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posted by Fnord666 on Friday March 27 2020, @11:52PM   Printer-friendly
from the buffers-work-up-to-a-point-and-then-all-hell-breaks-loose dept.

How stable is deep ocean circulation in warmer climate? Altered circulation might have cooled northern areas of North America and Europe

If circulation of deep waters in the Atlantic stops or slows due to climate change, it could cause cooling in northern North America and Europe – a scenario that has occurred during past cold glacial periods.

Now, a Rutgers coauthored study suggests that short-term disruptions of deep ocean circulation [also] occurred during warm interglacial periods in the last 450,000 years, and may happen again.

Ironically, melting of the polar ice sheet in the Arctic region in a warmer world, resulting in more fresh water entering the ocean and altering circulation, might have caused previous coolings.

[...] The study, published in the journal Science and led by scientists at the University of Bergen in Norway, follows a 2014 study on the same topic.

"These findings suggest that our climate system, which depends greatly on deep ocean circulation, is critically poised near a tipping point for abrupt disruptions," said coauthor Yair Rosenthal, a distinguished professor in the Department of Marine and Coastal Sciences and Department of Earth and Planetary Sciences at Rutgers University–New Brunswick. "Although the disruptions in circulation and possible coolings may be relatively short-lived – lasting maybe a century or more – the consequences might be large."

The warm North Atlantic Current -- the northernmost part of the Gulf Stream -- flows into the Greenland Sea. It becomes progressively colder and saltier due to heat loss to the air, eventually sinking and forming the North Atlantic Deep Water formation -- a mass of deep, cold water that flows southward. Melting of the polar ice sheet in the Arctic region would result in more fresh water entering the ocean and disrupting that circulation pattern, potentially causing cooling in northern areas of Europe and North America.

[...] The latest study covers three other warm interglacial periods within the past 450,000 years. During all of them, regardless of the degree of global warming, the scientists found similar century-long disruptions of the North Atlantic Deep Water formation. And they found that such disruptions are more easily achieved than once believed and took place in climate conditions similar to those we may soon face with global warming.

Journal Reference:
Eirik Vinje Galaasen, Ulysses S. Ninnemann, Augustin Kessler, et al. Interglacial instability of North Atlantic Deep Water ventilation. Science, 2020 DOI: 10.1126/science.aay6381


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  • (Score: 5, Informative) by Anonymous Coward on Saturday March 28 2020, @12:16AM (4 children)

    by Anonymous Coward on Saturday March 28 2020, @12:16AM (#976522)

    Temperature records from a few centuries ago are incomplete and less accurate just because of very limited coverage in observations and instrumentation. A lot of the estimates of temperature over the past few thousand years are actually based on climate proxies [wikipedia.org].

    As for your comment about the models, that is bullshit. Climate models have many components, not just an atmospheric model. The atmosphere model is coupled with a hydrosphere model (liquid water), a model of the cryosphere (ice cover), a lithosphere model (land), and a biosphere model (vegetation). All of these models are coupled together to simulate climate. Models of the deep ocean have been run for quite some time, but are being refined as better observations of the deep oceans become available.

    And many climate models have predicted a regional cooling in the North Atlantic as global temperatures increase. These predictions were made by much older models, not just new ones. This isn't a particularly new idea, we're just understanding the processes better. So to claim that this a new concept that the models haven't accounted for is outright fake news.

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  • (Score: 1, Insightful) by Anonymous Coward on Saturday March 28 2020, @07:55AM (3 children)

    by Anonymous Coward on Saturday March 28 2020, @07:55AM (#976586)

    Captival is obviously trolling, but he has a point about past records. The correct method is to report the actual readings and detail any adjustments and the reasons and methodology of those adjustments. The original data is sacrosanct.

    Every time some climate researcher adjusts past readings and then claims those adjusted figures as measurements, they are undermining the entire field of climate science.

    There are large swathes of adjusted data that are now claimed as original readings, and the original data is claimed to be "lost". That is bullshit.

    • (Score: -1, Troll) by Anonymous Coward on Saturday March 28 2020, @05:44PM (2 children)

      by Anonymous Coward on Saturday March 28 2020, @05:44PM (#976686)

      The big problem is more reasonable people think the idiots are trolling when they are not. He actually believes scientists manipulate the data in order to make their doom & gloom predictions true. Kinda like pewdiepie's fans who think his racism is all a big joke to "pwn the libs" or whatever.

      • (Score: 1, Informative) by Anonymous Coward on Saturday March 28 2020, @06:04PM

        by Anonymous Coward on Saturday March 28 2020, @06:04PM (#976691)

        Pewdiepie is clearly not racist. That's a terrible analogy that exposes your warped mind. Gee, maybe you're wrong about everything else you believe.

      • (Score: 3, Informative) by Captival on Saturday March 28 2020, @06:26PM

        by Captival (6866) on Saturday March 28 2020, @06:26PM (#976696)

        >He actually believes scientists manipulate the data in order to make their doom & gloom predictions true.

        I [reason.com] believe [theguardian.com] that [telegraph.co.uk] because [washingtontimes.com] that's [washingtonpost.com] true [cfact.org]