Aerosols and Atlantic aberrations

by Judith Curry

If Booth and colleagues’ results can be corroborated, then they suggest that multidecadal temperature fluctuations of the North Atlantic are dominated by human activity, with natural variability taking a secondary role. This has many implications. Foremost among them is that the AMO does not exist, in the sense that the temperature variations concerned are neither intrinsically oscillatory nor purely multidecadal.

Aerosols implicated as a prime driver of twentieth-century North Atlantic climate variability

Ben Booth, Nick Dunstone, Paul Halloran, Timothy Andrews Nicolas Bellouin

Systematic climate shifts have been linked to multidecadal variability in observed sea surface temperatures in the North Atlantic Ocean1. These links are extensive, influencing a range of climate processes such as hurricane activity and African Sahel and Amazonian droughts. The variability is distinct from historical global-mean temperature changes and is commonly attributed to natural ocean oscillations. A number of studies have provided evidence that aerosols can influence long-term changes in sea surface temperatures, but climate models have so far failed to reproduce these interactions and the role of aerosols in decadal variability remains unclear. Here we use a state-of-the-art Earth system climate model to show that aerosol emissions and periods of volcanic activity explain 76 per cent of the simulated multidecadal variance in detrended 1860–2005 North Atlantic sea surface temperatures. After 1950, simulated variability is within observational estimates; our estimates for 1910–1940 capture twice the warming of previous generation models but do not explain the entire observed trend. Other processes, such as ocean circulation, may also have contributed to variability in the early twentieth century. Mechanistically, we find that inclusion of aerosol–cloud microphysical effects, which were included in few previous multimodel ensembles, dominates the magnitude (80 per cent) and the spatial pattern of the total surface aerosol forcing in the North Atlantic. Our findings suggest that anthropogenic aerosol emissions influenced a range of societally important historical climate events such as peaks in hurricane activity and Sahel drought. Decadal-scale model predictions of regional Atlantic climate will probably be improved by incorporating aerosol–cloud microphysical interactions and estimates of future concentrations of aerosols, emissions of which are directly addressable by policy actions.

Nature (2012) doi:10.1038/nature10946  [link to abstract]

Amato Evans comments on this in News and Views, some excerpts:

Over the past century, the surface of the North Atlantic Ocean has gone through warm and cool periods that are not observed in other ocean basins.  This Atlantic multidecadal oscillation (AMO) is thought to affect climate processes ranging from the current high levels of Atlantic hurricane activity to the devastating sub-Saharan droughts of the early 1980s. Although the influence of the AMO on extreme weather events has long been recognized, the physical processes underlying these temperature changes are not understood. In a paper published on Nature’s website today, Booth et al. report their use of a state-of-the-art model of Earth’s climate to demonstrate that, at least over the past century, the AMO is largely the response of the upper ocean to changes in the concentration of pollution aerosols in the atmosphere. If correct, their results imply that the influence of human activity on the Atlantic regional climate is more pervasive than previously thought.

The AMO is best depicted as the difference between average ocean surface temperatures over the North Atlantic and those over the global oceans. It therefore reflects the deviation of the North Atlantic Ocean from global mean temperatures, which are dominated by the long-term warming that is forced by greenhouse gases. Conventional wisdom has held that the AMO is the natural result of internal processes in the Atlantic Ocean — most notably, fluctuations in deep-ocean circulation, as supported by multi-century climate-model studies.

Booth and colleagues’ evidence that the AMO is caused by changes in the regional abundance of aerosols is compelling, but their results are sensitive to model parameterizations of microphysical processes, particularly the interaction between cloud water droplets and aerosols, that are not well constrained by observations. In addition, their model was unable to reproduce observed multidecadal variability in outbreaks of African dust storms, which alter the tem- perature of the tropical Atlantic; this may explain why the model does a poorer job of simulating temperatures in the tropical North Atlantic Ocean than it does in the extratropical regions. Furthermore, the authors’ conclusion that internal variability of the Atlantic Ocean had a negligible role in shaping the AMO during the twentieth century is at odds with the findings of several previous studies. The reason for this discrepancy is not clear.

If Booth and colleagues’ results can be corroborated, then they suggest that multidecadal temperature fluctuations of the North Atlantic are dominated by human activity, with natural variability taking a secondary role. This has many implications. Foremost among them is that the AMO does not exist, in the sense that the temperature variations concerned are neither intrinsically oscillatory nor purely multidecadal.

Nature also has an editorial on this [here].  I’ll be nice and just ask who writes this stuff? It can’t be a scientist.

JC evaluation

The Jones et al. paper describing the simulations for HadGEM2-ES can be found [here].   The model has a fairly sophisticated atmospheric chemistry module.  Of particular relevance to the aerosol forcing:

In HadGEM2-ES sea-salt and mineral dust aerosol emissions are computed interactively, whereas emission datasets drive schemes for sulphate, fossil-fuel black and organic carbon, and biomass aerosols. Unless otherwise stated, datasets are derived from the historical and RCP time series prepared for CMIP5.  

Referring to Ch 9 of the IPCC AR4, particularly Fig 9.7, the CMIP3 version of the HADGEM1 has the spectrum of natural internal variability too low by about 40% for timescales beyond about 35 years (when compared with the spectra of uncertain observations).

The result of this paper is driven by the so-called aerosol indirect effect, whereby the aerosols change the physical and optical properties of clouds.  The uncertainty in the aerosol indirect effect is estimated in the AR4 to be by far the most uncertain element of radiative forcing, and the estimates in AR4 neglect many of the modes of the aerosol indirect effect, notably those associated with ice clouds.

Without having time to dig up references, there is another important issue.  Specifying aerosol characteristics (which is mostly done here, esp sulfate) and then allowing interactive cloud microphysics and optics results in an overestimate of the aerosol indirect effect, since compensating dynamics and precip don’t influence the aerosols.  van den Heever and Stephens have a recent paper on this, but even more than 10 years ago Rostayn(sp?) was writing about this.

I’m trying to find what the CMIP5 is using for historical aerosol forcing.  A quick google search doesn’t turn up much in the way of documentation, but I did spot this.   Not an error bar in sight.  Realistic error bars on current aerosol optical depth measurements are quite large; historical error bars must be huge.  The fortuitous agreement of the aerosol optical depth with temperature variability is serendipitous climate magic, almost certainly with circular reasoning buried deeply or not so deeply in the aerosol estimates.

And finally, if this paper is correct and there is no AMO other than aerosol forcing, this is going to overthrow a very substantial body of work by oceanographers on the Atlantic Meridional Overturning Circulation .  At best, the  period in this paper covers 2 oscillations.

Color me unconvinced by this paper.  I suspect that if this paper had been submitted to J. Geophysical Research or J. Climate, it would have been rejected.  In any event, a much more lengthy manuscript would have been submitted with more details, allowing people to more critically assess this.  By publishing this, Nature seems to be looking for headlines, rather than promoting good science.

A final reflection:  recall my previous post on Trends, change points & hypotheses.  This paper is squarely in the camp of hypothesis #1, where all climate variability (other than ENSO) is externally forced.  I think this view is incorrect, but it seems to be ruling the IPCC’s mode of thinking.

201 responses to “Aerosols and Atlantic aberrations

  1. I agree that some skepticism is warranted here based on the large uncertainties involved but this research would seem to dovetail with other recent studies related to the North Atlantic, volcanic aerosols, and the start of the Little Ice Age:

    • agreed that this is of a similar theme to the recent LIA research, which seems to have a stronger observational basis than this one.

      • You are right, Judge Judy: “If Booth and colleagues’ results, [published in Nature] can be corroborated . . .”

        But I have been around for a few decades and by a strange coincidence my research mentor was the same scientist that analyzed the ashes of Hiroshima immediately after 6 Aug 1945, about 65.667 years ago today.

        The rest of the remarkable story is documented here:

        With kind regards,
        Oliver K. Manuel
        Former NASA Principle
        Investigator for Apollo
        Emeritus Professor for
        Nuclear & Space Physics

      • CORRECTION: By one strange coincidence, early this morning over Hiroshima was exactly 66.66667 years after the seed of Climategate was planted in the hearts of world leaders as <b<instinctive fear of the "nuclear fires" that consumed Hiroshima !

        Two other strange coincidences exposed the rest of the story:

        1. My research mentor was the first scientist to analyze the ashes that remained of Hiroshima after 6 Aug 1945.

        2. Dr. Peter Gleick’s actions last month reminded me of AGU and NAS responses when Dr. Kuroda tried to report his findings in April 1956. .

      • Test

      • insert

    • It appears there is a climate hit squad that is working its way through the skeptics arguments and just fabricating counter arguments.

      Temperature leads CO2. No, magic melted the northern ice sheets.

      AMO. No. It was humans.

      PDO? Wait and see what will be fabricated.

      • Latimer Alder

        But it is interesting to see how the terms of engagement have changed. Three of four years ago the Gods of Climatology gave their messages to the High Priests who distributed them among the supplicants. The Gods drove the agenda.

        Now the faithful are having to respond to the sceptics. It is becoming the sceptics agenda. And it seems like the believers aren’t making much of a job of it.

      • You are right, Latimer.

        This hard-fought battle will end quickly if and when ordinary citizens and scientists recognize that they have been publicly demonstrating their own inability to govern every time they accept government-sponsored, consensus gobbledygook as scientific fact – “Big Bang”, “Higgs Bosons” (God particle), “Dark Matter”, “Dark Energy”, “Oscillating Solar Neutrinos”, etc., etc., ad infinitum !

      • Read all about it!

        “Humans responsible for Milankovitch cycles” – Nature Climate Change Journal, Jan 2013.

    • R gates

      The people who wrote the material in your link are crackpots. They refer to paintings of the frozen Thames and canals in holland as ‘proof”

      Web hub telescope called me a crackpot for making the same sort of references in my article The long slow thaw so by that criteria either they should be dismissed out of hand or he owes me an apology.

      On a more serious note, they are certainly not unique in citing 1275 as the start of the Lia. I have done so myself as have others. It is clearly incorrect however to then imagine that there was unremitting cold for the next four centuries that simply isn’t correct. I recently sent Judith a link to the Merle weather diaries of the 1340’s and they show no sign of this extreme weather.

      • Steven Mosher

        how did you calibrate the diaries?

      • Break wide error bars
        Men of industry, history.
        Chaucoid scholarship.

      • Steven, here is data file:
        Graph is via Excel

      • Steven Mosher

        Jesus vuk.
        1. show your source
        2. show the methods for getting the source data.
        3. show any processing code.
        4. provide methods for replotting.

        Reproduceable, open, and transparent. Same criteria I use for mann, hansen and Jones.

      • Vuk

        Alternatively-like Mosh-you can just say you have ‘substantial evidence’ then you don’t need to show anything at all :)

      • Steven
        Just click on the word graph (here or in the previous post), all info is at the bottom of the page. Use Excel.

      • Steven Mosher

        Wrong Tony. See the numerous papers I linked to.
        WHERE is the SOURCE. you have numbers on a page. show WHERE you got them. Show HOW you got them. show WHAT you did to them.
        This is EXACTLY the same standard we held mann to. I ask no less of you.

        Pointing me at data that you purport to be accurate does not allow anyone to audit or reproduce your work. its pretty damn simple.

      • Unless you are currently in Westminster (London) United Kingdom you have not looked at the web page
        If you are, then links are at the bottom of the web page. I don’t do anything to the numbers, just put them into Excel and plot, no scaling or coding of any kind is applied. To save bother of downloading the data they are in file also with a link provided. The GCR file can be downloaded in min, hr, or days, for convenience I provided the day values.
        I know you may be to0 busy to bother with all this, but as I can conclude it appears that GCRs do affect degree of cloudiness since this Forbush decrease event’s is a near repeat of what Svensmark found and described in his 2009 paper
        but as I suggest in the short comment, the net effect on the temperatures may be negligible.

      • Mosh

        But you weren’t citing numerous papers at the time, you merely said there was ‘substantial evidence.’ . That is why Willis, myself and others started joshing you.

      • Steven Mosher

        tony did you finish julios paper? knutti? any of the papers in the bibliography. i thought not. did you read ananns work? no. swchartz? thought not.

      • Mosh
        Your 9.18

        Did you read MY references within ‘The long slow thaw’ written four months ago? No? So when do you think I had time to read yours from a few days ago? I will do so but not over Easter.

        Here is my reply to your comments about the data used in my article;

        Have a good Easter.


      • Mosh

        David Parker-yes that one- did it back in 1972 as part of an official Met office study. The diaries were lost for some 300 years and were then translated from latin but then got lost again. They have not received a lot of attention until recent times

        One of these days I’ll use it to extend my reconstruction back from 1538, but I would want a variety of types of evidence to calibrate it properly. Unfortunately the observations between the 1340’s and 1538 are quite limited. The reasons for that, in case you are genuinely interested, is that we had the little matter of the dissolution of the monasteries around 1536

        A great many records were destroyed during this turbulent time which would have included those from farmers, landowners and the clergy which would collectively be the most reliable. The stuff is there, but its fragmentary, hence my visits to the Met office library and archives to try to unearth it.

      • You might find this interesting:

        Scientists have been able to reconstruct abnormal climate patterns that occurred during the 9th and 10th centuries in Iraq by examining and analyzing ancient manuscripts written by Islamic writers during the Islamic Golden Age.
        “Climate information recovered from these ancient sources mainly refers to extreme events which impacted wider society such as droughts and floods,” said Domínguez-Castro.
        “However, they also document conditions which were rarely experienced in ancient Baghdad such as hailstorms, the freezing of rivers or even cases of snow.”

        The details of the study are published in the journal, Weather: F. Dominguez-Castro, J. M. Vaquero, M. Marin, M. C. Gallego, R. Garcia-Herrera,  How useful could Arabic documentary sources be for reconstructing past climate, Weather, Wiley-Blackwell, DOI: 10.1002/wea.835

      • Handjive

        Thanks for those references. I will look up the paper you cite. We have some good records of that general period and area. I wrote about some of them here.

        “The rise of Rome coincided with the warm Roman optimum. We are fortunate that we have available the climate references from not only the Western Roman empire, but those of the Byzantine empire (the Eastern Roman empire after the collapse of Rome) approx 380-1453 AD.

        Collectively, the Egyptian, Roman and Byzantine empires can provide records of some 4000 years of climate change. Geographically this covers a large part of Europe, the Middle East and North Africa. Knowledge of the Vikings enables us to extend that geographic range far to the North. Studies from elsewhere in the world-including the Southern Hemisphere-provide tantalising glimpses of climate change elsewhere.

        Some of the Roman climate references are fascinating. This observation from a series of cold winters -after many warm ones- around the 8th century in Byzantium (centred around Modern day Turkey)

        “Theophanes’ account recalls how, as a child, the author (or his source’s author) went out on the ice with thirty other children and played on it and that some of his pets and other animals died. It was possible to walk all over the Bosporus around Constantinople and even cross to Asia on the ice. One huge iceberg crushed the wharf at the Acropolis, close to the tip of Constantinople’s peninsula, and another extremely large one hit the city wall, shaking it and the houses on the other side, before breaking into three large pieces; it was higher than the city walls. The terrified Constantinopolitans wondered what it could possibly portend.”


      • Steven Mosher

        i dont believe its possible to calibrate a document with out some physical measure. and your error bars are immense. worse than tree rings

      • Steven Mosher | April 7, 2012 at 1:36 pm |

        Is it even valid to call something with error bars worse than tree rings a physical measure?

        Isn’t “hallucination” more appropriate to the category?

      • moshe, the error bars may be incalculable, but are not likely immense.

      • Steven Mosher

        Bart. The thing that astounds me is the way in which the “skeptical” approach goes entirely out the window whenever one brings up “documentary” “evidence” of past climates. When I was a kid i walked 10 miles to school in 15 feet of snow. That’s not to say we can’t enjoy reading the documents, but If I have a document that says it was cold and a proxy that says it was warm, sorry I’m going with the proxy where some semblance of error bars can be applied. That said, I’d gladly read any methodology for reconstructing temperature from diaries. I’d like to see the calibration method and the verification method.

      • SM – the problem is that I can write a program that spits out an arbitrary trend with noise, then apply error bars. The error bars don’t make the numbers meaningful, they are just a mathematical construct. Your error bar test/criterion seems a bit arbitrary.

      • Mosh

        Take up your concerns with David Parker who I suspect has forgotten more about error bars than you have ever known (to date). You do know who he is don’t you?

        As for myself, I specifically state that all such pieces of work (such as ‘The long Slow thaw’) have very large (error bars but within worthwhile bounds . Much less problematic than tree rings however, which have three months of wild guesses followed by nine months of no information whatsoever. Its called the growing and dormant seasons.

        By the way what do you call ‘immense?’

      • Mosh

        Your 3.30 to Bart.

        When carrying out a study on an aspect of historical climatology, wherever possible you try to amass documentary evidence, proxy evidence AND a scientific study that all point the same way. 2 out of 3 might be ok, but a single documentary source comes into the realms of often very interesting but not definitive (but perhps the best we’ve got).

        As I’ve mentioned to you before, Hubert Lamb hit the nail on the head concerning past climates by saying something along the lines of that you can follow the tendancy but not the precision.

      • Steven Mosher

        Tony. I’ll repeat the request I made on your previous thread.

        1. the data
        2. your method.

        I’m particularly interested if you calibrated the accuracy of documentary evidence by looking at modern day samples where you have both documentary evidence and instrumented evidence.

        I remain unimpressed by either parkers work or lambs work. go figure

      • Mosh said

        ‘I remain unimpressed by either parkers work or lambs work. go figure.’

        Wow. So what well known climate scientists (and I exclude Vuk here) are you impressed by and whose work do you decry?

      • Mosh said

        Glad you’re around Mosh, I just got back from a nice meal in a new restaurant in our village and the only thing on tv is Shrek 2 (yet again.)

        ‘I’m particularly interested if you calibrated the accuracy of documentary evidence by looking at modern day samples where you have both documentary evidence and instrumented evidence. ‘

        I carry out historical climatology so by definition I wouldnt be looking at modern day samples. There are plenty of papers out there on modern circumstances without me adding to them, and its not an area that particularly interests me.

      • climatereason | April 7, 2012 at 4:13 pm |


        Were it that easy, everyone would do it that way.

        If I could take a little bit of data with really tiny error bars and toss in gossip I heard from a girl at a bar to increase the volume of my observations, and use just the really tiny error bars for that gossip, I certainly would and should.

        No. Error bars generally get worse with addition of bad data, not better. The more different breeds and species of errors, the bigger the error bars usually ought become, absent some spectacular mechanism for reduction.

        If you’ve got a gossip filter that applies to paintings and literature, diaries and Hollywood and Bollywood films in some provable way, by all means, share it.

        Otherwise, I think Steve Mosher is too kind to compare your figures only slightly unfavorably to tree rings.

        That said, the _context_ your research brings to better understanding the circumstances of the origins of observations is invaluable, and worthwhile, and you have a genuine talent for it that is clearly to be applauded. I’ve seldom seen the equal of your gift.

      • Well documented historical evidence is a constraint on spurious assumptions on extremal excursions in the climatological area,such as Gore 1998,or Trenberth and Hoar on ENSO eg Grove 1998 or 2007.

        In recent history the severity of the El Niño of 1997 and 1998, as well as the La Niña event that followed on from it, has tempted both politicians and scientists to suggest that the 1997–98 event was the worst known in history. Similar hasty claims had been made for the El Niños of 1982–83 and 1991–95. The historical as well as the prehistoric record tend to suggest otherwise.Indeed the documentary evidence suggests that, even in the last thousand years, very much stronger and longer El Niño events have been experienced globally, and particularly during the Little Ice Age between about 1250 and 1860. There are in fact many problems involved in reconstructing the conditions and severity of El Niño events that took place before the instrumental period.

        That all reconstructions involve both uncertainties,and assumptions that invoke both bias and model error are well known namely the abscence of a reference trajectory,and its inability to close the sensitivity problem suggest that it is indeed irreducible.

      • Mosh and Bart R

        You have both made similar comments so I have posted this to each of you separately, as your comments have become separated within the thread.

        As you are hopefully aware, my article ‘The long Slow thaw’ was split into two parts, each containing a number of sections. In turn they led to hundreds of references (scientific and observational) indicating weather/climatic/temperature patterns that I read and assimilated- if relevant- into my study. In turn many of these led to further references which I read and incorporated if useful, although second tier material often tends to become less relevant.

        This is the main article;

        Please read ‘Conclusions and postscript’ in the doc above. Just above section 5 was the linked research material which, as I mention, should be seen as a piece with the vast volume of material already documented in part 1, and the numerous references both in the appendices and also within my own linked articles-for example ‘A short anthology of changing climate.’

        In addition there were 4 large note books that I compiled whilst at the Met office Archives in Exeter (two full days) that were full of other records of short duration (several days rather than seasons)-which help to fine tune the generalities. I also compiled observations from 1659 (start of the CET instrumental record) through to around 1738. This was so the observations and instrumental figures and other studies can be cross referenced. There were lots of similarities with certain periods pre and post instrumental and clear evidence of blocking patterns. These resonate with other studies of instrumental records (such as Jones/Camuffo/Briffa)

        At no time did I make a claim for huge accuracy, in fact the opposite as I stated here;

        “3) Any attempt to construct a single global or even Northern Hemisphere temperature covering many centuries will encounter substantial difficulties, as incomplete information from novel proxies will probably not adequately represent the extremes that are experienced at either end of the temperature spectrum, so what is considered the ‘average’ is possibly representative of no climate state that actually ever existed. Considerable uncertainties abound in virtually every area of historic temperature reconstruction-including this one- and the ‘error’ bars are very broad. In the case of ‘1538’ plus or minus half a degree Centigrade.

        That there are flaws in historical climatology (as much as with ‘scientific’ studies) is fully admitted here, as was the point that this study was version 1 and others would follow;

        “10) The 1538 reconstruction will be updated as further evidence becomes available. In particular we need to assess the subjectivity of written records whereby one chroniclers ‘excessive heat’ may be someone else’s ‘pleasantly warm’.”

        I was attempting to get the right ‘shape’ of the changing climate within the error bounds that will exist. As I have said to you before, and in the article ;

        “To paraphrase Hubert Lamb we can know the ‘tendency’ but not the ‘precision’ when we delve back in time. Uncertainty shrouds much of the past and in consequence perhaps we believe we know much more than we currently do.”

        I repeated this here in the comments, for example;

        “I think we can get to within half a degree of reality for the majority of the record and indeed the various reconstructions from other sources seem to confirm this 1538 reconstruction sits comfortably within the parameters of our existing knowledge, but of course its not perfect and I intend to carry out a version two in due course and if possible try to find the extent of the peak noted at the start of the reconstruction.”

        And also;

        “Seriously, we can do very much better than what you suggest, as we have a huge wealth of information from a variety of sources. Please note figure 14. As you can see CET operates within quite tight bands. Anything around a mean average of around 9 to 9.5C is pretty average. We can readily identify prolonged events that would impact significantly on this approximate average by half a degree or more, as our ancestors recorded such events as it had a great effect on their lives.

        I have extended graphs of each months CET data and as well as other methods of interpretation already described, we can gather further evidence by reading the descriptions of events and work out the likely impact on temperatures by cross relating them to similar events that happened within the instrumental record.

        Winter has a greater potential for temperature variability and this will produce notable events that would be well recorded. Other seasons also have an impact of course, and again we can cross relate similar events with the instrumental record. Tie this in with crop records, droughts, harvest times and a myriad of other information and we can identify the likely spread of temperatures around this 9 to 9.5C average- which will vary according to the climate cycle. “

        Presumably the reference in the last sentences above is what you had in mind with your previous comment yesterday about cross referencing to modern temperatures? I carried out a 80 year overlapping of observations and instrumental record in order to try to calibrate the two. (1659-1738)

        Within the research I go into sufficient detail to point out some inconsistencies in published works, for example in note 2 that Briffa seems to have been incorrect in his assertions about the nature of certain summers which appeared in an article in ‘Nature.’

        My reconstruction graph bears close similarity to Craig Loehle’s (revised) reconstruction, and I corresponded with him on the similarities.

        Similarly other works also bear good similarities, such as this;

        “M. V. SHABALOVA and A. F. V. VAN ENGELEN : Evaluation of a reconstruction of winter and summer temperatures in the Low Countries, ad 764–1998

        My main interest is in the generality of trends, from which my peak in 1640 and the upwards trend from the 1540′s is mirrored in these other reconstructions. I’m not saying that either of these reconstructions (Loehle or Shabalova) is 100% correct, but the picture of considerable variability that was built up conflicts with the Met office view, which basically reflects Dr Mann’s line shown in figure 15a

        As I say this was Version 1 and subject to amendment as more information comes to light. Do I believe that I’m more likely than not more accurate than Dr Mann? Yes, because his main proxy is not a reliable indicator. Am I accurate to small fractions of a degree? Unlikely, except coincidentally in part. However, I am more likely than not within half a degree, plus or minus, for most of the reconstruction, if only because the CET variability is quite limited and if I were further out there would have to have been some remarkable extreme long lasting weather events which I missed.


      • Mosh
        My reply to you and Bart R seems to have miraculously ended up in the right place so no need to duplicate it.

      • climatereason | April 8, 2012 at 6:46 am |


        I get that you’re earnest, diligent and honest.

        However, when I look at tree ring proxies, I look not at the conclusions first, but at the observations in detail and what the standard methods of validating and verifying them are.

        The key observations are not of Temperature. They’re of distance between patterns in wood grain believed to represent one year’s growth in a tree and the next on a cross-section.

        These particular physical observations — or hard facts — come in fairly large sets (hundreds of years) with some of those qualities of observations cherished by scientists for their uniformity of distribution, comparability, and well-understood mechanism, making them susceptible to statistical analysis of how well they perform as an independent metric space.

        This is one of the reasons the opinions of a statistician — any statistician — weigh so much with regards tree rings.

        We only know how reliable the base dataset is for later analyses by its statistical treatment. Which is why the whole refusal to share data and code and precise methodology with McIntyre was shocking and not in the spirit of Science.

        Whatever conclusions came later from the tree ring analyses, and one’s beliefs about them, not particularly germaine. The many hundreds of direct observations, and the validation and verification of them, is the foundation of the study.

        We’ve seen how convoluted and complex things got with the tree rings, and this was with a fairly straightforward large group of numbers from a fairly simple physical source.

        You have set yourself the massively more daunting task — compared to tree rings — of repeating all the processes of tree rings many times over on small and indirect datasets much less susceptible to validation and verification — in some cases not subject to any means of validation or verification other than question beggingly by comparing to data unlike enough in origin and mechanism to not be said to properly share a probability distribution — and then patching the data together on the faith that the underlying ‘global temperature’ is enough to confirm your product.. the underlying global temperature.

        It’s a castle built on a cloud. Saying you believe you have an error bar of half a degree generated as you do is headspinning.

      • BartR

        Yes it is a daunting task and very time consuming to carry out original research and then try to validate it through several different lines of evidence.

        So if you can just point me in the direction of some useful research funding….camuffo and jones shared a 5 million euro grant to examine 7 long temperature data sets, but I could get by on little more than 90percent of this. :)

        All the best


      • Steven Mosher | April 6, 2012 at 4:10 pm |

        The tried and true method to validate a calibration is to repeat the method with better-known values.

        For example, if I take the Hollywood movies, “White Christmas”, “The Day After” and “The Thing”, and chart the weather depicted against temperatures in Beverly Hills for the dates they are supposed to depict, as tonyb does for paintings and literature, I think we can see what sort of error bars his work produces.

      • BartR

        Please cite where I have constructed detailed temperature data based specfically on just paintings and literature? They are part of the whole, as dozens of books on these subjects in the Met office library will testify. But if you want to create a temperature record they are not sufficient by themselves and I have never claimed otherwise.

      • Here is the clever way to test for man-made aerosol and pollution effects — you take the seasonal effects out of the picture and look for correlations against unnatural and artificial forcing functions:
        Why Tornadoes Take the Weekends Off in Summer : Weekday pollution supercharges storms in eastern U.S., study suggests.

        I looked at the statistical analysis for this and it is highly unlikely that this effect arises by chance. The researchers took enough data such that the central limit theorem and the law of large numbers reduces the uncertainty in the numbers significantly.

        The only possibility is in the systematic/epistemic biases that could creep into the event reporting. The authors do mention that weather observers may be more alert on the weekends when they have lots of free time and spend more of it outdoors.

        This kind of study makes you realize how biases might creep into historical anecdotal studies.

      • “Computer models suggest these droplets get lofted up to higher, colder air, leading to more plentiful and larger hail.”

        Tornadoes need the differential between warm and cold.

        Humans make the world around them warmer.

        UHI would be higher midweek. The heat bubble around human activity would be warmer and larger leading to higher chances of a collision between warm and cold.

      • It is indeed fascinating how humans can change climate on that kind of scale.
        The statistical observation has been that trailer parks always seem to be a more common target for tornadoes. The arguments have divided between whether it is due to the amount of black asphalt in a trailer park or is it that the trailer parks themselves show so much devastation if they get hit. The latter gets them the extra publicity, and the appearance that they get hit more frequently.

      • “Hailstorms and tornadic storms occur more frequently in more polluted moist air masses”

        UHI creates a warm moist bubble around human activity.

      • Tony,

        You’ve done an excellent job characterizing the LIA, both in terms of the start and the fact that it wasn’t some solid monolithic event and the period (like all climate periods) saw a great deal of variability, and though global in reach during some parts, was certainly strongest in Europe because of the strong North Atlantic connection.

        In general though, I think the evidence is getting stronger and more persuasive that aerosols have played a big role in driving the AMO (both natural and anthropogenic), and that especially the role of volcanic aerosols is proving to be very strong in determining what goes on in the North Atlantic. Thus, even though the LIA “might” have occurred on some level without the very strong volcanic series of nudges, being at least partially driven by weak solar activity, the period might not have been as severe nor as long-running…maybe a 75/25 split between natural aerosol and solar influence prior to the industrial era?..

      • R Gates said;

        ‘In general though, I think the evidence is getting stronger and more persuasive that aerosols have played a big role in driving the AMO (both natural and anthropogenic), and that especially the role of volcanic aerosols is proving to be very strong in determining what goes on in the North Atlantic.’

        We took Mosh for task for saying that sort of thing without cites, althoiugh to be fair he used the words ‘substantial evidence’. It was the ‘substantial’ that irritated us. :)

        I agree that volcanic eruptions are important, but how important we still don’t know. Would earthquakes have an effect to a greater or lesser degree and also natural fires? We get several accounts of enormous fires underground and overground. I’ve not seen much research on these aspects.

        Reading through the various English contemporary observations for The Long Slow thaw I was struck by the number of times that earthquakes and auro borealis were mentioned. As you know we are not at all earthquake prone and rarely see the Northern Lights.

  2. Sharp shootin’.

  3. Norm Kalmanovitch

    The 20th century warming is no different than the warming into the Medieval Warm Period, or the warming into the previous Roman Optimum, or the warming into the preceeding Minoan Warm Period other than the current warming is far below that of the preceeding three warm periods. The three previous warm periods did not have aerosols from humand contributing so the only possible conclusion is that if anything aerosols are responsible for reducing the amount of warming; not for creating it.
    Regardless of what people have been led to believe; it is changes to incoming energy from the sun and to some unknown extent from changes in geothermal heat transfer that change climate and human activity if it has any effect is strictly an effect of modification to the albedo from land use changes and from coalescing micro climates resulting from expanded urban heat island effect.
    There has been no detectable changes to the greenhouse effect based on satellite measurement of OLR since the launch of weather satellites in late 1978 so changes in the greenhouse effect therefore play no part in climate change and any contribution to the greenhouse effect postulated from aerosols or from CO2 emissions are clearly not scientifically verifiable drivers of climate.

  4. But their model was state-of-the-art!

  5. Judith

    Thanks for posting the link to the paper.

    Diagnosing the simulated climate response, and comparing responses across different models, is crucially dependent on assumptions of how the GCM/ESM has been driven – especially because the implementation can involve subjective decisions and may differ between modeling groups performing the same experiment. The writers of the paper do not know much about how any of the individual models have actually been constructed, and do not seem to evaluate how well the individual models have actually performed in matching actual observed conditions vs. forced hindcasts. They make assumptions about models of unproven validity and write a paper based on their assumptions. It is difficult to see the value of the paper, but maybe I am being thick.

  6. “There is disagreement in regard to the validity of the global warming hypothesis that states that there are positive feedback processes leading to gains g that are larger than 1, perhaps as large as 3 or 4. However, recent studies suggest that the value of g is much smaller. In a recent study involving aerosols Chylek et al. [2007] obtain climate sensitivities of λ = 0.29 to 0.48 K/(W m-2). Schwartz ( 2008) in a study of ocean heat content data reports a smaller value and Lindzen et al. [1998] and Douglass et al. [2005] report low values of λ from studies of the Pinatubo volcano event.”

    And, “g is the gain resulting from any feedback from the particular climate forcing being considered.”

    A list of various phenomena that lead to “variations in the surface temperature” include as follows: solar, climate shifts from changes in ocean currents, atmospheric aerosols, clouds, changes in albedo, recovery from the “little ice age”, and conversion of land to agricultural use are comparable in magnitude.

    (David H. Douglass and John R. Christy, Limits on CO2 Climate Forcing from Recent Temperature Data of Earth)

    • Steven Mosher

      schwartz was updated and lindzen and douglas are hardly the last word. Moreover they are looking at TCR and not ECR. different beast entirely

      • There be hippogryphs over the horizon.

      • “The Credibility Crunch: in the end, I predict that the real killer crunch with the public will be the ever-widening credibility gap between the rhetoric of the politicians and their appalling hypocrisy and abject failure to be able to reduce CO2 emissions in any meaningful manner. As coal-fired power stations are re-established around the world [without carbon-capture-and-storage (CCS), of course]; as gas flourishes; as tar-oil sands are developed; as car ownership continues to grow; and as politicians, and pie-in-the-sky academics, fly to ever more conferences, the public will call time on the Great ‘Global Warming’ Charade. After all, people now have real problems to face, like losing their jobs and being unable to pay the rent or the mortgage.” (Philip Stott)

  7. This is a classic case of shooting the arrow (anthropogenic CO2 global warming) and then drawing the target around it (computerized models).
    They will not change the failed hypothesis. They will twist the models, fiddle with and torture them to death until it spews something that shows what they want.
    It would have been funny if it wasn’t so sad

    • Your point is likely spot on. Any modeling of aerosol events/emission on a scale that covers “the North Atlantic” would have to derive from observational precision that hasn’t existed for the time period described in the report. I am very tired of the mantra, “We have good data that shows…” only to dig a bit and discover that very little actual data exists. Instead, there is a bit of data and a mountain of statistical extrapolation.

    • I like the arrow-target metaphor

  8. So now the PDO and LIA do not exist either?
    And what about the Indian Ocean oscillations?
    But of course the AGW believers still claim to have climate well understood enough to justify changing everything to fit their demands.
    How entertaining it is to watch our AGW true believers floundering through history, rewriting it to fit their dogma

  9. Oh God, now they hate air fresheners.

  10. Thank you Dr Curry for alerting this bystander to an important new emphasis that I at once expect to be reflected in AR5. The fact Nature prints something this radical without enough detail for it to be checked so close to IPCC deadlines rings all kinds of bells, none of them good ones. Though it’s possible I suppose to be pleasantly surprised every now and then.

  11. I hope Bob Tisdale weighs in on this one. (He might have some insight on missing variables.)

    Under the adage of “First Observe”:
    Multidecadal Changes In SST Anomalies (Blog Version), 2010.

    This video presents evidence that multidecadal variations in the strength and frequency of El Niño and La Niña events are responsible for the multidecadal changes in Global Sea Surface Temperature (SST) anomalies.

    NODC OHC Animation 1990 to 2010, 2011.

    The video presents animated maps of the National Oceanographic Data Center (NODC) Ocean Heat Content (OHC) data from 1990 to 2010. The data in each map has been “smoothed” with a 12-month filter to minimize noise and any seasonal component.

    Tisdale1, Bob. SST Animations – BobTisdale1 – YouTube, n.d.

    • Kudos and many thanks to Bob Tisdale. My citation app did not credit Bob Tisdale for the first cite (“Multidecadal Changes In SST Anomalies (Blog Version), 2010). Apologies to him. Also, “BobTisdale1” is Bob Tisdale.

      One of the things I “think” I saw in some of his animations is that the region containing the Indian Ocean lags ENSO, as does the AMO. Of course, the eyes play tricks and I can’t locate the video that points that out explicitly.

      If these interconnections prove out, the authors (Booth et al.) may have a missing variable problem. :-)

  12. “By publishing this, Nature seems to be looking for headlines, rather than promoting good science.”

    That could be said for most of what passes for “climate science” coming from the IPCC and its acolytes. The hockey stick, disappearing glaciers, vanishing MWP and now LIA, drowned polar bears, dried up Amazon, killer CAGW hurricanes and droughts.

    And the beat goes on….

  13. Thanks Dr. Curry for the alert of this paper. “I’m trying to find what the CMIP5 is using for historical aerosol forcing. A quick google search doesn’t turn up much in the way of documentation, but I did spot this. Not an error bar in sight. Realistic error bars on current aerosol optical depth measurements are quite large; historical error bars must be huge.”

    Your presentation to DOE Office of Biological and Environmental Research about models from a couple threads ago seems important here. Can the DOE help your search at some of their sites or at NCAR? It is hard to understand why you would have problems finding the details of publicly funded models.

  14. Paul Vaughan

    “evidence that the AMO is caused by changes in the regional abundance of aerosols is compelling”

    This is total BS – and so is “conventional wisdom” on AMO.

    I’ve been empirically auditing climate discussion claims & narratives since late 2007. The major claim that stands on absolutely solid empirical ground is the following one:

    Le Mouël, J.-L.; Blanter, E.; Shnirman, M.; & Courtillot, V. (2010). Solar forcing of the semi-annual variation of length-of-day. Geophysical Research Letters 37, L15307. doi:10.1029/2010GL043185.

    I extended that work to AAM (atmospheric angular momentum) here:

    Beyond the day and the year, we knew of the QBO (quasi-biennial oscillation). And now we’re aware of a clear solar-terrestrial-climate marker — December 2011 update:

    Recently I isolated the seasonal details:

    Mainstream Climate Scientists:
    The calculations to get this [ ] result can be done in a spreadsheet in a few minutes. Don’t underestimate the depth of the fundamental reforms demanded by this sheer simplicity. Contact me if you need help. [data: ]

    Aggregation criteria affect spatiotemporal pattern fundamentally. The serious hazards of statistical paradox are inevitable for climate discussion participants not willing to invest the effort necessary to benefit from the cautions of pages 4 & 9 here:

    Piers Corbyn knows about the generalization, but here he addresses just a specific instance (presumably to keep the presentation at a level accessible to a general audience):
    (This may be Piers’ best video presentation to date.)

    Multiparameter complex wavelets can be (and have been) used to detect the generalization empirically. It’s no different than the relationship between a crank shaft and the wheels on a car once the constraints of dominant terrestrial modes & the current distribution of continents are recognized. All the info needed to crack the code of ENSO is now publicly available. We shall see if any climate scientist is willing & able to follow through.

    • John from CA

      Thanks Paul,
      26 well spent minutes on an interesting presentation.

    • Pooh, Dixie

      Thank you for this link to Piers Corbyn’s presentation. Very thought provoking. The presentation slides went by so fast that I was unable to study them. So I went looking, and found this:

      Corbyn, Piers. “Scientific Reliable Forecasting of Extreme Weather Events, Climate Change and the Next Ice Age”. Powerpoint (PDF) presented at the Burlington House Nov 8, 2011, England, February 2011.

      It looks like most of the slides are the same as in the video.

      • Paul Vaughan

        Pooh, Dixie wrote: “The presentation slides went by so fast that I was unable to study them.”

        Youtube has a “pause” button — bottom left. Some of the slides convey important info not verbalized.

    • Piers in his video mentions New Zealand earthquake, at the time I started regular monitoring of solar storms. Few weeks later on 10th March 2011 ( 8 hours before Japan’s earthquake ) I posted this on WUWT:
      Currently geomagnetic field is getting seriously shaken
      didn’t mentioned earthquake since Dr. Svalgaard and mods previously have advised not to do so, also had to put disclaimer on my website too. More on earthquakes here

      • It seems intuitive that crustal forces must be near or at hair trigger leading up to an earthquake, and magmatic and crustal forces must be at or near hair trigger preceding an eruption.

        So how much force is required to squeeze off a hair trigger?

      • Paul Vaughan

        The shifts are in temperature gradients. They have a spatial orientation, so for anyone investigating further: It’s not just about timing but also about how the gun’s oriented.

        Vukcevic: No matter how many times Svalgaard was right, he was dead wrong when it counted most.
        (This comment’s not about earthquakes.)

      • No idea. There are different types of seismic failures, most people in such cases think of mechanical forces, but in one particular type I would favour a ‘thermo-electric’ failure. In the above link, first take a look at the article by lady from the Goddard Space Center, and then 3rd illustration from the top.

    • rubbish video, it’s pseudo-science.

      Why does he compare CO2 to *US temperatures* and not global temperatures?

  15. John Carpenter

    “By publishing this, Nature seems to be looking for headlines, rather than promoting good science.”

    Heard about it on NPR last night driving home from work. It was another, ‘we’re influencing the environment more than we thought’ story. The kicker was, because we are controlling aerosols better from smoke stacks via regulations, there are fewer cooling aerosols so the oceans are losing their ‘sunblock’ and we can expect a warmer Altantic Ocean.

    Yeah, we’re just driving the way the climate works so much more than we thought.

    • well nature will decide for us. I would say in another 10-20 years, we should switch to the cool phase of the AMO. If it is aerosol, then we won’t see a cool phase.

      • More details, please?

        I’ve heard enough oversimplified “in another 10-20 years, we should”s on all sides:
        In another 10-20 years, we should see 0.2C warming.;
        In another 10-20 years, my wager should prove something;
        In another 10-20 years, everyone will sign the petition;

        What’s the probability distribution? Parameters? Mechanism? Uncertainty?

        Four North Atlantic volcanoes spaced evenly would obscure the results for the entirety of the next 20 years. Many other effects could, too, some of which we understand and measure for poorly.

        I know you’re pressed for time on many fronts, Dr. Curry, but why not show the leadership the field needs by holding yourself to the better standard you seek of others?

      • Paul Vaughan

        Bart, your demands on Dr. Curry’s time & rotating priority balance are neither fair nor sensible (particularly as framed), but I can agree that nature will still be teaching us important lessons more than 10 to 20 years from now. Regards.

      • Bart agonally croaks. Three-headed dogdays bark all afternoon. Sticks fill the flood. All aboard, SS Catanthglowar loosens hawsers.

      • One of my favorite morbid limericks:

        When you ponder the ways you could die
        And what anguish and death throes imply,
        I would tell you, who knows
        About agonal woes?
        You could croak in the wink of an eye.
        by Chris Doyle, 2004

        Paul Vaughan, one hopes sometime in the next 10-20 years, our host has the time to make a better wager, more meaningful than ‘warm=right, cold=wrong’.

        All this ‘time will tell’ prognostication seems a waste of the talents of decent minds. We’re not even sure about things that happened 10-20 years ago and what they mean.

      • Mostly in 10-20 years a lot of the AGW promoters will have met their maker, and the urgency they have brought to the topic of climate science will have passed on with them.

      • Pooh, Dixie

        Corbyn (above) thinks much sooner than that, but I have not checked out his theory yet. :-)

      • Paul Vaughan

        I recommend extra caution with that particular weakly-framed suggestion: Not all of the cards are on the table.

      • Paul 4/6/2012 @3:36pm: Agreed. It took me a while to plow through the presentation linked above: ( )

        In my opinion, correlation and patterns of co-incidence can be useful in prediction (Pgs 35, 36) and as clues to mechanisms. Old Farmer’s Almanac, identification of the Gulf Stream and success in the corn/wheat markets.

        Here are some observations from the linked presentation:

        Pgs 14, 23: Geomagnetic Activity at earth’s surface is monitored and reported as Bz. It is a combination of the magnetic field carried by the solar wind and the earth’s magnetic field.

        Pg 35, 36: This has an interesting link to maps and animations of the Jet Stream. As the East Coast found out, the location of the Jet Stream affects weather. The full set of (modeled) plots is here:
        and the northern hemisphere is here:

        Pg 41: (the grid of What Does & Doesn’t drive Climate) The grid excludes Galactic Cosmic Rays (GCR) on the basis of no signal in 11 and 22 year cycles ( ).
        I suggest there are a few confounding variables in trying to match GCR to to solar cycles by year.
        a) Modulation of GCR begins at the heliopause (80 – 100 AU) or stagnation point (116-177 AU). Although diffuse at the extreme, and allowing 3 days to reach earth at 1 AU, the IMF of the solar wind (charged particles) would have about a year to affect GCR.
        b) The better agreement for a 22-year cycle may be understood as the effect of reversal of the sun’s magnetic field half-way through the solar cycle; aligned with the earth’s magnetic field for 11 years, then opposed to it.
        c) Cloud formation per Svensmark’s Cosmoclimatology requires very high energy GCR striking atmospheric nitrogen molecules, creating muons, which become ionizing electrons, leading to Cloud Condensation Nuclei (CCN) and forming clouds from atmospheric water vapor. The whole cascade depends upon a relatively humid lower atmosphere, with convection and circulation thereafter.

      • The second jet stream link does not work (sorry) but can be reached through the first link.

      • Paul Vaughan

        The concept climatologists call “thermal wind” is key. Watch out for talk of effects on temperature without attention to effects on temperature gradients. Research update: I’ve established pivoting coherence between neutron count rates & ENSO. Plenty to discuss moving forward. I appreciate your nature appreciation. Best Regards.

      • Paul. “Best Regards.”
        Likewise! :-)

      • John Carpenter

        Nature tends to cycle itself through highs and lows…. why should we expect the Atlantic or any of the other oceans to not behave in this manner? This has been the accepted theory. My bet… nature is still a lot more powerful than we thought.

      • Seems that 10-20 year range is very interesting from many perspectives, with the aerosol link to the AMO being only one. If another Maunder or at least Dalton Minimum is also upon us, then we’ll have some interest solar forcing data to look at as well. It would stand to reason that a great deal more will be known about the roles of aerosols, solar, oceans, and of course, greenhouse gases by then such that either a lot more skeptics will have become “warmists” or visa versa.

        The net effect will be, that at least in terms of attribution and uncertainty, there will be less of it in 10-20 years (at least in terms of the causes of climate change), but of course, that will not necessarily lend much assistance in the cause of regional climate prediction as the underlying uncertainty related to a system exhibiting spatio-temporal chaos will remain. But globally, we’ll certainly have a much better understanding of the true long-term climate sensitivity to various forcings, including greenhouse gas concentrations.

    • John Carpenter

      You can listen to the NPR story here:


  16. Perhaps the author’s understanding of natural events is not as good as he assumes.

  17. John from CA

    “they suggest that multidecadal temperature fluctuations of the North Atlantic are dominated by human activity, with natural variability taking a secondary role.” <– does natural forcing within the multidecadal fluctuations due to solar activity play a role in this equation?

    When Sun’s Too Strong, Plankton Make Clouds

    “The plankton try to protect themselves by producing a chemical compound called DMSP, which some scientists believe helps strengthen the plankton’s cell walls. This chemical gets broken down in the water by bacteria, and changes into another substance called DMS.”

    “DMS then filters from the ocean into the air, where it breaks down again to form tiny dust-like particles. These tiny particles are just the right size for water to condense on, which is the beginning of how clouds are formed. So, indirectly, plankton help create more clouds, and more clouds mean that less direct light reaches the ocean surface. This relieves the stress put on plankton by the Sun’s harmful UV rays.”

    “The researchers were also surprised to find that the DMS molecules completely refresh themselves after only three to five days. That means the plankton may react to UV rays quickly enough to impact their own weather. Toole and Siegel were surprised by the lightning-fast rate of turnover for DMS.”

    • When the fishes leave, they’ll say thanks for all the plankton.

    • This raises the excellent reminder of another important source of aerosols and yet another way that solar output can affect climate. It also reminds us that biological activity is another modulator of the climate. It would be interesting to do a study of all sources of aerosols: volcanic, anthropogenic, biological, etc., and compare their levels on both a short-term and long-term basis to the fluctuations of the AMO.

      • Paul Vaughan

        Yes, all sources.

      • AR4 chapter 7 contains a section which mostly concerns natural sources of aerosols.

        The study described in this post does what you ask to some extent. The model contains an interactive aerosol module so levels of natural aerosols fluctuate according to changing conditions (e.g. Temperature).

      • John from CA

        Thanks R. Gates,
        It also relates to the climate hacking craziness. There was a scheme proposed to increase plankton blooms by introducing iron to the oceans. Do they fully understand, if they do this it can also effect climate?

  18. “I’ll be nice and just ask who writes this stuff? It can’t be a scientist.”

    Well, let’s check the hypothesis, using “A scientist wrote the editorial” as our Null, and looking at observations.

    Perfunctory incidental insults disparaging anyone who may disagree? Yes.
    Was the political invective naive and simplistic? Yes.
    Uncritical hero-worship and appeal to authority? Yes.
    Use of French, or another foreign language, inappropriately? Yes.
    FOG Index >> 12? Yes
    Wandering all over the map before getting to the point? Yes.
    Assumes reader has read all references, however obscure? Yes.
    Assumes reader agrees with all references, however contentious? Yes.
    Uses “suggest” to mean “proven beyond all doubt”? Yes.
    Poor grasp of Economics? Yes.

    So far, the results well match the editorial writing of 89% of scientists (and 93% of posters to Climate Etc.).
    While we could go on and check the other 10 standard questions experimentally found to reliably predict the origin of anonymous opinion in a Science magazine, we’re already at or below 50%.

    As a result, we cannot reject the Null hypothesis at this time.

  19. This is like the CLAW hypothesis with steroids. I wonder if anyone has looked at the levels of Se isotopes in plankton? The human emitted Se from burning coal would be easier to track than looking for sulfur, given the relative backgrounds of selinites and sulphates.

  20. Bart R. annoyingly writes: “What’s the probability distribution? Parameters? Mechanism? Uncertainty?”

    Give the woman a break. She’s making an informal, common sense observation.

    • pokerguy | April 6, 2012 at 2:47 pm |

      An informal, common sense observation which happens to be patently wrong.

      • John Carpenter

        More details, please?

        I’ve heard enough oversimplified “patently wrongs” on all sides:

        patently wrong, we should see 0.2C warming.;
        patently wrong, my wager should prove something;
        patently wrong, everyone will sign the petition;

        What’s the probability distribution? Parameters? Mechanism? Uncertainty?

        What is the probability four North Atlantic volcanoes spaced evenly would obscure the results for the entirety of the next 20 years? (heh, name four North Atlantic volcanoes that could do that). What other effects could, too, some of which we understand and measure for poorly?

        I know you’re not pressed for time on many fronts, Bart R, so why not show the leadership the field needs by holding yourself to the better standard you seek of others?

        p.s. just funnin with you Bart… you get the drift?

      • John Carpenter | April 6, 2012 at 6:06 pm |


        Erm, no, actually.


      • John Carpenter

        Um… I guess not…. I thought you would?

  21. This is a good story until you realize there is NO DATA, there is only their ‘sophisticated model’. How anyone could give this opinion, and that is all it is, any credence says volumes about how true science no longer exists in the make-believe world of AGW.

  22. Steven Mosher


    You’ll find the historical forcings at the RCP site. Have a look at your mail. I’ll send it directly

    • Historical forcing error bars lost in transit. Should have insured them.

      • Steven Mosher

        Uncertainties included.
        But if you give me enough uncertainty i’ll explain away the bump in the 30s and the dip in the 60s and 00s

        Uncertainties make the job easier.

        see that bump in the 30s? the models cant get that correct right now
        1. the observations are wacked
        2. some forcings are missing from the models
        3. some physics is missing
        4. the climate is wiggly on some time scales.

        or some of all of the above. Go figure, there are things we understand–C02 warms– and things we dont: how much warming and where

      • “C02 warms”

        …except when it doesn’t.


      • 1 and 2 most likely. 1. The southern hemisphere instrumental data is pretty wacked around that time, the NH is overly weighted. 2. Pre bump there was a cluster of High NH volcanoes. Initially cooling, but ash makes dirty snow, followed by no volcanic activity in the NH for a few years. Radiant rebound plus more snow/ice melt due to dirty snow.

        The NH wags the dog.

  23. I did a CUSUM plot of the ASO data from 1856 to 2011.

    The plot shows that there are turning points at approximately 1903, 1928, 1964 and 1998. A really nice 65-ish year cycle is apparent

  24. In any event, a much more lengthy manuscript would have been submitted with more details, allowing people to more critically assess this.

    The supplemantary information contains a few more details.

  25. The doubts expressed here by Dr. Curry and others parallel those that I experienced when I read the paper a couple of days ago. I’m always troubled by studies that conclude that because a variable A, within its uncertainty bounds, can conceivably account for an effect B, that A is therefore an important cause of B. We have seen that conclusion in regard to attribution of climate changes to solar changes, cosmic rays, astronomical variations, and a variety of other hypothesized modifiers in the absence of additional supporting evidence, and it’s an unfortunate overreach on the part of authors. In this case, the strong dependence on aerosol indirect effects, with their large margins of uncertainty, compounds the overreach.

    This doesn’t mean that an article of this type should never be published, but rather that its authors should be required to acknowledge the very tentative nature of the conclusions, and the need to reserve judgment until much more data are available. It’s an interesting concept, and not unworthy of public attention as a theory rather than a set of conclusions, particularly since decisive evidence to confirm or refute the concept will not easily be obtained in the near future (i.e., the authors can’t simply be asked to go back and do a few more studies to make their work conclusive). In fairness to Nature, the News and Views section does call attention to weaknesses in the conclusions, but probably not emphatically enough.

    • Having read the Supplementary Information Paul S linked to above, which I hadn’t read when I first looked at the paper two days ago, I find the evidence for an aerosol contribution to the AMO more convincing, but it’s still not clear that it’s a dominant rather than a minor component. It seems likely that what we call the “AMO” in fact represents more than a single phenomenon, including internal modes related to the AMOC, anthropogenic aerosol forcing, and volcanic aerosol forcing.

      The historical record that Bob Tisdale has referred to isn’t very helpful in my view, because It’s clear that the “AMO” is not a cyclic event likely to represent a persistent cyclic mechanism. Rather, what we call the AMO is simply deviations from the global trend, and it would be amazing if over multiple decades, the North Atlantic followed the global trend with no deviations at all. What we can’t necessarily conclude is that the deviation observed at one time point was attributable to the same mechanism as a similar deviation at a different time. I expect that what we can look for in the future is not a single mechanistic explanation but rather a means of assigning relative strength to the multiple phenomena that operate to make the North Atlantic fluctuate from the global average over long time intervals.

      • Paul Vaughan

        North Atlantic has high amplitude variation (small basin close to a lot of land that has heat capacity much lower than water and ice that is “continental” for much of the year). Ever heard of leverage? Outliers pull averages. If you want a measure robust against that, there are medians …and other stats. The North Atlantic is just the highest amplitude expression (why IT catches eyes & imaginations) of a nonstationary multidecadal wave that is coherent (if you “look through” interannual/inter-regional variations) over much of the world – notably the Pacific and the northern hemisphere. The Southern Ocean might be tremendously important dynamically, but with so much water and so little land around, temperature amplitude is low and it doesn’t leverage global averages so hard per unit area. One thing I always wish for in these discussions is more care about the fundamentals of metrics.

      • “Changes in dust concentrations over the North Atlantic have been linked to changes in surface temperatures on short inter-years”

        Dust? From the Sahara?

        Are they trying to blame the AMO on dust from the Sahara?

      • Gobi and Saharan dust are very important. Had there been a population available to use the energy, from windmills at the wind gap in the mountains funneling wind into the Bodele Depression, the Amazon would have starved from lack of airborne nutrients from Africa.

      • er, uh, Amazon basin biosphere would have starved. I presume rainfall to sustain the Amazon River might have remained about the same, unless those same nutrients were also cloud forming nuclei.

      • Are they blaming Aerosols for changes in Sunshine?

    • David Springer

      Fred Moolten | April 6, 2012 at 5:23 pm | Reply

      “This doesn’t mean that an article of this type should never be published, but rather that its authors should be required to acknowledge the very tentative nature of the conclusions, and the need to reserve judgment until much more data are available. ”

      Yeah that ought to be a law, Freddie. If it were we wouldn’t be here arguing about climate change at all because its conclusions that anthropogenic forcings are

      1) significant
      2) practically preventable and
      3) not a net benefit during an ice age

      are very tentative and quite possibly very wrong.

      Thanks for playing.

  26. There is an immediate credibility problam concerning anything published in Nature because, “on the topic of ‘global warming’, it is the bloggers who have proved more reliable and critical than the mainstream media and the environmental journalists.” (Philip Stott)

  27. I am sure Nature has the IPCC’s Seal of Approval. But, that is the scarlet letter–about like an oversized picture of Mao hanging over a Leftist’s fireplace.

    The more you know the more you wonder why anything associated with the sort of delusional claims that the IPCC raves about still have any weight with anyone anymore. Let’s get real:

    “An underlying temperature trend of 0.062±0.010 K/decade was estimated from data in the tropical latitude band. Corrections to this trend value from solar and aerosols climate forcings are estimated to be a fraction of this value. The trend expected from CO2 climate forcing is 0.070g K/decade, where g is the gain due to any feedback. If the underlying trend is due to CO2, then g ~1. Models giving values of g greater than 1 would need a negative climate forcing to partially cancel that from CO2. This negative forcing cannot be from aerosols.

    “These conclusions are contrary to the IPCC [2007] statement: “[M]ost of the observed increase in global average temperatures since the mid-20th century is very likely due to the observed increase in anthropogenic greenhouse gas concentrations.”

    David H. Douglass DH, Christy JR. Limits on CO2 climate forcing from recent temperature data of Earth. E&E, V20:1&2 (2009)

  28. The sea surface temperature data for many of the CMIP5-based models, including the HadGEM2-ES, are not yet available through the KNMI Climate Explorer, so we can’t play with the data used in this study. It would have been interesting to determine:

    a. why they chose to exclude the period of 1941-1949 from their trend analyses listed in Table S1 of their Supplementary Material (the discontinuity they fixed in HADSST3 maybe?):

    b. if the multidecadal variability in their models also shows up in the North Pacific as well. It appears in the observations and shows up quite well if we compare detrended North Atlantic and detrended North Pacific SST anomalies that have been smoothed with a 121-month filter, which is how the ESRL presents the AMO:
    The graph is from this post:

    c. why they excluded the data after 2000. The CMIP5 historical simulations extend to 2005.

    Additionally, were anthropogenic aerosols also responsible for the multidecadal variability that shows up in the Gray et al (2004) paleoclimatological reconstruction of the AMO? See their Figure 2:

    Curiously, Booth et al (2012) is written by 5 Hadley Centre personnel, but they’ve used NOAA’s ERSST.v3b as the reference dataset in their paper, apparently/obviously because it provides the best correlation with the model than the other SST datasets.

  29. Eric Ollivet

    If there is no AMO other than (manmade) aerosol forcing, how Booth & al would explain why NH (or SH or global) SST warming rate over [1910 – 1940] period could have been similar or even higher than the one observed over [1970 – 2000] period ?
    Plots here

    In the early 20th century, human CO2 or aerosols emissions were about 5 to 10 times lower than in the 70’s and after !

    The inconvenient truth is that those pseudo scientists are using invalidated models (whose outputs are not coherent with observational data) to make junk science, only intending to support their AGW dogma !

    • The Medium is the Message: by their behavior the Leftists admit the efficency of the market–i.e., the govcernment understands that the more government is willing to pay for junk science the more of it there will be.

      And of course there is the rub. It’s not free enterprise it is going Greek. Like we see happening in California, takes money and provides nothing of value in return.

    • Paul Vaughan

      I’d like to hear them explain the line-ups on page 1 here:,%20Climate%20Shifts,%20&%20the%20Chandler%20Wobble%20Phase%20Reversal.pdf

      [Those who liked the work of Tsonis should take a look.]

      For example, are we supposed to believe anthropogenic aerosols changed the behavior of the sun? I do wish people had more respect & appreciation for nature. If researchers would get more serious, they could pinpoint the actual anthropogenic contribution by listening to signals in Earth Orientation Parameters (the arbiters of climate disputes), but politically-oriented climate discussion participants love the opinion-scrambling utility of uncertainty and will do just about anything to ensure its prolonged longevity.

      There’s one signal in EOP that could be one of 2 things (or some combo): (1) anthropogenic global warming or (2) slow warming of the cold deep oceans. I would like to work on this signal with mainstream climate scientists. LOD in particular is FULL of untapped signals that have been overlooked (due to unfortunate choice of methods). …But on the humorous side: What climate scientist is going to reply to an e-mail from someone who has posted articles at WUWT? Maybe there’s fear the reply will end up posted, twisted, & ridiculed with 100 “updates”. What option does one have but to laugh at some aspects of the climate discussion?

  30. To me the cooling in the 1960-1970 west Atlantic has always seemed connected to the cooling at the same time in the eastern US. With the prevailing winds and currents it would be easier to say that the cooler US causes the cooler west Atlantic, e.g. via increased aerosols and global dimming effects. The AMO would need the cooler water to originate in upwelling regions on the other side of the Atlantic, I would have thought. So I tend to think the paper is onto something.

    • Paul Vaughan

      Circulation’s seasonally strong off northern hemisphere east coasts:

      200hPa Wind:

      That’s where temperature gradients are STEEP in winter (due to land-ocean heat-capacity contrast).

      2m Temperature:

      Note how the flashy things coincide with features Bob Tisdale has patiently emphasized in articles (gulf, kuroshio, spcz):

      Net Surface Heat Flux:

      Column-Integrated Heating:

      The climatologies don’t sit still. Their movements are spatiotemporally coherent with the asymmetric distribution of continents & changing cadence of solar activity — easy to see with tools that can ‘see through’ interannual/inter-regional water vapor variability …i.e. see the forest for the trees. (Maybe we should affectionately (in good humor) call people who are hypnotized by ENSO “vapor eyes” — there’s so much vapor in their eyes they can’t see the sun.)

      What the climate discussion probably needs more than anything else to advance at this stage is widespread awareness of the concept climatologists call “thermal wind”.

  31. Stop Press!
    27 Mar 2012

    Man made oxygen & carbon emissions stops glacial/ inter-glacial periods:

    Speaking at the Planet under Pressure conference in London, Prof Will Steffen, a global change expert from the Australian National University said that this period of climate change caused by humans, known as the ‘anthropocene era’, could ultimately cause the whole system of ice ages followed by warm periods, that has allowed life on Earth to flourish,
    TO BE OVER. (my emphasis)

    Next: cO2 has stopped the planet from spinning. Sun stops rising.
    Virginal sacrifices needed.

  32. There’s a very good correlation between the AMO and solar cycle frequency or solar cycle length (inverse correlation).
    Figure 1 here:

    It looks like the AMO shape to me. If the correlation continues, the AMO will go negative in this decade.

    • Paul Vaughan

      Solar cycle length doesn’t show the best correlation with AMO [ ].

      It’s rate of change of solar cycle length (i.e. solar cycle phase deceleration) that shows coherence with AMO — which amplifies via land-ocean heat-capacity contrast & circulation a much broader-scale pattern) — for example, see p.4 here:

      Solar cycle deceleration should not be interpreted as a driver but rather as an indicator of differentially shifting terrestrial seasonal accumulation of different types of solar activity.

      Quite simply: Mother Earth isn’t equally responsive to Father Sun’s advances at all times & places (and his advances aren’t randomly distributed over time & place – on the contrary: they cycle). This has been known with respect to the geomagnetic field for a long time, but vapor eyes have been blinded by ENSO to the climate field analogy. (See above for a light-hearted definition of ‘vapor eyes’.)

      Analogy: The tachometer in a car might instantaneously indicate the frequency of a wheel fairly well, but recalibration is needed as gears shift and as turning radius tightens & loosens (so cars also have a speedometer).

      Similarly, cycle frequency varies locally in a vortex, so global coherence across the whole vortex is in the rate of change. If the vortex is gaseous and over water, cycling of the water will be an order of magnitude slower. A submerged object will cycle more slowly than a buoyed one, which has a sailing profile. A light object elevated high in the air will cycle faster than one in a surface boundary layer losing energy to turbulence. The coherence across height, depth, & medium is not in cycle frequency but rather in the rate of change. We need a better handle on differentials in the climate discussion. Too many look at the wrong markers and draw false conclusions.


  33. “the Atlantic regional climate is more pervasive than previously thought.”
    Well this really is an original paper with a really original statement as above?
    Unfortunately they missed out the beginning of their Narrative “Once upon a time in a land far far away…..
    Of course, and the ending “And they all lived happily ever after”
    It should be IPPC policy that all papers contained in their assessment carry the above beginning and ending.

  34. Maggie’s top aide Sir Bernard Ingham attacks ‘mad’ wind farms and ‘steady descent into hysteria over global warming’
    ‘Our politicians are besotted with every form of power generation that does not work in a modern economy.’

  35. Michael Hart

    Once I read the phrase “state-of-the-art” coupled to the word “model” I knew there was little point reading any further.

    • Paul Vaughan

      And what is art?…

      “It’s such a long answer that I think I should just say ‘No comment’ […]”

      “Perfectionism is the distraction.”

      “[…] Miles Davis had a great quote […] he painted his last stroke and said ‘That’s art’ – when it’s your last stroke – because the most difficult thing is knowing when to stop, and so maybe the most distracting thing is not knowing when to stop.”

      Metric – The Universe is a Distraction (Interview) [55 seconds]

  36. David Springer

    “Decadal-scale model predictions of regional Atlantic climate will probably be improved by incorporating aerosol–cloud microphysical interactions and estimates of future concentrations of aerosols, emissions of which are directly addressable by policy actions.”

    Aerosol emissions from volcanoes is addressable by policy actions?

    Really? How exactly does that work?

  37. Dave Springer, that was funny but they meant evil coal. It has to get hot and windy before the windmills work.

  38. Back in the 1990s when the NAO was high, Shindell, Miller, Schmidt and Pandolfo used their computer models to simulate these oscillations. Perhaps not surprisingly, they found that the “observed sea-level-pressure trends, including their magnitude, can be simulated by realistic increases in greenhouse-gas concentrations.”

    Thus, the observed trends could be attributed to GHGs rather than natural variations: “although the warming appears through a naturally occurring mode of atmospheric variability, it may be anthropogenically induced and may continue to rise.”

    Simulation of recent northern winter climate trends by greenhouse-gas forcing

  39. ‘During the descent into the recent ‘exceptionally’ low solar minimum, observations have revealed a larger change in solar UV emissions than seen at the same phase of previous solar cycles. This is particularly true at wavelengths responsible for stratospheric ozone production and heating. This implies that ‘top-down’ solar modulation could be a larger factor in long-term tropospheric change than previously believed, many climate models allowing only for the ‘bottom-up’ effect of the less-variable visible and infrared solar emissions.’

    ‘Solar activity during the current sunspot minimum has fallen to levels unknown since the start of the 20th century. The Maunder minimum (about 1650–1700) was a prolonged episode of low solar activity which coincided with more severe winters in the United Kingdom and continental Europe. Motivated by recent relatively cold winters in the UK, we investigate the possible connection with solar activity. We identify regionally anomalous cold winters by detrending the Central England temperature (CET) record using reconstructions of the northern hemisphere mean temperature. We show that cold winter excursions from the hemispheric trend occur more commonly in the UK during low solar activity, consistent with the solar influence on the occurrence of persistent blocking events in the eastern Atlantic.’

    The question of models is in one sense the breadth of the couplings included. If important physical processes are not included then the model is implausible.

  40. Sell natural variation; buy aerosols.

  41. Now I want to hear Obama say we can’t let China surpass us in nuclear energy!

    “China will accelerate the use of new-energy sources such as nuclear energy and put an end to blind expansion in industries such as solar energy and wind power in 2012, Chinese Premier Wen Jiabao says in a government report published on March 5.

    China will instead develop nuclear power in 2012, actively develop hydroelectric power, tackle key problems more quickly in the exploration and development of shale gas, and increase the share of new energy and renewable energy in total energy consumption.”

  42. The Medium is the Message. There are many languages in the world. No one feels the need to know them. And yet we all speak this language of Global Warming. That is proof that Global Warming Alarmism is a part of the woof and warp of Wesern Civilization much like a shared language and numbering system, the common cold and fears of many things, most of which we can do nothing about..

  43. Paul Vaughan

    Piers Corbyn emphasizes statistical paradox:

    “Global warming preceded by increasing carbon dioxide concentrations during the last deglaciation”

    Off-topic in this thread, so this isn’t the place to discuss — just alerting the community that this was released today (April 7).

    • That last link won’t be off-topic for long. Interesting interpretation and it will cause some adjustments on both sides.

      • I don’t think it’s outside mainstream understanding. The orbital alteration precipitated regional changes which *somehow* pushed ghgs into the atmosphere. After that, warming became globally coherent.

        Note that on Piers Corbyn’s “see, co2 does lag temperature” graph he mixes up which line is co2 and which is temperature. Presumably that means he does agree global temperature lagged the co2 increase.

      • Paul Vaughan

        Careful: The time axis runs backwards on that graph.

      • Not on the graph I’m looking at (second page, bottom-left) but I’ve realised I’m wrong about him mixing them up. My confusion was caused by him pointing to a period of flat CO2 & temperature, yet insisting one was decreasing and the other increasing.

      • Something more interesting at last – surely no one is sugggesting that CO2 isn’t a greenhouse gas? (LOL)

        ‘Our global temperature stack and transient modelling point to CO2
        as a key mechanism of global warming during the last deglaciation.
        Furthermore, our results support an interhemispheric seesawing of
        heat related to AMOC variability and suggest that these internal heat
        redistributions explain the lead of Antarctic temperature over CO2
        while global temperature was in phase with or slightly lagged CO2.
        Lastly, the global proxy database suggests that parts of the northern
        mid to high latitudes were the first to warm after the LGM, which
        could have initiated the reduction in the AMOC that may have ultimately
        caused the increase in CO2 concentration.’ Here is the paper outside paywall:

        But you can’t have it both ways – either natural CO2 emissions correlate with temperature or they don’t. They do of course – I noticed Will Steffen at the global doom conference suggesting global could create a global compost bomb – – he is the Australian director of the Climate Change Institute. An idiotic left wing thinktank. So let’s talk about this.

    • Corbyn says dangerous, I disagree. The consensus is disproving their own hypothesis by following its implications logically to an absurd consequence. Reductio ad absurdum. Bring it on!

  44. Eric Ollivet

    Evidence of correlation between T° variations and Solar Activity variations : plots here

    Evidence of correlation between T° variations and AMO variations : plots here

    All in 1 : plots here

  45. The AMO is an invention of Michael Mann according to Michael Mann hisself in an interview with him published in last month’s Scientific American. He, in a uncharactertistic burst of lucidity, admits that with only 150 years of spotty SST data it’s tough to pull 60-year long cycles out of it with any great confidence they’ll keep on repeating. Yo, really Mike? This is very encouraging. Michael seems to have gained some glimmer of understanding of the implications of small sample sizes. Now if he’d just apply that to the small number of trees he used to reconstruct a 1000 year-long northern hemisphere temperature reconstruction. What’re the odds he’ll take that great leap of applied intellect? I say little to none. But I have only a small sample size of Mann’s misdeeds to work with… ;)

  46. As a tax payer I’m seeing this as just more evidence this field is over-rated and over paid. Proof abounds that nobody knows for sure what is right and what is wrong. The whole enterprise is unbelievable.

  47. Mydogsgotnonose

    The Atlantic is coupled closely to the 50-70 year Arctic melt freeze cycle. The Arctic is now freezing which is why the N. Atlantic OHC is falling:

    Man-made aerosol emissions do play a role, but their effect is dwarfed by a natural process.The aerosols reduce cloud albedo. The natural aerosol concentration change is via phytoplankton biofeedback. The same process occurs in the Antarctic at a frequency determined by Milankovitch.

  48. stevefitzpatrick

    The paper kind of flies in the face of a big body of work relating the AMO to changes in both global temperatures and the overturing rate of the Atlantic. It is possible that this paper is 100% correct and all other relevant papers are mistaken, but I sure would not bet on it. The agument presented depends rather heavily on poorly quantiifed influences of secondary aerosols. I am more comfortable with the approach of Judith’s pending paper:
    I think that there is considerable, shall we say, “sensitivity” to pseudo-cyclical changes in surface temepratures. They add an unwelcomed (by many) level of uncertainty to GHG forcing based influence. If the magnitude of the influence of the AMO is in fact +/- 0.1C around a secular mean, then that makes climate senistivity near the center of the IPCC range (~3.1C per doubling) more difficult to support with available data. I suspect that is pretty much the whole motivation for this paper.

    • We now know of the significant impact on global warming due to the impact of cosmic rays due to changes the Earth’s albedo due to the resultant change in low cloud cover (nominally, it is the sun, stupid). And, IPCC models have ever allowed for the magnitude of such impact (e.g. see, Rao, UR. Contribution of changing galactic cosmic ray flux to global warming, Current Science).

      As as we are informed about other possible impacts–e.g., areosols–that should be factored into GCM the conclusion is unavoidable that all of the CO2-based predictions of global warming as claimed by the IPCC to date are wholly erroneous.

  49. The idea that the minute human contribution to atmospheric aerosols is a driving force for the Atlantic Multidecadal Oscillation is lunacy. That the idea has been programmed in to a single climate model and when run, the model produces the pre-programmed output is par for the course, so nothing new there.

    Perhaps this is a test of the global panic-alarm system, to see how many media transmitters are still working. Only the most committed media outlets will run this, so it will serve as a gauge of support in advance of the next meeting of the global warning kleptocracy.

    • Paul Vaughan

      Andrew30 | April 12, 2012 at 12:05 am | wrote:
      “Perhaps this is a test of the global panic-alarm system, to see how many media transmitters are still working. Only the most committed media outlets will run this, so it will serve as a gauge of support […]”

      Excellent idea for an article.

  50. Was this ‘adjustment’ made to support the computer model?

    “Sea Level Data Corruption – Worse Than It Seems
    Posted on April 11, 2012 by Steven Goddard”

    “The graph below shows changes in Envisat Northern Hemisphere sea level made this week. Previously, sea level was decreasing -0.241 mm/year, and now it is increasing by 2.37 mm/year. The most recent data magically went from lowest on record – to highest on record.”

  51. Judith, Could you elaborate on the following paragraph you wrote:

    Without having time to dig up references, there is another important issue. Specifying aerosol characteristics (which is mostly done here, esp sulfate) and then allowing interactive cloud microphysics and optics results in an overestimate of the aerosol indirect effect, since compensating dynamics and precip don’t influence the aerosols. van den Heever and Stephens have a recent paper on this, but even more than 10 years ago Rostayn(sp?) was writing about this

  52. People might be interested to read Ben Booth’s comment on his paper and on Judith’s post here:

  53. Judith Curry writes:
    “The fortuitous agreement of the aerosol optical depth with temperature variability is serendipitous climate magic, almost certainly with circular reasoning buried deeply or not so deeply in the aerosol estimates”

    So in one highly uncertain area (aerosol indirect effects), you dismiss agreement as “fortuitous” and, without evidence, dismiss it as circular reasoning, and in general seem to confuse uncertainty with ignorance.

    And in another highly uncertain area (natural variability and oscillations), you accept apparent agreement as meaningful, and despite deep uncertainty, are convinced of its importance.

    It would help if you’d explain why you interpret these so differently, lest people think there is an inconsistent view of uncertainty underneath these statements.