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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, @12:22AM (1 child)

    by Anonymous Coward on Saturday March 28 2020, @12:22AM (#976526)

    Global average temperatures are increasing. The observations show this very clearly.

    We know that the rate of temperature changes aren't the same everywhere. Observations clearly demonstrate that polar regions, especially the Arctic, are warming much faster than the rest of the planet. The observations clearly demonstrate that there isn't a single rate of global temperature increase, but that there are significant regional variations.

    It is outright disingenuous to deny global warming on the basis that a few regions may experience cooling while the planet warms significantly overall. But you knew that already, just from looking at the observations.

    Science denial is science denial, and it's dangerous. Whether we're talking about lifting social distancing guidelines before COVID-19 infections have peaked, claiming that vaccines cause autism despite significant evidence to the contrary, or denying that human activities are causing global warming, people who deny science are a menace to society and will harm all of us.

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  • (Score: 0) by Anonymous Coward on Saturday March 28 2020, @02:25PM

    by Anonymous Coward on Saturday March 28 2020, @02:25PM (#976636)

    >Science denial is science denial, and it's dangerous
    Science denial cannot happen.
    Case in point, study says circulation may affect cooling. Armed with this hypothesis scientists will formulate a prediction, true if hypothesis true and false otherwise. This will validate the theory.

    We have time to wait for this to happen while we keep polluting? different question. A wrong question to ask because of the term "we", the shield of evil actors, but let's pretend otherwise. Ideally we shouldn't risk, but ideally we shouldn't have tolerated the industrial revolution as it happened, nor wars, nor fiat money, nor political actions by religions...

    Sure, we must start to say no from one line in the sand.
    OTOH the climate change line has been drawn by the elite who is elite by excelling in all other destruction, not by the hero scientist hollywood style character. This might be a trap, it surely has been till now but, cry wolf forever and you will be right eventually.