New Chinese study in GRL disputes the hockey stick conclusions

China’s 2,000 Year Temperature History

The Chinese world temperature and anomaly - from the Beijing Climate Center - click to enlarge

While Mann claims his hockey stick science to be “vindicated”, we have this from World Climate Report, a new peer reviewed study that illustrates that the current warm period we live in is neither unique nor unprecedented. They also manage to point out the key issue, the uncertainty of proxies such as used by Mann et al. – Anthony

We constantly hear that the warmest years on record have all occurred in the most recent decades, and of course, we are led to believe this must be a result of the ongoing buildup of greenhouse gases. In most places, we have approximately 100 years of reliable temperature records, and we wonder if the warmth of the most recent decades is unusual, part of some cyclical behavior of the climate system, or a warm-up on the heels of a cold period at the beginning of the record. A recent article in Geophysical Research Letters has an intriguing title suggesting a 2,000 year temperature record now exists for China – we definitely wanted to see these results of this one.

The article was authored by six scientists with the Chinese Academy of Sciences in Beijing, the State University of New York at Albany, and Germany’s Justus-Liebig University in Giessen; the research was funded by the Chinese Academy of Sciences, National Natural Science Foundation of China, and the United States Department of Energy. In their abstract, Ge et al. tell us “The analysis also indicates that the warming during the 10–14th centuries in some regions might be comparable in magnitude to the warming of the last few decades of the 20th century.” From the outset, we knew we would welcome the results from any long-term reconstruction of regional temperatures.

The authors begin noting that “The knowledge of past climate can improve our understanding of natural climate variability and also help address the question of whether modern climate change is unprecedented in a long-term context.” We agree! Ge et al. explain that:

“Over the recent past, regional proxy temperature series with lengths of 500–2000 years from China have been reconstructed using tree rings with 1–3 year temporal resolution, annually resolved stalagmites, decadally resolved ice-core information, historical documents with temporal resolution of 10–30 years, and lake sediments resolving decadal to century time scales.”

However, the authors caution “these published proxy-based reconstructions are subject to uncertainties mainly due to dating, proxy interpretation to climatic parameters, spatial representation, calibration of proxy data during the reconstruction procedure, and available sample numbers.”

Ge et al. used a series of multivariate statistical techniques to combine information from the various proxy methods, and the results included the reconstruction of regional temperatures and an estimate of uncertainty for any given year. They also analyzed temperature records from throughout China over the 1961 to 2007 period and established five major climate divisions in the country (Figure 1).


Figure 1. Types, lengths, and locations of proxy temperature series and observation used in the Ge et al. study. The five climate regions were based on a “factor analysis” of the 1961–2007 instrumental measurements. Grey shading indicates elevation (from Ge et al., 2010).

The bottom line for this one can be found in our Figure 2 that shows the centennially-smoothed temperature reconstruction for the five regions of China. With respect to the Northeast, Ge et al. comment “During the last 500 years, apparent climate fluctuations were experienced, including two cold phases from the 1470s to the 1710s and the 1790s to the 1860s, two warm phases from the 1720s to the 1780s, and after the 1870s. The temperature variations prior to the 1500s show two anomalous warm peaks, around 300 and between approximately 1100 and 1200, that exceed the warm level of the last decades of the 20th century.” The plot for the Northeast shows warming in the 20th century, but it appears largely to be somewhat of a recovery from an unusually cold period from 1800 to 1870. Furthermore, the plot shows that the recent warming is less than warming that has occurred in the past.


Figure 2. Five regionally coherent temperature reconstructions with 100-year resolution; the dashed line is the part with fewer series used; and the solid line is the mean value. The shaded areas are the two coldest periods, during the 1620s–1710s and 1800s–1860s (from Ge et al., 2010).

The Central East region also has a 2,000 year reconstruction and Ge et al. state “The 500-year regional coherent temperature series shows temperature amplitude between the coldest and warmest decade of 1.8°C. Three extended warm periods were prevalent in 1470s–1610s, 1700s–1780s, and after 1900s. It is evident that the late 20th century warming stands out during the past 500 years. Considering the past 2000 years, the winter half-year temperature series indicate that the three warm peaks (690s–710s, 1080s–1100s and 1230s–1250s), have comparable high temperatures to the last decades of the 20th century.” No kidding – the plot for the Central East region shows that the warmth of the late 20th century was exceeded several times in the past.

Commenting on the Tibet reconstruction, Ge et al. state “The warming period of twenty decadal time steps between the 600s and 800s is comparable to the late 20th century.” In the Northwest, they note “Comparable warm conditions in the late of 20th century are also found around the decade 1100s.” Unfortunately, no long-term reconstruction was possible for the Southeast region.

In summarizing their work, Ge et al. report :

From Figure 3 [our Figure 2 –eds.] , the warming level in the last decades of the 20th century is
unprecedented compared with the recent 500 years. However, comparing with the temperature variation over the past 2000 years, the warming during the last decades of the 20th century is only apparent in the TB region, where no other comparable warming peak occurred. For the regions of NE and CE, the warming peaks during 900s–1300s are higher than that of the late 20th century, though connected with relatively large uncertainties.

We get the message – the recent warming in at least several regions in China has likely been exceeded in the past millennium or two, the rate of recent warming was not unusual, and the observed warming of the 20th century comes after an exceptionally cold period in the 1800s.

Declaring that anthropogenic greenhouse gas emissions have pushed modern temperature beyond their historical counterparts disregards the lessons of 2,000 years of Chinese temperatures.

Reference:

Ge, Q.-S., J.Y. Zheng, Z.-X. Hao, X.-M. Shao, W.-C. Wang, and J. Luterbacher. 2010. Temperature variation through 2000 years in China: An uncertainty analysis of reconstruction and regional difference. Geophysical Research Letters, 37, L03703, doi:10.1029/2009GL041281.

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85 Responses to New Chinese study in GRL disputes the hockey stick conclusions

  1. pat says:

    hmmm! tgus article may be ‘a game-changer’!

    4 June: UK Guardian: Fred Pearce: Climategate was ‘a game-changer’ in science reporting, say climatologistsAfter the hacked emails scandal scientists became ‘more upfront, open and explicit about their uncertainties’
    The climate scientist most associated with efforts to reconciling warring factions, Judith Curry of the Georgia Institute of Technology, said the idea of IPCC scientists as “self-appointed oracles, enhanced by the Nobel Prize, is now in tatters”. The outside world now sees that “the science of climate is more complex and uncertain than they have been led to believe”.
    Some IPCC scientists are in denial on this issue, she said, arguing that they would like to see the CRU incident as “an irrelevant blip” and to blame their problems on “a monolithic denial machine”, but that won’t wash…
    The veteran Oxford science philosopher Jerome Ravetz says the role of the blogosphere in revealing the important issues buried in the emails means it will assume an increasing role in scientific discourse. “The radical implications of the blogosphere need to be better understood.” Curry too applauds the rise of the “citizen scientist” triggered by climategate, and urges scientists to embrace them.
    But greater openness and engagement with their critics will not ensure that climate scientists have an easier time in future, warns Hulme. Back in the lab, a new generation of more sophisticated computer models is failing to reduce the uncertainties in predicting future climate, he says – rather, the reverse. “This is not what the public and politicians expect, so handling and explaining this will be difficult.”
    http://www.guardian.co.uk/environment/2010/jul/04/climatechange-hacked-emails-muir-russell

  2. Ben says:

    To think on this Fourth of July where we in the USA celebrate our freedom that a Chinese study puts to question our scientific and media bias…

    Kind of ironic and sad.

  3. Geoff Sharp says:

    The Chinese temperature records looks like a pretty close match to the 14C/10Be solar proxy records.

    There is another record that also tracks this trend.

  4. P.F. says:

    I wonder what happens when studies like this are time-scale calibrated to known geophysical events. Something that jumped out at me in Fig 2 was the dip around 500AD. The Sunda pyroclastic event is roughly dated to 535AD. Is a correlation close enough to warrant a look at the precision of the dating of either event?
    Rhodes Fairbridge had a detailed look at Late Holocene climate using changing sea levels (published 1976 in Science). When I overlaid Fairbridge’s Curve over a political history time line, the correlations were quite interesting. Overlaying [good] tree-ring data over cultural/political history might be similarly revealing.

  5. sHx says:

    I’d just offered the following quote in response to a CAGW cultist who asked whether I used telepathy to figure out what was in Keith Briffa’s mind regarding the recent warmth. Anyway, here it is again:

    “I know there is pressure to present a nice tidy story as regards ‘apparent unprecedented warming in a thousand years or more in the proxy data’ but in reality the situation is not quite so simple. We don’t have a lot of proxies that come right up to date and those that do (at least a significant number of tree proxies ) some unexpected changes in response that do not match the recent warming. I do not think it wise that this issue be ignored in the chapter.

    For the record, I do believe that the proxy data do show unusually warm conditions in recent decades. I am not sure that this unusual warming is so clear in the summer responsive data. I believe that the recent warmth was probably matched about 1000 years ago.”
    http://www.eastangliaemails.com/emails.php?eid=136

  6. latitude says:

    At the very least we now know that China also had the Medieval Warm Period and the Little Ice Age…………

    Aren’t these the guys that wouldn’t talk to our President? They obviously had something up their sleeve.

  7. Jimbo says:

    OT – They are getting there slowly but surely.

    “The climate scientist most associated with efforts to reconciling warring factions, Judith Curry of the Georgia Institute of Technology, said the idea of IPCC scientists as “self-appointed oracles, enhanced by the Nobel Prize, is now in tatters“. The outside world now sees that “the science of climate is more complex and uncertain than they have been led to believe”.”
    http://www.guardian.co.uk/environment/2010/jul/04/climatechange-hacked-emails-muir-russell

  8. etudiant says:

    Wonderful! A fine paper.
    This is more what science looks like, lots of hard work condensed into a few simple charts,
    with the uncertainties highlighted without prejudice to a robust conclusion.
    The stability of the temperature, with the anomaly within basically + or – 1 degree Centigrade,
    is very impressive.

  9. Kari Konkola says:

    Why did they not look at tree lines? How far north/ high up trees grow provides a very reliable proxy of past temperatures. Furthermore, old tree lines are easy to investigate, and the research produces solid, unequivocal evidence. For much of the world, changes in tree lines have been documented long ago — see for example Reid Bryson’s work — and the results totally demolish the hockey stick.

  10. DonS says:

    Loving this juxtaposition of the world’s oldest civilization, if we count bureaucracy as a mark of civilization, with the relatively primitive records of the northern Europeans who were still, by and large, painting themselves blue and wearing various animal antlers and horns in the forlorn hope of influencing destiny, while the Chinese were making astute and accurately recorded observations. Mann, I believe, is a surname derived during the dark ages from some Germanic custom, now obscure, at a time when the Chinese already had some 3,00o years of climatic observations at their disposal. Who are we to believe?

  11. Morley Sutter says:

    Just for the record, World Climate Report blog (http://www.worldclimatereport.com/index.php/2010/06/30/china%E2%80%99s-2000-year-temperature-history/#more-436) reported this on June 30th.
    Morley

    REPLY: Which is attributed and linked in the first paragraph. -A

  12. Morley Sutter says:

    Anthony
    My apologies; I missed your early mention of World Climate Report as your source.
    Morley

  13. D. King says:

    The desired number of coal fired power plants
    fits both results and would make an excellent
    temperature proxy.

  14. Dave Wendt says:

    “However, the authors caution “these published proxy-based reconstructions are subject to uncertainties mainly due to dating, proxy interpretation to climatic parameters, spatial representation, calibration of proxy data during the reconstruction procedure, and available sample numbers.””

    Gee, it only took 3 or 4 decades for someone in “climate science’ to admit what has been intuitively obvious from the beginning.

  15. rbateman says:

    There is data mining, and then there is mining data to pick your pockets.
    Of course there was a Medieval Warm Period in China, along with the Maunder and Dalton Minimums Cold Periods.
    Previous literary references have stated as much. Just got drowned in the sea of hysteria.

  16. Tsk Tsk says:

    What a shoddy paper. Clearly they couldn’t afford the computational power to properly model the regional Chinese climate so they had to resort to (proxy) measurements. ;)

    Happy 4th everyone.

  17. Chris in OZ says:

    Was that sound I just heard of the CAGW / Propaganda machines engines firing up ??

    In the next few milliseconds we will be told the Chinese Study was expected as the Chinese still want to burn that dirty coal.

  18. Amino Acids in Meteorites says:

    the plot for the Central East region shows that the warmth of the late 20th century was exceeded several times in the past.

    More evidence that the Medieval Warm Period happened in places other than Western Europe, Greenland, and the Eastern United States as has been claimed by some.

  19. Is anyone else getting tired of hockey sticks and the IPCC and the CRU?

    Anyone got any good fishing stories yet this year? I hope I get a job before August because I’m dying to hook into a nice big fat Chinook or Silver this fall. I haven’t been in two years and i’m literally shaking with withdrawls.

  20. rbateman says:

    Brad aka 1personofdifference says:
    July 4, 2010 at 8:35 pm

    With all the money that is being thrown away on global warming hysteria, you could put 100,000 persons of difference to work, and actually accomplish something worthwhile.

  21. Stop Global Dumbing Now says:

    This is very interesting. It will be hard for the warmers to come up with arguments against this. It appears that they used several sources (tree rings, sediments, stalagmites) and more than 1 sample of each. It was a large, diverse collaboration of scientists without pressure from NGOs, and was peer reviewed. Most importantly they stated the uncertainties and didn’t imply some sort of doomsday scenario – in other words it appears to be a proper scientific paper.
    The bonus is that it was “made in China” and the Chinese are set up to profit the most from foolish Western nations destroying their economies and the earth while trying to to save it.

  22. Gail Combs says:

    P.F. says:
    July 4, 2010 at 6:42 pm

    I wonder what happens when studies like this are time-scale calibrated to known geophysical events. Something that jumped out at me in Fig 2 was the dip around 500AD. The Sunda pyroclastic event is roughly dated to 535AD. Is a correlation close enough to warrant a look at the precision of the dating of either event?
    Rhodes Fairbridge had a detailed look at Late Holocene climate using changing sea levels (published 1976 in Science). When I overlaid Fairbridge’s Curve over a political history time line, the correlations were quite interesting. Overlaying [good] tree-ring data over cultural/political history might be similarly revealing.
    ___________________________________________________________
    I was thinking the same thing. When I read the title I thought the proxies were going to be tied to the Chinese historical record like William Herschel correlated sunspots and wheat prices in 1801.

    I hope that is the next step.

  23. Amino Acids in Meteorites says:

    P.F. says:
    July 4, 2010 at 6:42 pm

    I wonder what happens when studies like this are time-scale calibrated to known geophysical events. Something that jumped out at me in Fig 2 was the dip around 500AD. The Sunda pyroclastic event is roughly dated to 535AD. Is a correlation close enough to warrant a look at the precision of the dating of either event?
    Rhodes Fairbridge had a detailed look at Late Holocene climate using changing sea levels (published 1976 in Science). When I overlaid Fairbridge’s Curve over a political history time line, the correlations were quite interesting. Overlaying [good] tree-ring data over cultural/political history might be similarly revealing.

    Would you do the work and submit it for publication?

  24. Amino Acids in Meteorites says:

    latitude says:
    July 4, 2010 at 6:54 pm

    At the very least we now know that China also had the Medieval Warm Period and the Little Ice Age…………

    Aren’t these the guys that wouldn’t talk to our President? They obviously had something up their sleeve.

    I don’t think climate was in that sleeve. I think it was their recognition of his weak leadership skills and Americas debt for buying things beyond its means.

  25. Steve Oregon says:

    This is another of the many detriments from our own unethical scientists politicizing and distorting science. They’ve undermined the credibility of much of our scientific community while China demonstrates the results of honest science.
    And it’s only getting worse.

    This new piece by Lubchenco is pretty special.
    Jane Lubchenco 4th of July special
    http://www.open-spaces.com/article-v2n1-lubchenco.php

    But for some extraordinary eco-babble check her 1998 work she links to. Both old and new are staggering reads.
    http://www.sciencemag.org/cgi/content/full/279/5350/491
    http://www.sciencemag.org/cgi/reprint/279/5350/491.pdf

    IMO we have eco-loons heading our science institutions.

  26. Rattus Norvegicus says:

    And Mann 2009 shows that central China was one of the warm areas. So…

    It seems like this study confirms the findings, not contradicts them.

  27. evanmjones says:

    It will be hard for the warmers to come up with arguments against this. It appears that they used several sources (tree rings, sediments, stalagmites) and more than 1 sample of each.

    No problem. Just add Mannian data weighting and a dash of Mannian PCA.

    A penny will get you a pound that if you fed the data through the hockey stick algorithm you’d get a hockey stick.

  28. Geoff Sherrington says:

    This comment is made in ignorance of details, but arises from past reading of blogs. Is it possible that the Tibetan Ice cores shown are among those whose raw data are being withheld by Lonnie Thompson? Anyone have connections and speciality to track this down? The resolution of the map above is inadequate to pin down a named location.

  29. mike g says:

    Maybe the downturn in the proxies not matching the recent warming is because the yamal trees don’t grow in urban centers or near airports?

  30. Latimer Alder says:

    So this is the event that Prof. Mann was trying to prepare us for in his interview on Panorama (BBC).

    I thought that his unusual humility and jaw-droppingly unlikely remarks that his Hockey Stick had been overplayed were out of character and presaged some events for which he was preparing his defence. And I guess this is one of them.

    Oh dear! If the research in the article is shown to be robust, then he has nowhere to go. If the MWP has been reinstated in China, then together with known historical evidence from Europe/North America, a fair chunk of the Northern Hemisphere is shown to have experienced it.

    And yet Mann’s (in)famous reconstruction fails to show it at all…he had successfully removed it from the record as per the e-mail ‘We must get rid of the Medieval Warm period’. Is this becasue of methodological errors as described by McIntrye and McKitrick, from cherry picking the data, or just sheer bad luck that the data samples that Mike used didn’t happen to show it?

    Because if there was a Medieval Warm period, and it was about as warm as today. the thesis that CO2 as the sole contributor to warming must fail. If it was as warm 600 years ago, when CO2 levels were much lower (about 70% of current), then it cannot be argued that it is only the CO2 increase that has caused the atmosphere to warm. Indeed there must be other factors, because it clearly got colder after the MWP..and at a time when CO2 was stable (or possibly gently increasing).

    And as all the climate models since the Hockey Stick in 1998 have universally assumed that CO2 is the bad guy, then they too are shown to be fundamentally wrong. (which might explain why their agreement with real world observations is so poor).

    The fallout from this paper will take a long time to work through. No wonder Anthony kept it up his sleeve as a little surprise for us all while he was travelling. But it most definitely isn’t good news for the more Alarmists among the Warmers. Be prepared for a deluge of criticism from the usual suspects…no doubt focussing on imagined unpleasant characteristics of the Chinese people/government/motivations.

    But just rememebr ine simple thing. if shown to be true, the paper shows teh MWP is back. And all the CAGW theories fail because of it

  31. mike g says:

    AGW’ers will say the chicoms are just trying to justify their coal-burning ways.

  32. Al Gored says:

    Steve Oregon says:
    July 4, 2010 at 10:11 pm

    “And it’s only getting worse.

    This new piece by Lubchenco is pretty special.
    Jane Lubchenco 4th of July special

    http://www.open-spaces.com/article-v2n1-lubchenco.php

    Thanks Steve. just read it. Yep, according to her the debate is still over…

    “To summarize this brief summary of climate changes, it’s clearly erroneous and patently ridiculous for anyone to assert that there is no scientific certainty in this area. The IPCC represents the collective expertise and judgement of over 2000 of the most knowledgeable climate scientists in the world. Their conclusions carry substantial weight and are the definitive assessment.”

    And she was actually appointed to some important position by the Obamites, wasn’t she? Sigh.

  33. Marty Singh says:

    Mann’s study (and various follow ups) were referring to the last Millenium, and the NH mean temperature (with some seasonal biases). As interesting as the new 2000 year chronology is, it in itself does not invalidate or contradict the Mann reconstruction. It’s pretty well known that various regions in the world have experienced warmer and cooler periods over the last millenium. Whether these are co-incident, and whether they are large-enough scale to have a big impact on the hemispheric mean is another question altogether, and one that is not answered by this paper.

  34. barry says:

    This is the temp record for China, not the globe. It’s a small fraction of the northern Hemisphere. One of the key points in most reconstructions of NH millennial temps is that warming happened at different times in different regions, with as much as 500 years between warm events. This oft-referenced skeptical web page on the MWP can be checked to see that at while it is hot in some regions, at the same time it is cool in others.

    http://pages.science-skeptical.de/MWP/MedievalWarmPeriod.html

    This paper on a fraction of the landmass of the Northern Hemisphere is not a silver bullet for the conclusions of Mann et al and other Northern Hemispheric temp reconstructions that followed. Or did Mann say something specific about China in his millennial reconstructions?

  35. Martin Brumby says:

    Why should we believe Chinese scientists who are obviously in the pay of Big Coal?

    Surely Obummer, Dave Boy, Buff Huhne and Prince Chuckles have made everything clear?! no?

    These wily orientals are obviously just looking at weather, not climate!!

    Worse than we thought!!!!

  36. Latimer Alder says:

    ‘It’s pretty well known that various regions in the world have experienced warmer and cooler periods over the last millenium. Whether these are co-incident, and whether they are large-enough scale to have a big impact on the hemispheric mean is another question altogether, and one that is not answered by this paper.’

    Fair comment….no paper anywhere has yet attempted to work out the impact on the hemispheric mean..apart from the famous one with the Hockey Stick, where it was apparently demonstrated that there were no significant fluctuations before about 1900. Anywhere. No matter what the historical records said.

    And it sort of makes me want to ask..what practical use would the derivation of a real hemispheric mean be (even if we could all agree on how to measure it in a representative way?)

    Plants don’t grow according to the hemispheric mean..they grow according to the local conditions that they experience. Grapes didn’t grow in Yorkshire because Algeria was warmer or cooler or the same, they grew because Yorkshire was warmer.

    Ice caps don’t grow or shrink according to the hemispheric mean they change according to the local conditions that they experience.

    Sea levels because of thermal expansion may change based on the global (not hemispheric) mean. but the haven’t been doing anything at all worrying … we’ve lived with 1 foot per century increases for a long time without even noticing (depth of one standard housebrick every two generations — big deal).

    Apart from as a statistical artefact, what use would a true hemisipheric mean be to us? I’m genuinely puzzled. Because after about 40 years of supposedly dangerous global warming I have yet to see any of the dreadful consequences predicted. Lots and lots and lots of scare stories about what is going to happen…but no actual real proven bad consequences.

  37. barry says:

    according to her the debate is still over…

    “To summarize this brief summary of climate changes, it’s clearly erroneous and patently ridiculous for anyone to assert that there is no scientific certainty in this area….

    Huh? You just quoted something that gainsays your point.

    The IPCC represents the collective expertise and judgement of over 2000 of the most knowledgeable climate scientists in the world. Their conclusions carry substantial weight and are the definitive assessment.”

    You understand that a definitive assessment from experts can encompass uncertainties? Lubchenko actually emphasises what some uncertainties are. She’s not saying the debate is over, she’s reminding us of the credentials of the scientists having the debate.

  38. P.F. says:

    Amino Acids in Meteorites says: July 4, 2010 at 9:46 pm “Would you do the work and submit it for publication?”

    I am not close to the techniques used in dendrochronology data and modeling as a temperature proxy and, frankly, don’t trust it as a reasonable proxy for the historical climate and temps. All I would do is place the time-calibrated tree-ring data over the historical record of civilization and sea level data to find interesting correlations.

    What I have done already is . . .
    • put Fairbridge’s Curve over Usher’s history of human civilization. Quite interesting to say the least.
    • take the Vostok record and overlay the genetic timing model(s) of right whale and killer whale speciation. It appears the Pleistocene climate flux led to the radiation of these cetacean genera and punctuated the emergence of new species. For these two very different genera (one baleen whale, one toothed dolphin), the points of speciation are very similar. I’d like to compare other genera (Lagenorhynchus in particular).
    • overlay Bilal Haq’s Cenozoic sea level data (calibrated to the Gradstein GTS) on a comprehensive genus-level phylogeny of cetacean evolution. [Conclusion: major climate swings led to the extinction of prior forms and the emergence of new forms. This happened on generic and family-levels depending on the severity and abruptness of the climate changes.]

    If someone with a good handle on the dendrochronology data and results wants to work with the sea level data and historical record used in my previous comparisons, I’d be interested in the collaboration.

  39. barry says:

    no paper anywhere has yet attempted to work out the impact on the hemispheric mean..apart from the famous one with the Hockey Stick.

    That is simply untrue. There are some here.

    http://agwobserver.wordpress.com/2009/09/08/papers-on-the-mwp-as-global-event/

    This is a fairly well-known one.

    The Spatial Extent of 20th-Century Warmth in the Context of the Past 1200 Years (PDF)

  40. DirkH says:

    Ben says:
    July 4, 2010 at 6:22 pm
    “To think on this Fourth of July where we in the USA celebrate our freedom that a Chinese study puts to question our scientific and media bias…

    Kind of ironic and sad.”

    “The article was authored by six scientists with the Chinese Academy of Sciences in Beijing, the State University of New York at Albany, and Germany’s Justus-Liebig University in Giessen.”

    I’d like to remind you that it was mainly the Americans who liberated Germany and helped us establish a stable democracy. Your influence is not lost.

  41. Friar says:

    Marty Singh said:
    “July 4, 2010 at 11:45 pmIt’s pretty well known that various regions in the world have experienced warmer and cooler periods over the last millenium. Whether these are co-incident, and whether they are large-enough scale to have a big impact on the hemispheric mean is another question altogether, …”

    As I understand them, Dr Mann’s various papers are open to exactly this criticism. Even if taken at face value, they do not establish that the ‘hockey stick’ applies over the large scales contemplated by your own comment. Would you agree?

  42. tonyb says:

    History teaches us a lot of lessons-in this case about climate. Too bad that history seems to be a blind spot for many people.

    Tonyb

  43. KenB says:

    Brad aka 1personofdifference says:
    July 4, 2010 at 8:35 pm

    Is anyone else getting tired of hockey sticks and the IPCC and the CRU?

    Anyone got any good fishing stories yet this year? I hope I get a job before August because I’m dying to hook into a nice big fat Chinook or Silver this fall. I haven’t been in two years and i’m literally shaking with withdrawls.

    As a long time observational student of human beings, their behavioural trends and the psychology of crowd behaviour, I have noted that the rather strident “intelligent lay person” who accepted the scientific “consensus” without question, and applied and labeled sceptics with the worst of motives seem to now want to disengage from their version of the “debate” and distance themselves and change the subject, a version of the three wise monkeys now that its becoming clearer that things are not as they were when their “science reigned supreme.

    Unfortunately the tide of debate may be turning against CAGW but the manipulators and those who set the agenda will still be waiting in the wings to impose social and political change or look for other opportunities to make money on other misfortunes.

    I don’t suggest that you fit into any of those convenient “pockets” it is good to get away, do something you enjoy and recharge the internal energies, we learn by our experiences and become wiser and more alert to the scammers of the world.

    Enjoy your holiday respect the environment and above all catch some fish!!

  44. Patagon says:

    You have an example of medieval warm period and LIA from the Southern hemisphere here:

    A quantitative high-resolution summer temperature reconstruction based on
    sedimentary pigments from Laguna Aculeo, central Chile, back to AD 850
    Lucien von Gunten, Martin Grosjean, Bert Rein, Roberto Urrutia and Peter Appleby
    The Holocene 19,6 (2009) pp. 1–9

    or here: http://www.climatestudies.unibe.ch/students/theses/phd/24.pdf page 90

  45. Alexander K says:

    Dirk H, your comment re mainly America liberating Germany is both offensive and inaccurate. May I remind you that America wriggled and fought against entering both world wars until a) WWI was pretty much done, and b) when she was forced into WWII by the enormous loss at Pearl Harbour. Great Britain’s former Colonies of Australia, Canada, New Zealand, South Africa and others fought alongside the Brits from the beginning of both wars and the NZ government mistakenly declared war on Germany in 1939 hours before the Brits did, by getting the time difference for their declaration wrong. Many valiant Americans fought and died for a free world in both wars before America followed, but to over-claim America’s war record is jingoistic, ill-informed and divisive. If you were to research Gen. Dwight Eisenhower’s orders of the day for the Normandy Landings, you might be surprised by his humility.

  46. Turboblocke says:

    It’s interesting to see that the only time when all five regions show significant warming at the same time is the late 20th Century onwards…

    And please remind me again when the MWP is supposed to be… I thought the point was that it was supposed to be warm everywhere at the same time. Figure 2 above actually disproves the MWP as the NE region is cooling as the othertwo regions are warming up.

    YMMV.

  47. Peter Plail says:

    Can I echo echo Alexander K’s re Dirk H’s comment, most commentator’s refer to the Allies’ success, not any one country. I’d also like to add that I don’t think the German’s saw it as liberation, certainly not at the time. I know one German civilian who was about 3 at the time of the “liberation”. Her next year was spent living with her mother at starvation level in an allied internment camp near the Danish/German border.

    Back on topic, irrespective of the nationality of the scientists or the political stance of their political leadership, I hope the paper will be evaluated on its merit as a piece of peer reviewed research.

  48. Wren says:

    “New Chinese study in GRL disputes the hockey stick conclusions” (?)

    How can that be when Mann’s hockey stick conclusions aren’t just about China, and he acknowledges regional differences?

    Quoting from Mann’s 2009 study:

    “The Medieval period is found to display warmth that matches or exceeds that of the past decade in some regions, but which falls well below recent levels globally.”

    http://www.meteo.psu.edu/~mann/shared/articles/MannetalScience09.pdf

    Did Mann say China’s has recently been warmer than anytime during its “2000 year temperature history” ? If not, the article about the GLR study errs in concluding the study disputes the hockey stick conclusions.

  49. psi says:

    KenB: “As a long time observational student of human beings, their behavioural trends and the psychology of crowd behaviour, I have noted that the rather strident “intelligent lay person” who accepted the scientific “consensus” without question, and applied and labeled sceptics with the worst of motives seem to now want to disengage from their version of the “debate” and distance themselves and change the subject, a version of the three wise monkeys now that its becoming clearer that things are not as they were when their “science reigned supreme.”

    Last night I got into what turned out to be a very unfortunate “discussion” with a diehard AGW advocate who teaches in the public schools in Baltimore and considers herself a “scientist.” She had just returned from a Smithsonian training program on global warming for teachers. When engaging her I pointed out as a leading remark that Al Gore conceals the fact that temperature is the leading indicator in his CO2/temp. chart. I think she had never wondered about that and was shocked when she got the implication. Thereafter nearly every point I made was countered with “we know that” and the subject was changed. The extent of her ignorance was truly appalling. Not once did she concede a point. I know this is probably not news to most of the readers here, but this truly is a secular religion.

  50. RockyRoad says:

    It has been argued by some here that the “Medieval Warm Period” was only regional and not global, yet I look at current temperature maps of the earth and see some regions that are warm and some regions that are not, so the argument that the current warming period being global (or even hemispherical) doesn’t appear to be valid either. And when one considers that a good portion of the current “warming” is apparently due to instrument siting problems and skewing using homogenization factors, the argument that what we’re supposedly experiencing is unprecedented is very weak indeed.

    As time goes by and more anti-warming research is published and as the earth continues to refuse to march to the warmer’s errant modeling, the idea of CO2 being the culprit will become more and more laughable.

  51. Patagon says:

    Turboblock @ 4:50 am is quite right.

    Temperature does not seems well correlated in different regions. By year 300 – 400 there is cooling at high altitude (TB) and warming in the NW.

    Not even in the 20th Century the five regions seem to agree.

    The medieval warm period is not comparable to Europe, there is a short warming in the North ~1100 with a wide oscillation at high altitude.

    In a summary, the temperature record is quite different from Europe or South America and among the 5 Chinese regions themselves.

    This should require a bit more of attention. If consistent with other records it would show that regional variation is far more important than global averages…. Interesting…

  52. Latimer Alder says:

    @wren

    Quoting from Mann’s 2009 study:

    “The Medieval period is found to display warmth that matches or exceeds that of the past decade in some regions, but which falls well below recent levels globally.”

    At which point I see Angels Dancing on the Heads of Pins coming into view and terminal boredom setting in. Game over…slam dunk…the recent warming is not unprecedented…CAGW falls because these climatic conditions have happened before without catastrophe.

    End. Thank You. Good Night.

  53. mike g says:

    @ Alexander K

    We entered the war in 1939, with our growing economic might, without which, Germany would have prevailed on both fronts. It wasn’t immediately apparant that it wasn’t just another of Europe’s wars.

  54. Henry chance says:

    China has issues.
    Here is an American geologist that was tortured and sent to jail for 8 years for gathering data.

    During Xue’s closed-door trial, which ran over three dates last July and in December, the court document said he defended himself, arguing that the information he gathered “is data that the oil sector in countries around the world make public.”

    David Rowley, Xue’s thesis adviser at University of Chicago and a geologist, said that the location and seismic and other data of oil wells is commonly available and could not compromise Chinese security since the government controls access.

    “What frightens me most about this is that Xue Feng is, in my experience, a straight-up individual who worked hard, who didn’t push limits, or try to pull a fast one by, but was simply honest and entirely well meaning,” Rowley said in an e-mail. “That’s IHS’s business — acquiring and redistributing data (bases) so he was simply doing his job.”
    http://www.foxnews.com/world/2010/07/04/chinese-court-sentences-geologist-tortured-state-security-agents-years-jail-1624851947/?test=latestnews

    Now several days a week, the Commie supporting web site toughts the awsomeness of china. They are good, clean and pure. But they also are strict on who says what.
    I believe some chinese research gets out there that shows some of our claims to be false. I also accept they may push some untruthfull stuff at the same time.
    Where can I read their FOIA???

  55. Pascvaks says:

    Well documented “regional” histories serve to collectively show global conditions best. “Scientific” studies such as this may be perfectly researched, analyzed, documented, and presented; in this day and age, however, they may also reflect a “political”, “economic”, or “social” objective (do not ‘assume’ anything) –”trust no one” is probably the best advice. “Cult” and “Political” science is everywhere these days. Go slow, assume nothing. (But it sounds reasonable, doesn’t it?)

  56. micky c says:

    I know people get excited about proxies, but unless they are characterized by experimentation then they aren’t that much use.

    It’s like this little story:
    I own a farm on which I have an apple launching machine. It launches apples into a container 100 yards away. (Now the reason for this is just assumed that that is how it is). It turns out that I need to move the container by 10 feet. So on first glance I need to up the power in the launcher, but I’m not sure I can afford that. So I do some aerodynamical calculations and look up all the current theories and come up with this:

    If I polish the apples in a certain way my model tells me that they will actually fly another 50 yards. The polishing is within me budget. This is great as I can reduce the cost of running the launcher. But a little voice in my head is saying hmmm that’s seems a little far fetched, you might want to test that?

    So before this I recheck the calculations and theory and it turns out I can reformulate it, and the result is that my model says the apples will only go another 5 yards. Okay I say that seems more reasonable. Its not what I want but its a start, so I make the modifications and start launching apples.

    And nothing changes. The apples go the same distance as before, polished or not.

    Now as an experimental scientist rather than a theoretical one, I can see the problem here. Psychologically it is easier to accept the model predictions for the latter case because they are just a wee bit different. And being just a little extrapolation I decide to implement change. The former case just seems a bit far fetched so I am much more hesitant.

    Well the experimental scientist (and the marketer for that matter) would test BOTH without prejudice. Because both are extrapolations into the unknown. And so we see the same behaviour with models and proxies. Lots of little extrapolations that actually needed to be tested. But because people don’t mind the little extrapolations, soon we have an AGW machine in which every one is convinced. Like the spies always say: The best untruth is 95% truth.

  57. Liam says:

    Its just regional … its only weather … the authors are stooges for big oil … 3,000 scientists say otherwise…

  58. stogy says:

    This article needs to be retracted or at least corrected. Based on Mann (2009):

    “The Medieval period is found to display warmth that matches or exceeds that of the past decade in some regions, but which falls well below recent levels globally.”

    the only conclusion I can make is that it is highly misleading (right from the title: New ‘Chinese study in GRL disputes the hockey stick conclusions’ through to its conclusions). Whether or not you agree or disagree with Mann’s findings is completely irrelevant. The only way that you can reach the rubbish generalization that the title of this thread purports to offer is by substantially misrepresenting what Mann said.

    REPLY: Sorry, you are 10 years off. The “hockey stick” came from MBH98/99 not 2009 -A

  59. david says:

    Liam, are you serious? Over 31,000 scientist with over 9,000 PHDs dispute your 3,000. The 3,000 is also phantasy.

  60. Enneagram says:

    Chinese sure say:”Global warming tale from occident”

  61. bemused says:

    Did I miss the bit in the Ge et al where they construct a northern hemisphere temperature time series?

    The title of this article is:
    “New Chinese study in GRL disputes the hockey stick conclusions”

    Where is you reference that backs up this claim?

    The conclusion of MBH 99 is as follows:
    “Although NH reconstructions prior to about AD 1400
    exhibit expanded uncertainties, several important conclu-
    sions are possible, notwithstanding certain caveats. While
    warmth early in the millennium approaches mean 20th cen-
    tury levels, the late 20th century still appears anomalous:
    the 1990s are likely the warmest decade, and 1998 the
    warmest year, in at least a millennium. More widespread
    high-resolution data which can resolve millennial-scale vari-
    ability are needed before more con fident conclusions can be
    reached with regard to the spatial and temporal details of
    climate change in the past millennium
    and beyond.”

    Ge et al does not say anything about mean Northern Hemisphere temperatures. How exactly does it contradict the MBH99 conclusions? (especially given that MBH explicitly state that more data is needed before they can say anything about regional climate details).

    I’m sorry, but if you are going to hold IPCC to certain editorial standards (e.g. “AmazonGate”) then you should at least make an effort to meet those standards yourself. Is this the beginning of “ChinaGate”?

  62. barry says:

    It has been argued by some here that the “Medieval Warm Period” was only regional and not global, yet I look at current temperature maps of the earth and see some regions that are warm and some regions that are not, so the argument that the current warming period being global (or even hemispherical) doesn’t appear to be valid either.

    Global or hemispheric values are derived, roughly speaking, by combining the data and working out the mean. If you are assuming that anyone is trying to say there was no MWP, then you are unfamiliar with the science. Discussion centres on the amplitude, not the veracity of medieval warmth.

    There were cool and warm regions during the Little Ice Age, too, but the mean value was cooler than the 20th century.

  63. Wren says:

    Latimer Alder says:
    July 5, 2010 at 7:41 am
    @wren

    Quoting from Mann’s 2009 study:

    “The Medieval period is found to display warmth that matches or exceeds that of the past decade in some regions, but which falls well below recent levels globally.”

    At which point I see Angels Dancing on the Heads of Pins coming into view and terminal boredom setting in. Game over…slam dunk…the recent warming is not unprecedented…CAGW falls because these climatic conditions have happened before without catastrophe.

    End. Thank You. Good Night.
    ====
    If nature can cause global warming without catastrophe, nature plus man can’t cause catastrophic global warming.

    File that one under logical fallacy.

  64. Richard Sharpe says:

    Wren says on July 5, 2010 at 12:28 pm

    Latimer Alder says on July 5, 2010 at 7:41 am

    @wren

    Quoting from Mann’s 2009 study:

    “The Medieval period is found to display warmth that matches or exceeds that of the past decade in some regions, but which falls well below recent levels globally.”

    At which point I see Angels Dancing on the Heads of Pins coming into view and terminal boredom setting in. Game over…slam dunk…the recent warming is not unprecedented…CAGW falls because these climatic conditions have happened before without catastrophe.

    End. Thank You. Good Night.
    ====

    If nature can cause global warming without catastrophe, nature plus man can’t cause catastrophic global warming.

    File that one under logical fallacy.

    However, that is not the issue under dispute. Some, perhaps most, proponents of AGW claim that the current warming is unprecedented, which they then suggest is evidence that it must be human caused.

    Your dishonest attempt to redirect discussion is noted.

  65. Roy says:

    DirkH says:

    “I’d like to remind you that it was mainly the Americans who liberated Germany and helped us establish a stable democracy. Your influence is not lost.”

    That is debatable in several respects. Fist of all not one country went to war with the intention of liberating Germany. Britain (and France) went to war with unsuccessful aim of preventing Germany from conquering Poland. The Soviet Union went to war because it was attacked by Germany and some of Germany’s European allies. The United States went to war against Germany because Germany had declared war on the United States immediately after the Japanese attack on Pearl Harbor.

    Secondly, while not wishing to down-play the enormous part the Americans played in the war, I think your comments, like Hollywood films and even some serious American historians, try to make the American contribution look even more significant than it was by down-playing the roles of other countries. The war would not have been won without the enormous sacrifices made by the Soviet Union. Nor would it have been won if Britain had not decided to continue the fight in 1940 or if the RAF had lost the Battle of Britain. In addition the British inventions of radar and electronic code breaking machines (the forerunners of modern electronic computers) were also of enormous importance.

    Radar, electronic methods of code breaking, preliminary work on the atomic bomb, and penicillin (which prevented tens of thousands of deaths from infected wounds) were all given to the United States by Great Britain, as was the jet engine which Britain could, and should, have developed in the 1930s but unfortunately did not use until the final months of the war.

  66. Wren says:

    david says:
    July 5, 2010 at 10:08 am
    Liam, are you serious? Over 31,000 scientist with over 9,000 PHDs dispute your 3,000. The 3,000 is also phantasy.
    ====
    Not 31,000 climate scientists. Not even 31,000 scientists.

  67. Wren says:

    Richard Sharpe says:
    July 5, 2010 at 12:43 pm
    Wren says on July 5, 2010 at 12:28 pm

    Latimer Alder says on July 5, 2010 at 7:41 am

    @wren

    Quoting from Mann’s 2009 study:

    “The Medieval period is found to display warmth that matches or exceeds that of the past decade in some regions, but which falls well below recent levels globally.”

    At which point I see Angels Dancing on the Heads of Pins coming into view and terminal boredom setting in. Game over…slam dunk…the recent warming is not unprecedented…CAGW falls because these climatic conditions have happened before without catastrophe.

    End. Thank You. Good Night.
    ====

    If nature can cause global warming without catastrophe, nature plus man can’t cause catastrophic global warming.

    File that one under logical fallacy.

    However, that is not the issue under dispute. Some, perhaps most, proponents of AGW claim that the current warming is unprecedented, which they then suggest is evidence that it must be human caused.

    Your dishonest attempt to redirect discussion is noted.
    =====

    Scientists who are proponents of AGW claim that current warming is unprecedented in the history of the world?

    That’s news to me. Can you quote some of them?

  68. Barry (July 5, 2010 at 12:25 am)

    Nice try. Now match this one

    And btw, I looked at that website’s page of “anti-AGW papers debunked” and apart from Gerlich & Tscheuschner (which appears to be suspect), all the papers familiar to readers here (Lindzen, Svensmark, etc) have many supporters here who can debunk all those debunks. I always look hard at the best evidence on both sides to see who practises scientific method for themselves rather than appeal to authority, and can debunk the most thoroughly and still practice courtesy, and when I get to the end of the trail of clues and see who wins out, I have a strong sense for the future of whom I would start off by trusting. You might like to do likewise.

  69. David L says:

    Wren says:
    July 5, 2010 at 12:28 pm

    “If nature can cause global warming without catastrophe, nature plus man can’t cause catastrophic global warming.”

    Nature plus man??? Is man not part of nature? Talk about a logical fallacy! But this makes sense if there’s no evolution and man just showed up one day.

  70. jeef says:

    Wren, I’d rather 31,000 scientists of any hue than the political yes men infesting the ranks of the IPCC. Surely even you can recognise that 31,000 is much more of a consensus? ;-)

  71. latitude says:

    “”barry says:
    July 5, 2010 at 12:08 am
    This is the temp record for China, not the globe. It’s a small fraction of the northern Hemisphere. One of the key points in most reconstructions of NH millennial temps is that warming happened at different times in different regions,””

    Barry, can trees move?

  72. tim O'Brien says:

    Roy says:
    July 5, 2010 at 12:46 pm

    I think Ben and DirkH were speaking in the context of 4th July and independence, and bemoaning the fact that their democracy could not give exposure to a truth whereas the Chinese communist system could.

    I hope you are very young and not British (i am neither).

    The truth, whether you would like to accept it or not, is that the US saved Europe in both the 1st and 2nd World Wars.
    God Bless America, and I’m not American.

    tim

    tim

  73. Vincent says:

    Wren says in reply to Richard Sharpe,

    “Scientists who are proponents of AGW claim that current warming is unprecedented in the history of the world?

    That’s news to me. Can you quote some of them?”
    ==================

    Richard actually said: “, perhaps most, proponents of AGW claim that the current warming is unprecedented, ”

    He did NOT say “unprecendented in the history of the world.”

    By putting words into Richards mouth which he did not utter, in order to try and belittle his argument you are either dishonest or haven’t even bothered to read the post.

  74. Roy says:

    @ tim O’Brien

    I am British and I am not very young. In World War I American participation was on a far smaller scale than that of France and the British Empire and Commonwealth. The invention of tank (by the British) and its effective deployment transformed the military situation. American participation was important primarily because it caused the Germans to realise that they simply would not have the manpower to win if they continued fighting.

    Further to my original comments about World War II and the Battle of Britain, radar, code breaking, penicillin, early work on the atom bomb, and the jet engine, none of which you disputed, the tide in the west changed at the Battle of Alamein, before any American soldiers were in action against the Germans. The naval forces which won the Battle of the Atlantic (without which no American armies could have engaged the Germans) were predominantly British and Canadian.

    For the Normandy campaign, although the supreme commander was an American, the commanders of the land forces, the naval forces and the air forces were all British. The bulk of the naval forces were supplied by the UK. The landings on 3 of the 5 beaches on D-Day were by British and Canadian forces and from D-Day until some time after the American breakout the great majority of the German panzer divisions, were deployed against the British and Canadian forces which made the eventual US breakout possible.

    None of this is intended to disparage the American contribution to winning the war but your comments, which also totally ignored the massive contribution of the Soviet Union, show how the false Hollywood version of history has spread far outside America.

    However, as this blog is supposed to be about the world’s climate and not military history I had better resist the temptation to give more examples.

  75. Dr A Burns says:

    Interesting that graphs (a), (b) and (e) all show declining temperatures from the mid 1900′s … just like Briffa … the “hide the decline” stuff …

    http://eas8001.eas.gatech.edu/papers/Briffa_et_al_PTRS_98.pdf

  76. tim O'Brien says:

    Roy says:
    July 5, 2010 at 2:54 pm

    OT

    Roy,
    I applaud the courage, tenacity and ingenuity of th British in WWII.
    However, I think
    i) you should give some recognition to the (pivotal?) part played by Ameirca at El Alamein.
    ii) you should recognise the main cause of Battle of the Atlantic (to prevent, mainly American aid to her allies and Russia) http://en.wikipedia.org/wiki/Battle_of_the_Atlantic_(1939%E2%80%931945)
    iii) while acknowledging the great suffering of the Soviet people we should recognise that Stalin had a pact with the Axis powers and had no intention to be any help to the Allies
    iv) apart from the substantial material aid given to Russia by the US, the entry of the US into the war greatly facilitated Stalin by reducing pressure to defend to the East.
    v) while US was fighting a brutal war in the Pacific it made massive commitment to the war in Europe
    vi) the US made a massive reconstruction commitment to Europe after the war
    vii) Winston Churchill, were he alive, would be disappointed in you

    Sorry for going off topic but i thought it would be very unfair to let such a post go unchallenged.
    BACK ON TOPIC

    tim

  77. timheyes says:

    As you all know very well…

    Dr Mann has “always been very open about the uncertainties in his work”

    and

    Dr Mann was “surprised at the high profile his work was given”.

    :P

  78. Roy says:

    @ Tim,

    I agree with much of what you wrote. (A few minor quibbles; the defeat of the U-boats in the Atlantic was of vital importance to Britain in both world wars. Although the great bulk of Allied aid to the Soviet Union came from the United States most of what actually reached them during the first winter came from Britain and Canada as Pearl Harbor temporarily caused the Americans to concentrate on making sure their own forces had the equipment they needed. Britain tied down and eventually defeated significant Japanese forces in Burma).

    As I said, my posts were in no way meant to disparage America’s contribution to victory. M4 Sherman tanks, which the US went on to produce in enormous numbers were indeed first used at Alamein. My father who served in the British army in North Africa, Italy and northwest Europe from Normandy to Denmark was very proud of the British contribution, but freely admitted that we would not have won without the Americans.

    I emphasised the British contribution because I was responding to people who gave the credit almost exclusively to the United States. In fact the British, the Americans, and the Russians can all legitimately claim that it is probable that the war would either have been lost or would have ended in some sort of costly stalemate without them. (In that case it is quite likely that a third world war have broken out later). The Australians, Canadians, New Zealanders, South Africans and Indians etc. can also claim that the British owe them an enormous debt for their contributions in both world wars, and therefore the rest of the world also benefited from the sacrifices of people from those countries.

    RETURNING TO THE WEATHER:

    The role of the weather in military history is quite fascinating. The British Meteorological Office has, quite justifiably, had a lot of criticism in recent years, but it had its “finest hour” with the accurate forecast for D-Day when the Germans were expecting the bad weather (which, although they did not know it, had already caused the invasion to be postponed by 24 hours) to continue.

    However, as this thread was really meant to be about the climate over the last 1,000 years or so and not particular examples of weather I had better not continue!

  79. barry says:

    Lucy, thanks for the link. It doesn’t really attach to my post you referenced. I pointed to Hemispheric (and global) studies when someone said that the Hemispheric mean had not been attempted. I’m not sure a chart really qualifies as a “study”, and the mean certainly hasn’t been assessed there.

    You may not have noticed that I already posted upthread the well-known skeptical chart that appears on that webpage, pointing out that it actually corroborates that different regions show warming at different times. These are the circumstances described in Mann’s and proceeding reconstructions. The author of that post apparently failed to scrutinise his own source, referring to it as a graphic that “shows that the MWP is a worldwide event.”

    There are about 47 proxies in that “worldwide chart”, IIRC. Mann’s first studies used more, and more recent studies use hundreds. One must wonder about the selection process here. What about all the other proxies?

    Regardless, the ones that appear on that chart are not uniform in their warm/cool periods, though there is some confluence around 1000AD. Some graphs show cooler temps around 1000AD. Some of the peaks occur 500 years apart for some regions. I doubt anyone has crunched the numbers to see what the combined offsets produce.

    I’ll post that link again for you and you can check to see if I’m correct.

    http://pages.science-skeptical.de/MWP/MedievalWarmPeriod.html

    You can hover over the graphs and they’ll expand, or click on them for a larger picture.

  80. Pascvaks says:

    Discussing (aka ‘arguing’) WW1 or WW2, or anywhen or anywhat else, is a lot like discussing the weather or global climate change. Everyone has an opinion, no one is a true expert. But…. chances are that the more we discuss anything the greater the likelihood someone will say something truly intelligent and memorable. (I seriously doubt many of us are going to live that long however; or recognize it when it happens.)

  81. John A. Jauregui says:

    None of this is important now, given the fact that NASA’s new mission is outreach to Islamic nations. James Hansen is on-board with that and so is Prof. Mann.

  82. Lucy Skywalker says:
    July 5, 2010 at 1:08 pm

    Barry (July 5, 2010 at 12:25 am)

    Nice try. Now match this one http://wattsupwiththat.com/2009/11/29/the-medieval-warm-period-a-global-phenonmena-unprecedented-warming-or-unprecedented-data-manipulation/

    And btw, I looked at that website’s page of “anti-AGW papers debunked” and apart from Gerlich & Tscheuschner (which appears to be suspect), …..

    I publish an abstract of this paper in http://www.oarval.org/ClimateChange.htm and would be very interested in learning how G&T got it wrong (I think they did not).

    Thanks

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