glaciation originated through changes in the Atlantic thermohaline circulation in response to small changes in the hydrological cycle.[/QUOTE]

[PLAIN]http://wapedia.mobi/en/Quaternary_glaciation[/URL]

[QUOTE]No completely satisfactory theory has been proposed to account for Earth's history of glaciation. The cause of glaciation may be related to several simultaneously occurring factors, such as astronomical cycles, atmospheric composition, plate tectonics, and ocean currents. [2][/QUOTE]
 
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Maybe google with AMO Atlantic Meridional Overturning

To get for instance:

http://www.sciencemag.org/cgi/content/abstract/316/5821/66

But although the question is simple, the answer is worth several PhD level studies and then it's probably still different.

There is a whole more to that.
 
Probably worth mentioning that CO2 levels were a factor in the Antarctic glaciation. It not as if they were all that high at the time compared to the glacial free Eoecen and Oligocene. See the following:

http://earth.geology.yale.edu/~mp364/index.cgi?page-selection=2

The fall in pCO2 likely allowed for a critical expansion of ice sheets on Antarctica, and promoted conditions that forced the onset of terrestrial C4 photosynthesis.
 
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The key is that ocean currents are density driven and cold temps and added salinity increase the density of water. Changes in meltwater inputs and temperature can then alter the formation and movement of deep water. Wallace Broecker came up with the original conveyor belt idea. I had a meeting with him and George Denton back in the mid- 1980's when he was putting this together.
http://www.tos.org/oceanography/issues/issue_archive/issue_pdfs/4_2/4.2_broecker.pdf There are plenty of articles the first link is for a general look at how it is realted to present. The second in on the glaciation link in the past.
http://www.whoi.edu/page.do?pid=12455&tid=282&cid=10149
http://www.essc.psu.edu/~bjhaupt/papers/guest97.sh/guest-sh.html
 
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