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Scientists see stronger evidence of slowing Atlantic Ocean circulation, an ‘Achilles’ heel’ of the climate

https://www.washingtonpost.com/climate-environment/2021/02/2...

A growing body of evidence suggests that a massive change is underway in the sensitive circulation system of the Atlantic Ocean, a group of scientists said Thursday.

The Atlantic meridional overturning circulation (AMOC), a system of currents that includes the Florida Current and the Gulf Stream, is now “in its weakest state in over a millennium,” these experts say. This has implications for everything from the climate of Europe to the rates of sea-level rise along the U.S. East Coast.

Too early to be sure, and hard to know what conclusions to draw. But would probably be disruptive in many ways.
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This effect has been postulated for years. Gulf Stream is driven by density gradients. Melting polar ice dilutes the system causing changes in the gradients.
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Scientists see stronger evidence of slowing Atlantic Ocean circulation, an ‘Achilles’ heel’ of the climate...

No. Scientists do not see an AMOC slowdown. In fact, measurements that have been going on for 20 years do not show an AMOC slowdown:

"Abstract: In contrast to recent claims of a Gulf Stream slowdown, two decades of directly measured velocity across the current show no evidence of a decrease..." https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/201...

And Judith Curry:

"What we are seeing in the high latitudes of the North Atlantic is natural variability, predominantly associated with the Atlantic Multidecadal Oscillation. Based open observational analyses, there is no sign of a slowdown in the Gulf Stream or the Atlantic Meridional Overturning Circulation." https://judithcurry.com/2015/03/25/whats-up-with-the-atlanti...


-=Ajax=-
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On the long-term stability of Gulf Stream transport based on 20?years of direct measurements
Rossby et al.
https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/201...
"In contrast to recent claims of a Gulf Stream slowdown, two decades of directly measured velocity across the current show no evidence of a decrease."

A 30-year reconstruction of the Atlantic meridional overturning circulation shows no decline
Worthington et al.
https://os.copernicus.org/articles/17/285/2021/

DB2
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Rossby et al.
https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/201.........
"In contrast to recent claims of a Gulf Stream slowdown, two decades of directly measured velocity across the current show no evidence of a decrease."

A 30-year reconstruction of the Atlantic meridional overturning circulation shows no decline
Worthington et al.
https://os.copernicus.org/articles/17/285/2021/

DB2

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DB2,

You post two older studies from 2013 and 2020. These older studies were considered in the new study. At least one of the authors of new study were also on the previous studies.

So you are up to your old tricks trying to negate the new study results with old study results.

Jaak
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Too early to be sure, and hard to know what conclusions to draw. But would probably be disruptive in many ways.

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Thanks for posting this new information. The Europeans are mighty worried about disruption in the Atlantic Ocean circulation. They are the ones doing most of the studies. My wife has relatives in Ireland and they know all about the impact. They would be devastated with the North Atlantic turning colder.

Jaak
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You post two older studies from 2013 and 2020.

You seem to have an obsession with publication date. If, for example, I have data on the height measurement of people on the Isle of Wight over three decades then it doesn't matter whether I publish now or five years from now. The average height for that period is still the same.

As for the overturning papers, you are missing the differences. The Caesar paper used proxies to estimate the overturning rate. They found two periods of slowing -- the beginning of the 1800s and the mid-1900s.

The other two papers were anchored on real-time measurements. If fact, one of the titles is "On the long-term stability of Gulf Stream transport based on 20?years of direct measurements".

"In contrast to recent claims of a Gulf Stream slowdown, two decades of directly measured velocity across the current show no evidence of a decrease."

"the [30-year] time series shows no overall AMOC decline as indicated by other proxies and high-resolution climate models."

DB2
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"Atlantic Ocean circulation at weakest in a millennium, say scientists" - Guardian 2/26/2021
https://www.theguardian.com/environment/2021/feb/25/atlantic......

"New Study Suggests Atlantic Ocean Circulation System Could Collapse" - VOA 2/24/2021
https://www.voanews.com/science-health/new-study-suggests-at......

"Scientists see stronger evidence of slowing Atlantic Ocean circulation ..." Wash Post 2/25/2021
https://www.washingtonpost.com/climate-environment/2021/02/2......

"Current Atlantic Meridional Overturning Circulation weakest in last millennium" - Nature 2/24/2021
https://www.nature.com/articles/s41561-021-00699-z

Jaak
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"Abstract: In contrast to recent claims of a Gulf Stream slowdown, two decades of directly measured velocity across the current show no evidence of a decrease..." https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/201...

"Atlantic Ocean circulation at weakest in a millennium, say scientists" - Guardian 2/26/2021
https://www.theguardian.com/environment/2021/feb/25/atlantic...

"New Study Suggests Atlantic Ocean Circulation System Could Collapse" - VOA 2/24/2021
https://www.voanews.com/science-health/new-study-suggests-at... Jaak

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According to Joseph Goebbels, if you "Repeat a lie often enough it becomes the truth," except it doesn't work that way. Lies/propaganda are not the same as truth, science and honest data!


-=Ajax=-
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Global warming is speeding up Earth’s massive ocean currents
www.sciencemag.org/news/2020/02/global-warming-speeding-eart...
The oceans’ great continent-wrapping currents, each one moving as much water as all the world’s rivers combined, can rightly be considered the planet’s circulatory system. And this circulation, it appears, has started to thump faster: For nearly 25 years the currents have been rapidly speeding up, partly because of global warming.

That’s the conclusion of a new paper today in Science Advances. Based on observations combined with models, the authors claim that from 1990 to 2013, the energy of the currents increased by some 15% per decade. “This is a really huge increase,” says Susan Wijffels, an oceanographer at the Woods Hole Oceanographic Institution. “It’s going to stimulate a lot of other work.” If the acceleration is real, it could affect jet streams, weather patterns, and the amount of heat stored in the ocean’s depths.

Oceanographers have suspected that climate warming is affecting ocean circulation, but so far, observations haven’t shown a trend, says Hu Shijian, an oceanographer at the Chinese Academy of Sciences’s Institute of Oceanology and lead author of the study.

DB2
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Ocean currents are more in the domain of Lunar gravity nudges.
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Ocean currents are more in the domain of Lunar gravity nudges.
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Tides are not the same as the temperature and density driven ocean circulation. The Gulf Stream flow is not due to the tides, but rather the thermohaline ocean circulation, which goes by various other names and descriptions.

https://en.wikipedia.org/wiki/Thermohaline_circulation

- Pete
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