UPDATED – see below
From your “Day after Tomorrow” department (where a slowing Gulf Stream turned NYC into an icebox) comes this claim from the bowels of Mannian Science. Unfortunately, it looks to be of the caliber of Mann’s Hockey Schtick science.
As WUWT reported on a peer reviewed paper last year, H. Thomas Rossby says: URI oceanographer refutes claims that climate change is slowing pace of Gulf Stream saying in a paper published in Geophysical Research Letters:
“The ADCP measures currents at very high accuracy, and so through the repeat measurements we take year after year, we have a very powerful tool by which to monitor the strength of the current,” said Rossby. “There are variations of the current over time that are natural — and yes, we need to understand these better — but we find absolutely no evidence that suggests that the Gulf Stream is slowing down.”
Of course, Rahmstorf and Mann don’t list Rossby’s study in their references, nor seem to use the “highly accurate” ADCP data. Instead they use a model along with [proxies, reconstructions, and] the highly interpolated GISS data to come to the conclusions they want. So, it isn’t surprising they are chasing phantoms in their study. They claim (in Figure 1 from their paper) that this cold spot south of Greenland is caused by meltwater from Greenland and it is evidence of a slowed circulation:
I find it interesting that they note “…that the second cooling patch in central Africa is in a region of poor data coverage and may be an artefact of data inhomogeneities.” Yet somehow that cooling patch south of Greenland is free of such problems in the same GISS dataset. Go figure.
And then there’s this other problem; Greenland’s ice mass seems to be on the increase so far this year and above the 1990-2011 mean:
Source: http://www.dmi.dk/uploads/tx_dmidatastore/webservice/b/m/s/d/e/accumulatedsmb.png
Accessed from http://www.dmi.dk/en/groenland/maalinger/greenland-ice-sheet-surface-mass-budget/
Maybe this is the new Mannian science, wherein global warming causes cooling, and melting causes more ice accumulation. (h/t to Tom McClellan)
Of course, given that Stephan Rahmstorf thinks the “Day After Tomorrow” was just peachy, one wonders if this study isn’t just a embellishment of his movie review:
(Via Wikipedia) However, Stefan Rahmstorf of the Potsdam Institute for Climate Impact Research, expert for thermohaline ocean circulation and its effects on climate, was impressed how the script writer Jeffrey Nachmanoff was well informed about the science and politics of global climate change after the talk with him at the preview of the film in Berlin. He stated: “Clearly this is a disaster movie and not a scientific documentary, the film makers have taken a lot of artistic license. But the film presents an opportunity to explain that some of the basic background is right: humans are indeed increasingly changing the climate and this is quite a dangerous experiment, including some risk of abrupt and unforeseen changes. After all – our knowledge of the climate system is still rather limited, and we will probably see some surprises as our experiment with the atmosphere unfolds. Luckily it is extremely unlikely that we will see major ocean circulation changes in the next couple of decades (I’d be just as surprised as Jack Hall if they did occur); at least most scientists think this will only become a more serious risk towards the end of the century. And the consequences would certainly not be as dramatic as the ‘super-storm’ depicted in the movie. Nevertheless, a major change in ocean circulation is a risk with serious and partly unpredictable consequences, which we should avoid. And even without events like ocean circulation changes, climate change is serious enough to demand decisive action. I think it would be a mistake and not do the film justice if scientists simply dismiss it as nonsense. For what it is, a blockbuster movie that has to earn back 120 M$ production cost, it is probably as good as you can get. For this type of movie for a very broad audience it is actually quite subversive and manages to slip in many thought-provoking things. I’m sure people will not confuse the film with reality, they are not stupid – they will know it is a work of fiction. But I hope that it will stir their interest for the subject, and that they might take more notice when real climate change and climate policy will be discussed in future.” Source: http://www.pik-potsdam.de/~stefan/tdat_review.html
But…
In 2008, Yahoo! Movies listed The Day After Tomorrow as one of Top 10 Scientifically Inaccurate Movies. The film was criticized for depicting several different meteorological phenomena occurring over the course of hours, instead of the possible time frame of several decades or centuries.
UPDATE: I’ve added figures 5 and 6 from the Mann and Rahmstorf paper below.
When actual Gulf Stream measurement data (the ADCP data cited by Rossby 2014) is available, why would Mann and Rahmstorf use proxies? And why try to say that temperature is the indicator, when you have actual speed data? The obtuseness boggles the mind.
Further, note Figure 6, they claim that discharge exceeds gain, which looks like Mann’s proverbial “hockey stick” and this is based on Box and Colgan (2010) data, which is their citation #33. They claim data all the way back to 1850, which is quite some feat since as far as I know, no actual whole Greenland ice data was measured until the International Geophysical year of 1958, such as:
Bauer, A., Baussart, M., Carbonnell, M., Kasser, P., Perroud, P. and Renaud, A. 1968. Missions aériennes de reconnaissance au Groenland 1957-1958. Observations aériennes et terrestres, exploitation des photographies aeriennes, determination des vitesses des glaciers vělant dans Disko Bugt et Umanak Fjord. Meddelser om Grønland 173(3), 116 pp.
And further, previous papers from Jason Box only start with data at 1958:
It turns out Box and Colgan (2010) is a reconstruction, not actual measurement data.
However, even more puzzling, when you look at the Box and Colgan (2010) Figure 5 from their paper (free PDF here) the mass balance loss and accumulation shows no such “hockey stick” shape.
One wonders if Mann didn’t apply his “special Mannomatic math“, as he did to his “hockey stick” to the Box and Colgan (2010) reconstructed data to get the large divergence between accumulation and loss we see in Mann and Rahmstorf’s Figure 6.
More importantly though, the Box and Colgan (2010) data isn’t actual measurement data, it is a reconstruction based on some data, and some guesses:
According to our reconstruction, TMB has been positive for 39% of the 1840–2010 period (see mass balance surplus areas in Fig. 5). The positive decade-scale mass balance phases correspond with periods of low melting and runoff. For example, from 1970 to 1985 a positive mass balance phase corresponds to a period of enhanced sulfate cooling (Wild et al. 2009) pronounced along west Greenland (Rozanov et al. 2002; Box et al. 2009). Mass budget surpluses can also be produced by high accumulation years, even occasionally despite relatively high runoff (e.g., 1996).The reconstructed TMB values are compared 1) with those from the surface mass balance in Part II minus the Rignot et al. (2008, 2011)LM for 20 samples spanning 1958–2009 and 2) with the independent GRACE data spanning 2003–10 after Wahr et al. (2006) (Fig. 6). We find RMS errors of 31Gtyr for dataset 1 and 69Gtyr in comparison with dataset 2 (Table 1).
So, clearly, there’s no actual data prior to 1958. The Mann and Rahmstorf paper misleads the reader by not making this clear.
Duke University physicist Robert G. Brown, in comments noted:
Seriously — they found “good evidence” that such a slowing is occurring, only the actual evidence, consisting of the measured speed of the Gulf Stream itself, shows no such thing?
The cognitive dissonance involved is stupifying.
Indeed. Mann and Rahmstorf eschew reality for models and reconstruction. They live in an incestuous climate world of their own making.
Here’s the press release:
Atlantic Ocean overturning found to slow down already today
The gradual but accelerating melting of the Greenland ice-sheet, caused by man-made global warming, is a possible major contributor to the slowdown. Further weakening could impact marine ecosystems and sea level as well as weather systems in the US and Europe.
“It is conspicuous that one specific area in the North Atlantic has been cooling in the past hundred years while the rest of the world heats up,” says Stefan Rahmstorf of the Potsdam Institute for Climate Impact Research, lead author of the study to be published in Nature Climate Change. Previous research had already indicated that a slowdown of the so-called Atlantic meridional overturning circulation might be to blame for this. “Now we have detected strong evidence that the global conveyor has indeed been weakening in the past hundred years, particularly since 1970,” says Rahmstorf.
Because long-term direct ocean current measurements are lacking, the scientists mainly used sea-surface and atmospheric temperature data to derive information about the ocean currents, exploiting the fact that ocean currents are the leading cause of temperature variations in the subpolar north Atlantic. From so-called proxy data – gathered from ice-cores, tree-rings, coral, and ocean and lake sediments – temperatures can be reconstructed for more than a millennium back in time. The recent changes found by the team are unprecedented since the year 900 AD, strongly suggesting they are caused by man-made global warming.
“The melting Greenland ice sheet is likely disturbing the circulation”
The Atlantic overturning is driven by differences in the density of the ocean water. From the south, the warm and hence lighter water flows northwards, where the cold and thus heavier water sinks to deeper ocean layers and flows southwards. “Now freshwater coming off the melting Greenland ice sheet is likely disturbing the circulation,” says Jason Box of the Geological Survey of Denmark and Greenland. The freshwater is diluting the ocean water. Less saline water is less dense and has therefore less tendency to sink into the deep. “So the human-caused mass loss of the Greenland ice sheet appears to be slowing down the Atlantic overturning – and this effect might increase if temperatures are allowed to rise further,” explains Box.
The observed cooling in the North Atlantic, just south of Greenland, is stronger than what most computer simulations of the climate have predicted so far. “Common climate models are underestimating the change we’re facing, either because the Atlantic overturning is too stable in the models or because they don’t properly account for Greenland ice sheet melt, or both,” says Michael Mann of Pennsylvania State University in the US. “That is another example where observations suggest that climate model predictions are in some respects still overly conservative when it comes to the pace at which certain aspects of climate change are proceeding.”
No new ice-age – but major negative effects are possible
The cooling above the Northern Atlantic would only slightly reduce the continued warming of the continents. The scientists certainly do not expect a new ice age, thus the imagery of the ten-year-old Hollywood blockbuster ‘The Day After Tomorrow’ is far from reality. However, it is well established that a large, even gradual change in Atlantic ocean circulation could have major negative effects.
“If the slowdown of the Atlantic overturning continues, the impacts might be substantial,” says Rahmstorf. “Disturbing the circulation will likely have a negative effect on the ocean ecosystem, and thereby fisheries and the associated livelihoods of many people in coastal areas. A slowdown also adds to the regional sea-level rise affecting cities like New York and Boston. Finally, temperature changes in that region can also influence weather systems on both sides of the Atlantic, in North America as well as Europe.”
If the circulation weakens too much it can even break down completely – the Atlantic overturning has for long been considered a possible tipping element in the Earth System. This would mean a relatively rapid and hard-to-reverse change. The latest report by the Intergovernmental Panel on Climate Change (IPCC) estimates there to be an up to one-in-ten chance that this could happen as early as within this century. However, expert surveys indicate that many researchers assess the risk to be higher. The study now published by the international team of researchers around Rahmstorf provides information on which to base a new and better risk assessment.
###
Article: Rahmstorf, S., Box, J., Feulner, G., Mann, M., Robinson, A., Rutherford, S., Schaffernicht, E. (2015): Evidence for an exceptional 20th-Century slowdown in Atlantic Ocean overturning. Nature Climate Change (online) [DOI:10.1038/nclimate2554]
Weblink to the article: http://dx.doi.org/10.1038/nclimate2554
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.
Further information:
NASA animation “The Great Ocean Conveyor Belt” (downloadable video that shows the current system that now is found to slow down in the North Atlantic):
Weblink to a study on possible impacts of a shutdown of the thermohaline circulation: http://link.springer.com/article/10.1007%2Fs10584-009-9561-y
Weblink to the expert assessment of an AMOC tipping: http://www.pnas.org/content/early/2009/03/13/0809117106.abstract
The supplementary information:
http://www.nature.com/nclimate/journal/vaop/ncurrent/extref/nclimate2554-s1.pdf
shows how they create an AMOC index, that moves in the opposite direction to recent measurements of the AMOC:
http://www.rapid.ac.uk/
If this is a robust slowing signal (and with over-parameterized shaken and stirred data I doubt it), two things need to happen. 1) The study needs to be replicated to determine if the results are valid. 2) The signal needs to be demonstrated by other measures thus determining its reliability. However, since being granted global warming research money depends on producing results that adhere to the storyline, I doubt this study will ever be properly scrutinized.
In addition, if the use of over-parameterized data in this study makes you throw up a little in your mouth, don’t then eat it for dessert when similar tactics are used to confirm some opposing pet theory about warming and cooling.
Here is the noise-to-signal of your dreams, Pamela. No over-parameterization here!
http://news.bme.com/wp-content/uploads/200508272119-pix1.jpg
(One year of college and he would have “Mr. Confidence Interval” tattooed all over himself.)
I was thinking Error bars is where they hang out.
I’m thinking that these authors are “self smarted”
Pamela Gray,
Academic.
Speculation and well-poisoning. Supposed to be a no-no in these parts.
Slippery slope to just cause corruption, also supposed to be a no-no in these parts. I see a nice lecture about how to do good science in your comments, not much evidence of ability to walk the talk.
That’s what makes Pamela fascinating … kind of like Mr. Cool ICE.
I just have so many questions.
Brandon where are the error bars? If you want to legitimize Mann, help him produce error bars, and the rationale behind them. Real scientists either do this, or are soon caught out. “Climate Scientists,” not so much…
O’ contraire, I have walked the talk. I’ve been in the Ivory Tower. Not for long, but long enough. My published study was replicated. In fact I hoped it would be so made sure it could be. It was determined to be valid and reliable. I also know how grants are advertised. Many, if not most, grants are specific to a cause. The most money is still in the “Show connections to global warming” pile. Anybody can look that information up. The money available for research on global warning connections to human activity is much greater than the money available for natural weather pattern variation.
So my next move is, show me yours. If you have not been through the rigor of published research, you are just a teetering toddler in this game.
Pamela Gray,
Trenberth did suggest changing the null hypothesis. Did you agree with him?
And you say you left the Ivory Tower. Let me put it to you this way; credentials do not impress me in and of themselves. Quality of arguments do. Trading on thinly evidenced, meager credentials alone … singularly unimpressive.
Michael Moon,
Take it up with Anthony for the first one: UPDATE: I’ve added figures 5 and 6 from the Mann and Rahmstorf paper below.
The second one is from Mann, Bradley and Hughes (1998): http://www.meteo.psu.edu/holocene/public_html/shared/articles/mbh98.pdf
Figure 6b., p. 783 in the journal, p. 5 of the pdf.
Your original statement was: If you want to legitimize Mann, help him produce error bars, and the rationale behind them.
I’ve shown you two figures from papers with Mann listed as author with error bars. You, sir, have erred, and no amount of trundling out other oft-regurgitated memes will make it any less obvious. Good luck trying.
Michael Moon,
Where are your eyes?
If you want to legitimize Soon …
Yeah. Best you just don’t go there.
No need, they’ve been around since 1998:
http://www.climateaudit.info/images/mann/mbh98_fig5.png
Another swing and a miss. Strike three. Start about here:
Methods
Statistics. We use as our primary diagnostic of calibration and verification reconstructive skill the conventional ‘resolved variance’ statistic;
Real skeptics would at least bother to check that the error bars were indeed missing … and one would hope they could think of a more substantive argument to boot. Fake skeptics who only know how to argue, “If Mann’s name is on it, even if he isn’t the lead author, it must be wrong” …. not so much.
So zero change fits within your error bars (which are rather lacking in source and methods).
None of those charts were from the referenced paper. Mann’s wildly creative selective use of proxy “data,” the way he spliced thermometer data onto treemometer data, and invented a new, quite baseless application of Principal Component Analysis, are well-documented. You, sir, have drunk the Kool-Aid, good luck…
Real scientists pay attention to cautions related to spliced temperature reconstructions. The discontinuities are massive. Error bars more than likely underestimate the affect of records available to reconstruct temperatures. They also fail to consider the more highly variable Northern Hemisphere and because they do not consider this, they do not weight it as they should. This 2010 paper reminds us to interpret the hockey stick blade with caution. Funny how Mann banks on it over and over again, yet being slapped silly each and every time.
From its conclusion:
“Substantial parts of the Roman Warm Period, from the first to the third centuries, and the Medieval Warm Period, from the ninth to the thirteenth centuries, seem to have equalled [sic] or exceeded the AD 1961–1990 mean temperature level in the extra-tropical Northern Hemisphere. Since AD 1990, though, average temperatures in the extra-tropical Northern Hemisphere exceed those of any other warm decades the last two millennia, even the peak of the Medieval Warm Period, if we look at the instrumental temperature data spliced to the proxy reconstruction. However, this sharp rise in temperature compared to the magnitude of warmth in previous warm periods should be cautiously interpreted since it is not visible in the proxy reconstruction itself.”
Meaning that when using the proxies that continue to move forward to the current state, the sudden rise in temperature is not visible in proxy reconstructions of current temperature. In other words, when splicing an apple to an orange, you cannot then call the entire thing an orange.
http://scholar.google.com/scholar_url?url=http%3A%2F%2Fwww.agbjarn.blog.is%2Fusers%2Ffa%2Fagbjarn%2Ffiles%2Fljungquist-temp-reconstruction-2000-years.pdf&hl=en&sa=T&oi=gga&ct=gga&cd=8&ei=m_gRVay8G4G0qQHG34CwBw&scisig=AAGBfm3MFFNPm7HeA3LdV5jdJYMgHL6Yvg&nossl=1&ws=1600×747
At last, someone who can help us out with the irksome problem of how to calculate the confidence intervals in MBH98/99! Brandon, what’s the method? How did he do it?
Pamela Gray,
No, it says what it says, which you more or less faithfully interpreted in your lead comment: This 2010 paper reminds us to interpret the hockey stick blade with caution.
Keep in mind that no proxy reconstruction would make sense without comparison to modern temperature records.
Although partly different data and methods have been used in our reconstruction than in Moberg et al. (2005) and Mann et al. (2008), the result is surprisingly similar. The inclusion of additional records would probably not substantially change the overall picture of the temperature variability. The major uncertainty lies in the magnitude of cooling during the Little Ice Age. It is, for several reasons discussed earlier, quite likely that our reconstruction underestimates the actual cooling.
Funny how your reading skills are so very creative.
igsy,
Michael Moon said: If you want to legitimize Mann, help him produce error bars, and the rationale behind them.
Mann did both: http://www.meteo.psu.edu/holocene/public_html/shared/articles/mbh98.pdf
Whether his described methods are defensible or not is a different question. Moving the goalposts is dishonest.
Real skeptics would notice that your last graph is conveniently B&W! Better not to let facts get in the way of a good story, no! You don’t want to draw to much attention to the artful splicing of “actual data” with that poxy resurrection (Proxy reconstruction). The whole issue of error becomes problematic when the proxy doesn’t match the record and can’t be spliced to it in any Intellectually honest way!
But forget the proxy decline and smoothed splice, the pointy bit going vertical is more dramatic and has way less error associated with it. /sarc
Hit that out of the park, big man!
Thank you Anthony for a reasonable view on this topic. I went over to the Real Climate site to leave a comment and a question about the Mann Rahmstorf study and found out that they gatekeep every comment like vigilant gestapo commanders. I guess I’m not surprised. It will probably be buried in the Real Climate “Vault of Denier Thought.”
Ghandi,
I didn’t know the Gestapo blogged. I don’t know that all comments from every poster go to moderation by default, but I do know that all two of mine did.
Don’t count your chickens. #16 here got through:
Thomas O’Reilly says:
23 Mar 2015 at 10:00 PM
“Our recent study (Rahmstorf et al. 2015) attributes this to a weakening of the Gulf Stream System, which is apparently unique in the last thousand years.”
“this indicates that climate models UNDERESTIMATE the weakening of the Atlantic circulation in response to global warming”
“That this might happen as a result of global warming is discussed in the scientific community since the 1980s”
It is 2015 now – 35 years later.
What are you and the rest of the Climate Science community going to do about it now Stefan?
More “research”? More “reanalysis”? Another “Paper”? Another “article” for Real Climate? An “AR6 IPPC Report” in a few years time?
“Insanity: doing the same thing over and over again and expecting different results.” – Albert Einstein
[Response: What is your suggestion what we should do as scientists, other than study the system to our best ability and communicate what we find? -stefan]
Apparently, RC doesn’t have a vault for the banal and inane. Depending on what you wrote, the chances of your comment posting could be better than you think.
So in other words his comment, as he said, didn’t go through.
‘Thermohaline’ circulation notwithstanding, there is a MAJOR driver for oceanic currents that is independent of temperature ‘trends’ or atmospheric composition.
Tides.
They are driven by the orbital mechanics of the Earth-moon-sun system, and result in net clockwise circulation in the northern hemisphere and net anti-clockwise circulation in the southern hemisphere. The main source of the energy is the orbital energy of the moon around the earth. As the moon pulls the oceans around, stirring them, the moon itself is losing energy, which expands its orbit – about 3.8 cm/year.
Temperature gradients and salinity gradients will not be able to stop this circulation of ocean currents.
I really love the ‘burn, baby burn’ graphics. Even a scrambled egg yellow just won’t do. No, the most ominous and unattractive shade of superheated glowing cast iron orange is deemed necessary to represent the whole planet with the obligatory danger red shadings to indicate the spreading doom. And then, to provide a wink of contrast, a footnote to the supposed mythological scientific integrity of this birdcage liner paper and its conclusions we’re provided with a splash of anomalous blue below Greenland. Perhaps Rahmstorf and Mann need to have a conference call with John Holdren because where are the additional anomalous blues for the Polar Vortex’s that have been vomited into our ears?
In the end I think the major question here is; ‘how will this affect John Kerry’s Eastern Seaboard yacht?’
Just like Satan’s city of Dis with its glowing, red-hot iron walls.
2 Geographers + 1 crappy model (excel) + 1 facked dataset (GISS) = “We have hit a critical de-salinization point.”
IPCC notices central Africa “anomaly” and jumps up shouting, “There IT IS THERE IT IS, Africa is sinking, the world will implode because of Global Human Warming!”
Ha ha
The funny thing is that the mechanism they are describing is what they would usually call a “negative feedback” to warming that would act to reduce the magnitude of the warming.
Now, it is possible in theory for a huge negative feedback to overshoot the mark, but when it is very difficult to determine whether the effect is there at all, we are very, very far from that point.
I say this as someone who has made his living in feedback control systems for 30 years now.
I bet feedback control is a fascinating field to work in.
To be clear, I genuinely mean that.
Thanks, Max! It is a very interesting field. And it gives me some good perspectives to view many of the feedback issues in climate science. I often find myself screaming as I read the scientific literature with regard to climate feedbacks…
I took some time on a facebook discussion page describing to Box how it requires negative North Atlantic Oscillation conditions to increase warming of the AMO and Arctic, and how increased forcing of the climate increases positive NAO. Evidently facts get in the way when ones only motive is to scare everyone including his 3 year old daughter with yarns that we are responsible, and how “eventually the dragon becomes pissed off enough to trash the place.”
http://motherboard.vice.com/read/if-we-release-a-small-fraction-of-arctic-carbon-were-fucked-climatologist?
Seeing the extremes of rabid alarmism that Box exhibits, I highly suspected that he would be into astronomy, like Hansen, deGrasse Tyson, John Cook, and even Brain May. I do have a Jungian type theory for this association, those familiar with my take on climate change would see the funny side of it, however tragic it is.
At least Brian May has a fallback career to depend on.
When I consider how hard the climate of doom hypesters work the phrase, “lying liars and the lies the [liars] tell” comes to mind for some reason.
Toss in a liebaby here and there, just for emphasis: “Lying liebaby liars…yadda yadda yadda.)
Anthony,
Check.
Gulf Stream != AMOC. Learn how to read.
“Gulf Stream != AMOC. Learn how to read.”
So we have “absolutely no evidence that suggests that the Gulf Stream is slowing down”, but we have changes in the AMOC. For all you know the gulf stream may speed up during low AMOC events.
Leaving aside “possible” changes in the AMOC and examining the real changes, they are linked to negative NAO episodes:
http://www.rapid.ac.uk/
Ulric Lyons,
I don’t see an inherent conflict. The GS is a surface-driven phenomenon, the AMOC is a thermohaline circulation. That they share some common geography suggests a linkage between the two — and literature has done so [1] — but doesn’t necessarily demand that they march in lockstep over all frames of reference. I think it takes more than two papers to figure this out, and certainly a paper on one shouldn’t be expected to falisify the other. They could BOTH be completely wrong, after all.
Correct, not least because I wouldn’t claim to know very much about either phenomenon.
That splash page does not specifically mention NAO. Not that it matters much; NAO is a pressure differential index so until you explain what drives NAO you’ve only created another chicken-egg problem.
——————
[1] See:
Joyce and Zhang (2010), On the Path of the Gulf Stream and the Atlantic Meridional Overturning Circulation: http://journals.ametsoc.org/doi/full/10.1175/2010JCLI3310.1
Ezer (2015), Detecting changes in the transport of the Gulf Stream and the Atlantic overturning circulation from coastal sea level data: The extreme decline in 2009–2010 and estimated variations for 1935–2012: http://www.ccpo.odu.edu/~tezer/PAPERS/2015_GPC_AMOC_SL.pdf
…exactly, the first step after learning to read is learning how to think.
David A: That would explain it.
Ulric Lyons: I posted a substantive reply to you which went to moderation and has now evaporated. I suspect WordPress issues.
Brandon said:
“That splash page does not specifically mention NAO. Not that it matters much; NAO is a pressure differential index so until you explain what drives NAO you’ve only created another chicken-egg problem.”
True, it does not mention the NAO, it should have done really as the correlation is so strong at the noise level. Revealing the correlation does not rely upon an explanation of the cause of NAO variability in any way, and patently, negative NAO is not increased by an increase in forcing of the climate. So it’s the wrong sign to be associated with AGW.
In fact the RAPID article baits the chicken-egg problem by suggesting a link between low AMOC events and cold winters, while failing to mention the tight negative NAO correlation. While from my own experience of producing long range solar based forecasts for NAO/AO variability at finer than weekly resolution since 2008, the attribution is crystal clear.
Ulric Lyons,
Um. You wrote: Leaving aside “possible” changes in the AMOC and examining the real changes, they are linked to negative NAO episodes:
http://www.rapid.ac.uk/
???
This entire discussion is concerned with causality. Explanations are required. I’d settle for some citations.
NAO is an atmospheric surface pressure index. AMOC is a subsurface thermohaline-driven ocean current. Which is the more likely to influence the other?
Weekly? I’m talking about climate, you’re talking about weather. Solar fluctuation:
http://cdn.phys.org/newman/gfx/news/hires/2009/1-320851main_tsi2_full.jpg
CO2 fluctuation:
http://www.esrl.noaa.gov/gmd/webdata/ccgg/trends/co2_data_mlo.png
Bit of a difference in the short vs. long term fluctuations. Even if we zoom out a bit:
http://www.climate4you.com/images/SolarIrradianceReconstructedSince1610%20LeanUntil2000%20From2001dataFromPMOD.gif
Or maybe ESPECIALLY when we zoom out a bit:
http://climexp.knmi.nl/data/ico2_monthly.png
D.S said:
“NAO is an atmospheric surface pressure index. AMOC is a subsurface thermohaline-driven ocean current. Which is the more likely to influence the other?”
Atmospheric circulation variability drives all the oceanic modes, typically through Ekman transport and drifting rates.
D.S. said:
“Weekly? I’m talking about climate, you’re talking about weather.”
There would be no trend without variations in the the noise. Scrutinise the AMOC data, it all happens at the scale of weather. That adds up to climate over time. Note what the sign of correlation is at the noise level, so as not to to get your whole theory the complete reverse of reality.
The data showing they have no clue what they are talking about.
It supports a solar/ AMOC correlation. They have no data to show it is related to AGW theory. This is similar to their nonsense that Low Arctic Sea Ice values equates to a more meridional jet stream pattern.
They are full of it.
Salvatore Del Prete,
From 1025-1275, 10BE makes a big bowl. The blue subpolar gyre minus NH anomaly doesn’t budge. From 1900-present, the blue curve falls off the cliff and …
Look Ma! No Sun!
… the 10BE curve disappears.
You have no data showing it is related to the solar constant since:
1) The correlation is curiously AWOL for 250 years early in the record and which you’ve not explained.
2) The proxy reconstruction for solar constant you shows STOPS 100 years before the end of the plot.
Try your hand with this one:
http://www.landscheidt.info/images/steinhilber.png
Data for that one and others here: ftp://ftp.ncdc.noaa.gov/pub/data/paleo/climate_forcing/solar_variability/
Irony. Well, since you’re a fan of correlations:
http://climexp.knmi.nl/data/ico2_annual.png
I typically find that late Holocene reconstructions don’t make sense unless I also include Milankovitch orbital forcing. Berger (1978) is a big help: ftp://ftp.ncdc.noaa.gov/pub/data/paleo/climate_forcing/orbital_variations/berger_insolation/
Temps lag orbital forcing significantly on geologic timescales, but for this exercise there isn’t much need to account for that.
Brandon, Steinhilber’s data does not correlate all that well to the record of historical Grand Minima of solar activity. It shows decreases in some cases but they do not look like Grand Minima events.
A list of historical Grand minima of solar activity[27] includes also Grand minima ca. 690 AD, 360 BC, 770 BC, 1390 BC, 2860 BC, 3340 BC, 3500 BC, 3630 BC, 3940 BC, 4230 BC, 4330 BC, 5260 BC, 5460 BC, 5620 BC, 5710 BC, 5990 BC, 6220 BC, 6400 BC, 7040 BC, 7310 BC, 7520 BC, 8220 BC, 9170 BC.
Salvatore Del Prete,
All that tells me is that one proxy reconstruction doesn’t always agree with all others. Which is business as usual, and to be expected since this stuff isn’t easy. Que all the usual cationary tales about basing conclusions on the results of a single study. When studying a complex system using sparse and uncertain data, convergence of multiple lines of evidence is required for making reasonable conclusions.
You’ve avoided answering what happens to TSI after 1900 to present, and completely ducked the CO2 activity during that interval, which is the MOST RELEVANT part of this discussion. Why.
Brandon after 1900 TSI increased in response to strong solar activity(the modern maximum) and the N. Atlantic Gyre was more intense due to strong solar activity meaning if taken out of the mix N.H. temperatures would have shown a warm anomaly which is consistent with a +ao/+nao atmospheric circulation at times of high solar activity which equates to a cold Arctic ,warm Lower Latitude regime set up, along with a more intense N. Atlantic Gyre. Cold air being locked into high latitudes when a +AO/+NOA set up is in play.
CO2 has no correlation to sea surface temperatures or the NAO/AO.
It is the visible light from the sun and long wave UV light, that impact ocean temperatures since they penetrate the ocean to great depths in contrast to IR radiation which maybe penetrates the ocean surface to the tune of 1mm.
Thanks, Anthony.
The work of the Danish Meteorological Institute destroys the paper. Poor models.
Here’s a link to a different perspective regarding this study. What else can anyone say?
http://www.vox.com/2015/3/23/8277345/atlantic-overturning-circulation
Climate science urban legends are perpetuated by disingenuous scientists (who hide and/or suppress observational evidence and analysis that does not support CAGW) and by the fact that climate scientists do not understand (urban legends fill the theoretical void) what causes (there is unknown massive forcing function that causes abrupt climate change, there is no amplification mechanism that magically appears when there is abrupt climate change and then hides when there is not) the massive abrupt climate changes that cyclically initiate and terminate interglacial periods (for example the Younger Dryas abrupt cooling event or the 8200 BP cooling event.)
Realclimate blog contributors Michael Mann and Stefan Rahmstorf are disingenuously implying that a complete stoppage of the North Atlantic drift current would have a great impact on European winters by not explicitly stating the following fact which is known to all people who are knowledgeable about this issue.
It is the earth-climate equivalent of an urban legend that Europe’s mild winters are due to the North Atlantic Drift current which is referred by some incorrectly as the Gulf stream. The reason why European winters are 10 to 15 degrees Celsius warmer is primarily due to the fact that the prevailing winds are from the west. Each summer the North Atlantic ocean warms due to the increase insolation in the summer, as compared to the winter. The heat energy from summer warming is released in the winter and as the prevailing winds are from the west that released heat warms Europe rather than the east coast of North America. Basic model analysis (done in the 1980 and then repeated in 2002) indicates the release of the heat from the summer heating of the North Atlantic ocean is a factor of two more than the heat released by the North Atlantic drift current, therefore a complete stoppage of the North Atlantic drift current would only result in winter cooling of Europe of only a few degrees Celsius.
The same phenomena where the ocean warms one side of a continent as the prevailing winds are from the west occurs in North America. The average January temperature of Seattle 47 Degrees North is (6C) as compared to the average January temperature of Boston 42 Degrees North or (-1.5C).
http://www.americanscientist.org/issues/id.999,y.0,no.,content.true,page.1,css.print/issue.aspx
http://www.atmos.washington.edu/~david/Gulf.pdf
Comment: I have made the same comment as the above, multiple times at Realclimate. I provided the same peer reviewed paper link to a paper published in 2002 which are supported by a paper that was published in 1980s (i.e. The assertion that the a complete stoppage of the North Atlantic drift current would not have result in European winters being as cold as the winters on the east coast of the US is not controversial and should be understood by any competent physical scientist.) at the blog Realclimate in response to incorrect statements by Mann, Rahmstorf, and Schmidt in connection to the cause of Younger Dryas abrupt cooling event. The cause of the Younger Dryas abrupt cooling or the 8200 BP abrupt cooling could not be the stoppage of the North Atlantic drift current (see below for the reason why) and it is a fact that ‘stoppage’/slow down of the North Atlantic drift current occurred 1000 years before the Younger Dryas.
@ur momisugly William Astley, Thank you when I went to school (and a very strict one at that) in the 60’s our teachers in geography., history and physics (those were still taught in those days at that level) all had a very simple explanation, I do not know if it still stands, They called a “Sea climate” and a “Land climate” a little simple these days perhaps but to us as 12-13 year olds it made sense then as as it does now.
BTW those three guys including our German language and art teachers made the classroom come alive. I remember every single one of them vividly. It is a sad thing to see our education system give everyone a “medal” these days!
It seems that the most accurate part of the article is the disclaimer:
“AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.”
can these people not be incarcerated ?
Ha Ha ha HaaaaaaaaH!
For Mann he is a Moron, la, la, la, lah! etc. etc.
That’s how much I care about Mann’s latest BS.
They claim (in Figure 1 from their paper) that this cold spot south of Greenland is caused by meltwater from Greenland…
They claimed Greenland was melting all those years it was a warm spot too…..
My question to them based on if what they say below is correct, and their theory of high latitude cooling as a result is correct due to a slow down in the AMOC, is why then is the AMO in a warm phase if the AMOC is slowing down? According to your theory you suggest a cooling of the high latitudes should result due to a slow down of the AMOC, if so how does the AMO not only attain a warm phase and stay in that warm phase as the AMOC slows down , promoting high latitude warmth, when a slow down of the AMOC according to what you suggest should promote the opposite ?
The melting Greenland ice sheet is likely disturbing the circulation”
The Atlantic overturning is driven by differences in the density of the ocean water. From the south, the warm and hence lighter water flows northwards, where the cold and thus heavier water sinks to deeper ocean layers and flows southwards. “Now freshwater coming off the melting Greenland ice sheet is likely disturbing the circulation,” says Jason Box of the Geological Survey of Denmark and Greenland. The freshwater is diluting the ocean water. Less saline water is less dense and has therefore less tendency to sink into the deep. “So the human-caused mass loss of the Greenland ice sheet appears to be slowing down the Atlantic overturning – and this effect might increase if temperatures are allowed to rise further,” explains Box.
The observed cooling in the North Atlantic, just south of Greenland.
From Ulric
From the Abstract:
“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”
Given that low AMOC events are inextricably linked to negative North Atlantic Oscillation episodes, and that increased GHG’s should increase positive NAO, they have shot themselves in the foot.
Steady rise in accumulation based on Box and Colgan. Thankfully, for now, there has been a corresponding rise in run off and calving at the margins. For now …. :0
From Ulric, which I think gives an explanation to my question. Ulric, any commentary to add would be appreciated.
So if the gulf stream is not slowing, where does the warm flow go during a slow AMOC event?
It accumulates in the north Atlantic and spills into the Arctic instead of overturning.
Low AMOC events tightly correlate with negative NAO episodes, e.g. early summer 2007 and mid summer 2012, and cold winter months in 2010 and March 2013:
http://www.rapid.ac.uk/
IPCC models predict increasingly positive NAO with increased GHG’s.
Seas south of Greenland warm up from these negative NAO episodes:
http://weather.unisys.com/archive/sst/
Demonstrate a solar forcing of the NAO, and that would tie the whole thing up.
Yes, the IPCC models are correct in saying that increased GHG forcing will increase positive NAO, but then one has to account for why the NAO has been shifting negative since 1995.
Positive NAO in the last couple of years follows the pattern of AMO cooling at sunspot maxima when the AMO is in its warm mode. Hence the recent changes in sea ice and Greenland. This will be followed by a strong renewed warming of the AMO, moving out of phase with solar cycles, as it does in its warm mode, and the associated loss of sea ice and warming in Greenland.
http://www.woodfortrees.org/plot/esrl-amo/from:1880/mean:13/plot/sidc-ssn/from:1880/normalise
And UK temperatures will move in the reverse direction, in phase with the solar cycle:
http://snag.gy/MTnui.jpg
Fig 12 if the screen shot doesn’t load:
http://virtualacademia.com/pdf/cli267_293.pdf
Ulric posts outdated SSN data. I am sure Ulric is familiar with the discontinuities in the Wolf number. Why would he then knowingly post at Ulric Lyons March 24, 2015 at 10:46 am such an outdated SSN graph? Did he cherry pick that reconstruction because it fits his premise? Taking a lesson from Mann?
http://www.leif.org/research/Rudolf%20Wolf%20and%20the%20Sunspot%20Number.ppt
Sunspot number is immaterial as I am only addressing phase relationships with the solar cycle.
ULRIC how about this sequence- Maximum Solar Activity -amo cooling,+nao/+ao, +amoc, Europe warm, Arctic cold, general N.H. sea surface temperature as Paul indicates warm.
versus
Minimum Solar Activity -amo warming,-nao/-ao, -amoc ,Europe cold, Arctic warm, general N.H. sea surface temperature as Paul indicates cool.
Hold on – are we saying that the AMO drives the sun?
Or are we saying that every cyclical phenomenon on earth is driven by a corresponding cycle somewhere in the sun?
As below, so above?
Yes, the strong solar wind in the 1970’s driving it colder, and the decline since the mid 1990’s causing the AMO and Arctic to warm up. This negative feedback has raised the global average sea surface temperature, and raised average land temperatures even faster because of warm AMO driven reductions in regional continental precipitation.
http://snag.gy/HxdKY.jpg
Some people have a hard time learning to understand that reality always beats theory-models….
but then, why am I not surprised 🙂
But you can’t expect people like mr mann to admit that we’re entering a LIA, and accept that it’s due to solar activity. They have to wriggle out of it, do they not? I saw this one coming yonks ago, no surprises here.
Problem with Mr Mann isn’t that he has a hard time accepting reality. Problem for Mr Mann is that he show he lack not only credibility that comes by using Theories of Science. He also lack all needed skills a real “leader” has to have. Such as listning, reflecting but above all the skill to lift people up not critizes those who don’t agree with him….
I myself saw this coming in 2008. Klimatfrågan….. och över alltihopa lyser Moder sol, Norah4you 2008/07/25 unfortunatly not translated from Swedish to English …..
Oh No!! more mann made gorebull warming……..”it is way worse than we thought….. quick everyone stop breathing!!! Oh wait give over your wallets and valuables first!” Gadzooks it is models models models treated like empirical evidence. what a bunch of “maroons” to quote Bugs.
Cheers!
Joe
Low AMOC events tightly correlate with negative NAO episodes, e.g. early summer 2007 and mid summer 2012, and cold winter months in 2010 and March 2013:
http://www.rapid.ac.uk/
Ulric says above. I might add a -AO is also present with a -NAO which equates to a warm Arctic, while the lower latitudes experience a cold winter.
While all this is going on the AMO is in it’s warm phase while solar activity is on the decline.
I would say it is in AMO neutral territory, not its warm phase. Meaning that when in this territory, its affects would be more highly variable and unpredictable compared to its extreme warm or cold phase. Sort of like when ENSO patterns are in neutral territory.
http://stateoftheocean.osmc.noaa.gov/atm/amo.php
Not with Arctic sea ice, the range between maximum and minimum extent has reduced considerably in the last few years. Got any good examples of what has become ” more highly variable” in very recent years then?
So. I have some basic questions. Yes, the North Atlantic sea is less salty than other locations of the Atlantic because of fresh water dilution from melting ice. However, sea ice comes from the sea and then returns to the sea, meaning that is a closed loop with likely decadal variations due to waxing and waning of sea ice cover. To be sure, the entire water cycle is a closed cycle but lets look at less than millennial scales. The only addition for this trend of fresh water dilution must come from an increasing source of melt water from land ice or increasing river discharge. For the sake of argument, lets say that both are happening and the sea surface salinity in the NA region is getting diluted.
Places along the Gulf Stream have varying amounts of evaporation and less than/more than salinity because of precipitation and evaporation. Fresh water evaporates faster than salty water, plus it sits on top of the salty water, even though temps may be the same, salt water being heavier than fresh water. So the question is, is the North Atlantic undergoing evaporation? And is that evaporation faster due to the proposed Greenland land ice sourced freshwater sitting on top? Given this mind experiment, I am thinking that there is not enough change outside the normal range of the North Atlantic salinity to slow down a MASSIVE ocean current nor its final destination and action at the overturning location near/in the North Atlantic Arctic.
http://www.srh.noaa.gov/jetstream/ocean/seawater.htm
The North Atlantic also has the mighty St. Lawrence and the mighty Rhine pouring into it. Especially the former is still draining off the water from the Great Melt.