Arctic Melt leading to weakest Gulf Stream in up to 1,000 years!

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Well if that title doesn't say it all! Get ready friends. If you are not currently sitting in one of the states that is having major storms and tornados, maybe mountains of snow is your fate. Out here in CA we need water. Check out this article.

http://www.newsmax.com/SciTech/gulf-stream-weakest-1000/2015/03/23/id/63...

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MrsBJLee
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I try to avoid Newsmax-- here is the press release from the source organization: https://www.pik-potsdam.de/news/press-releases/atlantic-ocean-overturning-found-to-slow-down-already-today

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stwo
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Jul. 31, 2007 3:01 pm

A little more in depth information, including results of a recent study and some illustrations: Study: Melting Greenland ice sheet is rapidly slowing the Gulf Stream.

Here's a link to the study published last March, 23: Exceptional twentieth-century slowdown in Atlantic Ocean overturning circulation

Quote from the Abstract:

Possible changes in Atlantic meridional overturning circulation (AMOC) provide a key source of uncertainty regarding future climate change. Maps of temperature trends over the twentieth century show a conspicuous region of cooling in the northern Atlantic. Here we present multiple lines of evidence suggesting that this cooling may be due to a reduction in the AMOC over the twentieth century and particularly after 1970. Since 1990 the AMOC seems to have partly recovered. This time evolution is consistently suggested by an AMOC index based on sea surface temperatures, by the hemispheric temperature difference, by coral-based proxies and by oceanic measurements. We discuss a possible contribution of the melting of the Greenland Ice Sheet to the slowdown. Using a multi-proxy temperature reconstruction for the AMOC index suggests that the AMOC weakness after 1975 is an unprecedented event in the past millennium (p > 0.99). Further melting of Greenland in the coming decades could contribute to further weakening of the AMOC.

Perhaps a mini ice age would put the arctic methane monster back to sleep and slow a number of self reinforcing feedback loops that have been emerging as the whole globe warmed, year by year, since around 1980. That may even be something to hope for, though it would mean some serious challenges for Europe's population.

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.ren
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These currents are drive by a combination of heat and salinity differences. Winds evaporate water south of Greenland causing the water to become more salty, and heavier that surrounding waters. The current there begins to sink. If meltwater from the arctic is neutralizing this haline differential, I suspect sometime in the future we're going to use giant salting ships to encourage the flow of this current. Otherwise Europe is going to pay the price.

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ulTRAX
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Without the Gulf stream Europe will turn into an ice box. London is 51 degrees north latitude. Almost as far north as Moscow. Further north than Montreal. It is kept relatively warm by the gulf stream. It rarely has snow or even frost. Paris is about the same as Montreal. But is also much warmer.

Legend
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Nov. 27, 2012 6:46 am

Mrs Lee I also would suggest avoiding Newmax.

Legend
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Nov. 27, 2012 6:46 am

Does anyone really believe Europe would be the only place that'd suffer? That stream is part of a world wide stream or current, if any part is interrupted........let's guess what happens to the entire stream. deep sea currents

rs allen
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Mar. 15, 2012 4:55 pm
Quote Legend:

Without the Gulf stream Europe will turn into an ice box. London is 51 degrees north latitude. Almost as far north as Moscow. Further north than Montreal. It is kept relatively warm by the gulf stream. It rarely has snow or even frost. Paris is about the same as Montreal. But is also much warmer.

Europe's "been there, done that". There were decades when the Thames froze solid enough for vendors to sell the ubiquitous fish-and-chips from carts, ditto the Seine in Paris. At least once the canals of Venice froze over. I wonder what the people blamed it on then, the Devil?

The Little Ice Age:

"A cold period that lasted from about A.D. 1550 to about A.D. 1850 in Europe, North America, and Asia. This period was marked by rapid expansion of mountain glaciers, especially in the Alps, Norway, Ireland, and Alaska. There were three maxima, beginning about 1650, about 1770, and 1850, each separated by slight warming intervals."

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mjolnir
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Rahmsdorf presents an interesting paper relying heavily on models proxies and a plethora of "maybe's" and "possiblies" and "coulds" Another recent paper by T. Rossby et al presents data collected directly using an Acoustic Doppler Current Profiler that do not show any slowing in the Gulf stream despite what conjecture and modelling might hint at.

On the long-term stability of Gulf Stream transport based on 20 years of direct measurements

T. Rossby1,*, C. N. Flagg2, K. Donohue1, A. Sanchez-Franks2, J. Lillibridge3

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. Using a well-constrained definition of Gulf Stream width, the linear least square fit yields a mean surface layer transport of 1.35 × 105 m2 s−1 with a 0.13% negative trend per year. Assuming geostrophy, this corresponds to a mean cross-stream sea level difference of 1.17 m, with sea level decreasing 0.03 m over the 20 year period. This is not significant at the 95% confidence level, and it is a factor of 2–4 less than that alleged from accelerated sea level rise along the U.S. Coast north of Cape Hatteras. Part of the disparity can be traced to the spatial complexity of altimetric sea level trends over the same period.

http://onlinelibrary.wiley.com/doi/10.1002/2013GL058636/abstract

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stwo
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Quote stwo:

Rahmsdorf presents an interesting paper relying heavily on models proxies and a plethora of "maybe's" and "possiblies" and "coulds" Another recent paper by T. Rossby et al presents data collected directly using an Acoustic Doppler Current Profiler that do not show any slowing in the Gulf stream despite what conjecture and modelling might hint at.

On the long-term stability of Gulf Stream transport based on 20 years of direct measurements

T. Rossby1,*, C. N. Flagg2, K. Donohue1, A. Sanchez-Franks2, J. Lillibridge3

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. Using a well-constrained definition of Gulf Stream width, the linear least square fit yields a mean surface layer transport of 1.35 × 105 m2 s−1 with a 0.13% negative trend per year. Assuming geostrophy, this corresponds to a mean cross-stream sea level difference of 1.17 m, with sea level decreasing 0.03 m over the 20 year period. This is not significant at the 95% confidence level, and it is a factor of 2–4 less than that alleged from accelerated sea level rise along the U.S. Coast north of Cape Hatteras. Part of the disparity can be traced to the spatial complexity of altimetric sea level trends over the same period.

http://onlinelibrary.wiley.com/doi/10.1002/2013GL058636/abstract

Yeah, I've run across that study before. What a novel approach, actual measurements instead of reliance on algorithms.

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mjolnir
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Mar. 3, 2011 11:42 am

LOL, you guys just will not accept the over all conclusions of the scientific community. You find the few papers that contradict the many and for what reason I do not know. Are you just too scared to face the truth? I can understand that but you really are reaching for straws.

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Bush_Wacker
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In case anyone is not reading carefully, a study of twenty years of ocean currents is well within the time frame noted as a recovery period in the other study cited in post #2 and #3,

From post #9

On the long-term stability of Gulf Stream transport based on 20 years of direct measurements

T. Rossby1,*, C. N. Flagg2, K. Donohue1, A. Sanchez-Franks2, J. Lillibridge3

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.

The term "long-term" must be read carefully if one is going to jump to comparisons.

Whatever "recent claims" are being referenced in the abstract, they are obviously not the claims related to the study the Potsdam article linked in post #2, found referenced at the bottom, and another article and the actual study linked in post #3, with the abstract that contains these lines:

Quote Exceptional Twentieth-Century Slowdown in Atlantic Overturning...:

Here we present multiple lines of evidence suggesting that this cooling may be due to a reduction in the AMOC over the twentieth century and particularly after 1970. Since 1990 the AMOC seems to have partly recovered.

Twenty years is much less than a thousand years, or even the hundred years of the Twentieth Century.

One study is talking about slow down effects of the Atlantic meridional overturning circulation (AMOC) during the 20th Century, while looking back with complex sets of data over a thousand years, and of course with a noted recovery period taking place in the last twenty five years (since 1990).

The other study is merely about direct measurements taken during that the last twenty years of that twenty five year recovery period when it's very likely the measurments would be fairly constant. It turns out NASA concurs. Careful reading would indicate that direct measurements over a twenty year span would not seem contradictory to the long term study. Careful reading is all that's needed but careful reading takes effort and the denialist industry is well acquainted with the laziness of most readers today who are willing to let James Watts and others figure it all out for them.

Careful reading therefore will not be expected of the readers of many Heartland institute-related sites like Watts Up With That? The world's most viewed site on global warming and climate site, where you may find claims like this about that same study referenced in posts #2 and #3:

NASA refutes Mann and Rahmstorf – Finds Atlantic ‘Conveyor Belt’ Not Slowing

Well, the actual title of the article before the spin is: NASA Study Finds Atlantic 'Conveyor Belt' Not Slowing.

And if you read the actual NASA article you won't find any reference to the Mann and Rahmstorf's study. That link is where spin doctors like Heartland-affiliate Watts come in.

In the NASA article you'll find an explanation of a NASA satellite methodology developed for measuring the ocean currents, with a summary of data collected over the years from 1995 to 2010 showing no sign of a slowing during that period. Whether it had slowed before that, they hadn't measure, so no possible refutation of those claims. Therefore, not a refutation of a the Mann and Rahmstorf long term findings where they note that period has been showing a recovery. What it all means, of course, remains highly speculative.

But this is how Watts likes to portray it:

Quote Anthony Watts:

From the “we told you so yesterday” and the “settled science” department. This study was released in 2010, and they used actual measurements, rather than proxy data and reconstructions like Mann did. Gee, what a concept!

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.ren
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Quote Bush_Wacker:

LOL, you guys just will not accept the over all conclusions of the scientific community. You find the few papers that contradict the many and for what reason I do not know. Are you just too scared to face the truth? I can understand that but you really are reaching for straws.

NO fear here. I believe that a warming globe with more CO2 is much better for the inhabitants of the planet. It certainly has been better so far.

I am biased towards direct measurement over models, speculation and conjecture. I understand the value of the models and hypotheses, and also oppose wasteful policy that give more credence to them than to direct observation.

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stwo
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Quote stwo:NO fear here. I believe that a warming globe with more CO2 is much better for the inhabitants of the planet. It certainly has been better so far.

I am biased towards direct measurement over models, speculation and conjecture. I understand the value of the models and hypotheses, and also oppose wasteful policy that give more credence to them than to direct observation.

A warming globe with more CO2 is MUCH better for the inhabitants of the planet? And as self-proclaimed respecter of direct measurement over speculation and conjecture... your conclusion is based on which direct measurements exactly?

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ulTRAX
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Quote .ren:

In case anyone is not reading carefully, a study of twenty years of ocean currents is well within the time frame noted as a recovery period in the other study cited in post #2 and #3,

The 20 year study in question really doesn't address the area that would be effected by Greenland meltwater. The study area is a path from NJ to Bermuda.

http://www.pik-potsdam.de/~stefan/thc_fact_sheet.html

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ulTRAX
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Quote mjolnir:Yeah, I've run across that study before. What a novel approach, actual measurements instead of reliance on algorithms.

You're trying to present a study in a very limited cross section of the Gulf Stream as somehow definitive. I think the devil is in the details here. Just what is a "well-constrained definition of Gulf Stream width"? The study takes place on the same path... from New Jersey to Bermuda http://www.gso.uri.edu/blog/rossby-gulf-stream-is-not-slowing/ and would seem to be measuring current still driven north by topical heat. But the circulation time of the great ocean conveyor is about 1000 years. https://en.wikipedia.org/wiki/Thermohaline_circulation It would not just slowdown at once.

So if the problem is Greenland melt waters interfering with where there's deep water formation... where a branch of current called the North Altlantic Drift http://www.pik-potsdam.de/~stefan/thc_fact_sheet.html begins to sink near Greenland, then perhaps that might be a more relevant area of study... and in the last winter that's roughly where there was the coldest recorded deviation from temp norms http://www.realclimate.org/index.php/archives/2015/03/whats-going-on-in-...

Just a thought. I'm not sure what cooling there indicates. It's only a snapshot. What about summer when we'd expect more meltwater? Or is there a delay effect since meltwater would not instantly flow that far out to sea. What about salinity readings from that area?

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ulTRAX
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Quote mjolnir:
Quote stwo:

Rahmsdorf presents an interesting paper relying heavily on models proxies and a plethora of "maybe's" and "possiblies" and "coulds" Another recent paper by T. Rossby et al presents data collected directly using an Acoustic Doppler Current Profiler that do not show any slowing in the Gulf stream despite what conjecture and modelling might hint at.

Yeah, I've run across that study before. What a novel approach, actual measurements instead of reliance on algorithms.

It's apples and oranges. The current in question is NOT the main part of the Gulf Stream in the 20 year study... but possible changes in AMOC, the Atlantic meridional overturning circulation

https://www.pik-potsdam.de/news/press-releases/atlantic-ocean-overturnin...

So that 20 year study isn't a rebuttal to anything. It might be possible for the North Atlantic Drift to slow, and the Gulf Stream along the cross section of the 20 year study not to be affected. The Newsmax article http://www.newsmax.com/SciTech/gulf-stream-weakest-1000/2015/03/23/id/63... is unclear and seems to conflate the two

Gulf Stream water currents in the Atlantic Ocean have slowed to the weakest in as long as 1,000 years, threatening shifts in U.S. and European weather, as well as coastal sea levels including in New York and Boston.

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ulTRAX
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Quote ulTRAX:
Quote .ren:

In case anyone is not reading carefully, a study of twenty years of ocean currents is well within the time frame noted as a recovery period in the other study cited in post #2 and #3,

The 20 year study in question really doesn't address the area that would be effected by Greenland meltwater. The study area is a path from NJ to Bermuda.

http://www.pik-potsdam.de/~stefan/thc_fact_sheet.html

Yes. The "con" job here is to present one study as if it's the contradiction of the other.

I doubt if anyone has developed techniques to study ocean currents with direct measurements before the idea was even conceived, say 1000 AD and all the years leading up to the 20th Century. I think it was Ben Franklin in his crossings back and forth to Europe on sailing ships, who first struck upon notion there might actually be a current in the Atlantic. Thus we are left with elaborate speculations and debate about what they might mean.

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.ren
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And in the mean time we have idiocy like, " I think more co2 is good for mankind".

rs allen
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Quote .ren:
Quote ulTRAX:
Quote .ren:

In case anyone is not reading carefully, a study of twenty years of ocean currents is well within the time frame noted as a recovery period in the other study cited in post #2 and #3,

The 20 year study in question really doesn't address the area that would be effected by Greenland meltwater. The study area is a path from NJ to Bermuda.

http://www.pik-potsdam.de/~stefan/thc_fact_sheet.html

Yes. The "con" job here is to present one study as if it's the contradiction of the other.

And even the 20 year Rossby study doesn't claim to have all the data.... from http://www.gso.uri.edu/blog/rossby-gulf-stream-is-not-slowing/

For the last 20 years he and his colleagues have measured the Gulf Stream using an acoustic Doppler current profiler (ADCP) attached to a ship, the freighter Oleander, which makes weekly trips across the Gulf Stream from New Jersey to Bermuda. The instrument, which measures the velocity of water moving beneath the ship down to more than 600 meters, has collected some 1,000 measurements of the Gulf Stream since it was installed in late 1992.

Although he officially retired in 2011, Rossby is continuing his Gulf Stream research and hopes to install a new instrument on the Oleander in the coming years that will be able to profile currents to even greater depths.

“Once we do that, all of the water going north will be well within our reach,” he said.

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ulTRAX
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Quote rs allen:

And in the mean time we have idiocy like, " I think more co2 is good for mankind".

unqualifyingly beneficial for ALL life on the planet.

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stwo
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Quote stwo:
Quote rs allen:

And in the mean time we have idiocy like, " I think more co2 is good for mankind".

unqualifyingly beneficial for ALL life on the planet.

Let's review this discussion

[/quote]
STWO :NO fear here. I believe that a warming globe with more CO2 is much better for the inhabitants of the planet. It certainly has been better so far.

I am biased towards direct measurement over models, speculation and conjecture. I understand the value of the models and hypotheses, and also oppose wasteful policy that give more credence to them than to direct observation.

ulTRAX A warming globe with more CO2 is MUCH better for the inhabitants of the planet? And as self-proclaimed respecter of direct measurement over speculation and conjecture... your conclusion is based on which direct measurements exactly? [/quote]

I ask again... your conclusion "a warming globe with more CO2 is much better for the inhabitants of the planet. " is based on which direct measurements exactly?

Sounds like you took a home study class from the Greening Earth whackos.

http://web.archive.org/web/20000510222328/http://www.greeningearthsociet...

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ulTRAX
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Jul. 31, 2007 3:01 pm

.ren is correct in that the Rahmsdorf and Rossy papers don't report on the same pehnomena. I think the Rahmsdorf paper is serously flawed but agree that the Rossby paper doenst refute its conclusions.

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stwo
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Quote stwo:
Quote rs allen:

And in the mean time we have idiocy like, " I think more co2 is good for mankind".

unqualifyingly beneficial for ALL life on the planet.

So is water. Try living in it 24/7. So is sunlight. What would happen to the planet if their were no night time. More does not always equate to better.

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Bush_Wacker
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