New paper shows Medieval Warm Period was global in scope

Andrew Revkin writes:

Michael Mann can’t be happy about this work.

Here’s a chat with two authors of an important new Science paper examining 10,000 years of layered fossil plankton in the western Pacific Ocean. The paper finds that several significant past climate ups and downs — including the medieval warm period and little ice age — were global in scope, challenging some previous conclusions that these were fairly limited Northern Hemisphere phenomena.

(video follows, an interview with authors)

The study finds that the rise in ocean temperatures in recent decades is far faster than anything seen earlier in the Holocene, the period since the end of the last ice age. But the researchers say that this rise is from a relatively cool baseline. Between 10,000 and 8,000 years ago, at depths between 500 and 1,000 meters, the Pacific Ocean was 2 degrees Celsius (3.6 degrees Fahrenheit) warmer than today. (text from the video description)

The paper is here:

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.

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123 thoughts on “New paper shows Medieval Warm Period was global in scope

  1. “” 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. “”

    That means these water masses have only warmed ~0.25° C since the LIA? Does this conflict with the conclusions of Levitus et al 2012?

  2. The evidence that the Medieval Warm Period was global, & that it, the Roman & Minoan WPs & the Holocene Climatic Optimum, or whatever the latest fashion in its nomenclature might be, plus the deglaciation phase prior to it, were also warmer than now has been abundant & growing since Lamb, at least, ie 50 years. The LIA & previous cold periods were also global.

    Which is why Mann needed fraudulent “tricks” & apparently intentionally inept statistical techniques or lack thereof to try to show recent warming to be special & scary.

  3. To: Prof. Michael Mann
    REF: Irony
    Dear Sir,
    Thank you for providing us all the ironic and incredibly pleasing spectacle of watching your nasty arrogant attitude at play as the work of your life is brought down around you.
    Sincerely,
    Etc.

  4. see also the editor’s comment on sciencemag.org:

    Deep Heating

    Global warming is popularly viewed only as an atmospheric process, when, as shown by marine temperature records covering the last several decades, most heat uptake occurs in the ocean. How did subsurface ocean temperatures vary during past warm and cold intervals? Rosenthal et al. (p. 617) present a temperature record of western equatorial Pacific subsurface and intermediate water masses over the past 10,000 years that shows that heat content varied in step with both northern and southern high-latitude oceans. The findings support the view that the Holocene Thermal Maximum, the Medieval Warm Period, and the Little Ice Age were global events, and they provide a long-term perspective for evaluating the role of ocean heat content in various warming scenarios for the future.

  5. omnologos: “far faster? what temporal resolution did they manage to get, in the Holocene?”

    This^. Be good to hear from someone that can go beyond the paywall and comeback with a notion of how moving the moving average is. My bet: Like all other claims, they didn’t look, don’t care, or didn’t average the modern moving average over the same range for a same comparison. Which is why we keep getting:

    “The twitchy average is twitchier than the untwitchy one! We are doomed! Doomed, I say!”

  6. lurker, passing through laughing says:
    October 31, 2013 at 11:59 am

    Precisely. If he keeps it up, he’s aneurism-from-cognitive-dissonance bound.

  7. “New paper shows Medieval Warm Period was global in scope”
    We need to start using words like “postulates”, or “hypothesizes” rather than “shows”. Most of these papers are “theorizing”, at best. “Suggests” is also a good word used in a previous post. It’s kind of like saying that anomalies in the rotational velocities and movements of some galaxies “show” that there is dark matter involved when they really only show that we cannot explain the velocities and movements and dark matter is “theorized” as a solution to the problem.
    And latest experiments to find some have failed. Need more grant money.

  8. Acccording to what I’ve read elsewhere, “far faster” applies to the last 60 years. That’s back to about 1950. But surface temperatures increased as fast, or almost as fast, during the first half of the 20th century.

    This smells wrong.

  9. This is not the first research paper to confirm that the Medieval Warming Period was global. Prior to Mann’s hockey stick nonsense, it was generally accepted that the MWP was global in nature by the climate science community. Even the IPCC very early on published charts to show that the MWP was global. After Mann’s hockey stick nonsense, some in the climate science community reinvestigaged the MWP and confirmed that it was global in nature. There is nothing new here… move on.

  10. John W. Garrett said:
    October 31, 2013 at 12:02 pm
    Chalk up yet another chink in the crumbling edifice of Michael “Piltdown” Mann.
    ————————————-
    “Piltdown” Mann

    Good one Sir! Thanks for the LOLZ :)

  11. I just want to scream ‘what do you mean by heat?’ Ask a layman and heat means HOT. Here they are flagging 0.5-08°c, which is not HEAT. Revkin should stop pretending to be journalist.

  12. They don’t understand that the climate is the sum of all average temperatures. Strange? Naaaa not if you know how it works. All over the world the temperature is watch t so all those temperatures to getter make one number and that s the climate where in.

    So is the average temperature 16 degrees Celsius then we have the climate optimum. Whit 12 degrees its smack in the middle and whit 8 degrees its freezing cold. Now whit all the data manipulation going on where not sure were we at in this time, oke AGWers call it 14 degrees but I think where more like 11 degrees or there about. So closer to freezing than to nice warm.

    The only thing is that both half’s of the world have different seasons but that wont make the sum different. Only in the sick head off someone like Mann the world works like that. In the real world it docent matter. And yes it works now it will work over 10 years and it work d 2200 years ago.

    Its the same as CO2 being Capable to warm one spot and 1000 miles a way not. Stupid CO2 is as dump as the next AGWer it do sent know boundary’s. If Mann and all agwers for that mater really thinks the medieval warming was a local thing they are ready to have brain surgery. If only to look for some kind of brain or at least some thing looking like brain. A peace of hamburger from MC Donalds would do the trick.

  13. “The paper finds that several significant past climate ups and downs — including the medieval warm period and little ice age — were global in scope, challenging some previous conclusions that these were fairly limited Northern Hemisphere phenomena.”

    When looking at the _current_ global warming pattern, it looks fairly limited to Northen Hemisphere to me.

  14. Jim G, i couldn’t agree more. The Scientismic Elites in nearly every field speak with such absolute authority, such certainty about very complex things that happened 10,000 (or 100,000 millions) years ago. The hubris is absolutely breathtaking. How long until the next study ‘shows’ something different?

    The real crime is these are the people who direct and police academia, who then teach all the ‘skulls full of mush’ in the same manner. No intelligence allowed.

  15. Maybe the climate freak-outs should start describing temperature in Kelvin rather than °C. Then 273 “degrees” would sound even more scary than it actually is. Although, I wouldn’t want to go swimming in water about the same temperature as many people did when the Titanic sank.

  16. The oceans temps are more stable than the atmosphere, aren’t they. They find the opposite, when they compare the proxies. I think this is more evidence that the atmospheric temp proxies are missing a lot of activity.

  17. Jquip says:

    October 31, 2013 at 12:09 pm

    omnologos: “far faster? what temporal resolution did they manage to get, in the Holocene?”

    Heard this “far faster” term used last night while listen to Sirius/XM. They made the far faster than anytime in X million years claim along with “every day is earth day”.

  18. As most everyone knows, I am skeptical of “paleo” studies. However, let me set aside that skepticism for a minute to explain what this paper means to Mann and his followers.

    If the medieval warm period was global and reached temperatures comparable to today then natural variability can explain all warming to this time. Natural variability is the full range of our data. With regard to surface temperature data, it is the full range of data from lowest to highest value through the period of time that we can reasonably investigate.

    There is no need to invoke CO2 forcing to explain a rise in temperatures from 1979 to 1998. If Mother Earth has done it before then we cannot be surprised when she does it again. There is no need to invoke any forcing as there is nothing to explain.

    Of course, the fact that natural variation can account for the temperature rise does not prove that CO2 has no impact but it does put the ball in the warmest ballpark. They can no longer claim that CO2 is necessary to account for the rise. Now they must show the mechanism and the evidence for it; that is, they must solve the forcings and feedbacks equation and show that the net is positive. They have made no headway in that regard.

  19. jquip–

    I did go beyond the paywall as you requested. Haven’t got much time to look at the results but here is Figure 3 and the Supplementary materials. A little something for every one, as they show temps higher than now throughout most of the Holocene, but also show the rate of increase much higher at present day. That was in Figure 4 of the main paper but I wasn’t able to extract that separately.

    Figure 3 compares Mann to Moberg and to Oppel (2009) SST. Shows clearly how the Mann curve pushes down the Medieval period and raises up the modern, but the MOberg and Oppel agree in finding both the Medieval and the Roman periods higher than present.

    Marcott 2013 also makes an appearance in the main text. Unclear whether the authors are accepting the results, but they do show them.

    https://dl.dropboxusercontent.com/u/75831381/Rosenthal%20ocean%20temps%20%20Figure%203.docx

    https://dl.dropboxusercontent.com/u/75831381/Rosenthal%20ocean%20temps%20Supplementary%20Materials.pdf

    https://dl.dropboxusercontent.com/u/75831381/Rosenthal%20ocean%20temps%20Holocene%20Science%20Nov%201%202013.pdf

  20. from one ocean basin they jump to global conclusions.

    what would folks say if the sediments showed the opposite

  21. so we have a change in temperature….for centuries…that was a local event

    …who was stupid enough to believe that in the first place

  22. Given the location of the cores could it be that large ENSO events would be recorded? They did admit they only had decadal resolution. Darn paywall means I can only speculate.

    Wondering if Bob Tisdale has a thought on this?

  23. @Steve Mosher “what would folks say if the sediments showed the opposite”

    Why not try asking Professor Mann? He knows all about inverted sediments..

  24. They claim that a 1000m depth in the tropical latitudes imply that when it changes rapidly that it must have been global. Suspect it is based on a mixing model involving currents in both the north pacific as well as the south pacific. Perhaps reading the paper will clear that up @SteveM.

  25. Mann understands well enough how devastating this might be for him. So, as fast as lightening, he’s out with quite a ridiculous response in Huffington Post.

    http://www.huffingtonpost.com/michael-e-mann/pacific-ocean-warming-at-_b_4179583.html

    One funny thing is that his headline reads “Pacific Ocean Warming at Fastest Rate in 10,000 Years”. So the main take-away message where there is no doubt for him is the only thing that in the interview the authors clearly said they can not really be certain about. All the rest he finds BAD BAD BAD. And almost all of the refuting, of course, comes from “Mann”, “Mann et al”, realclimate (Mann), “Mann and Jones” and so on. What narcissism…

  26. This has been suggested by several earlier studies. Oppo’s 2009 reconstruction of the Pacific Warm Pool suggested the Medieval warm period was at least as warm as today.ReadOppo. D., et al., (2009) 2,000-year-long temperature and hydrology reconstructions from the Indo-Pacific warm pool. Nature, vol. 460, p.1113-1116.

    Esper’s reconstrcution of Scandinavian tree rings also showed that the Roman period was warmer than the Medieval Warm Period which was warmer than the 1940s which was warmer than today. http://landscapesandcycles.net/image/75158734_scaled_586x204.png

    And Esper’s tree rings agreed with local instrumental data that was not tainted by urbanization and data homogenization. Mann’s hockey stick relied on essentially calling tree rings deniers that diverged from his homogenized data set.

    The truth is out there! And it is slowly coming into view.

  27. With strong written evidence for MWP in Europe and East Asia (the main places they were writing stuff down) I rather guessed it might be global. Next we’ll be told it wasn’t a constant and regular warming. Sounds just like our Modern Warming, doesn’t it?

    Anyone notice some strenuous attempts lately to bring back that hockey stick in its pristine 1990s glory? What next? Ban the Icelandic Sagas from school libraries like they banned Noddy? Snorri Sturluson to go the way of Enid Blyton?

  28. Steven Mosher says:
    October 31, 2013 at 1:21 pm

    You don’t get it. CACA advocates have tried to argue that the Medieval Warm Period was restricted to the North Atlantic region. Study after study from around the world has shown this to be a bald-faced lie. Now the western Pacific has been added to that long list.

    Besides which, the site surveyed also samples water masses linked to North Pacific & Antarctic intermediate waters.

    But please by all means try to support a regional, not global Medieval Warm Period if you think that you can. I’ve observed its signs in southern South America myself, so you’ll have a hard sell.

  29. My apologies to the original author, as I neglected to note their name or bookmark it:

    One Tree to rule them all,
    One Tree to warm them,
    One Tree to graph them all
    and in Global Warming bind them.

    Mann’s Yamal tree still trumps the mountains of evidence from the rest of the world. In his own mind.

  30. Some years ago, Dr Willie Soon, and Dr Sally Baliunas wrote a paper that was a review of many papers and reports from worldwide that showed that the MWP and the LIA were global phenomena, and not local peculiarities.

    On the other hand, I believe if you look at the ORIGINAL presentation of Michael Mann’s hockey stick graph, which was in one of the IPCC reports, it states quite clearly on that graph that it is Northern Hemisphere only. In other words, Mann’s hockey stick was given to us as a local curiosity; not a global phenomenon. Of course, later expurgatory episodes, removed those limiting words, to hide the truth.

  31. Who’s the editor of Science? High time to get him sacked!
    We’ll probably find out more from the eventual Climategate 2014 mails. If “the cooch” will not succeed before that…

  32. Mosher: “from one ocean basin they jump to global conclusions.”
    As I understand it, the logic was that NH medieval warm period and little ice age were already agreed upon, though recently declared just regional by Mann and the Team. Now they found the same thing in the SH. So that’s the reason for “global conclusions”.

  33. @omnologos: “far faster? what temporal resolution did they manage to get, in the Holocene?”

    Your comment proposes a test:
    How must faster is now, than the rest?
    Did they slice the cores fine?
    How precise is their line?
    “Century-scale resolution, at best”
    — (at 4:00 in the video)

    BRAD: We have fossils that have been bioturbated … we have pretty high accumulation rates, but we don’t have annual resolution .. You could say that we probably have century-scale resolution at best… It’s possible that the sediments just didn’t record similar warmings in the past.” YAIR: The deep ocean tends to average and smooth the record … I think it’s fair to say that it’s unlikely that very rapid changes on the order of, let’s say, years or even decades … would show up in the record.”

    The presumption that this claims to “show”?
    They are stating here: They cannot know.
    But they quickly recover, at last:
    “Recent warming is very, very fast!”

    But they’re fuzzy on just how they’re sure
    Andy Revkin gave up. It’s obscure…
    They like Marcott! And they complement it
    And they compliment. They might regret it.

    They admit other parts may be cooling
    “Need more data!” (That’s always the ruling.)
    They’d like to talk to ocean scientists
    (And they haven’t yet? One gap that still exists…)

    ===|==============/ Keith DeHavelle

  34. Steven Mosher says:
    October 31, 2013 at 1:21 pm

    from one ocean basin they jump to global conclusions.

    what would folks say if the sediments showed the opposite

    Everyone knows the Pacific has no effect on the rest of the world.

  35. It’s about time real science caught up and with sediment cores. Now move the drill ship to the Atlantic.

  36. Steven Mosher says:
    October 31, 2013 at 1:21 pm

    from one ocean basin they jump to global conclusions.

    what would folks say if the sediments showed the opposite

    That “ocean basin” occupies nearly half the globe. You would be mistaken if you did not draw global implications.

  37. george e. smith says:
    October 31, 2013 at 1:49 pm
    …..On the other hand, I believe if you look at the ORIGINAL presentation of Michael Mann’s hockey stick graph, which was in one of the IPCC reports, it states quite clearly on that graph that it is Northern Hemisphere only. In other words, Mann’s hockey stick was given to us as a local curiosity; not a global phenomenon. ….

    ======================================================================
    And, if I’m not mistaken, Mann even got that wrong.

  38. Since Dana Nuttercelli insists the ‘missing heat’ went into the oceans and that it’s a robust measure of global warming I wonder what he has to say about the oceans now?

  39. @ Lance Wallace — THANK YOU (at 1:21pm today) for so generously sharing with the rest of us.

    A Lance for Truth and Liberty!

  40. Steven Mosher says:
    October 31, 2013 at 1:21 pm

    from one ocean basin they jump to global conclusions.

    what would folks say if the sediments showed the opposite

    Do you mean like Yamal?

    And what would you have said had it had come to opposite conclusions?

  41. John W. Garrett said:
    October 31, 2013 at 12:02 pm
    Chalk up yet another chink in the crumbling edifice of Michael “Piltdown” Mann.
    Thank you for that one, this was my laugh-of-the-day!

  42. IPCC – Medieval Warm Period – FAR
    “This period of widespread warmth is notable in that there is no evidence that it was accompanied by an increase of greenhouse gases” IPCC WG1 Report 1990 (p202)

    http://www.ipcc.ch/ipccreports/far/wg_I/ipcc_far_wg_I_full_report.pdf

    How widespread was the Medieval Warm Period? It looks like it was global according to lots of peer reviewed papers.

    I have a paper from Michael Mann who said that there is evidence of olives and figs growing in Germany and Greenland warmth as well as graped grown in England well north of their current positions. Can an ‘expert’ here please explain to me what mechanism could cause it to be so warm in Germany, England and Greenland for such a long stretch without the rest of the world generally getting warmer?

  43. Here is the Mann paper.

    Medieval Climatic Optimum
    Michael E Mann – University of Virginia, Charlottesville, VA, USA

    It is evident that Europe experienced, on the whole, relatively mild climate conditions during the earliest centuries of the second millennium (i.e., the early Medieval period). Agriculture was possible at higher latitudes (and higher elevations in the mountains) than is currently possible in many regions, and there are numerous anecdotal reports of especially bountiful harvests (e.g., documented yields of grain) throughout Europe during this interval of time. Grapes were grown in England several hundred kilometers north of their current limits of growth, and subtropical flora such as fig trees and olive trees grew in regions of Europe (northern Italy and parts of Germany) well north of their current range. Geological evidence indicates that mountain glaciers throughout Europe retreated substantially at this time, relative to the glacial advances of later centuries (Grove and Switsur, 1994). A host of historical documentary proxy information such as records of frost dates, freezing of water bodies, duration of snowcover, and phenological evidence (e.g., the dates of flowering of plants) indicates that severe winters were less frequent and less extreme at times during the period from about 900 – 1300 AD in central Europe……………………

    Some of the most dramatic evidence for Medieval warmth has been argued to come from Iceland and Greenland (see Ogilvie, 1991). In Greenland, the Norse settlers, arriving around AD 1000, maintained a settlement, raising dairy cattle and sheep. Greenland existed, in effect, as a thriving European colony for several centuries. While a deteriorating climate and the onset of the Little Ice Age are broadly blamed for the demise of these settlements around AD 1400,

    http://www.meteo.psu.edu/holocene/public_html/shared/articles/medclimopt.pdf

  44. milodonharlani says:
    October 31, 2013 at 1:48 pm

    Steven Mosher says:
    October 31, 2013 at 1:21 pm

    You don’t get it. CACA advocates have tried to argue that the Medieval Warm Period was restricted to the North Atlantic region. Study after study from around the world has shown this to be a bald-faced lie. Now the western Pacific has been added to that long list.
    =================
    I fully agree with Milodonharlani that previous examples of the MWP were restricted to the northern hemisphere, whether real or imagined by many so called AGW fanatics or wishful thinking on their part, however with the MWP showing up in the vast Pacific Ocean this is a whole new adventure never previously verified. In essence – Mann and others are flat out wrong – again.

  45. Jeremy Poynton says:
    October 31, 2013 at 2:47 pm

    Good article here about that nasty disease, McKibbenitis.

    ==================================================================
    If you studied pre-tree-ring-history you’d find the affliction dates back to at least the advent of Caronitis. (And, no, I don’t mean Johnny.)

  46. albertalad says:
    October 31, 2013 at 2:53 pm

    In the 1960s, Medieval Warm Period evidence was largely restricted to part of the Northern Hemisphere, but already by the 1990s, if not before, the preponderance of observations showed it to be global. Strong evidence came not only from the oceans, but from land sites in Asia, Africa, Antarctica, South America, Australia & New Zealand, & from a range of different proxies.

    Many have been cited on this blog before.

  47. For example, here’s the famous New Zealand stalagmite study from 1979:

    Wilson, A.T., Hendy, C.H. and Reynolds, C.P. 1979. Short-term climate change and New Zealand temperatures during the last millennium. Nature 279: 315-317.

    Opposite side of the world from the North Atlantic region, ie North America & Europe, to which CACA shills would like to restrict the climatic event.

  48. A big thank you to Keith DeHavelle for posting a partial transcript from the video. It has a critical couple of sentences that should be added to the top of the post, because it eviscerates any claim of an unprecedented rate of ocean warming in the last 50 years. It is the same shambolic Marcott incident all over again.

    “You could say that we probably have century-scale resolution at best… It’s possible that the sediments just didn’t record similar warmings in the past.” YAIR: The deep ocean tends to average and smooth the record … I think it’s fair to say that it’s unlikely that very rapid changes on the order of, let’s say, years or even decades … would show up in the record.”

  49. Steven Mosher says:

    from one ocean basin they jump to global conclusions.

    No.

    From one ocean basin that covers the vast majority of the southern hemisphere, they (meaning Revkin and Watts) correctly conclude that the MWP is indicated to not be “just a Northern Hemisphere event” as is typically claimed by the pudgy goatee crowd.

    For one who’s always driving by, you have an awful lot of trouble keeping up.

  50. As someone linked th co2science site has hordes of papers showing the mwp and others. Ive read through scores of them years ago, I certainly saw nothing unprecedented about current changes, actually many records show several periods that changed much faster, and heck early 1900s changed as fast when we had more reliable data. Im shocked this claim stands as well as it does. It certainly doesnt speak well for our scientific institutions.

  51. Plenty of government grants in Australia for climate research. Anyone looking for the MWP there? That might put the cat amongst the pigeons in Mann’s work.

  52. “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.”

    OYG!!!!

    They need to report that in Joules! It has to be something like a bajillion Hiroshima bombs worth of OHC. How did those poor bastards in their loin cloths and balsa wood Kon-tiki boats manage to survive? Surely they burst into flame immediately upon setting sail.

  53. Mosher: “what would folks say if the sediments showed the opposite”

    The opposite of what they said. No, wait… are the ‘folks’ climatologists?

  54. Huffpo doesn’t like what I posted it seems.

    “Due to the potentially sensitive nature of this article, your comment may take longer to appear publicly.”

  55. 06:40 (paper) “The modern rate of Pacific OHC (ocean heat content) change is, however, is the highest in the past 10,000 years…”
    08:06 (comment by Yair Rosenthal) I think it’s fair to say, although I don’t think we can prove it with the current data right now without doubt, that the rate of warming of the deep ocean is much higher than what we see [in the sediment record].

    In other words, the proposition is not necessarily true (can’t be proven), but is is fair to say such things in a scientific paper anyway. Uh-oh.

  56. Why on earth would anyone think it could warm warmer than today and it would stubbornly stay only in Europe or even the NH. Trenberth is busy chasing a pinball hot spot that appears in Russia, disappears, and then pops up over Australia and then dives down into the ocean deeps!! For Steven Mosher and all of you who would restrict the major warming and cooling periods to only the NH (some even to Europe), we live on a ball with interlinked ocean and atmosphere. The Sun is the heater. Look, you guys have essentially all the anthropo CO2 produced in the NH but it manages to distribute itself around the globe apparently and remember humans contribute only a few percent of the CO2 flux. Given CO2 as the control knob, how do you explain a hot NH and cold SH? Or are you guys slowly letting go of the knob.

  57. milodonharlani says: October 31, 2013 at 11:50 am
    The evidence that the Medieval Warm Period was global, & that it, the Roman & Minoan WPs & the Holocene Climatic Optimum, or whatever the latest fashion in its nomenclature might be, plus the deglaciation phase prior to it, were also warmer than now has been abundant & growing since Lamb, at least, ie 50 years. The LIA & previous cold periods were also global.
    Which is why Mann needed fraudulent “tricks” & apparently intentionally inept statistical techniques or lack thereof to try to show recent warming to be special & scary.

    **********

    Agreed Milodon.

    We knew that Piltdown was wrong at the time his papers were published (MBH98, etc.).

    I published the following article in E&E in early 2005, in defence of several legitimate climate scientists.

    Full article at http://wattsupwiththat.com/2011/11/28/the-team-trying-to-get-direct-action-on-soon-and-baliunas-at-harvard/#comment-811913

    Natural climate variability trumps global warming extremism.

    Regards, Allan

    Drive-by shootings in Kyotoville
    The global warming debate heats up
    Allan M.R. MacRae
    [Excerpt]

    But such bullying is not unique, as other researchers who challenged the scientific basis of Kyoto have learned.

    Of particular sensitivity to the pro-Kyoto gang is the “hockey stick” temperature curve of 1000 to 2000 AD, as proposed by Michael Mann of University of Virginia and co-authors in Nature. Mann’s hockey stick indicates that temperatures fell only slightly from 1000 to 1900 AD, after which temperatures increased sharply as a result of humanmade increases in atmospheric CO2. Mann concluded: “Our results suggest that the latter 20th century is anomalous in the context of at least the past millennium. The 1990s was the warmest decade, and 1998 the warmest year, at moderately high levels of confidence.”

    Mann’s conclusion is the cornerstone of the scientific case supporting Kyoto. However, Mann is incorrect.

    Mann eliminated from the climate record both the Medieval Warm Period, a period from about 900 to 1500 AD when global temperatures were generally warmer than today, and also the Little Ice Age from about 1500 to 1800 AD, when temperatures were colder. Mann’s conclusion contradicted hundreds of previous studies on this subject, but was adopted without question by Kyoto advocates.

    In the April 2003 issue of Energy and Environment, Willie Soon and Sallie Baliunas of the Harvard-Smithsonian Center for Astrophysics and co-authors wrote a review of over 250 research papers that concluded that the Medieval Warm Period and Little Ice Age were true climatic anomalies with world-wide imprints – contradicting Mann’s hockey stick and undermining the basis of Kyoto. Soon et al were then attacked in EOS, the journal of the American Geophysical Union.

    In the July 2003 issue of GSA Today, University of Ottawa geology professor Jan Veizer and Israeli astrophysicist Nir Shaviv concluded that temperatures over the past 500 million years correlate with changes in cosmic ray intensity as Earth moves in and out of the spiral arms of the Milky Way. The geologic record showed no correlation between atmospheric CO2 concentrations and temperatures, even though prehistoric CO2 levels were often many times today’s levels. Veizer and Shaviv also received “special attention” from EOS.

    In both cases, the attacks were unprofessional – first, these critiques should have been launched in the journals that published the original papers, not in EOS. Also, the victims of these attacks were not given advanced notice, nor were they were given the opportunity to respond in the same issue. In both cases the victims had to wait months for their rebuttals to be published, while the specious attacks were circulated by the pro-Kyoto camp.

    *************

  58. thingadonta says:
    October 31, 2013 at 3:43 pm

    From Michael Asten in the Australian, 2010:

    One of the giants of global warming science, Wally Broecker of Columbia University in New York, wrote a discussion in 2001 of evidence for the MWP being a global phenomenon, concluding tentative support for its global nature. Three years later, Phil Jones, now director of the Climate Research Unit, East Anglia, co-authored a review that concluded the MWP was a regional phenomenon. The IPCC4 report of 2007 concluded similarly; curiously, Broecker’s paper did not get a mention.

    http://www.theaustralian.com.au/opinion/csiro-should-establish-if-there-was-medieval-warming-down-under/story-e6frg6zo-1225865724876#sthash.40u3Ucy4.dpuf

    Article goes on to urge looking for the MWP & LIA in Australia, which would be great, but suggestive evidence of both has already been found there, however not in abundance. But the continent is bracketed by very good & plentiful studies from the Pacific & Southern Oceans (don’t know about the Indian), New Zealand, Antarctica & southern Asia.

  59. Yeah, and one more thing. Note that the instrument watchers have all stopped tracking the arctic ice expansion just when it was rising faster than anytime in the last 60 years! Watch for an adjustment in the works after long pauses in plotting information. When they say faster warming in the last 60 years, the only warming in the last 60 years was between 1980 and 1998 – a stretch of 18 yrs, boxed in by cooling periods. Have we got annual granularity in their last 10,000 yrs? Well yes we have. The rise from early 1900s up to the forties was just as fast, and don’t forget, Hansen, Hadcrut, etc. have added on several tenths to the recent record!

  60. Steven Mosher says:

    October 31, 2013 at 1:21 pm

    from one ocean basin they jump to global conclusions.

    what would folks say if the sediments showed the opposite
    ===========
    Erect more windmills.

  61. Mosher writes “from one ocean basin they jump to global conclusions.”

    As far as your comment goes, I haven’t read the paper but it seems to me they went to a few randomish places on the earth and found medieval warming. The definitely supports the idea of medieval warming not being local like the team have suggested in the past.

    I’m pretty sceptical about implications the Pacific ocean was 2C warmer than now though! Thats an enormous amount of energy and represents a lot of heating over a very long period. In that sense, I suspect either the proxy isn’t saying what they think its saying or the warming was coincidentally highly localised and not representative of the ocean in general (supporting Mosher’s argument but not for the reasons he thinks)

  62. TimTheToolMan says:
    October 31, 2013 at 4:44 pm

    Two K might seem like a lot, but the drop from “normal” to La Niña conditions along the west coast of South America can be twice that much. Granted, that’s from the upwelling of cold water from below, but even in the western Pacific, centuries of greater warmth could IMO produce a difference of two K warmer than now, coming off the LIA as we are.

  63. Steven Mosher says:
    “from one ocean basin they jump to global conclusions.
    what would folks say if the sediments showed the opposite?”

    Steve, we would say the same thing you would: “Show me the data so I can try to replicate your results”.

    But you knew that already, didn’t you?

  64. At Huffpo, Mann writes:

    ‘They argue that, while the present rate of ocean warming is unprecedented, the actual level of ocean heat content (which depends not just on surface temperature, but also sub-surface ocean temperatures) is not as high as during Medieval times, i.e. during what they term the “Medieval Warm Period”…’

    Does anyone believe that rates of ocean warming are reflected in proxies? I am talking about “unprecedented” ocean warming. How would the rate, as opposed to the extent, show up in proxies? Take tree rings for a familiar example. I recognize that the extent of warming might show up in individual tree rings but how would the rate show up? The extent of warming can be determined by several different things including length of season, cloud cover, precipitation, and other factors. These different factors have to be teased out. How is it possible to find a rate of warming among them that allows comparison over several centuries and includes relative rates of unprecedented warming?

  65. milodonharlani writes “centuries of greater warmth could IMO produce a difference of two K warmer than now, coming off the LIA as we are.”

    I dont think ENSO effects the waters from 500m to 1km depth so much. But even if it did, that would be a localised effect and Mosher’s argument is back on the table if they manage to pick locations that had those kinds of localised effects. Still no props to you though Mosher :-P

  66. According to the study Continental-scale temperature variability during the past two millennia, involving 78 scientists all over the World which was published in april this year large parts of the Northern Hemisphere experienced MWP from ~ 800 to 1200 AD but not simultaneously and not equally warm.In the Southern Hemisphere it was delayed by ~ 100 years. The study is based on temperature reconstructions from a variety of proxies. All continents except Africa are covered.

    http://www.nature.com/ngeo/journal/v6/n5/full/ngeo1797.html

    Figure 2 shows the temperatures of each continent. To see the figure in higher resolution go to Supplementary information at the link below.

    http://www.nature.com/ngeo/journal/v6/n5/full/ngeo1797.html#affil-auth

  67. If you had a time machine and took Michael Mann on a trip, would you be able to change his mind?

    It would be an interesting journey into human psychology if anything. Might have to stop in and get Mann to see Sigmund Freud once or twice.

  68. I am really going to have to scour my records. Back in the mid-90s, on UseNet (ask your grampa), a certain Mr. Connolly of the British Antarctic something or other “debated” me and was pretty certain that the LIA was only regional to Europe. And a bit of North America. I actually love to say I told you so…

  69. Steven Mosher on October 31, 2013 at 1:21 pm
    from one ocean basin they jump to global conclusions

    One ocean basin, bit like one tree I suppose

  70. Mosher, Have you ever considered getting you infrared spider senses recalibrate? If there is a region that is truly teleconnected to “global” climate, the IPWP looks about right.

    Of course paleo, just like BEST, is baseline dependent, doncha know :)

  71. Dave in Canmore says:
    October 31, 2013 at 1:27 pm
    Given the location of the cores could it be that large ENSO events would be recorded?
    ————————————
    That would only be an issue for short term data. In 10000 years of data such high frequency wiggles should not obscure trends and means.

  72. Funny ain’t it, the concerted effort to regionalize the MWP and other variations of past temperature is the very thing that got me to pay attention to this “climate science”.
    People who rewrite history can not be trusted.
    Sadly I am still waiting for the science. Trillions spent world wide, government science working overtime, endless propaganda, but no empirical science to support the contention that increasing atmospheric CO2 concentrations cause increasing global heat retention.
    I regard the actions of my, canadian, government employees in this sordid affair to be particularly odious.
    Treason in my book.

  73. Is logical thought dead?

    This paper is damning to the CAGW swindle as it shows once again that the Medieval Warming Period was WARMER than today and, more importantly, was a global event and not just limited to the Northern Hemisphere as CAGW grant whores tried so desperately to promote.

    It also shows that the Little Ice Age was a global event that significantly lowered global ocean temperatures and, more importantly, the 20th century warming was a simple NATURAL recovery from the LIA.

    The fact that the LIA begins and ends with the Grand Solar Minima: Wolf, Sporer,, Maunder and Dalton, gives further support that the Sun is the primary driver of climate and NOT CO2. The fact that the solar cycles from 1933-1996 were the strongest 63-year string of solar cycles in 11,400 years also supports the premise that the Sun is the driver of climate. Furthermore, the fact that the global warming trend ended the same year these strong solar cycles ended in 1996, is further support of solar induced climate change.

    Moreover, Lockwood’s recent findings that solar activity over the past 20+ years is dropping at the fastest pace in 10,000 years, corresponds perfectly to falling global trends since 1997 (RSS) and 2001 (HADCRUT4).

    Research by Penn & Livingston, and Lockwood suggest a high probability that the Sun could enter another Grand Solar Minimum from the next solar cycle, which starts in 2020, suggesting the Modern Warming Period is in its final stages and that global cooling is on its way.

    CAGW is dead.

  74. Here’s a repeat of part of my guest post of 10/29 which shows developments following Mann’s Hockey stick and suggests a suitable replacement as a basis for discussion.
    “Central to any forecast of future cooling is some knowledge of the most important reconstructions of past temperatures after all the infamous hockey stick was instrumental in selling the CAGW meme.
    Here are links to some of the most relevant papers-starting with the hockey stick.

    http://stephenschneider.stanford.edu/Publications/PDF_Papers/MannBradleyHughes1998.pdf

    http://www.ncdc.noaa.gov/paleo/pubs/mann_99.html

    note Espers comments on the above at

    http://eas8001.eas.gatech.edu/papers/Esper_et_al_Science02.pdf

    and see how Mann’s hockey stick has changed in later publications

    http://www.pnas.org/content/105/36/13252.full

    http://www.meteo.psu.edu/holocene/public_html/shared/articles/MannetalScience09.pdf

    an important paper by Berggren et al relating solar activity to climate is

    http://www.eawag.ch/forschung/surf/publikationen/2009/2009_berggren.pdf

    and another showing clearly the correlation of the various climate minima over the last 1000 years to cosmic ray intensities -( note especially Fig 8 C ,D below ) is: Steinhilber et al – 9400 years of cosmic radiation and solar activity from ice cores and tree rings:

    http://www.pnas.org/content/early/2012/03/30/1118965109.full.pdf

    for Holocene climate variability in general there is much valuable data in Mayewski et al :

    http://yly-mac.gps.caltech.edu/AGU/AGU_2008/Zz_Others/Li_agu08/Mayewski2004.pdf

    Of particular interest with regard to the cause of the late 20th century temperature increase is Wang et al:

    http://www.atmos-chem-phys.net/12/9581/2012/acp-12-9581-2012.pdf

    A review of candidate proxy data reconstructions and the historical record of climate during the last 2000 years suggests that at this time the most useful reconstruction for identifying temperature trends in the latest important millennial cycle is that of Christiansen and Ljungqvist 2012 (Fig 5)

    http://www.clim-past.net/8/765/2012/cp-8-765-2012.pdf

    The shape of the curve of Fig 3(Fig 5 Christiansen) from 1000 – the present should replace the Mann-IPCC hockey stick in the public consciousness as the icon for climate change and a guide to the future i.e. the temperature trends from 1000- 2000 will essentially repeat from 2000- 3000.”

  75. These climate change deniers (such as Mike Mann) are running out of excuses. They tried to deny the medieval warm period. They tried to deny the little ice age. They tried to deny the cooling from 1945 to 1975. Slowly but surely science is overcoming these deniers. Someday they will be forced to admit that climate change has been real for the life of the planet.

  76. philjourdan says:
    October 31, 2013 at 1:49 pm

    Mann’s Yamal tree still trumps the mountains of evidence from the rest of the world. In his own mind.

    Yamal was Briffa, not Mann. Fail.

  77. Keigwin, L.D. 1996. The Little Ice Age and Medieval Warm Period in the Sargasso Sea. Science 274: 1504-1508.

    This paper confirms Keigwin’s paper in regards to ocean temperatures of the MWP. Keigwin did not go back 10,000 YBP as these fellers did, but he did go back 3,000 years.

    It is amazing how consistent the ocean temp is between the two large basins.

    And for sure confirms the MWP was global in scope.

  78. Michael Mann?

    He can pound sand for all I care.

    And that’s the best “compliment” I can come up with.

    If pressed, I’d have to remain silent.

  79. TimTheToolMan says:
    October 31, 2013 at 5:11 pm

    Keigwin, L.D. 1996. The Little Ice Age and Medieval Warm Period in the Sargasso Sea. Science 274: 1504-1508, cited by Camburn above, found, based upon a radiocarbon-dated box core in the Sargasso Sea (SW North Atlantic), that the sea surface temperature was about one K cooler than today approximately 400 years ago (the Little Ice Age) & 1700 years ago (Dark Ages Cold Period), & around one K warmer than today 1000 years ago (the Medieval Warm Period).

    Doesn’t seem strange to me that in the western Pacific the Medieval Warm Period might have enjoyed SST two K higher than now.

  80. This paper, press release and author comment present a complete mess of information. Revkin seems to see this, but skips reckless over it all.

    Firstly, let’s remember that these are a few results from one area only, the oceans around the islands of Flores and Celebes and a climatically extraordinary place — the warm pool. In themselves these results say nothing about global phenomena. Anyway, I don’t recall any major dispute over the global nature of the Holocene optimum or Little Ice Age since they were identified 100 years ago.

    The authors admitted only centenary scale resolution, and the core top problems does not allow results from the period of the recent local instrument record — see also Mann on this.

    Thus, the press release makes a claim that the paper could not pretend to make:
    “In a reconstruction of Pacific Ocean temperatures in the last 10,000 years, researchers have found that its middle depths have warmed 15 times faster in the last 60 years than they did during apparent natural warming cycles in the previous 10,000.”

    They use Marcott’s mid-Southern Hemisphere data for comparison with air temperature and this shows much less dramatic cooling. From this stark difference in the trend they draw various conclusions about the differential behavior of the ocean temp/heat (in general?) and the air temperatures (in general?). But could not the differential indicate that one or both of the results is wrong, or that something special might be happening in (and over?) the Indonesian warm pool.

    The only rapid recent warming they can and are talking about is warming out of the LIA, warming over the last 3 or 4 centuries — not over the last 3 or 4 decades when AGW is supposed to have impacted. Thus, it is the non-AGW recovery from the LIA that requires explaining, yet they are pushed to say that it is not. This makes them look particularly stupid.

    Finally, support for global MWP?? Well yes, perhaps, if the MWP includes a collapse in temperatures from the second half of the 11th century — that is right when Lamb has his CET chart taking off into the warming to support the high middle ages. If you cut the chart off at the turn of the last millennium (as per the hockey stick) there is no MWP but only a general decline. (see their fig 3)

  81. Yes, the globe is cooling at multimillenial scales (since the Holocene peak). It’s almost basic education.

  82. A few back of postage stamp calculations from this, if they’re right that current oceans are approx 0.65K colder than during the MWP. Or, to put it another way, the oceans would have to absorb enough heat energy to raise their temperature by 0.65K in order to get to where we were back then.

    Total mass of the oceans is setimated at 1.4 x 10^21 kg
    Specific heat capacity of seawater is (very approximately) 3900 J.kg-1.K-1
    So, total heat energy needed to raise the oceans by 0.65k is about 2500 x 10^21 J

    Trusting the opposition’ s figures here: http://www.skepticalscience.com/Measuring-Earths-energy-imbalance.html they show an imbalance of about 10 x 10^21 J per year in the earth’s energy budget.

    So, if every single joule of that imbalance goes into heating the oceans, it would require about 250 years for the oceans to warm back up to where they were when mankind was thriving in an optimum climate.

    That doesn’t need model assumtions, only data ones – IF the various figures used are about correct then its a matter of very simple physics that it’ll take at least 250 years for the oceans to be back where they were in the good times.

  83. Mr. Mosher this is why I believe we are are talking past each other in this debate:

    In short, the data is enormously sparse, of low quality/accuracy, and the uncertainty is large enough to accommodate multiple theories. This is especially true of the paleo reconstructions, where we have conflicting data you alluded to. Serious skeptics think mainstream climate scientists have picked from this one narrative which fits their viewpoint and fits within the overwhelming uncertainty, using assumptions that skeptics believe are not any more justifiable than many alternatives. Skeptics also think the assumptions and their effects are often glossed over in a manner which obfuscates (for example, hiding the decline, where assumptions about tree-ring divergence is alluded to in only a very obscure and unresolved manner).

    When an alternative narrative like this study comes along it is attacked (or ignored or is never allowed through peer review) with a level of criticism which does not seem to be applied to the mainstream theory’s supporting studies. In fact if this same level of criticality were applied to mainstream climate studies, I wouldn’t be surprised if the result would be “we really don’t know”. This is a fine answer to have if it is the truth. However, as things stand, the deck is stacked one way from on top; climate-gate laid that bare for all of us to see.

    So yes you are right; there is plenty to criticize with this paloe-reconstruction. And plenty to criticize in the mainstream reconstructions. Which ones will see the light of day in IPCC reports and politician decision-making? Which points of view will be pursued via public science funding? Does the paleoclimate community have enough incentive to be honest about the uncertainty?

    When you see skeptics cheering when a paper like this comes out, you are right when you point out that many are not exploring the weaknesses of such a study. What I don’t think you realize is that in the background most of these same skeptics are probably not accepting this paper as the absolute truth on the matter either. They are interested in revealing a different viewpoint to try to balance against the mainstream to provide a more balanced big picture veiw. If you were to ask them to create a reconstruction themselves, and they took you up on the task, they would probably end up telling you it may not be possible unless you want your uncertainty bands so high as to render it meaningless. These are not the sorts of mentalities that attract government grants for controversial science effecting huge swaths of the economy demanding high levels of certainty (though perhaps they should be as a check/balance).

  84. Many years ago I tried to edit wikipedia to balance the biased view that the mwp was purely an european event giving many citations to papers which were ignored. This was tag team edited by the GW brigade who live there and blocked. Perhaps we can have another go?

  85. The implications of a global Medieval Warm Period are not as clearcut as you think wrt Mann.
    Mann’s statement that the MWP was regional, implies that there was a negative feedback that moderated the warming that did happen. This negative feedback would mean that there is a natural mechanism that would moderate CO2 warming. If the MWP was global, then this feedback leaves Mann’s equations, and he is free to declare runaway warming.

  86. It used to really, really annoy me when the warmists would refuse to call the MWP for what it is being of course the MWP. They would call it a “Local Abnormality”. Well they can all suck eggs now, not that will make any difference as they suck, suck and dribble ” It was Local Abnormality, really was, MM said so.!

  87. I am glad to see signs the obvious is being recognized. I can’t tell you how irked I was by the “science” which attempted to downplay the MWP. What was most irksome was that, in downplaying the MWP, they were dismissing the hard work of many good scientists, who often labored in uncomfortable surrounding in the arctic, back before we had arctic vehicles with heated cabs, or DEET.

    I think we shall now see a creep towards a vision of a warmer and warmer MWP, as it becomes less a sort of professional suicide to dare say it was warmer in the past.

    Having the ocean only a half degree warmer may not seem like much, however it makes quite a difference in terms of sea ice. I think we will eventually see a vision of a MWP where the sea ice formed later and melted earlier, and the northeast and northwest passages were wide open in the summer. (Imagine a time when a map like 2007’s would be representative of an especially cold year.)

    Rather than a bad thing, I think a less-ice-choked arctic was a very good thing. One thing I have noticed is that, until those arctic waters freeze over in the autumn, the north, off-the-water winds in arctic regions are not as harsh and bitter as they get, once the sea becomes a wasteland of white. For example, in Siberia in early October a sea breeze is a “warm” breeze, relative to winds off the snow-covered Tundra.

    In terms of the Vikings in Greenland, I think this made a huge difference to the growing season. If, in the the MWP, the autumnal months saw north winds come from an Arctic Sea which was not frozen until December, they had two or three months where the north winds were maritime air, and their pastures stayed unfrozen. It would have been like northern Norway, where the days grow too short to grow anything, but the pasture doesn’t turn to permafrost.

    Looking at old papers, I get the feeling that the idea of a relatively ice-free Arctic Sea was already known, or, at the very least, was seriously considered, in the past. As the attempt to “erase the MWP” falls apart due to the weight of its own stupidity, I think we will see a time of rediscovering what we already knew.

  88. Dr Mann does not understand how the global weather work, perhaps because he does not work with the weather each day. If he did, he would understand that by and large there is always back and forth, and if he wants to argue that their was regional warmth HE HAS TO PRODUCE THE REGIONAL COLD THAT BALANCES IT ( assuming there was no global warmup). Practicing meteorologists are well aware of teleconnections, for instance a large ridge in the southwest Pacific and a westward moving typhoon usually means one will find a ridge in the southeast or southern plains of the US several days later. The ridge position in this crucial source region will telegraph a chain of events that will occur in many cases. Recurving typhoons mean the ridge is further east, allowing the pattern to help with troughs deepening in the east. Anyone notice as typhoons recurved near and east of Japan, the cold came east from where it was when they were moving west? The latest modeling is showing alot of ridging back the first 1-2 weeks of November over the southeast.. we just had a typhoon move west through the Philippines .

    Here is my point. There is only a very small chance, perhaps .04% ( thats a joke okay, its small but not as small as the amount of co2 in the atmosphere) that it could have been warm in just one place in a repetitive fashion without compensating reactions on global scale. Dr Mann’s work is flawed right off the bat in that if there is no global warm period, he has to find where it was cooler to compensate for the warmth that did occur in areas we know it did. If he worked as a meteorologist, he would understand that. Remember Climatology is a BUILDING BLOCK for meteorology, its only recently that somehow its status was elevated to a level where ideas count more than the reality of the ideas. So where was it? Can he please let us know. If we are to assume the earth was not warmer in that time, the areas known to be warmer had to have had compensating areas that should have been colder. That is simply the way the atmosphere works. for one and for two, if in telling us there was no period globally that was warmer, where was it colder to balance it out?

    In a way, its intuitive, that in the grand scheme of things, the big long lasting events are the main controllers, and there is nothing new under the sun

  89. Have any of the papers that claim the MWP was a European phenomena explain the conditions that could stall warm meteorological structures over Europe and only over Europe from AD 950–1250 during the MWP ???

  90. Caleb,

    I look forward to the day when crocodiles are back swimming in arctic waters, now those were the days.

  91. The terms “Meltdown Mann” and “Piltdown Mann” are pretty good, but my favorite (coined by Mosher as I recall) is “Siltdown Mann”, for MM’s incorrigible inversion of the Tiljander sediments in his temperature “reconstructions”.

  92. “””””…..milodonharlani says:

    October 31, 2013 at 4:56 pm

    TimTheToolMan says:
    October 31, 2013 at 4:44 pm

    Two K might seem like a lot, but the drop from “normal” to La Niña conditions along the west coast of South America can be twice that much. Granted, that’s from the upwelling of cold water from below, but even in the western Pacific, centuries of greater warmth could IMO produce a difference of two K warmer than now, coming off the LIA as we are……”””””

    Well I believe 2K is below the freezing point of Hydrogen, so yes, it would not seem like a lot, on your thermometer. The freezing point of water, is about 273.15 K

    I think they mean the Temperature is/was 2 deg C warmer.

  93. george e. smith says:
    November 1, 2013 at 1:08 pm

    I used 2 K instead of typing “two degrees C”. It is confusing, since it’s wrong to use “degrees” with Kelvin units. I didn’t mean two degrees above absolute zero. I should have said 2 K higher or lower, you’re right, in which case typing two degrees C would have been just as easy.

  94. milodonharlani writes “Doesn’t seem strange to me that in the western Pacific the Medieval Warm Period might have enjoyed SST two K higher than now.”

    Various people (eg Lucia, Lubos and I think Willis) have calculated that given the amount of energy accumulated in the oceans their temperature is increasing at around 0.065C per 45 years for the 0-2000m depth range.. So to change 2C for half that volume (ie 0-1000) would be around 0.13C per 45 years or 700 years.

    And that’s at today’s “rapid” rate. How can that have happened for the MWP? There’s just not enough time. So for me it fails the plausible sniff test and hence I believe the proxy isn’t saying what they think its saying and/or it was a local effect.

  95. TimTheToolMan says:
    November 1, 2013 at 3:05 pm

    Why would you say not enough time? The Medieval Warm Period was hotter than now & lasted hundreds of years; the Modern Warm Period only about 150.

  96. milodonharlani writes “Why would you say not enough time?”

    Because 700 years is too long to fit into history. I quoted 700 years as a “very best” but in fact I dont think you can ignore the deeper water and I think the warming rates would actually be closer to our measured values of 0.065C per 45 years and that makes a more realistic 1400 years to change 2C. It doesn’t feel right to me.

  97. Its revealing of the political distortion of climate science that a few mosses from a small Arctic island allow proclamation of warmest temperatures since the middle of the last ice age, but data from the Pacific ocean covering half the world has only regional implications, apart from a fraudulent Marcottian claim to fastest temp rise based on comparing sharply resolved recent data with more smoothed older data. (In image processing this is called the “unsharp mask”. Perfect for un-sharp scientists.)

  98. TimTheToolMan says:
    November 1, 2013 at 3:45 pm

    The observations (please see graphs from Climate Audit below) disagree with your feel. Forgive me, but I don’t know to whom you refer by “our”. I’m also mystified by your cryptic, “700 years (being) too long to fit into history”. Why should warming or cooling always occur at the same pace, anyway?

    McIntyre eviscerates the bogus press release touted by Mann:

    http://climateaudit.org/2013/11/02/rosenthal-et-al-2013/#more-18530

  99. writes “The observations (please see graphs from Climate Audit below) disagree with your feel.”

    No they dont. That graph shows about 1C change (downwards) in about 700 years and then another 0.5C change in about 350 years (upward). And that is about twice the rate of 0.065C per 45 years that we’re measuring today and calling “rapid”. And none of it a 2C change for anything.

    I am highly sceptical of these ocean temperature reconstructions. I dont think we’ve got a good handle on the OHC when we were sporadically measuring it in the 50s let alone when we weren’t measuring it at all. You can see in the Rosenthal graph enormous OHC changes in very short amounts of time. My intuition strongly tells me the proxy isn’t primarily temperature dependent in those cases.

  100. From the abstract,

    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.

    Can anyone figure out the relative temperatures of the MWP and recent decades from this? First glance suggests that recent decades are 0.25C warmer than the MWP, but it’s actually not that straightforward.

  101. The fact is people were farming on Greenland during the medieval warm period. This is not possible at this time and should be simplistic for settling any argument.

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