What is the relationship between Arctic sea ice decline and Eurasian cold winters?

by Judith Curry

We conclude that the observed cooling over central Eurasia was probably due to a sea-ice-independent internally generated circulation pattern ensconced over, and nearby, the Barents–Kara Sea since the 1980s. — McCusker et al.

Published earlier this week in Nature Geoscience:

Twenty-five winters of unexpected Eurasian cooling unlikely due to Arctic sea-ice loss

Kelly E. McCusker, John C. Fyfe and Michael Sigmond

Abstract. Surface air temperature over central Eurasia decreased over the past twenty-five winters at a time of strongly increasing anthropogenic forcing and Arctic amplification. It has been suggested that this cooling was related to an increase in cold winters due to sea-ice loss in the Barents–Kara Sea. Here we use over 600 years of atmosphere-only global climate model simulations to isolate the eect of Arctic sea-ice loss, complemented with a 50-member ensemble of atmosphere–ocean global climate model simulations allowing for external forcing changes (anthropogenic and natural) and internal variability. In our atmosphere-only simulations, we find no evidence of Arctic sea-ice loss having impacted Eurasian surface temperature. In our atmosphere–ocean simulations, we find just one simulation with Eurasian cooling of the observed magnitude but Arctic seaice loss was not involved, either directly or indirectly. Rather, in this simulation the cooling is due to a persistent circulation pattern combining a high pressure over the Barents–Kara Sea and a downstream trough.We conclude that the observed cooling over central Eurasia was probably due to a sea-ice-independent internally generated circulation pattern ensconced over, and nearby, the Barents–Kara Sea since the 1980s. These results improve our knowledge of high-latitude climate variability and change, with implications for our understanding of impacts in high-northern-latitude systems.

Full access version available [here].

JC Comment:  John Fyfe sent me this paper a few weeks ago, I think it is very interesting.  I had hoped to have more time to write some comments on this, but unfortunately no time.  So I will put the paper out there for you to discuss.

116 responses to “What is the relationship between Arctic sea ice decline and Eurasian cold winters?

  1. Pingback: What is the relationship between Arctic sea ice decline and Eurasian cold winters? – Enjeux énergies et environnement

  2. Curious George

    The article makes references to the Canadian EarthSystem Model, version 2 (CanESM2; ref. 17), but the actual reference 17 seems to be something else. Probably a typo. I would appreciate a real reference.

  3. Interesting paper but difficult to read online, which is hardly the authors fault of course It is good that it IS online without charge as so many papers are pay walled

    . Has the author checked the hypothesis with the reduction in arctic sea ice in the 1920 1950 period? this period also suffered sea ice loss in the Barents-kara sea area.

    Also, does the observed cooling hold true for a wider area than central Eurasia?

    tonyb

  4. Arctic amplification is an illusion. The decline in indirect solar has increased negative NAO/AO, which is responsible for both the cold winters and the Arctic sea ice loss.
    Time to move on from the internal variability paradigm.

    • Time to get away from linear trend plus net-zero “oscillations” as a paradigm. That has been an unjustified a priori assumption for the last 30 years which perverted any objective analysis and wasted most of the enormous resources given to the endeavour.

      Starting by assuming the result has meant all effort has gone into trying to explain the deviations from the assumption rather than into investigating how the system works.

      • The net-zero assumption is based on the false premise that the oscillations are internal variability. The point is that increased forcing of the climate from due to solar or higher GHG’s increases positive NAO/AO, so the observed increase in negative NAO/AO since the mid 1990’s (apart from +NAO/AO around the last two sunspot maxima) directly indicates how little that rising GHG’s are doing in the face of declining solar factors since exactly then.

    • ulric lyons: Time to move on from the internal variability paradigm.

      What does that mean? Internal variability exists, but has not been completely characterized. I would say that it would be worthwhile to continue to study internal variability.

      • means he doesnt understand it, so he wants people to stop talking about it.

        its the sun you know.. its all the sun.. man is tiny. sun big. ugg ugg. must be the sun

      • means he doesnt understand it, so he wants people to stop talking about it.

        As opposed to not understanding it so it must be a unicorn?

      • Steven Mosher says:
        “means he doesnt understand it, so he wants people to stop talking about it.”

        That is exactly what has happened by calling the AMO and ENSO ‘internal variability’.

      • I think Ulric understands perfectly.

        If you ASSUME that all “internal variability” is a net zero “oscillation” and detrend it , you are by simple definition deciding that any and all “trend” is reserved for AGW.

        You impose the result before beginning the analysis. You already “know” what the trend is and are using some kind of wobbly Fourier-like decomposition to attempt to account for the wiggles.

        this is all the GCMs can do with their dozens of poorly constrained parameters, it’s kind of ad hoc multivariate regression where you fiddle with the parameters until you reasonably close fit to the calibration period and pretend that this has some objective validity.

        The only parameter you try not to move is the sensitivity to CO2 radiative forcing. Luckily you have plenty of other play with so that’s not a problem in an over-fitting exercise with far too many free parameters.

        That is the paradigm which needs to change.

      • The point is that Arctic warming is due to declining solar causing increased negative NAO, it is not *forced* warming. That’s why Arctic Amplification is an illusion. Stick that in your models.

      • Rising CO2 forcing is modeled to increase positive NAO/AO, yet it requires increased negative NAO/AO for the Arctic to warm.

        http://www.ipcc.ch/publications_and_data/ar4/wg1/en/ch10s10-3-5-6.html

      • ulrich
        Doea the earth climate system including oceans with 1000 year circulation, really need to be totally 100% passive and inert in order for your zodiacal climate astrology theory to be tenable?

        If you think climate is only changed by outside forcing then you will find the most like-minded crowd at skeptical science or real climate, or maybe hotwhopper.

      • Plotemy2, no, and it is ‘Planetary Ordered Solar Theory’.
        SkS and RC would love my ideas of why the Arctic is warming wouldn’t they just….

      • Steven Mosher

        Internal variations are net zero. Almost by definition.
        Since they ate unforced they can neither create nor destroy energy. The Smart skeptic question is are there long pseudo oscillations that masquerade as agw? Or where does one look for these. But Since Skeptics Deny The Very Validity Of HistoricAl Measurements. .they have nothing to contribute to the discussion.

      • Steven Mosher

        Ding dong who can’t find a paper thinks a gcm is like a regression.

        Oy vey

      • Steven Mosher: “means he doesnt understand it”

        As if you would know…

        PS For an English major, your grammar and especially knowledge of apostrophisation is atrocious, almost as bad as your understanding of mathematics, science and engineering.

        Perhaps you should think about going back to school?

      • There, we now have Mosher’s pontification, the matter must be settled.

      • Internal variations are net zero.

        Hmmmm….
        Glacials?

      • Steven Mosher
        Internal variations are net zero

        Well if our universe has enough mass density then its entire history from Big Bang to big crunch is also net zero. But to people living at certain times it doesn’t feel that way.

        For instance the ice cores at Antarctica and Greenland (green line) show that during the last glacial period there were many spikes of warming then cooling of 10 deg C or more over just a couple of centuries, real climate change. These violent excursions of climate would have been disruptive of human and animal populations and may explain why human societal development did not begin till the much more stable Holocene.

        The micro-interglacials were driven by internal climate variations. Specifically, the positive feedback loop of salinity-downwelling-Greenland ice melt which gives the AMOC its chaotic bistability..

        Nonlinear internal fluctuations of ocean driven climate are fractal and occur on all on all time scales. And as Lorenz showed in DNF63 they never arrive at amean. So in no possible sense can they be net zero.

      • Steven Mosher says: “its the sun you know.. its all the sun.. man is tiny. sun big. ugg ugg. must be the sun”

        If AMO variability is strongly solar forced, then deeming it without question ‘internal’ guarantees you’ll never understand it ugg ugg.

  5. I was not able to find the alleged free access version, all I can find in the abstract and S.I.

    However, the abstract is enough to see the major flaw : it is an in depth study of models that do not correctly reflect the climate, and especially sea-ice variability of the region.

    Models notoriously under estimated the extent of ice loss in the Arctic and did not anticipate the astounding increase in sea ice volume following the 2012 record minimum. They do not reproduce the cooling in question. End of story.

    Unless the models accurately reproduce historical climate in the region in question, there seems little point in going in to the details of what they have got wrong and inferring what will necessarily be spurious conclusions.

    The fact that only one of all the atmosphere only and ocean-atmosphere models produced the observed cooling simply tells you to stop there. They do not work. It is not the basis for inferring causality or lack thereof because they DO NOT work.

    “We have models that do not reproduce climate which we have used to prove that there is no linkage between Arctic sea ice extent and the cooling which they fail to reproduce”.

    There seems to be a glaring logical error here.

    Maybe it would make more sense if I had access to the full paper.

    • Alan Longhurst

      Not surprising you cant get it. Nature journals seems to have found a clever way to prevent authors from sending one a “pdf-reprint”. They can read what they send because their institutes are subscribers, but the recipients of the pdf cant open them. I’ve had several frustrated authors finally send me a preprint odf that had not passed through Natures hands.

      • many thanks for the explanation, I thought I was just not finding the proper link.

      • When I click on the link I get “redirecting to basic pdf” momentarily, then it delivers the abstract page at Nature geoscience.

        I also found a ReadCube link which says I need a “modern browser”. I have an up to date Firefox.

        My guess is that they are browser sniffing and if they do not detect some special plugin ( probably platform specific ) they redirect to the main journal website.

        Since they do not say what the requirement is the is little chance of being able to conform with it.

      • > When I click on the link I get “redirecting to basic pdf” momentarily, then it delivers the abstract page at Nature geoscience.

        If you want to get help, that’s better.

        ***

        > Since they do not say what the requirement is the is little chance of being able to conform with it.

        That misunderestimates the power to diagnoze and think things through.

        Here’s your chance.

      • Hey, I’m not going to go into hacker mode to try and understand exactly how useless they are a putting a user interface together.

        Since you clearly have no idea and I have already got a copy from elsewhere thanks to someone willing to help rather than snipe, I guess it’s : end of story.

      • > I’m not going to go into hacker mode

        You overestimate the challenge you are facing, GregG:

        http://lmgtfy.com/?q=firefox+nature+readcube

        Tell me what’s your first hit.

    • I could get it from two different computers and two different IPs.

      End of story.

      • Willard has a copy , whoopee!

        No one else in the world needs a copy now, Williard has it.
        End of story !

      • Greg can’t figure it out. No one else in the world can. No one else will ever will.

        End of story.

      • So why is the fact that you managed to get it on different IPs, “end of story”?
        What was that smart alec comment actually supposed to mean?

      • > So why is the fact that you managed to get it on different IPs, “end of story”?

        For the same reason you could end your first smart alec comment with “end of story,” GregG.

        Here’s a pro-tip – if you want to get help, don’t act like a smart alec.

      • Three computers and my phone… No problem… Goodman is a clown

      • and Mosher’s a fool because he thinks everyone has the same phone as him and if they don’t they’re ” a clown”. Grow up.

        There is clearly a browser/plugin issue. That’s not hard to figure out.

        I thought you slightly more intelligent that Willard but apparently not.

      • Steven Mosher

        Now..Greg sees a clear problem. ..too funny.

        First he attacks. Then he is shown to be wrong.
        Then he beclowns himself. .

        Must be an EE.

      • Steven Mosher

        Second phone. 4th computer.

        Maybe greg has an amiga.

      • Steven,
        Skeptics would love amigas – the OS was called ‘Intuition’ after all.

      • It’s all a ghastly conspiracy.
        Trust no-one :-)

    • It’s being made available through Nature’s protected viewing system. My guess is that their system doesn’t work on all browsers. But it’s available as a standard downloadable PDF on sci-hub via the doi: 10.1038/ngeo2820. (Without the final period.)

      • Thanks AK, that did it.

      • Yr welcome. In general, the DOI can be found on the abstract page (as of today), so the easiest way to get a copy of a paywalled paper is to go straight to Sci-Hub. But it’s also possible to search Google or Google scholar using the title, or a snippet of the abstract that looks unique. Often somebody else will have put a copy up.

        If none of those work, sometimes (usually for older papers) you can find an open-access paper that references it with a link that will let you in. (I’d call this method deprecated, lots of publishers have stopped using such links.)

      • AK, thank you for the link.

    • Models notoriously under estimated the extent of ice loss in the Arctic and did not anticipate the astounding increase in sea ice volume following the 2012 record minimum. They do not reproduce the cooling in question. End of story.

      The atmosphere-only model setup incorporates prescribed sea ice from observations, so these models by definition don’t underestimate sea ice loss.

      The fact that only one of all the atmosphere only and ocean-atmosphere models produced the observed cooling simply tells you to stop there. They do not work. It is not the basis for inferring causality or lack thereof because they DO NOT work.

      It seems like you don’t really understand the nature of these models or of the Earth system. The question is whether there is a deterministic nature to this Eurasian Winter cooling, or if it is simply normal “chaotic” variability. If it is normal variability there are so many different possible patterns of variability that, probabilistically, we would not expect a model to reproduce the same pattern as observed very often. It absolutely does not suggest they don’t work.

      For me, I think some context is missing from the discussion. This plot shows historical Central Eurasian Winter temperatures – observed against CMIP5-mean, smoothed using simple 11-year running means. The cooling under discussion is the one you can see from the 1990s to around 2010. As can also be seen, the start point for this trend is a massive warm spike, way above that expected from the forced response alone. To me it seems like a strong cooling trend was statistically inevitable.

    • Zero problems finding the paper.

      Also, the models work just fine.

      and even when they dont they are still of use.

      someday you’ll get it. or publish a contrary result.

      • Well, it doesnt load for me. But it is nice we have ‘hackers’ who obviously can load it legally or illegally. So nice. Just if they’d grow up.

        I’m pretty much fed up with loading papers from some random darknet source. Given how much tax money is used to make the science in the first place, it shouldnt be that way.

        I’m sure there is a nice word of Willard, I just can’t come up with any right now.

      • > Given how much tax money is used to make the science in the first place […]

        How much of your tax money funds the science, wert?

        How about Nature?

        ***

        > it shouldnt be that way.

        Agreed – browsers should have worked out how to render HTML5 seemlessly by now. Yet they don’t.

        Not that this has anything to do with your tax money.

        ***

        Not so far ago, teh Donald kept using the “our tax money” line.

      • loaded legally. Chrome Browser.

        But here is the point.

        Rather than Assume that He might have done something wrong
        or rather than just asking for help.

        greg attacked.

        not a good skeptic.
        fooled himself

  6. figure 10 in the SI shows a scatter plot of model results and the observational data point. The observation is totally outside the range of model results.Surrounding text says:

    Similarly, regression maps computed using the CESM ensemble (Fig. S10b-e) are similar to those using the CanESM2 ensemble (Fig. 4 in the main text). We conclude that our findings are reasonably model independent.

    Conclusion none of the models produce useful output of these parameters.

    The proper conclusion from this is that the models to not work and are of no help in assessing the presence of absence of any possible link between Arctic sea-ice coverage and Eurasian SAT.

    • > The proper conclusion from this is that the models to not work[.]

      To “not work” fails to capture what the authors tried to do: to investigate whether our AOGCM results are model dependent

      End of story.

      • There is nothing in the title nor the abstract which states they were investigating model dependence. They were investigating whether the temperature was related to ice coverage and that was the subject of their conclusions.

      • > There is nothing in the title nor the abstract which states they were investigating model dependence.

        It’s in the first sentence of the paragraph you declared was end of story, GregG:

        To investigate whether our AOGCM results are model dependent […]

        The onus is on you to argue that your reading of their quasi-experimental setup invalidates their rejection of the sea-ice hypothesis.

        In fairness, you could argue that the authors may go a bridge too far by speaking of AGCM experiments.

      • Willard, he cant follow instructions on how to get a paper. You expect him to understand the English therein once he is helped tying his shoes?

        Plus he has a bot like argument

        If post contains the the word model, then spew ” models dont work”

        Easy peasy.

  7. “we use over 600 years of atmosphere-only global climate model simulations” Yeah, who could argue with 600 years of model simulations considering how well climate “scientists” have done with other models. What are the proxies for 600 years ago… more tree rings???

  8. Looks like more toy computer models being used in lieu of actual science, based on hypothesis, experiment . . .

    Even New Scientist agrees “criticism is the backbone of the scientific method”.

    Trying to criticise the output of purpose built toy computer models makes about as much sense as trying to criticise the number 2.

    This is science?

    Cheers.

    • err no.

      the question is simple.

      you have a one off event — the last 25 years.

      you try to explain it.

      Its like when a plane flys into the twin towers. and some skeptical clowns like you suggest that the buildings could not collapse.

      We dont go out and fly more planes into buildings.

      We use the best tools ( simulation) to show that what we observed
      ( the buildings came down) is consistent with what we see in simulation.

      But then again you are the Flat Earth Flynn and there is no reasonaing with folks who deny GHG, who deny believe the earth is flat, and that planes cant take a skyscraper down

      • Steven Mosher,

        You can’t provide a falsifiable hypothesis suggesting a mechanism to explain the so-called greenhouse effect. No one can, because anyone who tries to do so realises how ridiculous they appear. Care to try yourself?

        Your witless and irrelevant analogies, coupled with near incoherent comments on occasion, are a fair example of the GHE crew’s attempts to deny, divert, and confuse, when faced with facts.

        The Earth has cooled for four and a half billion years or so. Until the interior becomes isothermal beyond the influence of the Sun, it will continue to do so.

        Deny all you like, but facts are facts. Believe or don’t believe – the choice is yours.

        Cheers.

      • “We use the best tools ( simulation)”

        Which for a number of reasons – all of which have been explained to you on innumerable occasions – are about as helpful for analysing historical and projecting future climatic states as a stone axe for adjusting a Swiss watch.

        As to pathetic accusations of denying GHG and 9/11 trutherism, just about the biggest climate science denier on this or any other blog is YOU, by a very considerable margin.

        Things have come along a bit since the pre-pause era, Mosher.

        Live with it.

  9. Prof Curry, the paper can be read at the link that you provided, but not downloaded. Still, thank you for the link to the paper.

    Here we use over 600 years of atmosphere-only global climate model simulations to isolate the eect of Arctic sea-ice loss, complemented with a 50-member ensemble of atmosphere–ocean global climate model simulations allowing for external forcing changes (anthropogenic and natural) and internal variability.

    I suppose that matters to people who have high confidence in the accuracy of the models. I respect the models and the modelers, but I think that the models need much more work and testing before the results are relied upon for more than more modeling and research.

    • “I suppose that matters to people who have high confidence in the accuracy of the models.”

      Not really.

      The goal is simple. Evaluate the hypothesis about the last 25 years
      using the best tool you have..

      Basically they find the hypothesis isnt consistent with our best understanding.

      Its EXACTLY what GCMS were designed to do..

      • Steven Mosher: Not really.

        You mean it does not matter to people who have high confidence in models?

        Its EXACTLY what GCMS were designed to do.

        I don’t disagree. The models need more work.

      • “Its EXACTLY what GCMS were designed to do..”

        And the Ford Edsel was EXACTLY designed to take the car market by storm…

        We all know how that worked out.

      • Its EXACTLY what GCMS were designed to do..

        Yes, ironically, GCM spaghetti indicates a huge range of possible.

        The spaghetti is natural variability, all of which is possible, even with constant CO2.

  10. Here we use over 600 years of atmosphere-only global climate model simulations to isolate the eect of Arctic sea-ice loss, complemented with a 50-member ensemble of atmosphere–ocean global climate model simulations allowing for external forcing changes (anthropogenic and natural) and internal variability.

    Why would climate researchers use atmosphere-only climate models when we live on an atmosphere-ocean system (i.e. Earth)? That’s like projecting how many mansions I’d be capable of owning if I won the lottery rather than relying on the meager salary I currently earn.

    • Why?

      It’s called an experimental control

      Here is the QUESTION:

      “Surface air temperature over central Eurasia decreased over the past twenty-five winters at a time of strongly increasing anthropogenic forcing and Arctic amplification. It has been suggested that this cooling was related to an increase in cold winters due to sea-ice loss in the Barents–Kara Sea.”

      1. Observations indicate a COOLING over central Eurasia. WHY?

      A) Hypothesis: “Its the ICE LOSS DUMMY!!”

      Well how do we go about testing that ? Just HOW?

      Can we go back in time… and re run the EARTH like it was a lb experiment? And run the earth 100 times with ice loss and 100 times with no loss? NOPE we CANNOT because we LIVE IN THE FRICKING BEAKER.

      So, that leaves Two options if we want to increase our understanding.

      A) Historical studies
      B) simulation

      For A we would to find MULTIPLE PERIODS of low ice in the area.
      We dont have that data.
      That leaves B

      Simulation.

      What can simulation do?

      It can tell you that the the hypothesis– Hypothesis: “Its the ICE LOSS DUMMY!!””— Is INCONSISTENT WITH or CONSISTENT WITH our
      best, albeit flawed, understanding of the climate (GCMS)

      That’s it.

      simple.

      • GCMs are by no means our best understanding of the climate.

      • > GCMs are by no means our best understanding of the climate.

        Indeed, and hammers are by no means our best understanding of kynetic energy.

      • Thx Mosh, for explaining the logic.

        Wojick interjects: “GCMs are by no means our best understanding of the climate.”

        Ok. I’ll bite. What is (or embodies) our best understanding of the climate?

      • Jim, it is embodied in the scientific literature, including blogs like this one. Much of this understanding is simply ignored by the GCMs, some of it deliberately. In some ways the GCMs are our worst understanding.

        Keep in mind that “our” includes hundreds of thousands of people.

      • The dominant feature of climate change science is that we understand so little. It is therefore hard to see how the idea of our best understanding is even meaningful. Or our best understanding is that there is a lot we do not understand. I do not see how a computer program can embody this fact.

      • > The dominant feature of climate change science is that we understand so little.

        The stoopid modulz can’t even implement our own ignorance.

        Lulz.

      • Guesses are not understandings. And there is no understanding when people disagree.

      • > Guesses are not understandings. And there is no understanding when people disagree.

        There are still people to disagree about the theory of relativity, DavidW, and pointing at the Internet suffices to generalize your claim: people disagree about everything, therefore there is no understanding.

      • “GCMs are by no means our best understanding of the climate.”

        Sorry Wrong.

        And you think BLOGS understand the climate?

        OK.

        using your trees please explain what the best science says

        about the QUESTION AT HAND.

        the last 25 years of cold eursasia.

        Caused by ICE loss: yes or no.

        Cite your evidence. show your work

      • “If you had to readjust the constant in Newton’s law of gravity every time you got out of bed in the morning in order for it to agree with your scale, it wouldn’t be much of a law   But in finance they just keep on recalibrating and pretending that the models work.”
        https://www.scientificamerican.com/article/finance-why-economic-models-are-always-wrong/

        Something like you can get the model to match the historical past or present with different initial conditions. Say the GMST was 15 C. You can reach that with over and over again with different equations and different initial conditions. You could reach it with predominant positive or negative PDO and ENSO.

        One may say I have argued the GCMs are spun up. That gives us time zero with acceptable stability. Time zero of 15 C can consist of a near infinity of different inputs including both drought and flooding in 75% California. With both high and low sea ice in the North.

        I think that the more complex economic models all fail over time. I reason backwards from the result that is not obtained. If I had a good enough model, I would eventually have all the stock market’s money. Does Warren Buffet have such a model? I don’t know. He does not have all the money and feels the need to offer his product to me, and yes I have some Berkshire Hathaway stock, but not a lot. I mostly use low cost index funds. So I am not betting on economic models but if I am they are quite simple ones. Gas at $1.60? Buy a bit of ExxonMobil. Predominantly buy and hold.

        What is going on with the financial industry? Movement away from smart brokers to low cost index funds. The rejection of expertise. Are we all mad? We are voting with our money, but not on complex economic models.

        What have complex economic models and derivatives given us? Creating and trading derivatives has had some bad results. My own city got sucked into that deal not too long ago. I would suggest derivatives are partly the result of complex economic models. Learning is good yes, until the whole thing crashes and 1/3 of your money is gone while everyone else still has 90% of their money.

        Economic models ought to give is prosperity all the time. It’s just math. All countries ought to have prosperity if they just use our models.

      • I’m very suspect of model dependent research, but I agree with Mosher and Willard on this one. You can take the results with a huge grain of salt if you want, but no need to dismiss out of hand.

      • With a little more thought, compare sophisticated economic model with climate models. Who is buying them? With the change from financial experts to low cost index funds we have the case of the money knows. It devalues experts opinions. Money is being spent on GCMs I suppose mostly by large governmental or near governmental entities. Compare this to Lockheed Martin spending on models for products they hope to sell. So the question is, who wants to buy GCM model output? Where is the market demand? What do we get for our money? If it’s done by a governmental entity, the money often loses its power to point to truth as it does in the financial case. That truth being that sophisticated economic models have little value when compared to simpler models. Do insurance companies buy GCM output? The money knows. It knows value. I mean aren’t they the expert risk assessors dealing in markets? We think we know that shorter term models have a market being able to predict at times the weather 3 months out. When do we see capitalists spending their own money on GCM output?

  11. Dear AZ1971, This study utilises atmosphere-only and atmosphere-ocean experiments. The atmosphere-only experiments are designed to isolate the impact of observed Arctic sea-ice loss alone.

  12. > It has been suggested that this cooling was related to an increase in cold winters due to sea-ice loss in the Barents–Kara Sea.

    The source for that suggestion is harder to find than it need be.

    Also, “it has been suggested” is a little vague – it stops short of telling what’s the current understanding.

    That the latest citation in the 7-12 set is dated 2013 looks fishy to me.

    What would be the prime suspect for the circulation change?

  13. I’m not criticizing this paper it seems legit and logical. Funny thing is it seems to support Popes climate theory LOL.

  14. Twenty-five winters of unexpected Eurasian cooling unlikely due to Arctic sea-ice loss

    I fail to see the rationale for the question that triggered this research, perhaps because I don’t know enough of it.

    Water in the Arctic is significantly warmer than the air, specially during the winter night. Less sea ice during the winter means more water surface exposed and therefore more heat (and humidity) lost to the atmosphere. Although it could lead to more snow, I fail to see how it could lead to cooling in Eurasia.

    • Dear Javier, The previous evidence suggested that the heat anomaly associated with the sea-ice loss (that you refer to) generated an atmospheric circulation feature which in turn transported relatively cold air from the Arctic to Eurasia. The McCusker et al. paper shows, however, that this sea-ice-loss-induced circulation feature is to localised to explain the Eurasian cooling.

      • No, it does not such thing because the models do not ( with one exception ) even produce the cooling they want to examine.

        So if your models do not produce the feature they can’t tell you squat about why it is or is not there.

        There is an inherent assumption that the models do represent the real world in getting to the conclusion they draw.

        Until you establish that the models you wish to refer to accurately produce the historical climate at a regional level in both the parameters in question you have no basis to go any further.

        In the case of A-only models you have to establish that they respond correctly the sea-ice changes and produce valid regional level pattern of response to that forcing.

        The first thing I would expect to see is a graph of the GCM output for BKS sea ice compared to observations. When instead I see them comparing two dots made from decadal averages at each end it seem likely that that graph does not look too convincing.

      • Dear Greg Goodman,

        In this problem one can validate that the model reproduces the observed co-variability between annual anomalies of BKS ice and Eurasian surface temperature. This has been done. One cannot, however, validate that the model reproduces the observed co-variability between 25-year trends. This is because we only have two non-overlapping observational trends of 25-year length. Hence the necessity of using a climate model wherein many independent realizations can be obtained (given a sufficient computing resource).

        Greg, I agree that this not a perfect situation but it is reality until such time we have several hundreds of years of observations to work with.

        If you believe that Arctic sea-ice loss is responsible for the recent period of Eurasian cooling then you can do as the authors of this paper have. And that is: 1) apply for a grant (through a very competitive process), 2) work hard to recruit a top-notch postdoctoral fellow, 3) work for 2-3 years designing, executing and analyzing many model simulations and all available observations, 4) submit a paper to a high-impact journal and go through a lengthy and stringent review process. Short of that it’s all just speculation.

      • I see. Thank you for the explanation, JF.

        I would think that warmer air would rise and that would cause air from surrounding areas to move in, not the opposite, but clearly this a too simplistic view of atmospheric circulation to be of much value.

        For what I know cold winters in Eurasia are due to the blocking of the Siberian High more often than to polar vortex. I am sure somebody has looked at how the Siberian High has done for the past 25 years.

        One final note is that if you have 25 years of something unusual, I would not call it unusual, but the new normal. After all we live in a planet that has a strong desire to cool, since obliquity is falling at its fastest pace in 40,000 years and northern summer insolation is very low. Not precisely the kind of conditions that give reassurance that Winter (with capital W) is not coming.

      • One cannot, however, validate that the model reproduces the observed co-variability between 25-year trends.

        Before worrying about the “covariability” how about just checking whether they get ice coverage closer than just going in the right direction? Like I said the studious way in which they avoid any clear, direct comparison probably speaks volumes about that.

        As for the validation of co-variability, the graph SI 4a showed that the observed variables were totally OUTSIDE all the model derived values.
        If you consider that to be validation of the models you are very generous.

        Using comparison of the annual cycle to infer whether decadal scale change is correct has no validity either, so that is a red scarf trick anyway.

        If you believe that Arctic sea-ice loss is responsible for the recent period of Eurasian cooling

        I don’t have any “beliefs” one way or the other and never even offered an opinion about that. Neither do I believe a models otutput until I see it give consistently accurate results over a statistically significant number of runs.

        … submit a paper to a high-impact journal and go through a lengthy and stringent review process. Short of that it’s all just speculation.

        Even if I did that, it would remain speculation. However, there does seem to be good living to made out of publishing speculation.

        This paper’s conclusions rely on an unstated, implicit assumption that the models realistically reproduce the relevant features of the real climate, without which the results are groundless.

      • In principle I don’t disagree with anything you’ve said here. You do though sound, to my ears at least, overly sure of yourself. Also, I’m not certain that you have a complete grasp of the paper and the motivation for it.

        There exists the widespread notion that Arctic sea-ice loss has impacted mid-latitude weather and climate. In many cases the evidence for this is an extrapolation of a relationship that exists from year-to-year to one that may, or may not, exist from decade-to-decade. To investigate the latter the authors of the present paper employ a climate model which enjoys a very close agreement to observed trend in Arctic sea-ice extent, as well as to the observed inter-annual variability.

        Beyond this I don’t know what I can say, except perhaps that I’ve enjoyed the discussion. — JF

  15. From the paper –

    “We conclude that the observed cooling over central Eurasia was probably due to a sea-ice-independent internally generated circulation pattern ensconced over, and nearby, the Barents–Kara Sea since the 1980s.”

    Translation from Warmese –

    Cooling has been observed. The toy model results are worthless, but we’ll claim this improves our knowledge of climate variability, anyway. With any luck, nobody will realise we get taxpayers’ funds to play computer games. Ain’t life grand!

    Cheers.

  16. “Abstract. Surface air temperature over central Eurasia decreased over the past twenty-five winters”

    Decreased?
    Eurasia is really big.
    So where is the warming part of global warming taking place?

  17. Judah Cohen would disagree….

    http://web.mit.edu/jlcohen/www/papers/Cohenetal_NGeo14.pdf

    “In September and October, sea-ice loss has been most pronounced
    in the Chukchi and East Siberian seas. Warming of the
    atmosphere due to increased heating from newly ice-free ocean
    causes geopotential heights to increase in the mid-troposphere,
    which suppresses the jet stream southward over east Siberia. This
    pattern, referred to as the Arctic Dipole, has strengthened during
    the era of sea-ice loss61. A southward shift in the storm tracks over
    East Asia allows for a more rapid advance of Eurasian snow cover
    in October. Enlarged areas of open water north of Siberia also provide
    increased moisture flux to the atmosphere, which precipitates
    as snow as the air mass is advected southward over Siberia58,71 (left
    globe in Fig. B2).
    In October, a more extensive snow cover cools the surface leading
    to lower heights and a trough in the mid-troposphere. Increased
    troughing over East Asia favours upstream ridging near the Barents
    and Kara seas and the Urals. Concurrently, the large sea-ice deficits
    and the associated strong surface heating anomalies migrate from
    the Chukchi and East Siberian seas in September and October to
    the Barents and Kara seas in November and December. This favours
    mid-tropospheric ridging in the Barents and Kara seas region with
    downstream troughing over East Asia. Therefore, the extensive
    snow cover over Siberia in October and November and the sea-ice
    loss over the Barents and Kara seas in November and December
    produce same-signed mid-tropospheric geopotential height patterns
    over Eurasia. This planetary wave configuration is favourable
    for increased vertical propagation of Rossby waves from the
    troposphere into the stratosphere98–100 (middle globe in Fig. B2).
    Increased vertical propagation of Rossby wave energy from the
    troposphere to the stratosphere weakens the polar vortex, resulting
    in a stratospheric warming event. Circulation anomalies associated
    with the warming event appear first in the stratosphere and subsequently
    appear in the troposphere in January and February. These
    circulation anomalies resemble those associated with the negative
    phase of the NAO/AO; that is, ridging over the Arctic especially near
    Greenland, and a weaker, equatorward-shifted polar jet stream. As
    a result, warmer conditions prevail in the Arctic regions, but colder
    and more severe winter weather occurs across the mid-latitude continents
    with a greater likelihood of snowstorms in the population
    centres of the Northern Hemisphere mid-latitudes (right globe in
    Fig. B2)”

    Latest ideas/analysis:
    https://www.aer.com/science-research/climate-weather/arctic-oscillation

  18. This study puts climate science in danger of falling into the morass of the reproducibility crisis affecting other branches of science such as psychology and biosciences:

    https://en.m.wikipedia.org/wiki/Replication_crisis

    One theme to emerge in this crisis is that biotech cell and molecular genetic studies are very sensitive and unpredictable, subject to unknown sources of internal variability. As a result, scientists have been caught – or have even admitted – the practice of running experiments several times and selecting for publication the “run” that gives the most pleasing result.

    The study in this article looks like a similar practice – dozens of simulations and one or two seized on for giving the right result. This is not where science should be going.

    • BTW “unknown internal variability” – sounds familiar, another thing biological system and the climate system have in common.

      • Well the sun has always been there I guess. Interesting article, I also think neural networks are an under-utilised resource in research. However, the very first forward prediction of Per Strandberg (curious surname – how can you have a beach on a mountain?) is likely to be wrong – the ENSO conditions appear to be heading for weak La Nina or just below neutrality, not a strong La Nina.

        The peleton of solar/astrophysics cyclists in the climate debate make the same mistake as the CO2 crowd, that is to assume the climate system is passive and only changes due to outside forcing. This is nonsense. Ocean circulation is the primary driver of climate. External forces only affect climate insofar as they entrain oceanic oscillations, such as by weak nonlinear periodic forcing.

    • Nothing to blame this paper for, climatologists invented the morass decades ago so they one to jump into.

  19. Curious George

    I wonder why eurasian cold winters? American winters have been pretty cold lately.

    • Dear Curious,
      Please see this article in this months issue of Nature Climate Change: http://www.nature.com/nclimate/journal/v6/n10/full/nclimate3069.html.

      • Curious George

        From your abstract: “The North American continent generally experienced a cooling trend in winter over the early 2000s. This cooling trend represented a significant deviation from expected anthropogenic warming and so requires explanation.”

        So cold eurasian winters have one explanation, and cold north-american winters are caused by something else. This may be true, but it leaves me with an unpleasant feeling.

      • Unpleasant feeling? Well that suggests that you should be less curous, George.

        Seriously, the argument in either region is the same – a relatively rare episode of internal variability.

  20. Forget global climate simulations, they have not worked since Hansen started the cult in 1988. If I understand correctly those cold winters and sea ice decline you speak of were simultaneous which rules out a common cause. Talking of strong anthropogenic warming is non-sensical because demonstrably carbon dioxide does not cause any warming. That follows immediately from the observation that none of the warm peaks in the global warming history have ever had a counterpart in the Keeling curve that monitors atmospheric carbon dioxide. As to the sea ice decline, it started at the turn of vthe twentieth century when the North Atlantic current system was reorganized such that the warm Gulf Stream water floating on the surface was pointed more directly into the Arctic Ocean. Spielhagen et al. [1] took an Arctic excursion there and measured directly the temperature of the Atlantic water entering the Arctic Ocean. They reported that this temperature exceeded anything seen in the Arctic within the last 2000 years. The original change of currents was not entirely smooth. Warming started at the beginning of the century but switched back to cooling by 1940. The cool phase lasted thirty years but by 1970 the warming was back and has been active ever since. I would put that stretch of cooling down as a temporary return of the original pattern of North Atlantic currents. All reports of Arctic warming date from after this turnabout and give you no inkling of what happened before. Actually, nothing happened for 2000 years before the twentieth century arrived, except for a slow, linear cooling. We must remember, however, that what nature has done it can do again. A return of a similar cooling is not out of the question and it could cause problems with Arctic transportation and development.

    [1] Spielhagen et al. Science, 331:450-453
    (28 January 2011)

    For more information read: Energy & Environment, Volume 22, Issue 8, Page 269.

  21. The exclusion of internal variability is done because of bias towards a planet that can only be made to vary from an outside source. Which boggles the mind. This external driver thinking has been debunked time and again. The planet is highly variable and will continue to be so. The very shape and positioning of our continents as they currently are positioned are momentary snap shots. The oceanic currents we now follow are momentary snap shots. Those who constantly seek an outside driver, as well as those who constantly point to human pollution drivers cannot see past the membrane on their eyeballs, yet alone their noses, as they look elsewhere to explain every up and down of the past 100 years plus, and go on to make some kind of prediction on these unproven implausible speculations going forward.

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