Yet another study illustrates that the Medieval Warming Period was not regional, but global

Michael Mann and his team of data manglers like-minded scientists like to tell us the Medieval Warming Period was just a “regional” event rather than global, because if it was global, that destroys their narrative. This new study shows it also occurred in South America, and adds to the growing body of southern hemisphere locations. as we can see in this map below, note the red markers where it was warmer than normal. Sure seems global to me.

Climate reconstructions of the ‘Medieval Warm Period’ 1000-1200 AD. Legend: MWP was warm (red), cold (blue), dry (yellow), wet

Interactive map source: https://www.google.com/maps/d/u/0/viewer?mid=1akI_yGSUlO_qEvrmrIYv9kHknq4&ll=18.92594518076072%2C-12.335967063733051&z=3

Preindustrial climate change in South America: the Middle Age was warm, glaciers shrank

By Dr. Sebastian Lüning and Prof. Fritz Vahrenholt
(German text translated/edited by P Gosselin)

The climate of the Middle Ages is still a mystery. In many parts of the world a warming period occurred, which can still not be satisfactorily simulated by the current climate models.

The problem: natural climate factors play almost no role in the models.

It is therefore all the more important to first carry out a proper mapping of the climate for this important period. A research group led by Sebastian Lüning has presented an overview of the medieval climate in South America and now appears in the journal Quaternary International.

Here the scientists summarized a large number of case studies of the entire continent. The climate archives included pollen surveys in lake sediments of the Andes, which documented the rise and drop of the tree line.

Other studies reconstructed the oscillating shrinking and growth of Andean glaciers or dealt with tree rings. As a result, Lüning and his team found that the vast majority of the 76 individual studies indicate warming during the early 2nd millennium. The Medieval Warm Period was also strongly represented in South America. Exceptions were some coastal waters, where increased buoyancy of cold water led to a cooling.

Full story here


Here is the paper:

The Medieval Climate Anomaly in South America

SebastianLüning. Mariusz Gałka, Florencia Paul, Bamontec Felipe, GarcíaRodríguezd, FritzVahrenholte

The Medieval Climate Anomaly (MCA) is a climatic perturbation with a core period of 1000-1200 AD that is well-recognized in the Northern Hemisphere (NH). Its existence in the Southern Hemisphere (SH) and the level of synchronicity with the NH is still a matter of debate. Here we present a palaeotemperature synthesis for South America encompassing the past 1500 years based on multiproxy data from 76 published land and marine sites. The data sets have been thoroughly graphically correlated and the MCA trends palaeoclimatologically mapped. The vast majority of all South American land sites suggest a warm MCA. Andean vegetation zones moved upslope, glaciers retreated, biological productivity in high altitude lakes increased, the duration of cold season ice cover on Andean lakes shortened, and trees produced thicker annual rings. Similar MCA warming occurred in coastal seas, except in the year-round upwelling zones of Peru, northern Chile and Cabo Frio (Brazil) where upwelling processes intensified during the MCA due to changes in winds and ocean currents. MCA warming in South America and the NH appears to have occurred largely synchronous, probably reaching comparable intensities. Future studies will have to address major MCA data gaps that still exist outside the Andes in the central and eastern parts of the continent. The most likely key drivers for the medieval climate change are multi-centennial Pacific and Atlantic ocean cycles, probably linked to solar forcing.”

 

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190 thoughts on “Yet another study illustrates that the Medieval Warming Period was not regional, but global

  1. Does it really matter if the MWP was global or regional?

    The fact is, ‘regional’ man didn’t simply survive the period of extra warmth, he flourished during it. It demonstrates that warm is better than cold.

    It also rather demonstrates to me that CO2 has little to do with temperature change as, presumably, CO2 levels would likely have been around the same levels across the planet.

    If warming were regional, how could consistent atmospheric CO2 affect one area and not another?

    • If it was global, it would break (as in falsify) Mann’s hockey stick graph. It was in the early IPCC reports, then in the climategate emails they said it had to go away to protect the narrative, and it did, and out came the hockey stick. But the evidence around Greenland and area was too strong to ignore, so they started claiming it was regional.

      There’s lots of other studies showing it is global, this is one of many. I think C3 has a whole bunch of them archived.

      • davidmhoffer

        I get all that. What I’m saying is, who cares whether it’s regional or otherwise, humankind has demonstrated its ability to thrive during periods of higher temperatures, so what’s all the big deal with another 0.5ºC in the next 12 years?

        I know, it’s pseudo scientific fodder for the MSM, the point I’m trying to illustrate is that instead of picking a fight with Mann, simply tell the public the truth, higher temperatures have been demonstrably good for humans.

        It seems to me the debate over its regional or global status of the MWP is academic, in that, scientists are determined to expose Mann as a fraud to the scientific community, whilst the public doesn’t give a fig.

        • Problem is, Mann and his ilk are in charge of what “Truth” gets put out to the media and thereby the public. With the media being firmly entrenched in the Mann’s jock strap, it is difficult to publicly alter the narrative

          • Bryan A

            Trump did pretty well without the MSM. Still is doing well without them, indeed, despite them.

            There’s more than one way to skin a cat and Twitter/Facebook etal are incredibly powerful assuming some simple messages can be created.

            All the man in the street is looking for are some withering one liners to put down their alarmist mates.

            Sceptics need to stop trying to win the scientific debate, it’s unwinnable until we descend into another ice age with CO2 still rising. Even then the alarmists will call it a ‘blip’.

            Mann’s hockey stick is a case in point. Whether or not the MWP was global or not is academic, the fact is it happened, regionally or otherwise and mankind flourished. Proof positive that global warming is not only survivable it’s entirely beneficial.

          • HotScot:

            “sceptics need to stop trying to win the scientific debate.”

            Doesn’t it seem paradoxical (to put it mildly) that we should be incapable of winning a debate when the other side has literally zero scientific evidence confirming their hypothesis?

            Shouldn’t that be the easiest thing in the world to win, in theory?

            How do you explain this bizarre impasse?

            I agree with your agreement with my ‘deride and conquer’ doctrine, however. I think you’re right to endorse what I’ve always advocated. Of course, that’s just my opinion. On the other hand I do think I’m right to opine it.

            Brad

            PS how do you know we haven’t ALREADY won the scientific debate? What is your victory condition?

          • “when the other side has literally zero scientific evidence ”

            That’s because they aren’t using science to win. They’re using emotional appeals, threats of disaster and appeals to authority. The work to prove Mann was wrong simply misses the point on all of these. At best it’s an attempt to undercut the appeal to authority of a single activist (note, not scientist). But it is still almost completely ineffective.

          • Doesn’t it seem paradoxical (to put it mildly) that we should be incapable of winning a debate when the other side has literally zero scientific evidence confirming their hypothesis?

            Who is “we”?

          • jim hogg

            The past is a moveable feast. The more we learn, the less we understand.

            Scientifically of course that’s nonsense. In practical terms, however, the more data there is the more confusing the subject, especially when there’s debate about even the sources of the data. Mann’s hockey stick is a case in point. The source data for his theory is being questioned, no one cares any more about the conclusion.

            So there we have it. Scientists spiralling down the hole of their own navel in search of an unattainable truth because thanks to science itself there is too much data to analyse.

            Climate change will never be concluded because it is inconclusive. And if the conundrum of atmospheric change seems challenging, just wait until we address the oceans influence, seriously, and begin to examine what the hell goes on down there.

            Climate change will seem like a children’s puzzle compared to that.

          • Bryan A,

            There is no “Mann and his ilk.” Mann is one scientist. There are thousands of climate scientists out there, very different from each other. The vast majority of them are not advocates.

          • Kristi, the IPCC bought into Mann’s exercise in computer programming. Claiming he has no major influence is preposterous.

          • Brad Keyes,

            “… the other side has literally zero scientific evidence confirming their hypothesis?”

            This is exactly why some people call skeptics, “deniers.”

          • Tom Halla,

            “Kristi, the IPCC bought into Mann’s exercise in computer programming. ”

            I’ve no idea what you mean by this.

          • As in factor analysis is a rather woo-woo exercise in statistics, using a computer program to do factor analysis made it even more obscure to anyone who did not note the lack of real data behind Mann’s bit of sagecraft.
            If it had remained his analysis of tree ring proxies for temperature, his readers would have a better idea of what he was claiming. Instead, he ran a group of proxies for temperature (if they actually were) through a factor analysis program, and produced a single chart with no error bars. Just how much it depended on one tree is something that is hotly disputed.

          • The only thing that signifies ‘winning’ within this climate circus is politically-winning power, on the basis of using cyclic noise blips as their ‘evidence’.

            It has nothing to do with science.

          • Kristi Silber

            you say my evidence-denial is why skeptics are called ‘deniers.’

            I am a skeptic. And I’m a denier. I deny that there is any scientific evidence for CAGW. But please understand, I only do so because there isn’t any. If there were some, I wouldn’t deny it.

            I also deny CAGW.

            So call me a CAGW denier, please.

            Oh, no, you can’t, can you? Because that would be admitting you’re a CAGW believer. And that plays poorly in focus groups, so you can’t do that!

            What most opponents do call me is a ‘denier.’ Of what, they don’t say. Just a denier.

            They do this in a childish attempt to irrationalize me, as though I just deny stuff for the sake of it.

            Interestingly, they can’t seem to name a single validated scientific finding (on any topic whatsoever) that I ‘deny.’

            Neither can you.

            I don’t deny cigarette smoking raises your risk of lung cancer by a factor of 23. I don’t deny anything science has demonstrated to be true.

            Because I’m not a ‘denier.’ I’m just a ‘denier of things that are bollocks.’

          • HotScot

            who is “we” you ask?

            LOL. You must be the only person here who STILL doesn’t know which “side” you and I are on.

            I’m not about to take pity on you simply because we agree on CAGW, however.

          • “How do you explain this bizarre impasse?”

            How do you explain that after the complete ridicule of the pandemic flu, the fakestream medicine is still pushing the flu vaccine as if nothing happened?

            If you say nothing about the explosion of mandatory useless vaccinations, why do you expect the left to take you seriously about climate science?

          • Tom Halla,

            “As in factor analysis is a rather woo-woo exercise in statistics, using a computer program to do factor analysis made it even more obscure to anyone who did not note the lack of real data behind Mann’s bit of sagecraft.”

            “Woo-woo exercise in statistics”? What does that mean? Why isn’t it acceptable? What else besides a computer is one going to use, paper and pencil?

            There was plenty of data behind Mann et al. You have to remember, too, that this was the first attempt of its kind; it was admirable for its time. Other reconstructions have been done since, improving on it.

            You evidently have not even read the paper. There WERE error bars on his graph.

          • Factor analysis is quite woo-woo in actual use, and likely to be treacherous. If one does not really understand the mechanisms of what is going on, the use of factor analysis can hide either something perfectly trivial or show an artifact of something that was never there.
            I was a psych major, and the use of factor analysis in intelligence testing was pseudo-profound. Similarly, the use of factor analysis in proxies is just complex enough to obscure manipulating certain inputs to the degree that M&M found that any hockey stick shaped input would dominate the output.

        • If regional, they could assert other causes, such as ocean circulation, etc. If global, then whole planet analysis applies – ie it contradicts claims regarding the CO2 and Temperature relationship.

          • Lily,

            “it contradicts claims regarding the CO2 and Temperature relationship.”

            No it doesn’t. Different factors are more important at different times, and often they operate synchronously.

          • wrong

            [You know, people wouldn’t think of you as such a condescending jerk if you’d take a moment to support why you think that. You’ve started to act like Mann. -Anthony]

          • If regional, it means that you can’t “reconstruct” climate with a few trees.

            If regional, it means that the local trend anymore can diverge from the trend anywhere else for a very long time, and you can’t tell anything about the future of any place.

        • Why not do both? It seems very reasonable, I agree, to argue that a little more warming (a lot more would be good in the case of Scotland) will have more benefits than costs, but it is also necessary, if we are really concerned about furthering knowledge and understanding, to take all steps possible to ensure that the science is as good as possible.

          And if we are to understand the future and be capable of making reasonable predictions, then it surely won’t do any harm to understand the past as fully as possible.

        • HotScot,

          I agree with you (for once) – at least about some of what you’re saying. Why focus on Mann and his research? I get so tired of hearing attacks on him. Mann doesn’t represent the scientific community.

          (Of course, there are other things about which we disagree.)

          This study is about South America. It is not global. The MWP could still be a regional phenomenon – even the map presented makes it look that way, though it’s missing so many areas, it’s hard to interpret. Most of the U.S. is blank.

          I don’t really care if the MWP was warm. Even if it was as warm as today, big deal. That says nothing about what was driving the climate. It also doesn’t mean that it’s at all comparable to today in terms of its effects. The temperature didn’t change as rapidly as it’s doing today, and it seems like people don’t understand how important a factor this is. Society, agriculture, demographics…all were much different then.

          How do we know that mankind as a whole “flourished”? What records do we have from most of Africa, the Americas, Australia? I’m sure there have been archaeological studies, but I don’t know what they’ve come up with.

          The fact that it might have been as warm then as today (at least in some areas) makes no difference in terms of the potential future temperature change.

          • Kristi, it was that the Medieval Warm Period was rather warmer than the present. As it is not yet possible to grow barley in Greenland, or raise dairy cattle there, it was warmer in the MWP.
            And if there is that much inherent variability in climate change, without any anthropogenic gasses involved, the UNFCCC presumption looks like a hysterical overreaction.

          • Tom Halla,

            OK. Fine. Say it was warmer, at least in some regions. But what was the rate of change? Don’t you understand how important that is? Or that we are living in a vastly different world?

            Just one example. People talk a lot about the UHI. That didn’t exist back then. Add the urban heat to the warmest of the MWP during a week of extreme high temperatures. Then imagine the effects on the economy. No outdoor labor. Huge expenditure of energy on A/C. Deaths due to heat stroke.

            People in the MWP had time to adapt, to move to higher latitudes and altitudes and to the coasts. Populations were much smaller then. Crop moncultures didn’t cover the vast areas they do now.

            Comparing the two periods in terms of human welfare doesn’t make sense.

          • Kristi, the issue is the pushing of a model which oversimplifies atmospheric physics, and goes full Orwell on historical records, all in the interest of pushing a socio-political cause.
            No way is CO2 levels the only factor determining temperature, if one uses the estimates from proxies for the last several hundred million years.
            If one reads Tony Heller’s blog, he documents how the actual instrumental records have been stepped on to support a theory.
            A significant faction of the green blob are socialists, rather more than they are greens. Their hostility to capitalist economies is a given, and this is but the latest rationale.

          • Tom Halla,

            The fact that there were significant crops in Greenland shows that it had been warmer for a long time, allowing the ice cap to recede.

            Rate of change is more important than absolute temperature (within limits).

          • ” … The temperature didn’t change as rapidly as it’s doing today, and it seems like people don’t understand how important a factor this is. …”

            It isn’t “important” at all, Kristi, in fact it doesn’t exist at all, it’s another figment from your vivid and naive imagination once again, as the evidence from the planet itself does not support your laughable myth of accelerated and unprecedented changey-ness of Earth.

            Earth says you’re full of it, Kristi:

            Temperature Record That Closely Aligns With Paleo-Proxy Data

            It’s Here: A 1900-2010 Instrumental Global Temperature Record That Closely Aligns With Paleo-Proxy Data

            By Kenneth Richard on 3. May 2018

            A global-scale instrumental temperature record that has not been contaminated by (a) artificial urban heat (asphalt, machines, industrial waste heat, etc.), (b) ocean-air affected biases (detailed herein), or (c) artificial adjustments to past data that uniformly serve to cool the past and warm the present . . . is now available.

            http://notrickszone.com/wp-content/uploads/2018/05/Instrumental-Temperatures-World-10-Regions-1900-2010-Lansner-and-Pepke-Pedersen-2018.jpg

            Composed of 450 instrumental records from temperature stations sheltered from ocean-air/urbanization/adjustment biases throughout the world, a new 20th/21st century global temperature record introduced previously here very closely aligns with paleoclimate evidence from tree rings, ice cores, fossil pollen and other temperature proxies.

            The Alignment Of Paleoclimate Proxy Data & Instrumental Records

            The paleoclimate proxy data for the Northern Hemisphere (NH) consistently show an oscillation rather than a linear warming trend between 1900 and 2010: (a) a substantial warming trend between 1900 and the early 1940s, (b) a substantial cooling trend between the 1940s and 1970s, and (c) a subsequent warming trend since the 1980s that matches or comes close to matching the warming peaks in the 1930s and early 1940s (rather than greatly exceeding it).

            In 2016, Dr. Pei Xing and co-authors unveiled a new method (MVDM) for calibrating low-frequency NH tree-ring data (utilizing 126 tree-ring records) for the last 1,200 years in The Extratropical Northern Hemisphere Temperature Reconstruction during the Last Millennium Based on a Novel Method. The proxy evidence shows an oscillation — including substantial cooling between the 1940s and 1970s — and no net warming since the early 1940s.

            http://notrickszone.com/wp-content/uploads/2018/04/Northern-Hemisphere-126-Proxy-Temperatures-1800-to-2000-Xing-2016.jpg

            http://notrickszone.com/2018/05/03/its-here-a-1900-2010-instrumental-global-temperature-record-that-closely-aligns-with-paleo-proxy-data/

            Your endlessly marinating in false memes does not make them any more correct or valid, once you brazenly plop them into your invariably absurd and naive comments and assertions. 😉

          • Kristi Silber
            Hello.
            The AGW position is based on the experiments of one scientist in the 1890’s. (can’t spell his name.)
            What do you know about the tech of the time? Could the devices to accurately measure CO2 levels and temperature be manufactured? Have you ever worked with 1890’s machine tools fresh out of the box?
            I am one of the few who have. In 1979, I was involved with taking a Ballard VTL that was designed to run off of a water wheel and rebuilding it to run off an electric motor. I was an apprentice toolmaker. Our goal was to get it modified to the point where it could be used in the production of aircraft parts. We did finally succeed.
            It was in its original grease packing never used. The feed screws and spindle bearing were in perfect condition and usable. We replaced the belt and pulley system and had to re-calibrate the measurement dial calibrations. To put it simply, there was no way this machine could hold tolerances of less then +/- .007 in its original form. I remember this after all these years from our joke that it would be wrong seven days a week.
            This was for the time, the top level machine tool.
            Good rule to remember, you can’t built a more accurate apparatus then the machine tool that makes it.
            So the accuracy of any device for making measurements of CO2 would only be as good as the tooling producing them.
            Now Kristi, go look up the year Starrett micrometers were first patented.
            Oh do I have to mention the unreliability of manufactured atmospheric gauges at the time? Train boilers going boom, ship boilers going boom.
            Too many possible errors with the 1890’s hardware used.

            michael

          • Kristi Silber: I always read your thoughts with interest – it’s great that there are people on here who question the site consensus, just as there are those who question the global warming consensus. It keeps the debate focussed on facts, rather than personal opinions. You (along with Nick Stokes’and one or two others) seem to come in for more than your fair share of personal, or patronising, comments, and I’m sorry about that. They are unnecessary and undeserved. Please keep on posting!

            You say somewhere, that “People in the MWP had time to adapt, to move to higher latitudes and altitudes and to the coasts.” I’m not sure about the global response, but in Europe at least, people seem to have extended their range northward during warm periods, rather than abandoning their land and moving northwards. It’s an important difference, and one reason why I’m skeptical about the “1.5 degrees and it’s the end of the world as we know it” stuff. Colder weather is more likely to force people to move, not warm.

          • WXcycles,

            I see. So you accept these papers as good evidence, and ignore what doesn’t fit your ideas of what should be the case. Now, there’s skepticism! And on that basis you think the rate of change isn’t a problem. Well, you’re entitled to your opinion, but it sure doesn’t justify, “another figment from your vivid and naive imagination once again, as the evidence from the planet itself does not support your laughable myth of accelerated and unprecedented changey-ness of Earth” when I’m not using my imagination – that WOULD be silly!

            Ha, “evidence from the planet”! That’s a good one.

            I’m aware of the Lasner et al. paper, but it’s paywalled. Because I have significant concerns about the methods, I won’t accept it unless I can read the whole thing. Just the fact that they used only raw data without adjustments is more than enough to make me skeptical. The raw data is faulty. Some adjustments DECREASED the rise in temperature.

            From Xing et al.:

            ” Nevertheless, at the end of the 20th century, obvious discrepancy between MDVM reconstruction and CRU was found, which was probably due to the sharp decreasing of the chronologies’ total number in recent decade.”

            …Or maybe it’s due to the well-known fact that tree ring proxies in the late 20th C are not any good. This is why the instrumental record replaced the proxy record in Mann’s work. How can any dendroclimatological researcher not know this problem with the tree ring record by now? Did you notice that the CRU data was appended to their graph (the main one, not the one doctored by the blog)? How about the fact that the MWP wasn’t as warm as the late 20th C, even in their proxy reconstruction? Or that there are no error bars? Or the fact that the total solar irradiance has not risen substantially since the mid 20th C, and dropped a bit at the end of it?

            And did you notice that the method they used was validated using the CMIP5 simulations skeptics so despise?

            Have you even looked at the paper? It’s quite interesting, in some ways. Thank you for the link.

          • Tom Halla,

            “Kristi, the issue is the pushing of a model which oversimplifies atmospheric physics, and goes full Orwell on historical records, all in the interest of pushing a socio-political cause.”

            Um, “oversimplifies”? In what way? Do you know the models are over a million lines of code? Do you know all the variables that they look at?

            “Full Orwell.” Don’t know what to make of that.

            I completely, totally disagree with you suggesting the science is just pushing a socio-political cause. There’s just no evidence for it. And it’s foolish to think that it’s a bunch of socialists behind it all. Conspiracy theory BS.

            “No way is CO2 levels the only factor determining temperature, if one uses the estimates from proxies for the last several hundred million years.” Duh.

            “If one reads Tony Heller’s blog, he documents how the actual instrumental records have been stepped on to support a theory.”

            I don’t trust a blog for my science. He could say what he wants about how the instrumental records have been changed. The question is, are there legitimate scientific reasons for doing so? This is documented in the scientific literature. Have you read that?

          • Heller is quite meticulous in documenting how the reported numbers have been changed over the years, essentially always in the interests of buttressing the AGW narrative. That is what I mean by “full Orwell”.
            Can one claim the infill and changes in the past by GISS are innocent?

          • Mike the morelock,

            Sounds like an interesting project! Fascinating to be able to work with something that old, and yet never used. Where was it found? I don’t know what a VTL is.

            All the same, your experiences with a single piece of machinery shouldn’t be used to generalize to all scientific apparatus. Besides, even though the measurements may not have been precise, it’s the theory that counts. and the theory stands to this day.

            “The AGW position is based on the experiments of one scientist in the 1890’s.”

            No, it is based on the work of a few scientists – Fourier, Tyndale, Angstrom, Arrhenius, Ekholm, for instance; Ekholm (published 1901) did an amazingly thorough job of looking at a variety of aspects of climate, building on the work of his predecessors – this paper doesn’t go into the measurements and calculations they did, but it’s very readable for that reason.

            My guess is you haven’t read it. I’ve read some of the most relevant bits (the paper is 61 pages, covering a massive amount of detail, but I’ll get to it one day). It’s quite amazing how far the science had gotten way back then. Have a look, it’s very impressive. (He calls CO2, “carbonic acid” – that section starts on page 20.)

            http://nsdl.library.cornell.edu/websites/wiki/index.php/PALE_ClassicArticles/archives/classic_articles/issue1_global_warming/n5._Ekholm__1901.pdf

          • Kristi,

            if Your Side wants skeptics to move on and quit bashing Michael Mann with a stick of his own making, all you have to do is disavow him.

            He’s a poster child for bad science, so what have you got to lose?

            Continuing to defend the indefensible makes Your Side looks ridiculous, which is why we enjoy putting you in that position and watching you squirm. It’s one of the better tactics we employ, because the public doesn’t have to understand adiabatic lapse rates to draw the obvious conclusions about Your Side when they see you circling the wagons around self-evidently dodgy “science.”

            Your Side routinely claims that Mann’s “sloppy” [h/t: legitimate, mainstream, respectable scientists] research doesn’t matter, because you have so many independent lines of evidence all adding up and pointing clearly to the same one single [1] conclusion: that only a progressive tax on an industrial metabolic byproduct will save our kids’ kids’ kids from being burned alive by acidic oceans, or something.

            But if you had anything else, you’d throw the really bad scientists under the bus.

            The fact is, if you jettisoned the overtly repellent eggs like Mann, Jones, Lewandowsky and Oreskes, there’d be nothing left in your basket. (Prove me wrong, please—I beg you.)

            The rotten eggs are the only eggs you’ve got.

            People aren’t (infinitely) dumb: when they see Your Side insisting its schtick doesn’t stink, they grasp the corollary.

            So, no. You can implore us all you like but we’re never going to give Mann et ilk a pass. There is no statute of limitations on pseudoscience.

        • Wow, you got to four words — congrats, I guess. In fact, prb’ly better for everyone NOT to expound on your “thoughts”.

    • Am I wrong in taking it as read that catastrophists are calling modern warming unprecedentedly bad for manking (and not just unprecedentedly warm)? And that in order to make that claim with a straight face they have to discount the MCA, which they attempt to do on the grounds that its thermal badness wasn’t globally synchronized?

      But but but….

      if global warmth is catastrophic, why would staggered, region-by-region warmth be any less so? What difference could it possibly make, in other words, whether all the nations of the Earth were sodomized to death by the ravages of mild winters simultaneously versus serially? And conversely, if everyone survived the horrors of the Medieval Climate Optimum just fine thanks, would the Millennial Carbon Optimum really be any worse just because we all had to suffer through it at the same time?

      Or do these questions misunderstand the “logic” of catastrophism?

      • Brad Keyes

        Please stop with your attempts at ‘English’ wit and subtlety, you are really, really bad at it because you don’t understand it. It’s inherent within our naturalised English speaking cultures and it’s nuances shift almost daily.

        You have no chance of understanding it far less using it effectively because you haven’t been immersed in it since birth. You just succeed in presenting yourself as an incomprehensible idiot. Sadly, your blog site confirms it.

        • HotScot,

          thank you for being the first person with the gonads to say this to my face.

          You’ve provided a long overdue corrective to the hubris that has taken me perilously close to the Sun* with the connivance, indeed the abetment, nay the enabling, of those I counted as friends.

          Your honest rudeness is more of a kindness to me than all the years of polite dishonesty with which my supposed buddies have indulged me.

          Perhaps you could let my faux amis at CliScep dot com know that I can’t, in fact, speak English, and that even a child could see through my cringe-making attempts to do so. They’ve seen fit to promote such delusions as…

          ….Brad is “without doubt the funniest blogger in the climate world”. He could have added that he is one of the funniest (and the least politically correct) writers around, period.
          When he’s not writing paeans to Gore, Oreskes, Pachauri & co here, he’s busy shafting trolls elsewhere, most recently and effectively here….

          All these years, their flattery was little more than a practical joke at my expense, a sickeningly successful plot to take advantage of my complete lack of self-insight.

          And only you, HotScot, have the childlike integrity to speak the truth to such deviants: that the Emperor is naked, and in flagrant violation of his parole by being within 50 feet of a minor.

          *…or as “close” as Bronze Age Red Bull contestant could have gotten by taking off from a Minoan rooftop, heading across the Mediterranean yet at no point leaving the breathable atmosphere, which I suppose is not very close after all.

          • …..Brad is “without doubt the funniest blogger in the climate world”. He could have added that he is one of the funniest (and the least politically correct) writers around, period. When he’s not writing paeans to Gore, Oreskes, Pachauri & co here, he’s busy shafting trolls elsewhere, most recently and effectively here….

            They were taking the piss mate. You’re just not familiar enough with the subtleties of English speaking cultures to recognise it. 🙂

          • HotScot

            Yes, I KNOW that.

            I KNOW they were taking the p!ss. I explained this to you. In my comment. In plain English. So plain even a foreigner like me could understand it. More than once (since I’m familiar enough with your one-man HotScottish speaking culture to know it doesn’t place a high premium on reading comprehension).

            Wild guess: are you one of those kinesthetic learners who responds better to hand-puppet-based teaching than traditional chalk ‘n’ talk syllabi? Not that there’s anything wrong with that. It doesn’t make you less intelligent than the rest of us. Just… uh… differently intelligent.

            Anyway, I need YOU to go and tell them, since I feel too violated and betrayed and aburinated right now to face them. In this apoplectic mood, I’d probably wind up saying something I regret, like ‘manking’ (or worse).

            (If they don’t remember you, just say you’re the guy who still hasn’t figured out that the Climate Nuremberg blog is a parody of econatzism, despite claiming to have read not one but multiple posts!. Not sentences—whole posts. LOL. That’ll narrow it down.)

          • ….Brad is “without doubt the funniest blogger in the climate world”. He could have added that he is one of the funniest (and the least politically correct) writers around, period…

            I second that notion. )

          • Hugs,

            I’m not BradBohemian, in case you thought I was. Who is he anyway… your Czech mate?

            Anyway which point was ‘good’? (Which one had you been wondering about?)

            Secondly, yeah, the thought crossed my mind, too, that perhaps HotScot’s idea of funny is to channel an unfunny bore who thinks my idea of funny is unfunny and boring, and that the solution is to stop humoring me and instead bore me with an unfunny manifesto denouncing foreigners who think they’re funny.

            The problem with this interpretation is, satire is supposed to have an object. It’s supposed to make fun of someone. Even when you self-satirize, you’re actually using yourself as a proxy for the person (or type of person) you’re really making fun of. So when I do my wide-eyed-yet-pompously-ill-informed Ecojugend character, everyone’s met one of those, so they know who and what I’m making fun of. HotScot’s schtick—if it’s meant to be funny—goes down like a lead balloon because it’s untargeted and pointless.

            So either HotScot is—bravely, I must say!—publicly making his first attempt at satire without even understanding the basics of the exercise, or I’m afraid something far less interesting is going on here. 🙁

          • if global warmth is catastrophic, why would staggered, region-by-region warmth be any less so?

            This comment upstream was very good. Let mediaeval climates be Goldilock’s climate on average, by present standards they were just pure CAGW regionally.

            (Perhaps HotScot could remind me what it is that I actually speak… am I German or Austrian, or something in that vicinity?)

            By now we have learned, by means of guilt-by-association, of your near-Austrian roots. Böhm is somewhere ‘near’ Nürnberg, if not exactly at Climate Nuremberg. I wish you the best creative writing. I also congratulate you on being capable of *satirizing* something that appears to be completely impossible to make parody of.

            And yes, I’m afraid HC was dead serious after all. I was hoping upon seeing the first one or two comments that the Sprachpolizist was just joking. It hurts me more, because I know my weakness in my third and fourth languages. My Chinese and isiZulu are also less than perfect. Qingwen?

        • Brad – fair enough point. I see the logic of it. Of course, the CAGW “consensus” is predicting more heat in the long term than was prevalent during the MWP (regionally or globally), and therefore more disastrous consequences.

          Hotscot . . . to my mind that’s a remarkably abusive comment . . .

        • HotScot, are you saying Brad Keyes isn’t a native English speaker or that Strine – Australian English – isn’t the Queen’s English? 😉

          Seriously, do you know that English is his second language or are you justing “aving-a-go?

          I’m from a multigenerational English speaking family and Brad seems to have a better grasp of the written English language than I do! At least he has a bigger vocabulary, as I find I often have to look up words – new to me – every time I read him.

          *Having-a-go: to criticise someone strongly

          • “justing”, “manking” now I’ve caught the disease! “Just having a go”, was what I meant to write.

        • Leo,

          isnt isn’t how you spell isn’t, is it?

          Then again, apparently English isn’t my first language. (Perhaps HotScot could remind me what it is that I actually speak… am I German or Austrian, or something in that vicinity?)

          • Don’t you mean isnt how you spell “ain’t”?

            They hate the Medieval Warm Period because it spoils the narrative that Man’s CO2 is causing the temperatures to be higher than they’ve ever been since the Earth’s crust cooled:
            therefore, Man must be politically controlled to prevent Nature from taking its course.

          • Brad Keyes

            …….am I German or Austrian, or something in that vicinity?

            Seriously, who cares?

            Your grasp of English speaking cultures is appalling and you appear an idiot to everyone. Nor is that meant to be insulting, simply constructive. Drop your attempts at English humour and people might listen to you.

            PS…….It’s not convention to begin a sentence with a bracket, thus; “ Then again, apparently English isn’t my first language. (Perhaps HotScot could remind me…….

            Best not throw stones in a glass house. We all make typo’s, some of us make grammatical errors, and others haven’t a clue what they’re doing.

            Is that a good enough reminder? 🙂

          • Gunga Din November 3, 2018 at 12:15 pm

            You are being played by “Bradley” here. His English is excellent, likely taught at a private academy. He does not make to many mistakes in spelling and grammar. His word use while on the surface gives the appearance of ignorance is in reality calculated. You see it is Bradley way of feeling self-important; being that in life he his never accomplished anything of real value, worth or use.
            He is reduced to playing a modern “Lord Haw Haw” .

            michael

          • mike the morlock

            You’ve exposed me. Well done.

            Yes, my low self-esteem sends me in search of victims even lower than myself. I may be a bit of an Untermensch but when I’m lolzing at the expense of a clueless schmendrick like HotScot I feel, just for a few minutes, like an Eloi by comparison.

          • mike the morlock November 3, 2018 at 1:47 pm
            Gunga Din November 3, 2018 at 12:15 pm

            You are being played by “Bradley” here.

            I don’t think so.
            I was having a bit of fun with him about the “isnt” “aint” thing.
            He never responded to the rest of my comment.

            They hate the Medieval Warm Period because it spoils the narrative that Man’s CO2 is causing the temperatures to be higher than they’ve ever been since the Earth’s crust cooled:
            therefore, Man must be politically controlled to prevent Nature from taking its course.

          • Gunga,

            Apologies—I “never responded to” the rest of your comment because I thought it was a good point that spoke for itself without further comment.

            Not because I was deliberately avoiding acknowledging or agreeing with you, if that’s what you thought.

      • Brad
        One comment
        We aren’t now and never were in a “Carbon Optimum”.
        If at all, the only “carbon optimum” in the history of the planet was about 540MY ago during the Cambrian period with CO2 levels of 7000 ppm.
        We are however entering a Modern “Climate Optimum” similar to the Roman Climate Optimum and the Minoan Climate Optimum but not a Watermellon reviled Carbon Optimum

        • Thanks Bryan, I was actually aware of the much higher levels of atmospheric Schweppervescence enjoyed in the past (though I’d forgotten the details), and I can see why my made-up term was misleading if taken seriously. I just wanted something with the initials “M.C.O.”, and nobody seems to understand words like capnophobic and chiliastic, so I dumbed it down. Too far down!

          • Hot,

            Just because you don’t appreciate Brad’s sense of humo(u)r, as is of course your God-given natural human right and privilege, isn’t IMO a reason to call him dumb.

            He’s actually smart.

            And call me cracked, but I also think he’s funny. “Schweppervesence”, for instance. Maybe you didn’t have that commercial in the Mother Country.

          • “Just because you don’t appreciate Brad’s sense of humo(u)r, as is of course your God-given natural human right and privilege, isn’t IMO a reason to call him dumb.”

            Appreciating a sense of humor, and putting up with it on EVERY.SINGLE.POST. are two different things. It gets very old very quickly.

          • Jeff,

            “Appreciating a sense of humor, and putting up with it on EVERY.SINGLE.POST. are two different things.”

            That is coherent. You are being logical, not absurd. Nay, you ARE logical.

            It doesn’t show (as some have cruelly insinuated) that it’s all going over your head! You understand it, because you’re smart. You realize I’m “taking jabs at skeptics” with my warmist sense of humor, which you appreciate, because you’re smart.

            In fact you’re so smart, you’re ahead of your time. You’re probably the only person here (unless you count HotScot) who understands that I’m NOT a skeptic.

            Appreciating comedy and liking it are two different things.

            But try explaining to a human rights magistrate that you *appreciate* other cultures, you just can’t put up with having a rich ethnic tapestry in your neighborhood EVERY SINGLE DAY.

            They’ll call you intolerant. Intolerant? You?

            Welcome to the new-old, politically-correct EUtopia. Enjoy your stay in Hate Prison.

          • Kristi,

            Humans can survive at twice that level of CO2.

            For human survival, what matters is O2 concentration.

          • John Tillman,

            CO2 levels over 1600-2000 ppm can cause declining plant growth in modern-day adapted land plants – and even more so under stressful growing conditions. Over 4000 can completely disrupt stomatal regulation in many species.

            Perhaps we could survive on seaweed and ocean animals, but it would be tough.

          • Kristi,

            Obviously Mesozoic plants and the animals which fed upon them flourished under CO2 concentrations of 1700 to 2000 ppm.

            Please show declining plant growth in that range.

            I agree that optimum would be only three times current CO2, not five times, but am not aware of how 2000 ppm would actually hurt C3 plants, whose optimum levels are 1200 ppm.

            Thanks!

          • Ms. Silber treats us to this bit of wisdom:

            “Bryan A,

            Humans cannot survive at CO2 level of 7000 ppm. Why is that an optimum?”

            So sorry, but that is wrong; United States nuclear submarines often operate at internal CO2 levels either approaching or exceeding 5,000 or 6,000 or even 7,000 ppm CO2. There are numerous references and links at an article on WUWT from 17 October 2012, titled, “Claim: CO2 makes you stupid? Ask a submariner that question”, which includes (very early in the article) this statement:

            ” We try to keep CO2 levels in our U.S. Navy submarines no higher than 8,000 parts per million, about 20 time current atmospheric levels. Few adverse effects are observed at even higher levels. – Senate testimony of Dr. William Happer, here”

            Your response?

          • John,

            “For human survival, what matters is O2 concentration.”

            Actually CO2 concentration is equally important, i.e. critically so.

            Surprisingly, the respiratory urge is driven primarily by (receptors that detect) high CO2, not low oxygen, in the blood.

            So-called respiratory acidosis results if you are unable to excrete (exhale) CO2 efficiently. And the shedding of CO2—i.e. the exchange of CO2 from blood to air that occurs in the alveoli—is a passive process; it relies on a concentration difference.

            Therefore, sufficiently high environmental CO2 would cause serious medical problems no matter how much O2 was available.

            But it doesn’t follow that Kristi is correct about the level at which problems start to manifest.

            I’m just pointing out that one of Our Side’s memes (carbon dioxide is harmless as long as you have enough oxygen) is false.

            PS The neat thing is that, even in the enclosed atmosphere of a hospital ward, there is essentially zero carbon dioxide in the air—which is why the equations doctors use (e.g. to calculate the oxygen-flow-rate to deliver to a patient) expect 0 to be plugged in for the room-CO2 term.

            Which sounds harmless enough. But if we continue to spew human pollution into the sky, that variable could double or even triple!

      • Brad, just for the record, I quite enjoy your sarcy rants. Forget what the others say.
        I’m English and I don’t usually have a problem understanding your humour. But then, my own humour is a bit off-beam, so maybe I’m not the guy to say.

    • That map is really quite instructive. It shows very clearly that the greatest warmth was at high latitudes, with no net warming in the tropics. Just the pattern that most warmists and serious sceptics expect from any warming, however caused. But most also agree that the CO2 concentration was below 300ppm at the time.

      The status of the MWP as a historical fact is quite secure. I haven’t seen any recent work that tries to deny it that doesn’t look contrived and desperate. We ought to start talking about ‘the consensus’ on the MWP and call out the deniers.

      Not only does it show the present warmth to be anything but unprecedented, and very doubtfully linked to CO2, but as HotScot says, shows that it should be welcomed.

      • global warming is happening largely due to an over-emittance of these gases and fossil fuels and There is more carbon dioxide in the atmosphere today than at any point in the last 800,000 years (“Climate Milestone: Earth’s CO2 Level Passes 400 ppm.” National Geographic Society, 2013) that too was in 2013 but seeing these red balloons more make me think what i can do as a common man?

        • Welcome! I think you are new here, and perhaps you have misunderstood my comment, and also the whole thrust of the post. Those red balloons are an indicator that we have nothing to worry about. Please try to read some more about the Medieval Warm Period, and why it seriously undermines the present claim that our industrial gases are damaging the planet.

          I applaud your earnest desire to do something to help the earth, but you can rest easy. Nothing you do, and even if millions of others do as well, will achieve what you seek. And, in any case ,a bit of warming, certainly up to 2° C and perhaps some way beyond, should be welcomed for the sake of humanity.

          Do not believe what you hear on the news, or in the press!

          • Lepidopteraptor,

            your reply to Farad is an object lesson in how to reach out to the genuinely curious climate “believer”—and we have to have faith that such a demographic exists, or what’s the point of any of this?

            As too few of us understand, it’s not about changing their minds (something no blog comment has ever been known to achieve), it’s about respecting their ability to change their own minds on closer inspection of the realities.

            Fence-sitters can’t expect that kind of respect at alarmist blogs, that’s for sure—for the obvious reason that most alarmist bloggers know full well that reality is not on their side, and all they’ve got left is rudeness.

            So—well done, mothcatcher. Stay classy.

            /notsarc

      • The lack of data in the lower latitudes is also driven by problems with palaeotemperature proxies here. When it is warm, it is hard to detect small temperature changes. Palaeoclimate reconstructions work much better in high altitudes and higher latitudes. Shifts of tree lines etc. are easier to detect. One of the challenges therefore is to develop and calibrate better paleotemperature tools for lower latitude lowlands.

        • Sebastian, I think you agree when the debate here makes me wonder. IMO the question about the reliability of Mann et al ( long, long time ago) is only of minor interest in the light of the availibity of new (proxy) data. In the conclusions of your paper you focus on the skill of the latest available GCM to replicate the MWP/LIA. IF the MWP would be only local ( more or less internal variability) the CMIP5 would be “excused” not showing this up and down. If both anomalies were globaly ( the confidence is increasing more and more) the doubts in the skill of the used GCM are also increasing. To bring it on the target: The claering of this question in a scientific way shines a light on the skill of the GCM based predictions which is of great interest. Thank you for your paper which seems to be a milestone because the defenders of the GCM also claim that the MWP is only a phenomenon of some parts of the NH. South America is not part of the NH, therefore this claim is strongy shattered.

      • Hm.. (here is the “checkmate” on “climate change”):
        Andrill – Stands for Antarctica Drilling Project. A consortium of nations engaged in specialized drilling on continental shelf under ice during limited time slots available during year. Findings were (have to read small print results – was much to chagrin of most scientists involved) that during last 2 million years there have been 60 cycles of ice ages with necessary “interim global warming” in Antarctica with some global water level changes up to 300 feet. Confirmed by research on New Zealand coast lines. Naturally during those 60 cycles/2 million years man not a factor. In future all you need to do is supply Google reference link (or cut and paste this entry) which is brief explanation. That will suffice to “checkmate” any individual who says “humans” cause global warming. And you can ask (on future posts here on LinkedIn) as an introductory question does individual proposing human caused global warming ever go to Las Vegas and gamble. If they say no because of “odds” against them then they are up against same type of “odds” by supporting “human caused” global warming. In other words global warming does occur. Just not by humans.

      • mothcatcher,

        “Not only does it show the present warmth to be anything but unprecedented, and very doubtfully linked to CO2.”

        Not true at all. The fact that different climate drivers acted at different times is not news.

        • Silly comment. Until you can satisfactorily explain the MWP (with its low CO2), you can have no confidence whatsoever if ascribing modern warming to ANYTHING.

          • mothcatcher,

            It seems to me the more relevant question is, can you ascribe the rapidly rising temperatures today to something besides CO2?

          • can you ascribe the rapidly rising temperatures today to something besides CO2?

            More silliness. Did you even read mothcatcher’s reply? How ’bout the same things that caused the MWP?

            Please, people here play hardball. Go back to your Power-Puff Girls site if you can’t keep up here….

          • There sure is a lot to digest here. Above, Ms. Silber was asked about her statement that, ‘ … humans cannot survive at CO2 levels of 7000 ppm … ‘, yet when shown that US nuclear-powered submarines operate at that level, often for months at a time, she does not respond.

            We then get this series of statements:

            “November 3, 2018 at 7:53 pm

            The temperature didn’t change as rapidly as it’s doing today, and it seems like people don’t understand how important a factor this is.

            “November 3, 2018 at 8:39 pm

            But what was the rate of change? [Referring to MWP — — TDVTI annotation] Don’t you understand how important that is?

            “November 3, 2018 at 8:43 pm

            Rate of change is more important than absolute temperature (within limits). ”

            As skeptics (sceptics, for our non-US readers), we have often asked what the next meme will be. First it was ‘global warming’, until the globe made a screeching halt to the “rapid” warming, so it became, ‘climate change’ (fairly ubiquitous — — — any ‘change’ at all could thusly be ascribed to ‘human-caused’), so the new meme, verified by our own tree-ring-hugging ecologist, is “Climate-Rate-Of-Change”, and not just ‘climate change’.

            Be on the lookout for more ‘climate-rate-of-change’ in the media, on blogs, in the published “literature” (sensu amplo).

            This one just about took the cake:

            “November 4, 2018 at 11:27 pm

            mothcatcher,

            It seems to me the more relevant question is, can you ascribe the rapidly rising temperatures today to something besides CO2?”

            We’re not given any definition of ‘ … rapidly rising … ‘, so we have to fill in the blanks, as it were. But, in almost the same breath of air, we are advised that,

            “November 3, 2018 at 8:01 pm

            No it doesn’t. Different factors are more important at different times, and often they operate synchronously.”

            and,

            “November 3, 2018 at 8:50 pm

            The fact that different climate drivers acted at different times is not news.”

            So, once again, Ms. Silber contradicts herself, telling at the same time that different factors (factors = undefined) act at different times, and that they are, ‘ … more important … ‘ at those different time (more important = undefined), so all of us great unwashed have to accept that the anointed ones have determined that we MUST ascribe the ‘rapidly rising’ temperatures to CO2, and none of the other, undefined climate drivers, that act at different times with different importances … … … …

            My ability to follow that train of thought (or lack thereof) has been de-railed.

            I have previously challenged Ms. Silber to discuss the assessment of the geological community, concerning Plio-Pleistocene glacial/interglacial transitions. I have pointed out to her that Richard Alley himself has taken the new consensus to a whole, new level. In Ms. Silber’s world, a temperature change of about 1 Celsius degree (or 1.5) in a time span that starts around the Industrial Revolution, constitutes a ‘rapid’ change. As an undergrad in the ’60’s {“If you can remember the Sixties, you didn’t PARTICIPATE!!!!”}, the available evidence suggested that climate changes between glacial/interglacial events took, on the order of, thousands of years. In the 1990’s, it became increasingly clear that this dogma was most incorrect. Before the turn of the century, the available evidence was decidedly in favor of global temperature changes measuring between three and six Celsius degrees, taking place in a time frame of DECADES. Alley has been a champion of the concept that these changes very likely took place in LESS than a decade; in one video I watched of him, he was even tending to suggest that the time span could be as little as a single year.

            But, I am content to support the main consensus that we are likely looking at over five Celsius degrees temperature change in a nominal number of decades. To me, that far outweighs the contention of the numerically-challenged, that a Celsius degree in about 1.5 centuries is, ” … … rapid … … “.

            Challenges posed: challenges unanswered. Victory by default. Victory by internal self-contradiction.

            Regards to all,

            The Mostest Deplorable-est Vlad the “Climate-Rate-Of-Change” Impaler-est, a crashing bore-est, and an even bigger bully-est, according-est to one Mr. C. T. at JoNova

            Licensed Professional Geologist, State of Wyoming
            Certified Petroleum Geophysicist, AAPG
            Commercial Pilot w/ IFR and MEL ratings (11,000 hours PIC, including 1,000 hours in actual IMC); 3,000 hours Night; no incidents, no accidents, no enforcements
            Terminator of wayward prairie dog towns
            Tree-ring burner
            Bar empty-er (in the sense of reducing the inventory to minuscule levels … )
            Ace virgin converter ( OK, mods, I understand if that’s a bit over the top, but, for Heaven’s sake, I’m ON A ROLL here!!!!!)
            TwinOtter skewer-er

    • It matters because Mann and his crew say that the MWP was caused by regional climatic actors (currents, etc.) and do not indicate a world-wide warming. Showing that MWP is world-wide demands that you either say that there were region-specific warming factors in many places or (using Occam’s razor) the world as a whole warmed with CO2 remaining constant. Note that the warming is more pronounced in the higher latitudes of S America, as would be expected in a planetary warming — more at the poles, less at the equator.

    • It matters because global temperature is made up of all those places added together. If some are hotter and some are colder, they cancel each other out. If they’re all hotter than some warmist ideal, then current events of global warming are not unusual and don’t need CO2 to stoke the temperatures significantly hotter.

      If the MWP was the same as today, and the previous warm periods were warmer then all the panicking going on is stupid.

      • TinyCO2 – what do you think the global temperature average will be in another 80 years? 150 years?
        And what will that mean for ice caps and the intensity of storms and seasonal shifts and hot summer conditions, droughts and floods, etc.

        That’s the question, not whether we’re already almost as warm as the MWP.

        • You’ve missed the point. If the MWP could occur in a time of low CO2, and only 1000 years ago, that at a very minimum undermines, and quite likely invalidates, the ‘control knob’ theory of CO2 v temperature, thereby casting a massive blow against the ‘consensus’ and rendering very, very wrongheaded the huge societal changes demanded by the warmist juggernaut. That’s the issue at hand, nothing more nor less.

          • “If the MWP could occur in a time of low CO2, and only 1000 years ago, that at a very minimum undermines, and quite likely invalidates, the ‘control knob’ theory of CO2 v temperature…”

            Really? Tell me why. What if we continue to warm from now?

            Has there been a 30 year cooling trend since 1900 to allay our fears?

          • Meteo –
            I don’t claim to know whether we will continue to warm, or not.

            What the MWP tells us is that attempting to control the temperature by attempting to control the level of CO2 is very unlikely to work. It’s what some call the “attribution problem”

            Your handle suggests you are a scientist, but your logic suggests maybe you aren’t.

    • HotScot,
      You said, “If warming were regional, how could consistent atmospheric CO2 affect one area and not another?”

      +1

      • Consensus “climate science” (TM) has no problem with the what should be inconvenient fact that CO2 apparently warms the Arctic, where sea ice fell from 1979 to 2012, but cools the Antarctic, where sea ice grew from 1979 to 2014, both under rising concentration of the magic molecule.

        • The Antarctic ice growth and Arctic ice loss should have been expected.

          The blocking circulation gained strength slightly (shape of Antarctica fits the midlevel flow pattern) and the temperature went up slightly.

          • The Antarctic ice growth and Arctic ice loss should have been expected.

            Should? And wasn’t. And won’t, because alarmists need Antarctic warming to say Antarctic is about to disintegrate and flood West Side Highway (it was scheduled for 2018 but Hansen reweaseled it to 2040 so that a good decadal waiting was wasted in goalpost moval.)

            The only things worse than the greenhouse effect forecasts are the completely reversed forecasts laid after the first ones fail.

            It’s gonna be hot soon. But not yet, next it is gonna be cold, unless the warming starts for real. And it could change when Greenland collapses. Sea levels will rise from 0.3m to 300m. Or more before year 2500. Or later. Give us your money and do as we say.

      • The map projection is a little misleading.

        How do you explain the areas of cooling with your warming mechanism?

        Looking at events so long ago can be confusing.

    • Well I think that the MWP was global as I clearly show in my blog http://www.rogerfromnewzealand.wordpress.com

      However it is also true that if the MWP was regional, the argument that it was only a regional disturbance gains a certain foothold.

      As you will read in the above link and peruse the heading bar at the right of the page, evidence of the MWP is found in such places as:

      New Zealand http://ruby.fgcu.edu/courses/twimberley/EnviroPhilo/Glacial.pdf

      Pacific Warm Pool http://www.spaceweather.ac.cn/publication/jgrs/2006/pdf/2006GL027234.pdf

      China http://www.springerlink.com/content/gh98230822m7g01l/and a number of others.

      Check for the heading “Links to illustrate the Globalness of the Medieval Warm Period and other Warmings”

      Cheers

      Roger

    • HotScot, while I agree with the notion of a flourishing mankind, possibly not just because of higher temperature but increased regional stability (less regular disasters creating frictions or disasters) you might have missed the finer points of the alarmists revolving around the idea “run away warming”. Meaning that the projected problematic warming would be several times more than any MWP numbers currently provide. For example, the so desired max of 1,5 for 2100 is still around 3x more than projections for any global MWP. While going back in time and finding similar numbers in combination with a global population or disaster reports might be a bit harder. For this reason I do think it’s extremely relevant to examine the mechanisms of MWP in case they do relate to the 19-20th century warming (as it’s the same order) which would question the theory of “run away” warming and the human factor in all of that.

  2. Great to see this…….but I doubt we’ll see it reported on any of the MSM. I’d love to be proved wrong on that comment but I won’t hold my breath. Those “scientists” who deny the existence of previous naturally-occurring warm periods on our planet (including the MWP) obviously choose to ignore our planet’s history and the numerous records written in its sediments. Pretty sad!

    • Tom

      Sad to say, but the study doesn’t emanate from a major American seat of learning like Penn State so it won’t even be hand waved away, it’ll just be ignored.

      As an interested observer, it seems to me that climate studies acknowledged by the MSM mostly come from the US simply because of the resources of NASA, NOAA and the major Universities etc.

      • Mann sued Ball and Steyn. Somehow, he has managed to avoid producing discovery. We keep hoping that, if he does eventally have to cough up his documents, his work will be shown to be as bad as we all suspect it is. link

        The good thing is that the hockey stick conflicts with my knowledge of history. Mann turned me into a skeptic.

        • commieBob

          My ‘enlightenment’ was much more rudimentary than yours.

          My inclination would be to stop pursuing Mann for his data. The hockey stick has already been removed from the IPCC reports (I believe), and most reasonable scientists will accept the MWP is a fact of life, regional or not. Mankind flourished and enjoyed higher temperatures. These are demonstrable, well researched, documented observations, not only by science but by the arts of the period.

          • “most reasonable scientists will accept the MWP is a fact of life”.

            But if they do, how do they explain it since it since they cannot link it to CO2? Or are se saying that most reasonable scientists do not believe in CAGW?

          • RE: My inclination would be to stop pursuing Mann for his data.

            Except, HotScot, Mann is the go to voice for the crooked media and is considered a hero by the left. As an example, when I got into a discussion about CAGW with a leftist family member, she sent me a copy of Mann’s book, suggesting I might learn something from it. My reply was to send her a copy of Mark Steyn’s book, “A disgrace to the Profession” which she promptly called “propaganda” and refused to read. Mann needs to be publicly exposed and humiliated for his sloppy, biased “science”. The sooner the better.

        • commieBob,

          Stop reposing hope in discovery.

          Who’s we? I don’t keep hoping further disclosures will be the magic bullet that finally proves Mann’s work to be as bad as we suspect. Because that’s already been proven. Nobody cared then, and they won’t care next time.

          Sloppy doesn’t entail “fraudulent,” so the articles about Mann would still be defamatory if he were guilty only of sloppiness.

          What I’m hoping—increasingly forlornly—is that someone will have the savvy to pursue the strategy I outlined in a comment Mark Steyn himself was kind enough to retweet a couple of years ago.

          To paraphrase, I said all we can prove in court is that Mann is a dishonest antiscientist, regardless of the “truth” about temperatures in the Middle Ages.

          And we can prove this in five fracking minutes.

          One proof (among others) would be to read out in court a 2005 Wall Street Journal piece by Antonio Regalado—no climate skeptic—in which Dr Mann blurts out, SEVEN YEARS LATER, that he’s still not prepared to reveal the information needed to replicate his “groundbreaking” (i.e. career-making) graph because,

          “Giving them the algorithm would be giving in to the intimidation tactics these people are engaged in.”

          (Ah yes, ecneics—the bizarro universe in which replication = bullying.)

          If the judge doesn’t grasp that these are NOT the words of someone committed to the advancement of human knowledge, but of an an avowed retardant of progress and enemy of science, then my opinion of the judiciary may have to be revised downwards to approximate my opinion of the academy.

          To put it another way, the stuff Mann is hiding may or may not contain proof that he is inept at science.

          But the fact that he is hiding it proves he is NOT INTERESTED IN science.

          Which amply vindicates, and insulates against any libel charge, the Simberg/Steyn word choice:

          “fraudulent.”

  3. lt looks like to me that there was little change at the equator but increased warming as you move towards the poles. The warming seems to have happened all year around and was largely caused by a increase in movement of warmth into the poles from around the equator.

  4. ‘probably linked to solar forcing.’ We just don’t know why it got warm nor do we know why we into LIA or warmed up to present day. We just don’t know. Scientists who study the “why” may have to collect data for the next 1000 years.

  5. This is skeptical science at is most useful.

    I’m on record that trying to ‘rebutt’ the IPCC reports is both futile (since nobody with a life has the patience to follow the arguments, so they’ll just go with the mythical majority by default) and masochistic (since it muddies the simplest and best point we should be hammering home about the IPCC—it’s not a scientific panel/process/document so nothing it says should be taken seriously—by taking it seriously).

    But debunking a specific, bite-sized piece of bunk like MBH and Son of MBH is a different story.

    Don’t bite off more than you (or any human) can possibly chew.

    Win one point, resoundingly, at a time. Then another. Then another.

    This is surely a banal, self-explanatory tactic.

    Naturally, it hasn’t stopped a certain Michael Mann elevating it to the status of evil genius by calling it The Serengeti Strategy.

    But it’s really nothing but the age-old discovery of Mr Snake that if you try to ingest Mr Dead Donkey holus bolus, without chewing, and without the advantage of cutlery, your anatomy will regret it.

    I’d love to ask the respected, thrice-investigated, thrice-vindicated scientist:

    Didn’t your mother read the classic animal fables to you? Didn’t she tell you what would happen if you ate an ass whole?

    • Clarification: when I wrote “this is skeptical science at its most useful” I didn’t mean the paper in question was good—I haven’t even had time to read it!

      I just meant that this genre of argument (scientific research that, IF IT CHECKS OUT, would problematize a specific catastrophist premise) is the best use, rhetorically, of non-establishment, non-bought-and-paid-for scientific research.

      But it should go without saying that science isn’t about being useful as ammunition in a conflict, but about increasing our knowledge about nature, no matter which “side” that knowledge happens to vindicate.

      I do not for a second mean to suggest that science *is supposed to* produce findings that refute catastrophism.

      Science *is supposed to* produce evidence as to the truth, whatever the truth happens to be, without fear or favor.

      I’ll say all this anyway because this is climate, and in climate, nothing is sufficiently obvious that somebody out there won’t misunderstand it.

      Ah, forget it all to heck. My original comment requires so many “clarifications” (i.e. backpedallings, qualifications and caveats and amendments) as to be stupid. I should have saved time and not written it in the first place.

      • Brad Keyes

        Ah, forget it all to heck. My original comment requires so many “clarifications” (i.e. backpedallings, qualifications and caveats and amendments) as to be stupid. I should have saved time and not written it in the first place.

        The most sensible thing I have seen you post. No idea where “Ah, forget it all to heck. emerged from though. Perhaps some Germanic interpretation of English language humour that went tit’s up?

      • Sorry, but anything anyone says against Michael Mann is because of the big bad oil companies who pay scientists off to deceive us so they can continue to make billions selling us products we want. Naomi Oreskes said it herself, and ’tis written in one of the Bibles of the movement, “Merchants of Doubt.”

        Michael Mann did bad science. Oreskes legitimizes that science through ad hominem attacks on anyone who disagrees with Mann. Oreskes is a big problem because she’s defining the narrative and because her writing and speaking is highly deceptive; in many cases it’s just outright lies. http://www.nicolasnierenberg.com/uploads/1/1/6/6/1166378/oreskescritique.pdf Mann is a little problem by comparison.

        Here is a recent media story that purported to demonstrate how insects in the Luquillo Forest of Puerto Rico are dying because of climate change. It is clearly nonsense. http://www.wbur.org/onpoint/2018/11/01/the-cost-of-climate-change-across-the-animal-kingdom

        Personally I think we need to respond to reports such as these as soon as they come up, and in a rational and calm way point out how they’re wrong. Chip away slowly but surely at the false narrative that people swallow.

        IMHO
        Don132

        • Thanks Don.

          How about quoting the impeccably orthodox colleagues of Mann who wrote (not for public consumption, obviously) that his work was sloppy and McIntyre was right and Mann was doing a disservice to climate science and his speeches made them want to barf and (….)

          Wouldn’t that tactic circumvent the fossil-fuel-funded libel? (The irony being, of course, that Mann’s alarmist colleagues ARE bankrolled up to the gills by BP, Exxon Mobil and the rest.)

          • Like I said, anyone who says anything against Mann is because they’ve been deceived by the merchants of doubt who are trying to wean us from the One True Truth that Oreskes proclaims.

            Mann and the question of the medieval warm period aren’t the real problems. Oreskes is. Her book sets the stage that Mann and company dance on. In a world of narratives and cross-narratives, she sets the meta-narrative that allows bad science to flourish: all those who disagree with the 97% (itself a fiction!) are just paid off or influenced by those who are paid off. It’s an insidious poison and wholly false, yet wholly believed by far too many.

            Don132

          • Don,

            that’s perceptive of you. (I know because I perceive the same thing!) It all goes back to Oreskes. That’s why I expend almost as many GIFs on her as on Lewandowsky.

            And her one-page 2004 essay, the foundational myth of the entire climate movement, is an insultingly unserious imitation of scholarship.

            Did you spot Gore’s lie-by-implication in An Inconvenient Truth (“none of the 928 scientists disagreed”), which insinuates but never actually says “they all agreed”?

            And did you see the 2014 MOD movie, which avoids this suggestio-falso-suppressio-veri approach in favor of the oldest trick in the book: baldfacedly lying?

            An infographic in the film—a film Oreskes claims academic responsibility for on her CV, and obviously gave approval to every aspect of—shows that 928 scientists AGREED.

            Never mind that Oreskes had previously made a big deal of the fact that none of them said anything (for or against) the proposition, and that this magicologically proves they all agreed with it so strongly, it didn’t need to be mentioned out loud.

            Never mind that. Now, in her 2014 retelling of her 2004 retelling of events she probably invented to begin with, the scientists ALL AGREED.

            These shysters have certainly heard the advice “pick a lie and stick to it,” but they’ve found it’s not really necessary. They think they can say anything with impunity. And they’re right, so far.

  6. That the MWP-period, 1000-1200 AD, was global and not regional is highly important!
    The next study must show the preceding global COLD period at 700-800 AD (LALIA), and before this, the global RWP (Roman Warm Period)…..[ compare temps of the GISP2, Alley, 2004 chronology].
    A two millenial picture will show alternating periods of a WARM period (RWP 300-400 AD) a COLD period (LALIA 700-800 AD)- a WARM period (MWP 1000-1200 AD) a COLD period (LIA 1600-1700 AD) and a WARM period (CWP -contemporary warm global period 2000-2100 AD), which will be followed by a future global cold period at 2400-2500 AD …..
    By calling the global MWP only regional, all warmist proponents deny this about 400 yr long cyclic climate evolution. This is the aim and intention of the “regional” argument!
    We may derive 2 conclusions:
    1. There is an about 400 yr long global external driving cycle of warm-cold
    over the past 2 kyrs,
    2. the GISP2 chronology is a proxy for GLOBAL temps and is not limited to
    only regional or local significance, which is the repeated false warmist meme….
    More details see: http://www.knowledgeminer.eu/climate-papers.html
    which provides empirical,detailed prove for over 10,000 years – here in this case, the PART 6 and PART 7 of mentioned Holocene papers.
    Hopefully, Sebastian and his team will continue to focus onto the above named previous periods.
    At the moment, all agree on the contemporary warm CWP, the cold LIA,
    the warm MWP. The next period to be comprehensively documented has to be the cold LALIA anf the warm RWP.

    • There is already a lot of evidence for a global RWP and Dark Ages Cool Period, aka Vandal Minimum. Such as this from 2013, Wang et al.:

      Seasonal climate change across the Roman Warm Period/Vandal Minimum transition using isotope sclerochronology in archaeological shells and otoliths, southwest Florida, USA

      https://www.sciencedirect.com/science/article/pii/S1040618212033241

      Abstract

      “Archaeological evidence suggests that southwest Florida experienced variably warmer and wetter climate during the Roman Warm Period (RWP; 300 BC–550 AD) relative to the Vandal Minimum (VM; 550–800 AD). This hypothesis was tested by reconstructing seasonal-scale climate conditions for the latter part of the RWP (1–550 AD) by using high-resolution oxygen isotope ratios (δ18O) of archaeological shells (Mercenaria campechiensis) and otoliths (Ariopsis felis). Eight shells radiocarbon-dated to 150–550 AD recorded that the RWP summers at 150–250 AD were insignificantly different from today and the RWP summers at 250–350 AD and 450–550 AD were drier relative to today. Eight otoliths indicate that the winters were variable during the RWP, colder than today at 150–200 AD and 250–300 AD, similar to today at 200–250 AD, 300–350 AD and 450–500 AD, and warmer than today at 500–550 AD. The climate reconstructions agree with archaeological observations and are partially coherent with the history of sea-level change, with a drying and cooling trend at the 95% confidence level across the RWP/VM transition. The climate transition is not only consistent with falling sea level, but also coherent with reduced solar radiation. Reduced solar radiation may have triggered a change in atmospheric circulation patterns that precipitated the observed climate transition.”

      This paper finds the same for the NW Pacific, to include the Minoan, Roman and Medieval WPs, but also the strong counter-trend cycle during the Dark Ages Cool Period called the Sui-Tang (minor) WP.

      http://hockeyschtick.blogspot.com/2012/07/another-broken-hockey-stick-new-paper.html

  7. The next line of defense or desperation is ” the MWP or WCA wasn’t as warm and the LIA wasn’t as cold “.
    But I have faith in AGW, they will come up with another line of abject reasoning to explain it away. Just like the recent sloppy findings that the heat is hiding in the oceans. Let’s forget about the Arctic melting for awhile and focus on the heat hiding in the ocean. Those SLR’s can’t be right, they will need adjustments. Adjusting the adjustments till the numbers agree with the models, that’s scientific. Maybe an El Nino will save them.
    Any day now .

    • I’m waiting on the solar minimum mid-latitude volcano to blow. Add -2C on top of -2C, throw in flaky wind and solar power and we will be in a world of hurt.

  8. I agree to to fact that those “scientists” who deny the occurrence of earlier naturally-occurring warm periods in the world are clearly choosing to ignore our world’s history and the several records composed in its sediments.
    but again it is another example that undermines IPCC “settled science”
    As any half-decent scientist could say or state – scientific knowledge is always provisional but in actually science has never settled. New theories with facts and figures always come as the research goes on…

  9. Another small bit in the evidence that warming was more global in the both the Roman warming and MWP was that this was also when there was a lot more migratory movement in the southern and equatorial Pacific Polynesia Islands by early Austronesian peoples with numerous migrations at different times from west to east, with several of the islands being settled for the first time. This is because under El Nino conditions, the trade winds reverse direction, blowing from west to east (Asia towards Peru). The warm waters off Asia start migrating across the tropical Pacific towards Peru, and the waters cool off Asia. If there was many more such El Nino events, this would have allowed the sea faring Polynesians to run with the wind, rather than trying to tack against the normal trade winds which normally blow from the east. Sailing into the prevailing winds with those sailing rafts was certainly more difficult. If there was multi century warming during those times, exploration would have been much more favourable for many of these small dugout sail rafts to reach and settle uninhabited islands. We do know that discovery and settlement of many of these numerous islands did happen approximately congruently in these longer warm periods in both the time of the Roman and Medieval warm periods that are known to have happened in the mid to northerly latitudes of the NH.

    Perhaps this research is already old and verified that there was many more El Nino’s burping out heat in these warmer times making the planet over all much warmer, along with the reversing winds that come with the ‘little child’. I only thought of the coincidence the other day after watching a good documentary about South Pacific discovery of numerous islands discovered and inhabited by the early Malayo-Polynesians, and that their time of exploration was usually when the trade winds reversed with an El Nino. Perhaps this is further evidence that there was a rapid expansion and settlement of Pacific Polynesia eastwards throughout these warmer time periods that was prevalent across the entire planet, and the source of that warming was the numerous El Nino events, probably from solar forcing and/or cloud formation.

  10. The markers on the map show not only did the high latitudes become warmer but also become abit wetter as well. This suggests that the MWP was linked to warming oceans or at the very least large movements of warm moist air coming up from the tropics.

    • So in modern climate science all one needs to do is build a model and find an algorithm that shows catastrophic warming after 100 years.
      Based on this data.
      The colours are not sufficiently scary though.
      There should be much much more red and orange, with yellow highlights.
      A hockey stick at the end after a .5C increment should just about finish the argument.

  11. “like to tell us the Medieval Warming Period was just a “regional” event rather than global, because if it was global, that destroys their narrative.”
    Often said, but not often backed with proper quotes. The one linked here goes back to 2002 (nothing more recent?). But if you read what it says:
    “Regional temperature patterns elsewhere over the globe show equivocal evidence of anomalous warmth (see Wigley et al., 1981; Hughes and Diaz, 1994) and, as Lamb (1965) noted, episodes of both cooler as well as warmer conditions are likely to have punctuated this period.”
    and look at the map shown here, it seems to be quite a good descriptor. There are cooler and warmer spots, and it isn’t as if S America is solid red. The map confuses the issue by trying to cover dry/wet and warm/cold with just four colors, but it isn’t clear that the mix of colors is much different in S America from what you would get at other times.

    The AR4 had a special box (6.4) on the ‘Medieval Warm Period”. It seems quite consistent with this map.

    • Nick Stokes

      What are you trying to say here Nick?

      That warming was indeed regional? Fair enough, I accept that, but mankind flourished in these warmer temperatures, so why is the next 0.5ºC the IPCC predicts so disastrous to mankind when it has already been successfully dealt with, regionally or otherwise?

      Is there a regional coping mechanism? i.e. that folks from colder climes can’t take the extra warmth? In which case why have so many northern Europeans managed to live so well in Northern Australia, Africa and the Middle East etc.?

      • “What are you trying to say here Nick?”
        Just that there isn’t much to it. Scientists aren’t as negative about the MWP as claimed, and there isn’t that much evidence to say that anyone in particular is wrong. Maybe it was warmer than usual in S America – it’s hard to tell, since many of the colors tell about wet/dry. Was the MWP supposed to be a wet time or a dry time?

        • Nick S., earlier this year, Mann, in the debate with Judith Curry, presented the Hockey Stick as still valid, and claimed great support for it.

          • Was the MWP supposed to be a wet time or a dry time?…

            warmer than usual…which could mean it just wasn’t as cold…not necessarily higher temps

          • It was warmer globally. Regionally, it was wetter in some places, and at some times, while drier at others. WX patterns shifted around.

            My region, the Pacific NW of North America, appears generally to have been drier, at least during the growing season, based for instance upon tree rings, but possibly wetter in winter, based upon lake sediments.

            But, as with most temperate and polar regions of the planet, the MWP here was warmer.

        • I suggest that we all take to the streets to protest Nick Stokes’ interjections, and do so in the most scientifically sound manner possible. I recommend that we all go out and purchase a Costco-sized case of Ramen noodles, and run about scattering them willy-nilly in protest against Nick. No one of any scientific stature will be able to deny the reality of Anti-Stokes Ramen Scattering….

          • Nick,

            I always suspected you guys were as anti-humor as you are anti-science. Deducting a point for the crime of making an objectively-funny pun, SRSLY? The score you awarded Michael seems almost calculated to confirm my prejudice. Or am I just being humorless about your (meh) mathematical joke? Or is this just my imagination? It’s all so complex….

            (Now THAT’s the kind of pun you should feel free to downvote.)

          • Brad, thanks for the counter comment to Nick’s. But you have to admit, that has to be one of the most delightfully intelligent down-votes ever!

          • Michael,

            I admit nothing.

            Let Nick’s deprecation of your joke be as witty as all get out, it STILL exposes him as profoundly anti-laughter. Don’t be fooled by the sheep’s clothing. Nick’s schtick stokes humorlessness using Alinsky’s ultimate weapon: comedy. Did you ever see those old throat-lozenge commercials with the tussive, laryngitic guy in a frog costume? Stokes’ anti-joke jokes are like the proverbial croak: beyond the pale.

          • It’s difficult to argue with your logic, having had several tumblers of Knob Creek 100 proof. So is Nick is using Saul Lewinsky’s (Hannity’s pronunciation) ultimate weapon: comedy, it stands to reason that we must counter with ours: gravity. That leaves him with only anti-gravity, and everyone knows that’s a joke.

    • Yes, the map has the limitation of only four colours. Whenever there is temperature information, these are shown in red or blue. Many of these temperature sites also have hydroclimate info in the respective text box, which is not shown in the colour-coding. While this is of course not ideal, it allows to collect all information in ONE map, rather than two. One stop shop. Saves lots of time.

        • Nick,

          They are saying exactly what you said nobody is saying, namely that the MWP wasn’t global. SkS says that not only wasn’t the MWP global, but that it was globally cooler than now. Both of which are false and one of which is the statement which you wanted shown to you since 2002.

          • John,
            ” Both of which are false”
            Where do you see in this paper (or any other) a claim that the MWP was warmer than present? The MWP is characterised as a period that was warmer than the years before and after. The SkS article, like others, doesn’t contradict that. The MWP could easily have been global without being warmer than present.

          • SkS says that globally Earth was cooler during the MWP than now. That is false.

            You could look at early editions of IPCC reports to see that the MWP was warmer than the present, or at least the 1990s. And since then, but for super El Ninos, temperature has been flat.

            Have you really never read a paper which the MWP was found globally warmer than now? There has not yet been a single 50-year interval in the Modern Warm Period warmer than three such intervals during the Medieval WP, in the reconstructed CET.

            And of course not just NW Europe was warmer than now then. So was at least most of the rest of the world, such as, among areas well sampled, North America, Andean South America, temperate Africa, China, New Zealand and the Pacific Ocean.

            Apparently you missed this post:

            https://wattsupwiththat.com/2013/10/31/new-paper-shows-medieval-warm-period-was-global-in-scope/

            http://www.sciencemag.org/content/342/6158/617

            Pacific Ocean Heat Content During the Past 10,000 Years

            Yair Rosenthal, Braddock K. Linsley, Delia W. Oppo

            Abstract:

            Observed increases in ocean heat content (OHC) and temperature are robust indicators of global warming during the past several decades. We used high-resolution proxy records from sediment cores to extend these observations in the Pacific 10,000 years beyond the instrumental record. We show that water masses linked to North Pacific and Antarctic intermediate waters were warmer by 2.1 ± 0.4°C and 1.5 ± 0.4°C, respectively, during the middle Holocene Thermal Maximum than over the past century. Both water masses were ~0.9°C warmer during the Medieval Warm period than during the Little Ice Age and ~0.65° warmer than in recent decades. Although documented changes in global surface temperatures during the Holocene and Common era are relatively small, the concomitant changes in OHC are large.

          • And no doubt you’re familiar with GISP2 data, showing Greenland warmer than now during the Medieval WP, with the Roman WP warmer still and the Minoan WP warmest of those four post-HCO WPs.

            https://wattsupwiththat.files.wordpress.com/2014/09/d1a5b-interglacial2btemperatures.jpg

            The downward trend is not our friend. If human activity can indeed warm the planet a bit to help reverse that trend, all to the good. But so far the main benefit of more plant food in the air has been to green the planet.

          • RE: Where do you see in this paper (or any other) a claim that the MWP was warmer than present?
            Try written history. Then move to Greenland and try to farm barley and ranch cattle there today as was done during the MWP. Good luck.

          • Bill,

            Or try to grow grapes in N. England or Scotland which produce wine superior in quality to the best from France.

          • Nick,

            It the MWP were indeed cooler than the Modern WP, why do you suppose that “climate scientists” felt the need to get rid of it?

            And tried to do so with Mann’s bogus “hockey stick”?

          • John
            “Have you really never read a paper which the MWP was found globally warmer than now?”
            No. Please cite one, and quote what they actually said. You list a lot of things which are either not true, or just irrelevant.
            1. CET goes back to 1659. And it does not show any period of early warmth comparable to present, but anyway gets nowhere near the MWP.
            2. The Rosenthal paper says nothing about surface temperature. It is about bottom temperatures at 500m or more depth, which can’t be expected to respond yet to modern warming. And all but one core stops before 1950.
            3. The GISP2 data that you show stops at 95 BP, which is 1855.

        • Nick Stokes .
          The MWP was warmer than present and the proof is right there for every one to see .
          The Vikings farmed in Greenland and grapes were grown in northern England for wine .
          Then you state ” but it was not warm all over the world ,this was a localized event ” and” it was not global”.
          It had to be warmer then than it is now ,that is a fact. You can not deny this .
          Please explain how the Vikings could farm in Greenland if it was not a great deal warmer than now.
          Then explain why or how it could be much warmer in Greenland 1000 years ago and that warming did not affect the rest of the world .
          You guys are quite dishonest stating that the MWP and the other climate optimum’s were not as warm as present .
          It dose not fit your beliefs so you close your mind and scream” it was not global “and then “it was not as warm as present ”
          There are none as blind as those who do not want to see.

          • “It dose not fit your beliefs so you close your mind and scream” it was not global “and then “it was not as warm as present ”
            There are none as blind as those who do not want to see.”

            After that bit of irony.
            Would you like to link to studies that indicate that the MWP was warmer than present?

  12. The Medieval Warm period was global.
    This is a inconvenient fact that the warmist scientists deny vehemently and they have done everything in there power to dismiss and insist that the MWP was not a global event.
    I have been following this for 30 years when I met John Maunder a New Zealander who was a member of the WMO and had attended the very first climate conference in Villach in Austria and the second in Rio de Janeiro .
    John’s opinion was that the MWP and the earlier climate optimums were global and that most of the warming in the last 30 years is natural variability and the world was still warming from the little ice age.
    Our warmist scientist James Renwick formerly of NIWA has written that the MWP is an inconvenient fact and that( they) have to disprove that it was global.
    His mate Jim Salinger has stated the same but he has his name an early paper that involved stalactites in the Waitomo caves proving that the MWP was an influence in New Zealand .
    James Renwick is now a professor at Victoria University in Wellington and the news media trot him out to reinforce the dire warnings that we have to stop using fossil fuels to save the world.
    Of course that only applies to you and me ,not them .
    I have rigorous debates with my younger brother who is a geothermal scientist and he insists that the MWP only occurred in Europe and CO2 is driving the climate of the world because as a scientist he knows that air with a little CO2 added warms a little.
    I agree with that but the emphasis has to be on little .
    The theory of CO2 global warming depends on positive feed backs to amplify the warming and the tropical hot spot that has not been identified .
    I have not seen any proof that the small amount of warming from added CO2 will do any harm at all and will most probably be beneficial and the extra CO2 is already improving plant growth around the world.

  13. Whether or not the MWP was global or not is academic
    ==================
    A regional warming raises the global average. As such, there is no such thing as regional warming without global warming. They are mathematically linked by the definition of average.

    For example, the current modern warming is mostly regional, mostly in the Arctic, yet it raises the average temperature globally. Thus it is scientifically dishonest to claim regional warming is not also global warming.

  14. Please less arguments about the writton word and more about what to do over the fact that the Media likes scary stories and not good news.
    Read George Orwells 1984, and study the very sucessfull properganda of Dr . Gobbles. Its no good us saying that Michael Mann is a phony, we all know that. We have to beat the Media and the only way is to use the nternet and its various outlets.
    It would be nice if we had a skeptial billioneer, but we don’t, so use what all the kids are using.

    Nature and the cooling will take too long, n the next 10 years the warmers will destroy Western civilisation economically, unless we can convience enough people that the UN IPCC and much of the Media are trying to destroy our Western way of life.
    Trump for all his eratic ways is our best hope at the moment.

    MJE

  15. There plainly is not nor was there ever a coherent argument for CAGW. I base this on one simple truth alone (there are many others); The models and thus the implications and recommendations which have come from the IPCC are based solely on the premise (obviously preconceived, confirmation bias) that CO2 is THE cause.
    This is so clearly and laughably incorrect that the argument itself has failed utterly even to the working “man” on the street and would have long since been a footnote in history had not the forces behind it convinced, forced and bought the media coverage this nitwit scheme has received.
    Now all of that said there are numerous lists of the creators of this fraud on mankind admitting openly that it is about creating a new world (socialist) order. So my point to all would be we are wasting energy on the distraction of CAGW and not keeping our eyes on the real prize which is the unceasing attempts to seize power and money from the people and concentrate in this (evil) new world order.

  16. According to David Appel, skeptics should be barracking FOR the HS, because it implies lower climate sensitivity. The MWP, he says, is bad news for skepticism and excellent news for warmism.

    I was going to say David Appel et al., but alas, in terms of other humans on the planet agreeing with his crank fringerie, Appel is still at an Adam in search of an Eve stage.

  17. One way to illustrate the Medieval Warm Period, that Mann”disappeared”, is to start with the the magnificent cathedrals in England and Europe.
    Both regions required exceptional prosperity to pay for very expensive non-economic structures that took decades and decades to build. Barely staying alive cannot afford to feed many construction workers.
    Climate warming equals big prosperity.
    The long warming trend improved harvests from existing fields and allowed cultivation further north and in regions with higher relief further up slope.
    Universities such as Cambridge kept annual accounts of weather, crop conditions, and prices into the 1300s.
    Then, as Rosen writes in “The Third Horseman”:
    “In May 1315, it started to rain. For the seven disastrous years that followed, Europeans would be visited by a series of curses unseen since the third book of Exodus: floods, ice, failures of crops and cattle, and epidemics not just disease, but of pike, sword, and spear. All told, six million lives–one-eighth of Europe’s total population–would be lost.”
    And today’s promotion of hysteria is based upon climate warming.
    What a crock!

  18. Well Mann’s twisted bristle-cone tree bit was also rather regional. And just Northern Hemisphere at that.
    Weighted 375 times or not, still quite regional…

    Or did I miss something?

  19. I think the AGW movement is a left wing fraud but also think man made global warming is possibile. Mankind uses the oceans as a toilet for industrial, human, and animal waste. The third world and Asia are the biggest problems. Polluted (darker) ocean water absorbs more sunlight than clean water. If the oceans are warming its because of this and not because of a blanket effect of CO2. If wastewater is the problem addressing atmospheric CO2 will do nothing to solve the problem, and it will hurt economies greatly. Waste water treatment if properly done would cost a small fraction of that proposed to pointlessly address reducing atmospheric CO2. Ocean pollution depletes ocean oxygen levels and adds carcinogens. CO2 makes plants grow better.

  20. This particular argument is really an argument over the Jones/Mann discredited “hockey stick” graph.

    It used to be that most scientists agreed that, over the last few thousand years, the Earth’s climate has oscillated, on timescales of a few centuries, between warm “climate optimums” and unpleasant cold periods: the long Holocene Climate Optimum (when temperatures were apparently substantially warmer than now), followed by a cooler period, then the Minoan or Bronze Age Warm Period, followed by another cool period, then the Roman Warm Period or Roman Climate Optimum (“RWP”), then the Dark Ages Cold Period (“DACP”), then the Medieval Warm Period or Medieval Climate Optimum (“MWP”), then the Little Ice Age (“LIA”), and finally the Current Warm Period (Modern Climate Optimum). However, that chronology represents a problem for climate alarmism, since it indicates that there’s nothing particularly unusual about the warming which occurred during the 20th century.

    In 1999, Mann, Bradley & Hughes challenged that orthodoxy with a new temperature reconstruction, in their heavily-hyped “hockey stick” paper, which erased the MWP and LIA to create a straight “hockey stick handle” from 1000 AD to 1900 AD, followed by a sharp “hockey stick blade” of rising temperatures in the 20th century.

    A variant of the hockey stick graph from that paper, created by Phil Jones, also appeared on the cover of the World Meteorological Organization’s alarming 1999 Climate Statement. In that graph, Jones infamously used “Mike’s Nature Trick” (“Mike” was Michael Mann), of splicing measured temperature data into a graph of temperature “proxies,” to hide the decline in climate proxies, which would have spoiled the “hockey stick shape” of the graph, discredited their tree ring proxy-based temperature reconstruction methodology, and undermined the narrative of alarming global warming.

    Jones used identical colors for the proxy reconstruction data and instrument data, and rounded the three splice points to hide the splices. He even “bent” the bottom of the blue instrument data trace out to the left a bit, to connect it with the blue (Mann) proxy trace. Despite the graph labels which claimed that the three traces were proxies, from 1981 on all three traces were actually real (instrument) temperature data (and the green trace was real temperature data from 1961 on). Yet the three traces of the same instrument data were slightly different, because, to hide the splice points, Jones had to bend the traces a bit, to make them line up with the three proxy traces.

    The emails between Jones, Mann, Bradley, Hughes and others, discussing that graph and “trick,” were among the most infamous revelations of the Climategate scandal.”

    ● On one side, the indispensable CO2 Science project has compiled an extensive collection of studies and papers with evidence for the traditional view: that the MWP and LIA were real and global. Also, here are two  articles and a map, showing the preponderance of studies which support that view.

    ● On the other side, the Pages 2K Network (or here) was created in 2008, to compile evidence for the merely “regional nature of the Medieval Warm Period and the Little Ice Age.” (That contention is quoted from the caption on Fig. 1 of their poster, though they more frequently use the revisionist term, “Medieval Climate Anomaly” or MCA.) Canadian mathematician Steve McIntyre offers an excellent multi-part critique of the Pages2K project, here.

    (I copied most of the above from my web site at https://sealevel.info/resources.html#mwp_lia )

    • Temperature variation during Holocene is interesting. I think the best proxy for this is glaciers. It has been known for some years now that glaciers retreated during MWP on a world wide basis. So the results from Dr. Sebastian Lüning and Prof. Fritz Vahrenholt don`t come as a surprise.

  21. Interesting question is, if the MWP only applied to Europe, how much colder would it have had to be in the rest of the world to give the zero overall change claimed by Mann?

  22. It’s totally depressing that people like Mann and Hayhoe can actually have jobs in scientific fields.

    Truly depressing, and a sign that we have a long way to go as a species

  23. no one on this site understands what manns regional claim was.
    and this paper does not address it in a quantitative way

    • Now there is a mighty ignorant and sweeping statement.
      You presume to know this,how?
      Why do you even bother your keyboard?

  24. One of the most famous French “climatologue” said on TV that it happened ONLY IN FRANCE.

    Another one said only in Europe.

  25. From my studies, the source of most of the global climate change seems obvious. North and South America separated from Europe and Africa very rapidly. That generated lots of super sonic steam and ash and lots massive tidal waves that flushed the world’s land masses. The brand new Atlantic Ocean was pretty hot. That hot water kept the earth covered with clouds preventing solar energy from getting in. So the land was cold due to lack of sunshine and the oceans were very warm. That caused massive hurricanes which came into the lands and created all of the snow which turned into the ice of the ice age. Once the oceans cooled, the hurricanes got smaller and less frequent and the ice age slowly retreated. I believe much of the global warming today is just the continued retreated of those glaciers. Those glaciers protect us from hot summers by melting. It takes tons of energy to melt ice (80 cal/ml). Glaciers keep our summers from overheating, but do little to make winters colder. So as the glaciers get smaller and smaller, our summers get hotter and drier. As for CO2, if we had more of it and less pollution in the air, our plants would grow bigger and better. The extra plant life would evaporate more water keeping us cooler and decreasing the intensity of droughts. I believe air pollution makes our trees and plants more diseased and that leads to faster death and that creates more deserts and reduces our forests. I believe air pollution is our major problem, not global warming. I think we need to focus on getting rid of most or all harmful air and water pollution. My conclusions for cleaning up the planet are the same. I just disagree with the causes of the problem and I disagree with pumping our CO2 waste into the ground. That is to survive and be more healthy, we need much cleaner air and water that what is available today. Currently our air is roughly 80% nitrogen and 20% oxygen with only traces of CO2 plus pollutants. It is those traces that cause health issues. It is proven that if we had cleaner air, we would be more healthy. The small amounts of CO2 in our air does not harm plants or animals, but it does provide materials needed for plant growth (CO2 and water plus sun are the majority of the basics of all living things). I think we need to focus on getting rid of what poisons our air and water. I like solar energy and solar panels because once installed, they are green and can work for 50 years or more generating enough electricity to displace tons and tons of coal and other pollutants. Now if we could have battery powered cars, the cars could connect to our grid day and night anytime they are not on the road and they could contribute much to the maintenance our our grid energy, supplying power to the grid when needed and charging from the grid when the grid has extra with the overall everyday average goal of maintaining car batteries at perhaps 50 to 80% full. Then add natural gas generation to back things up when days are cloudy, dark, and snowing.

  26. Glaciers in Alaska have been shrinking long before the Industrial Revolution according to the National Park Service. Go up to Alaska and visit the glacier national park that is located south of Anchorage. As you drive into the park on your way to the major glacier, it gives dates and location showing the retreat of the glacier going back something like perhaps 300 years ago, and well before the Industrial Revolution started. I believe there is lots of evidence showing the retreat was happening as far back as there are records and those records go back well before the Industrial Revolution perhaps to the exploration and global mapping age in the 1600s to 1800s. As glaciers retreat, there is a stream of water that flows from the glaciers that eventually connect to other streams or the ocean. Some of those streams are very long and the evidence from the rock damage seem to indicate centuries and centuries of retreating based on current rates of retreating. But you can’t base things on current rates because as global warming warms things up, the retreat gets faster and faster. When the glaciers were a lot bigger, they had so much ice that should have protected them from rapid retreating. If you put 2 ice cubes in a barrel, each cube will melt a lot faster than if those two cubes were among 2000 cubes in that same barrel. Right now, we are down to 20 cubes left compared to what it was at the supposed end of the ice age or what it was several thousand years ago.

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