A regional approach to the medieval warm period and the little ice age

Nicola Scafetta sends this along, I found this figure quite interesting, but there are many more in the full PDF available below.

 

A regional approach to the medieval warm period and the little ice age
Fredrik Charpentier Ljungqvist
Stockholm University
Sweden

1. Introduction
In order to gain knowledge of the temperature variability prior to the establishment of a widespread network of instrumental measurements c. AD 1850, we have to draw information from proxy data sensitive to temperature variations. Such data can be extracted from various natural recorders of climate variability, such as corals, fossil pollen, ice-cores, lake and marine sediments, speleothems, and tree-ring width and density, as well as from historical records (for a review, see IPCC 2007; Jones et al. 2009; NRC 2006). Considerable effort has been made during the last decade to reconstruct global or northern hemispheric temperatures for the past 1000 to 2000 years in order to place the observed 20th century warming in a long-term perspective (e.g., Briffa, 2000; Cook et al., 2004; Crowley and Lowery, 2000; D’Arrigo, 2006; Esper et al., 2002; Hegerl et al., 2007; Jones et al., 1998; Jones and Mann, 2004; Juckes et al., 2007; Ljungqvist, 2010; Loehle, 2007; Mann et al., 1999; Mann et al., 2008; Mann et al., 2009; Mann and Jones, 2003; Moberg et al., 2005; Osborn and Briffa, 2006).

Less effort has been put into investigating the key question of to what extent earlier warm periods have been as homogeneous in timing and amplitude in different geographical regions as the present warming.

It has been suggested that late-Holocene long-term temperature variations, such as the Medieval Warm Period (MWP) and the Little Ice Age (LIA), have been restricted to the circum-North Atlantic region (including Europe) and have not occurred synchronic in time with warm and cold periods respectively in other regions (Hughes and Diaz, 1994; Mann et al., 1999; Mann and Jones, 2003). This view has, however, been increasingly challenged through the ever growing amount of evidence of a global (or at least northern hemispheric) extent of the MWP and the LIA that have become available (see, for example, Esper and Frank, 2009; Ljungqvist, 2009, 2010; Moberg et al., 2005; Wanner et al., 2008).

A main obstacle in large-scale temperature reconstructions continues to be the limited and unevenly distributed number of quantitative palaeotemperature records extending back a millennium or more. The limited number of records have rendered it impossible to be very
selective in the choice of data. Palaeotemperature records used in a large-scale temperature reconstruction should preferably be accurately dated, have a high sample resolution and have a high correlation with the local instrumental temperature record in the calibration period (see the discussion in Jones et al., 2009).

The number of long quantitative palaeotemperature records from across the globe, of which a majority are well suited for being used in large-scale temperature reconstructions, have been rapidly increasing in recent years (Ljungqvist, 2009). Thus, it has now become possible to make regional temperature reconstructions for many regions that can help us to assess the spatio-temporal pattern and the MWP and LIA. Only by a regional approach can we truly gain an understanding of the temperature variability in the past 1–2 millennia and assess the possible occurrence of globally coherent warm and cold periods. Presently, only four regional multi-proxy temperature reconstructions exist: two for eastern Asia (Yang et al., 2002; Ge et al., 2010), one for the Arctic (Kaufman et al., 2009), and one for South America (Neukom et al., 2010). Six new quantitative regional multi-proxy temperature reconstructions will here be presented in order to improve our understanding of the regional patterns of past temperature variability.

4. Conclusion
The presently available palaeotemperature proxy data records do not support the
assumption that late 20th century temperatures exceeded those of the MWP in most regions, although it is clear that the temperatures of the last few decades exceed those of any multidecadal period in the last 700–800 years. Previous conclusions (e.g., IPCC, 2007) in the opposite direction have either been based on too few proxy records or been based on instrumental temperatures spliced to the proxy reconstructions. It is also clear that temperature changes, on centennial time-scales, occurred rather coherently in all the investigated regions – Scandinavia, Siberia, Greenland, Central Europe, China, and North
America – with data coverage to enable regional reconstructions. Large-scale patterns as the MWP, the LIA and the 20th century warming occur quite coherently in all the regional reconstructions presented here but both their relative and absolute amplitude are not always the same. Exceptional warming in the 10th century is seen in all six regional reconstructions.
Assumptions that, in particular, the MWP was restricted to the North Atlantic region can be rejected. Generally, temperature changes during the past 12 centuries in the high latitudes are larger than those in the lower latitudes and changes in annual temperatures also seem to be larger than those of warm season temperatures. In order to truly assess the possible global or hemispheric significance of the observed pattern, we need much more data. The
unevenly distributed palaeotemperature data coverage still seriously restricts our possibility to set the observed 20th century warming in a global long-term perspective and investigate the relative importance of natural and anthropogenic forcings behind the modern warming.

 

Full report here (PDF)

a_regional_approach_to_the_medieval_warm_period_and_the_little_ice_age

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94 thoughts on “A regional approach to the medieval warm period and the little ice age

  1. Yes it seems that if one rejects the global nature of the various warming and cooling periods of the past, then there is no basis for predicting, as has been the CAGW hypothesis that a global scale warming catastrophe is assuredly in our future.

  2. Very interesting. Although the report says that the last few decades have been the warmest in the last 700-800 years, it is also relevant that this warmth did not suddenly appear in the last few decades at the time when CO2 emissions were greatest, but rather developed slowly over the last two centuries. This argues against a large role for human influence.

  3. Now, the critical question:

    Could every one of those observed regional climate changes be accounted for by a simple latitudinal shift of the air circulation systems above the regions concerned ?

  4. Well Nick. Maybe you should shit can those proxies. Because I guaranty you that Greenland was pasture and grapes grew in Labrador during the MWP.

  5. I placed this sarcastic post over at the Bradley thread but it seems even more relevant here as the graph at the top of this thread confirms the point I was making. Look at the year 1700 in the graph then read the charts in my post;
    (Sorry for reinflicting it on everyone)

    “Anthony

    A very interesting post.

    Did you realise that you must have accidentally transposed the image, as the second half of the temperature record on the Hockey stick is upside down? Our instrumental and anecdotal records show a slow steady temperature rise (with advances and set backs ) from around 1700, long before Dr Hansens Giss figures kicked them into the stratosphere.

    12 of the oldest instrumental records shown graphically in next two links.

    Scores of old instrumental records collected on my site here.

    http://climatereason.com/LittleIceAgeThermometers/

    Anthony, to prevent embarassment to Dr Mann can you correct your inadvertent mistake and readjust the graph so it shows this steady increase instead of the decline?”

    tonyb

  6. I’ve always wondered just how confident we are in the timing of regional proxies. Yeah, there appear to be some regional differences on timing across those proxies, but how much of that is due to observational error and/or overlapping error bars?

    It makes less sense to me that there was a warm period that marched from region to region over a couple hundred years than that we’ve just screwed up the timing of individual regional proxies, artificially creating sine waves that cancel each other out rather than reinforce.

  7. Large-scale patterns as the MWP, the LIA and the 20th century warming occur quite coherently in all the regional reconstructions presented here but both their relative and absolute amplitude are not always the same.

    Let’s be clear on this, the MWP is here pre-millennial, 900 to 1000. Lamb’s central England graph (which morphed global in IPCC 1990) gives a peak a couple of centuries later, and many have followed putting the MWP peaking around 1200 (high middle ages with time of gothic cathedral boom etc).

    The early work of Bruckner (1880s and 1890s) and Huntington (1910s to 30s) examined temp and rainfall together, talking of climate optimum and minimum and tell a much more complex story. ‘Optimums’ were easier to find in the proxies (Huntington pioneering tree ring analysis), but they were operating on assumptions (first in Bruckner) of cycles from warm-dry to cool-wet in high lats. Huntington was looking at the way the polar-circling storm belts advance more or less into the desert zones, and so what was optimal for wheat belt was not for irish potato farmers etc.

    See some of the early graphs here:

    http://enthusiasmscepticismscience.wordpress.com/global-temperature-graphs/

    The recent fixation on temperature, and on global temp, is a curious development when we know so much more about the nature of cyclic climate variation. As this fixation seem have arisen as an essential element in the AGW scare, I do wonder, as an observer, why sceptics dont try more to shift the debate away from this fixation with temperature. One place to start would be avoid using the IPCC 1990 graph, but perhaps we should try to give a proxy global temp at all – I’m with Lindzen on that.

  8. I never heard of Fredrik Charpentier Ljungqvist, so I tried to find out using Google. It seems he is a graduate student in the department of history at Stockholm U.

    http://su-se.academia.edu/FredrikCharpentierLjungqvist

    It was published in the Journal of the Swedish Society for Anthropology and Geography.

    http://agbjarn.blog.is/users/fa/agbjarn/files/ljungquist_temperature_reconstructions_2009.pdf

    I wonder if any climate scientists peer reviewed it. It will be interested to see it deconstructed.

    REPLY:Good point! We’ve never heard of you until you appeared here one day. Where are you from and what have you published? – Anthony

  9. At the very least this confirms that the issues aren’t clear cut and are probably (my take on what I understood) much more complex than the Alarmists make out.
    So, do we once more get back to what often gets lost in the detail: if what is happening now isn’t unique, then we don’t need to look for a historically unique cause e.g. industrial CO2 emissions, that were fingered because (IMO) of general anti – industrial bias plus couldn’t think of anything else so obviously not present before…

    My view, shouldn’t this kind of work have been done and argued about before all the alarms were sounded?

  10. Regional climate analysis is the only way to make sense of what is going on. The following temperatures would get buried in an average across the US.

    Record Report

    000
    SXUS76 KPDT 241814
    RERPDT

    RECORD EVENT REPORT
    NATIONAL WEATHER SERVICE PENDLETON OR
    1013 AM PST WED NOV 24 2010

    …NEW DAILY RECORD LOW TEMPERATURES FOR NOVEMBER 24TH…

    NOTE: STATIONS MARKED WITH * INDICATE THAT THE STATION REPORTS ONCE
    PER DAY. FOR CONSISTENCY…THESE VALUES ARE CONSIDERED TO HAVE
    OCCURRED ON THE DAY THE OBSERVATION WAS TAKEN BUT MAY HAVE ACTUALLY
    OCCURRED (ESPECIALLY FOR MAX TEMPERATURE) ON THE PREVIOUS DAY.

    STATION PREVIOUS NEW RECORDS
    RECORD/YEAR RECORD BEGAN

    *JOSEPH, OR 9 / 2007 -9 1893
    *LONG CREEK, OR -10 / 1993 -10 (TIED) 1957
    MEACHAM, OR 2 / 2007 -24 1948
    *PENDLETON(CITY), OR 0 / 1993 -7 1890
    *BICKLETON, WA -5 / 1985 -12 1931
    *GOLDENDALE, WA 14 / 1929 -3 1931

  11. eadler says:
    I never heard of Fredrik Charpentier Ljungqvist, so I tried to find out using Google. It seems he is a graduate student in the department of history at Stockholm U.

    I’m sure if you keep googling you can find some connection between Ljungqvist and “Big Oil”. Maybe his grandfather had greasy hair.

  12. So you have; tonyb, ( payed alarmist ) and “eadler” anonymous troll. This is on the eve of the warmists’ biggest (I”ll try my luck ) wankfests? they can only marshal one poster and his glove puppet?

    A bit like the EURO they are boned.

  13. Ljungqvist (Professor, Doctor, what is his title?) is clearly a very level headed guy. This is a good paper, carefully examining the details of the data, and letting it lead to whatever conclusions are justified. That is science. Budding researchers please take notes.

  14. @ eadler on November 24, 2010 at 3:15 pm

    Nice use of an ad hominem and an appeal to authority in one failed argument.

  15. A day in the life of a mini-me ice age:

    I’ve been cleaning house at the ranch in frigid Wallowa County. I mopped the linoleum landing inside the back porch that leads into the attached wood house. Before it could dry it froze. I tried unfreezing it with hot water but I couldn’t mop up the water to dry the floor fast enough before it froze again. So I threw rock salt on it.

  16. A nice review of the published but, what’s more interesting, also unpublished and non-archived proxies.
    And the comment at the page 17, that Briffa’s (2000) Yamal trees show too much of an increase in 20th century compared to other circum-Arctic trees nearby mentioned in Esper et al. (2002) is quite an understatement ;-)

  17. I know where you are ‘coming from’ Anthony, however “where are you from?”
    and, “what have you published?”
    Are moot questions in reality.

    If I was back at University, made the right noises in a few places, twisted some arms to get a grant and…………….. if I said, I want to “prove AGW!”
    Then I’d be virtually guaranteed (even in these straitened times) a grant, irrespective of my expertise or field, so to me, questions (such as the above) are completely irrelevant.

    Lets face it, the IPCC will publish aught (even undergrad’ dissertations and other more dubious sources) if it says the right thing, what’s needed is a new approach to the whole damnable process and we need to start with ‘peer review’.

    Some good ideas here:

    http://noconsensus.wordpress.com/2010/11/23/how-a-scientific-integrity-act-could-shift-the-global-warming-debate/#more-10878

  18. So how many studies exist now from a variety of disciplines over several decades that consistently show the MWP was warmer than present? Sea floor sediments, coral, ice cores, entomology, archaeology, geology, botany, literature, even the Norse Sagas. All go against MBH98 and the closed-system papers that attempted to support MBH in the subsequent nine years.

    But to remind everyone — according to the IPCC Working Group III co-chair, it’s no longer about protecting the environment, but rather the “equitable” redistribution of the world’s resources under the perverted notion of Social Justice.

  19. Is this in press or what?

    Eight of 26 pages are references. Just sayin…

    Interesting things. Recent May-Sept temps are not as elevated as winter. China and Europe are only regions as warm today as during MWP. That must be where the people most responsible for post-industrial warming are residing. Nice.

  20. Ljungqvist’s blog is here (in Swedish)

    http://blogs.su.se/fchar/

    and Google translate here

    http://translate.google.com/translate?js=n&prev=_t&hl=en&ie=UTF-8&layout=2&eotf=1&sl=sv&tl=en&u=http%3A%2F%2Fblogs.su.se%2Ffchar%2F

    The paper was self-published apparently and available as part of an anthology here

    http://www.intechopen.com/books/show/title/climate-change-and-variability

    He does not mention whether he tried to publish it in a peer reviewed journal.

    Craig Loehle has compared another paper by Ljungqvist with his own results on extratropical northern hemisphere temperature reconstructions here at WUWT and found a good correlation.

    http://wattsupwiththat.com/2010/09/28/loehle-vindication/

  21. The assumption that late 20th century warming is man made rests on two lines of “evidence”:

    1. Present warming is unprecedented for the last 2000 years (hockey stick, etc)
    2. Climate models can not reproduce 20th century warming without man made CO2 as a decisive factor in the equation.

    Both have now been called into question.

    1. Present warming is not unprecedented on at least a hemispheric scale.
    2. If there was a similar warming 1000 years ago, we know that present warming can also be caused by natural variability, no matter if models can not reproduce it.

    It will be interesting to see how the IPCC will deal with this. My guess is that the Team Machine will kick into action, that there will be serial “debunkings” of these results, and that the IPCC will stick to the good old story.

  22. eadler says:
    November 24, 2010 at 3:15 pm

    I wonder if any climate scientists peer reviewed it. It will be interested to see it deconstructed.

    Oh, dear! It may have slipped past the climate gatekeepers.

  23. Alan Simpson etc. – tonyb is hardly a paid alarmist . I suggest you review his comments and occasional posts here .

  24. eadler says: November 24, 2010 at 3:15 pm
    I never heard of Fredrik Charpentier Ljungqvist, so I tried to find out using Google. It seems he is a graduate student in the department of history at Stockholm U. It was published in the Journal of the Swedish Society for Anthropology and Geography. I wonder if any climate scientists peer reviewed it. It will be interested to see it deconstructed.
    ——————————————————————————–
    Eadler This statement says more about you than it does Ljungqvist. Why don’t you try to ‘deconstruct’ it yourself and give us the benefit of your endeavours.

    Douglas

  25. EW says: November 24, 2010 at 4:15 pm
    “that Briffa’s (2000) Yamal trees show too much of an increase in 20th century compared to other circum-Arctic”

    Those other circum-Arctic trees were missing the necessary Briffa adjustments.

    valadj=[0.,0.,0.,0.,0.,-0.1,-0.25,-0.3,0.,-0.1,0.3,0.8,1.2,1.7,2.5,2.6,2.6,2.6,2.6,2.6]*0.75 ; fudge factor
    yearlyadj=interpol(valadj,yrloc,x)
    densall=densall+yearlyadj

    Source of above IDL Source Code:
    “FOI2009/FOIA/documents/harris-tree/briffa_sep98_e.pro”.

    See Also: http://www.thespoof.com/news/spoof.cfm?headline=s5i64103

  26. Billy Liar says:
    Oh, dear! It may have slipped past the climate gatekeepers.

    Here, let me fix that for you…

    It may have slipped past the climategate keepers.

  27. Leif… I’d be interested in your thoughts on the following passage starting at the bottom of page 17:

    Although it is outside the scope of this article, we can briefly discuss the possible influence of variations in solar and volcanic forcing on the reconstructed temperatures. All the six 18 Climate Change and Variability regional temperature reconstructions show some agreement with the assumed lowfrequency variability in solar forcing of the last 12 centuries (Bard et al., 2000). The medieval period, with high temperatures, had a general high solar activity, whereas the cold LIA was dominated by lower solar activity (Ammann et al., 2007). The warming in the 20th century coincides with an increase in solar forcing, although the warming trend has probably also been amplified in the last decades by anthropogenic greenhouse gas emissions (IPCC, 2007).

  28. AJ says:
    November 24, 2010 at 7:38 pm
    All the six 18 Climate Change and Variability regional temperature reconstructions show some agreement with the assumed lowfrequency variability in solar forcing of the last 12 centuries (Bard et al., 2000).

    The ‘some agreement’ is very weak [and mostly a hangover from Jack Eddy's notion of the Little Ice Age caused by the Maunder minimum]. If we look at modern reconstructions there is no agreement of significance: http://www.leif.org/research/Loehle-Temps-and-TSI.png
    The top panel is a temperature reconstruction, the middle panel a recent reconstruction of solar activity [expressed as TSI]. The bottom panel is a comparison of 10Be [blue] and 14C [red] variations. I recently gave an invited lecture at the University of Tromsoe on this: http://www.leif.org/research/Does%20The%20Sun%20Vary%20Enough.pdf
    This is, of course, just my [reasoned] opinion.

  29. I found my self uplifted by Fredrik Charpentier Ljungqvist’s blog, education and his understanding of history and climate. He brings an honest well-researched picture of weather and climate history. He writes well, is peer reviewed and published. I have reached to the conclusion that he is the real thing and a breath of fresh air. He has a brilliant future in his profession, as long as he can stay untainted and on the path of honesty and integrity. Please look him up and see if you agree.
    Ted.
    ————————————————————————————–
    Speaking of “An Inconvenient Truth: The Earth’s climate has always changed.

    The drama documentary “An Inconvenient Truth by Al Gore in 2006 painted a dramatic picture up of global warming, as in the movie entirely attributed to emissions from burning fossil fuels.
    The problem with film is that today’s warming is not at all put into a historical perspective.
    In An Inconvenient Truth produced it as if today’s temperatures were higher than they’ve ever been before and it is presented as if no climate change of significance had not occurred in history before the 1900s.
    The climate has always been highly variable.
    In addition, measurable amounts of global warming over the last hundred years to no more than about 0.7 to 0.8 ° C
    Disaster scenarios for future warming of as much as 5-6 ° C based on computer models, based on hypotheses about how climate is affected by the emission of a certain quantity of greenhouse gases. “An Inconvenient Truth will be biased by failing to mention that the earth from the 1300s until about in 1900 were in the world’s coldest climate period since the last ice age.
    A serious debate about global warming would require a discussion of not warming during the 1900s at least partly be interpreted as a natural recovery from the “Little Ice Age” that lasted between 1300 and 1900.
    We have actually returned to an environment similar to what has been the mainstream in a longer historical perspective (any cause)
    It may be appropriate to give examples of some past climate changes.
    So, for example, large parts of the Sahara were a fertile savannah for only 3000 or 4000 years ago.
    Some research indicates that the Mediterranean climate was far up in Central Europe at the time around the birth of Christ.
    Climate variations in the last 2000 years has been all cultures to join in the marginal areas as climate and vegetation zones ever been on “walk”.
    In the longer term, climate variations have been even greater.
    The best example of this is the Ice Ages: the whole of Sweden was covered by a three-kilometer thick ice.
    Probably the climate was during the early Middle Ages as hot as it is now. Some studies suggest that average temperatures in many places even higher than today.
    When the Arctic is now warming up, we must not forget that the polar regions were at least as hot a thousand years ago.
    The tree line in the mountains was then further up and tundra was in many places
    The sea ice was also rare along such large parts of Greenland’s coasts.
    The reason for this has been left out in An Inconvenient Truth bottoms probably in large part to the impact that the prominent climatologist Michael E. Mann received.
    His reconstruction of global mean temperature in the last thousand years does not permit any climate variability and omits both the Medieval Warm Period as the “Little Ice Age
    Mann’s temperature reconstruction has been a kind of official status since it gained recognition from the UN’s climate panel (IPCC) and is often used as “evidence” that the current warming only be attributed to the burning of fossil fuels.
    While this appears to climate reconstruction increasingly untenable
    An increasing number of climate history data (drill samples from glaciers, pollen analysis and analysis of tree rings, etc.) was often indicates the presence of both the Medieval Warm Period and the Little Ice Age
    [Comment: Mann published in 2008 a new temperature reconstruction that clearly showed the Medieval Warm Period and the Little Ice Age.]
    However, it should not be denied that it is probably true that the enhanced greenhouse effect, as the burning of fossil fuels causes, is one of the factors affecting today’s climate.
    But this is hardly the only factor. In a historical perspective, today’s warming to see as an expected and natural recovery after a cold spell.
    A good indication that this case is that the global temperature actually fell slightly in 1950 – and 1960’s even though the burning of fossil fuels also increased exponentially.

    Author: Fredrik Charpentier Ljungqvist ·

    http://translate.google.com/translate?js=n&prev=_t&hl=en&ie=UTF-8&layout=2&eotf=1&sl=sv&tl=en&u=http%3A%2F%2Fblogs.su.se%2Ffchar%2F

    http://translate.google.com/translate?js=n&prev=_t&hl=en&ie=UTF-8&layout=2&eotf=1&sl=sv&tl=en&u=http%3A%2F%2Fblogs.su.se%2Ffchar%2F

  30. Pamela Gray and others, I may have related this before, but I knew the last Flight Service Station manager that worked Meacham, Oregon back in the days of the old radio
    range and airway beacons. Back in the 70’s I was a NOAA certified weather observer,
    on a notably cold January day, Meacham was similarly cold. The FSS Fellow, Ron, as I
    recall, said when I turned in the Observations for La Grande, “I see Meacham had another minus twenty today.” “Yep, third this week.” I replied, He said:” You know,
    Meacham is a lot like Alaska, Spent a lot of time at North Pole, and Soldatna, Meacham’s
    kind of like a little of both, ‘cept Soldatna’s a lot warmer…”

  31. EW says: November 24, 2010 at 4:15 pm

    “that Briffa’s (2000) Yamal trees show too much of an increase in 20th century compared to other circum-Arctic”

    Those other circum-Arctic trees where missing the necessary briffa adjustments.

    valadj=[0.,0.,0.,0.,0.,-0.1,-0.25,-0.3,0.,-0.1,0.3,0.8,1.2,1.7,2.5,2.6,2.6,2.6,2.6,2.6]*0.75 ; fudge factor
    yearlyadj=interpol(valadj,yrloc,x)
    densall=densall+yearlyadj

    Source of above IDL Source Code:
    “FOI2009/FOIA/documents/harris-tree/briffa_sep98_e.pro”

    See Also:
    http://www.thespoof.com/news/spoof.cfm?headline=s5i64103

  32. [these are better posted to Tips & Notes . . mod]

    OT but I don’t know if this has been posted on WUWT yet in any thread. This looks like a very important peer reviewed paper just published. This is strong support for Henrik Svensmark’s cosmic ray theory.

    See article here:

    http://hockeyschtick.blogspot.com/2010/11/paper-compelling-evidence-of-cosmic-ray.html

    and the paper here:

    http://www.pdfdownload.org/pdf2html/view_online.php?url=http%3A%2F%2Fwww.atmos-chem-phys.net%2F10%2F10941%2F2010%2Facp-10-10941-2010.pdf

    In Atmospheric Chemistry and Physics 10, 10941-10948, 2010 doi:10.5194/acp-10-10941-2010

    Cosmic rays linked to rapid mid-latitude cloud changes
    B. A. Laken 1,2, D. R. Kniveton 1, and M. R. Frogley 1

    1Department of Geography, University of Sussex, Falmer, Brighton, England, BN1 9QJ, UK
    2Instituto de Astrofísica de Canarias, 38205 La Laguna, Tenerife, Spain

    Svensmark’s co-author of The Chilling Stars, Nigel Calder, has been hinting on his blog that we will soon see the first results from Svensmark’s CLOUD experiments at CERN. This paper comes as possibly a surprise precursor (at least to me).

  33. Be on the lookout for tampon bombers!

    Please don’t ban me for this.

    You will make history by not doing so.

  34. eadler says:
    November 24, 2010 at 3:15 pm

    “I wonder if any climate scientists peer reviewed it. It will be interested to see it deconstructed.”

    Why is it only the ones that support CAGW need to be “deconstructed”?

    Where is your concern for these papers and their “deconstruction”:

    Briffa, 2000; Cook et al., 2004; Crowley and Lowery, 2000; D’Arrigo, 2006; Esper et al., 2002; Hegerl et al., 2007; Jones et al., 1998; Jones and Mann, 2004; Juckes et al., 2007; Loehle, 2007; Mann et al., 1999; Mann et al., 2008; Mann et al., 2009; Mann and Jones, 2003; Moberg et al., 2005; Osborn and Briffa, 2006).

  35. Sorry, mod, somehow the existence of “Tips and Notes” has escaped this long time WUWT reader.

    I have done as you suggested and you can remove the post in this thread if you so desire.

  36. “Less effort has been put into investigating the key question of to what extent earlier warm periods have been as homogeneous in timing and amplitude in different geographical regions as the present warming.”
    Is homogeneous really preferable to similar?

  37. Pamela Gray says: (November 24, 2010 at 4:11 pm) I’ve been cleaning house at the ranch in frigid Wallowa County. ..
    How did grandma do it, Pamela? Back in the late 1800s? Lysol? where the secret was in the scrubbing…

    Wallowa County, Oregon
    In 1871, the first white settlers came to the area, crossing the mountains in search of livestock feed in the Wallowa Valley.

  38. Stephen Wilde says:
    November 24, 2010 at 2:37 pm
    Now, the critical question:

    Could every one of those observed regional climate changes be accounted for by a simple latitudinal shift of the air circulation systems above the regions concerned ?
    But that also begs another question: What would have caused those shifts?

    Further, what would have been the cause (driver) of that particular cause?

    To presume one thing of necessity demands that its driver be identified.

    It’s not unlike this: The spoon stirred the coffee. A hand caused the spoon to move. The brain of the owner of that hand caused the hand to move and stir the coffee.

    If we look only at the spoon, we’ll miss/neglect its driver. Heck we might even misattribute the cause to something entirely unrelated.

    With all of the various data which have been collected, and all of the anecdotes (historical references) from ages past, with all of the ice core data and the sun spot data having been analysed, there are few other effects which haven’t been otherwise determined as having affect, such as planetary gravitational influences and the Sun’s current sheets inducing heating in the upper atmosphere by interacting with the Earth’s own magnetosphere.

    Knowing what we know already, even if we don’t completely comprehend the lot of it, the correlations in all of the collected information are overwhelmingly in favor of external forces as having the greatest affect upon this planet’s climate and weather.

    With the mass of information available, there’s just no way that humans could have caused any of the past events, and since the past events happened when humans weren’t a viable cause for those, and those past events are cyclic in nature, and because the current event is happening with the same periodicity, then there’s no way that humans could even be considered as any kind of agent.

    It’s staring us in the face, and yet there are people with a vested interest telling us to ‘Don’t look behind the curtain!!!’

    Gee, I wonder why?

    Why? They’ll see Al Gore and his banker buddies staring back at us, with the greedy smiles of vampires just waiting for darkness to set in.

  39. Alan Simpson not from Friends of the Earth says:

    “November 24, 2010 at 3:58 pm
    So you have; tonyb, ( payed alarmist ) and “eadler” anonymous troll. This is on the eve of the warmists’ biggest (I”ll try my luck ) wankfests? they can only marshal one poster and his glove puppet? A bit like the EURO they are boned.”

    Ithink your comprehension needs a little refining. The idea that I am a paid alarmist will be hilarious to those that follow my posts here or read my articles on historic examples of climate change.

    You might start on your education by reading something of mine such as this seasonal offering of mine;

    http://noconsensus.wordpress.com/2010/01/06/bah-humbug/

    Numerous other articles and records of temperatures from 1660 can be found on my web site here.

    http://climatereason.com/LittleIceAgeThermometers/

    You might like to then apologise publicly for your stupid, ill considered, and offensive comments.

    Tonyb

    [Note: tonyb is a regular and well respected contributor to this site. ~dbs, mod.]

  40. I believe that I’ve found an error in Figure 2 based on the data in Tables 1 and 2.

    Figure 2 has the “correct” locations for Greenland numbered 10-15 in Table 1.

    Based on these six station bounding (lat/lon) coordinates I obtained the following;

    81.21N,-69.30W (NE corner)
    60.40N,-29.60W (SW corner)

    Figure 2 shows E, F, and G as being within these bounding coordinates. While Table 2 shows that the letters for Greenland are actually G, H, and I.

    Could someone else, or the author of this paper, check/validate my coordinates/Figure 2/Table 1/Table 2?

    If I’m right, and this paper has already been published (physical and/or electronic formats) as is, why didn’t the peer review process/editors catch such a glaringly obvious bookkeeping/tabulation error?

    If I’m wrong, oh well, we all make mistakes.

  41. Leif Svalgaard says: “Nice hockey stick. The blade is a bit small, though.

    The hockey stick was their global warming phallus …

    Strange what a dose of cold reality does … more like turkey giblets than the tower of Pisa!

  42. Following the 1st link from this post (thanks to Ed Waage);

    http://wattsupwiththat.com/2010/11/24/a-regional-approach-to-the-medieval-warm-period-and-the-little-ice-age/#comment-536643

    or directly;

    http://blogs.su.se/fchar/

    This paper is actually the 1st chapter in the following edited edition of this book;

    http://www.intechopen.com/books/show/title/climate-change-and-variability

    The book is free, just download 379.zip from the above link.

    So a couple questions come to mind; 1) Why is this book for free and bot for sale (behind a pay wall), and 2) this is not published in a well respected peer reviewed climate science journal, why is that, and will the author publish this in something mildly resembling a peer reviewed publication of any sort?

    Note, his previous paper (2009 paleo-reconstruction) was published in some rather obscure (IMHO) Scandinavian geography journal. If it were ground breaking or new original research, I’d expect something of this nature to be published in a much more respected journal, from purely a climate science perspective.

  43. Notice, that the “small hockey stick” occurred in 1900-1940 period, when the climate was still virgin. FYI, until 1990 Greenland cooled back to 19th century level and then warmed back to the level of 40ties. Not much of CO2 forcing manifested up there.

  44. eadler says:
    I never heard of Fredrik Charpentier Ljungqvist, so I tried to find out using Google. It seems he is a graduate student in the department of history at Stockholm U.

    Yes, keep on Googling!

    Maybe the guy smokes? Black-list him!
    Maybe he believed in Jesus when he was 5 years old? Heaven forbid!
    Maybe he bought a litter to oil to his car ? Oh no! Big Oil!
    Maybe he doesnt work for the swedish Government? Private industry !! Banned!!

    And for crying out loud! Dont you ever read any of his arguments?! It could ruin the little world Al Gore built for you.

  45. Anthony,

    In fact, scepticalscience did a pretty good story on Ljungvist 2010 :

    http://www.skepticalscience.com/new-remperature-reconstruction-vindicates.html

    Which shows the comparison of all major temperature reconstructions, including the ones accumulated for Ljungvist 2010, and the differences and communalities between them.

    In contrast, you only show a local temp record from Greenland (sent to you by Scafetta), without any mentioning of any peer-reviewed paper where that graph is presented, nor where the data came from.

    And then your story from Ljungvist. What are you trying to prove with that ?
    Ljungvist 2010 itself mentions in the conclusions :

    “Although partly different data and methods have been used in our reconstruction than in Moberg et al. (2005) and Mann et al. (2008), the result is surprisingly similar. The inclusion of additional records would probably not substantially change the overall picture of the temperature variability.”

    So Anthony, the question really is : What are you trying to say in this post, and why are you cherry-picking a local temperature record when the global record is widely different from it, even as confirmed by Ljungvist himself ?

  46. I was taken by this quote from the paper – “Late 20th century temperatures are lower than those of the MWP in the Scandinavia, Siberia and especially in the Greenland temperature reconstruction and equal to the medieval warming in the North America reconstruction. However, in the China and the Central Europe reconstructions late 20th century warming exceeds the medieval one, although this is not clear from the proxy reconstructions themselves but only from the instrumental temperature data spliced to the reconstructions.” End Quote

    This made me think of the Chinese temperature records, which seem to have Phil Jones’s fingerprints all over them, ensuring that there are no UHI corrections applied. Could this be the reason that the temperature records from China stand out as being high, when they are spliced to the reconstructions?

  47. November 24, 2010 at 11:17 pm
    Stephen Wilde says:
    November 24, 2010 at 2:37 pm
    Now, the critical question:

    This is something about climate research that has bugged me for ages. When training to be an EE&E1radio engineer my mentor always used to say “go to the source”. I’ll just explain that in case you think its the well :); He used to put faults onto circuits and then I had to find them. Being a youngster, I used to head straight for the component I thought the symptons indicated and invariably got it wrong. Go to the source.

    In weather climate you get, for example, ” The cold weather in coming to the UK because the jet stream has moved south” Yes BUT WHY. See what I mean? They never go to the source. In the teams example, its back to the model which they think is the source. Its sooo annoying.

  48. Anthony :

    Another comment on the Greenland graph :
    Ljungqvist himself mentions about this graph (Fig 7 in his paper) :

    “The Greenland temperature reconstruction has been calibrated against the annual mean temperature from the 85–60°N × 15–70°W CRUTEM3 grid cells (Fig. 7).”

    In other words, this graph represents the diversion from the CRUTEM record.
    It is NOT a representation of absolute temperature in the Greenland area.
    So not only are you cherry-picking a local record which is not representative for the Northern Hemisphere (let alone the global record), you do not even present the actual temperature trend for the region. Just the difference between two records.

  49. “eadler says:
    November 24, 2010 at 3:15 pm
    I never heard of Fredrik Charpentier Ljungqvist, so I tried to find out using Google. It seems he is a graduate student in the department of history at Stockholm U.”

    So he’s a grad student? In academia the graduate students are typically the ones that do all the work and publish all the papers. The PI typically does the final edits and tacks their name last on the paper. The most successful PI’s (principle investigator) have huge teams of grad students and post docs. The PI’s in these cases are typically way out of the loop in the research: they guide the overall broad research topics and function at a more general level. Except The Team. They are unique in having a closed group of PI’s that publish and referee each other.

  50. [Note: tonyb is a regular and well respected contributor to this site. ~dbs, mod.]
         That needed saying, dbs.

  51. Rob, this is the instrumental record from given area:

    If Greenland (even as a “ground zero” for global warming) is not representing the Northern hemisphere, neither does Mann’s bristlecones.

  52. Rob 1.47 and 2.17

    I am seriously concerned at the reading comprehension of some of the people looking at this article. In the first line Anthony says;

    “Nicola Scafetta sends this along, I found this figure quite interesting, but there are many more in the full PDF available below.”

    That is a clue that there are many more in the full pdf available below.
    Below at the bottom of the article is the obviously invisible (to some) line;

    “Full report here (PDF) which goes to the link;

    a_regional_approach_to_the_medieval_warm_period_and_the_little_ice_age

    This links to the comprehensive selection of studies that might give a clue as to the nature of the story which is headed;

    “A regional approach to the medieval warm period and the little ice age”

    I have suggested that ‘Alan Simpson not from Friends of the Earth’ apologise to me for his unwarranted comment, perhaps you would like to do so in this instance to Anthony?

    Tonyb

  53. @Rob,

    You are misunderstanding the word “calibrated.”. The Greenland reconstruction has been tied into (calibrated) CRUTEM3; it is not an anomaly series (diversion from) CRUTEM3.

  54. From http://onlinelibrary.wiley.com/doi/10.1111/j.1468-0459.2010.00399.x/abstract

    A NEW RECONSTRUCTION OF TEMPERATURE VARIABILITY IN THE EXTRA-TROPICAL NORTHERN HEMISPHERE DURING THE LAST TWO MILLENNIA

    1. FREDRIK CHARPENTIER LJUNGQVIST

    Article first published online: 6 SEP 2010

    DOI: 10.1111/j.1468-0459.2010.00399.x

    © The authors 2010 Geografiska Annaler: Series A © 2010 Swedish Society for Anthropology and Geography

    Issue
    Geografiska Annaler: Series A, Physical Geography
    Geografiska Annaler: Series A, Physical Geography

    Volume 92, Issue 3, pages 339–351, September 2010

    Additional Information(Show All)

    How to CiteAuthor InformationPublication History
    How to Cite

    LJUNGQVIST, F. C. (2010), A NEW RECONSTRUCTION OF TEMPERATURE VARIABILITY IN THE EXTRA-TROPICAL NORTHERN HEMISPHERE DURING THE LAST TWO MILLENNIA. Geografiska Annaler: Series A, Physical Geography, 92: 339–351. doi: 10.1111/j.1468-0459.2010.00399.x
    Author Information

    1.

    Department of History, Stockholm University, Sweden

    *Correspondence: Fredrik Charpentier Ljungqvist, Department of History, Stockholm University, SE-106 91 Stockholm, Sweden. E-mail: fredrik.c.l@historia.su.se
    Publication History

    1. Issue published online: 6 SEP 2010
    2. Article first published online: 6 SEP 2010
    3. Manuscript received Oct. 2009 revised and accepted Jan. 2010

    cheers
    Roger

  55. E.M. Smith says:

    “Billy Liar says:
    Oh, dear! It may have slipped past the climate gatekeepers.

    Here, let me fix that for you…

    It may have slipped past the climategate keepers.”

    I would suggest the following:
    It may have slipped past the climate goalkeeper.
    After all they are a team and the previous post suggests they all have their own hockey stick.

  56. Weather pattern variability (the natural oscillating range within a climate type) and climate change (as in ice ages), can only best be understood regionally. If one keeps focusing on some kind of global indices, you will miss opportunities to uncover mechanisms that could prove crucial to understanding these changes and mitigating against them.

    I have no doubt that our next ice age will happen regionally at first. And it appears to me that both a sustained colder Pacific and a colder Atlantic are probably necessary. How would the Atlantic turn cold? Either winds must blow away the warm surface, revealing colder water beneath, or some cold current that feeds into the Atlantic begins feeding it big time. Clearly though, winds and water temperature needs to be conducive to ice growth and low summer melt in the Arctic and the surrounding upper latitudes.

  57. tonyb says: at 4:25 am

    I am seriously concerned at the reading comprehension of some of the people . . .

    I’ve made similar comments. My word last time was “astonished.”

    Likewise, I was astonished at the remark about you being a “payed” (sic) alarmist.

    I also find your posts informative and several are warmly tucked on my hard drive.

  58. ~dbs, mod
    [Note: tonyb is a regular and well respected contributor to this site. ~dbs, mod.]

    Tony B is not only well respected contributor but a gentleman too, which I know from our personal correspondence.

    Leif Svalgaard says:
    November 24, 2010 at 8:04 pm
    ……………….
    Here are two temperature’s reconstructions in more detail:

    http://www.vukcevic.talktalk.net/LL.htm

  59. Despite substantial uncertainties, especially for the period prior to 1600 when data are scarce, the warmest period prior to the 20th century very likely occurred between 950 and 1100, but temperatures were probably between 0.1°C and 0.2°C below the 1961 to 1990 mean and significantly below the level shown by instrumental data after 1980.

    Is William Connolly still at it, School children refer to this crap.

    http://en.wikipedia.org/wiki/Medieval_Warm_Period

  60. vukcevic says:
    November 25, 2010 at 10:33 am
    Here are two temperature’s reconstructions in more detail
    As I said, the fact that you have to reverse the correlation for some of the time is the clearest evidence that the correlation is spurious.

  61. @ 899: “To presume one thing of necessity demands that its driver be identified.
    It’s not unlike this: The spoon stirred the coffee. A hand caused the spoon to move. The brain of the owner of that hand caused the hand to move and stir the coffee.”

    That is nicely put. It reminds me of:

    ” I call the effects of nature the works of God, whose hand & instrument she only is; and therefore to ascribe his actions unto her, is to devolve the honour of the principal agent, upon the instrument; which if with reason we may do, then let our hammers rise up and boast they have built our houses, and our pens receive the honour of our writings.” (Sir Thomas Browne, Religio Medici, I, 16 (1643)

  62. Leif Svalgaard says:
    November 25, 2010 at 12:06 pm
    As I said, the fact that you have to reverse the correlation for some of the time is the clearest evidence that the correlation is spurious.

    I do not generate or change correlation, it is a natural process, that I have brought to the attention.
    I’ve just pointed out elsewhere that in certain cases correlation can flip from positive to negative, even in a case of causation, I am not claiming the causation is case here.
    That makes your remark questionable.

  63. Guys, being a “geographer” is not a point which is against someone on this issue. Not long ago every single person who studied climate in academia was in a geography department: climatology was considered a sub-field of geography, because it was thought that it was all about know the relevant climate zones-which were thought of as fixed geographic locations, not unlike the positions of the continents were thought to be. There are few “climate” departments at few universities even today, and many studying climate still work in the geography department. Many still regard climatology as a “geography” thing.

  64. @ David Middleton : You are right regarding my comment (in my 2:15 post) on the calibration issue. Thank you for pointing that out.

    @ tonyb (4:25) : I am not sure what your issue is with my (1:47) post.
    The point I was making had nothing to do with finding Ljungqvist’s Pdf.

    The point was that Anthony picked ONE regional graph from that pdf, even though that one is not representative for the larger set that Ljungqvist posts in his pdf, and certainly not representative for the entire Ljungqvist 2010 presentation.

    Also, the “skepticalscience” post shows very clearly that the Greenland graph that Anthony prominently posts here is not representative for Ljungqvist’ 2010, nor for the Northern Hemisphere as a whole, and that Ljungqvist 2010 overall shows very close resemblance to Mann 2008 and Moberg 2005.

    Anthony could at least have mentioned that, since otherwise some readers may misinterpret what Ljungqvist actually found, and start to see ‘opposite’ hockey-sticks (at cherry-picked time points) in a graph that has no association with the overall Northern Hemisphere reconstructions.

  65. Anthony;

    In regard to “eadler” I am compelled to raise the issue of troll quality with you. Both the quantity and the quality have been in decline of late. Could you perhaps put more effort into recruitment? There was a time on this blog when trolls abounded, could carry on a logical discourse, and sometimes even made valid points. One can hardly learn anything from an argument which rests on the premise that a paper may be questionable because it was not peer reviewed by the scientists who wrote papers that are falsified by it.

    Not only is the argument so pathetic that it hardly deserves response, it is in fact so pathetic that one can’t even make fun of it. Its just sad really. If you could put some effort into getting some decent trolls, I’d appreciate it.

    Until then I shall content myself with rereading accusations that Tonyb is a paid alarmist. Debunked of course by many long before I had a chance, but at least there were some facts on the table to debate, and a conclusion tabled that was so wrong it was hilarious.

  66. 899 and stephen richards:

    I drew attention to the latitudinal shifting of the jets aspect because that is what links regional changes in climate to changes in the global pattern of climate distribution. That simple observation makes it highly unlikely that events such as the MWP and LIA could ever be merely local or regional events.

    Elsewhere, I have gone to quite some lengths (continuing) to try and account for such shifting.

  67. Uh huh. That’s just about what the literature indicates happened: The LIA and the MWP were pretty much a global thing, as far as the writings exist. It’s been a slow roll down the hill from the Holocene Optimum.

  68. DavidmHoffer

    “Not only is the argument so pathetic that it hardly deserves response, it is in fact so pathetic that one can’t even make fun of it. Its just sad really. If you could put some effort into getting some decent trolls, I’d appreciate it.”

    Wonderful! A career in satire beckons.

    For those that defended me against the charge that I was a paid alarmist thank you. Now, about my Christmas present…

    Tonyb

  69. @Rob, November 25, 2010 at 5:33 pm

    Mann 2008 and Moberg 2005 are fairly similar. The main difference is that Mann employed a version of Mike’s Nature trick to the last ~40 years of his curve. Moberg did not; nor did Ljungqvist. Moberg and Ljungqvist calibrated their reconstructions to the instrumental data. Mann over-rode his reconstruction with the instrumental data.

    The problem with Mann’s methodology lies in the fact that the instrumental data and reconstruction proxies are different things. They have very different sampling rates, resolutions, frequency content and amplitude spectra.

    The proper way to merge two signals with such differences is to condition one series to fit the other. In signal analysis, this is usually done by deriving a mathematical operator to transform one series to fit the other. This is similar to the process employed in merging seismic reflection surveys of different vintages, with different recording parameters.

    Mike’s Nature Trick basically splices a high frequency, high resolution signal onto the tail-end of a low frequency, low resolution signal. This will almost always create the impression of an anomaly at the tail-end. The same thing happens with the CO2 reconstructions. The Antarctic ice core data are very low frequency, low resolution. MLO is very high frequency, high resolution. The modern CO2 level is far less anomalous when compared to plant stomata reconstructions, because those data are closer to MLO in resolution.

  70. eadler says:
    November 24, 2010 at 3:15 pm
    I never heard of Fredrik Charpentier Ljungqvist, so I tried to find out using Google. It seems he is a graduate student in the department of history at Stockholm U.
    I wonder if any climate scientists peer reviewed it. It will be interested to see it deconstructed.

    Nice logic. The paper (or whatever) reviews regional, previously published studies from around the world. Pardon me, but I thought geography relates to location. Why would a person want a climate scientist to review published geographical proxy studies?
    Data is data. We don’t need no stinkin’ opinions.

    EFS_Junior says:
    November 25, 2010 at 12:31 am
    So a couple questions come to mind; 1) Why is this book for free and bot [sic] for sale (behind a pay wall), and 2) this is not published in a well respected peer reviewed climate science journal, why is that, and will the author publish this in something mildly resembling a peer reviewed publication of any sort?
    Note, his previous paper (2009 paleo-reconstruction) was published in some rather obscure (IMHO) Scandinavian geography journal.

    This journal has a long and storied history. It is well respected in knowledgeable science circles. It is peer reviewed. Appeals to authority are ignorantly misplaced in this instance.

    http://www.docstoc.com/docs/43740994/Geography-in-Sweden

  71. Rob, the point is that “overall Northern Hemisphere reconstructions” are averaged together. Which means that vital information was kicked out in the search for some odd “Global Temperature”. It would be like sending someone to the doctor for some mysterious illness and when you get there all the doctor can say is that you are sick, because the only thing that matters is your rectal temperature.

  72. Pamela,

    Now lets agree that the average temperature of the patient taken over many differents part of the body and different times shows a fever, and most doctors agree that the reason is Antropogenic, just like theory predicted.

    Just some people still believe that by looking at checky-picked measurements and cherry-picked areas of the body (and by showing a graph of that area with these measurements on wattsupwiththat) shows that there is nothing unusual going on, and that the patient is somehow immune to the substance that in theory should cause a fever indicative of a desease that can potentially be quite devastating.

    Now which “vital information” did I leave out ?

  73. Rob says:
    November 26, 2010 at 9:38 pm
    Pamela,

    Now lets agree that the average temperature of the patient taken over many differents part of the body and different times shows a fever, and most doctors agree that the reason is Antropogenic, just like theory predicted.

    Just some people still believe that by looking at checky-picked measurements and cherry-picked areas of the body (and by showing a graph of that area with these measurements on wattsupwiththat) shows that there is nothing unusual going on, and that the patient is somehow immune to the substance that in theory should cause a fever indicative of a desease that can potentially be quite devastating.

    Now which “vital information” did I leave out ?

    Which “vital information” did you leave out?

    You left out your diagnoses of Earth’s identical fevers from 863 AD to 897 AD and 1911 to 1944.

    Here are the HadCRUT3 Northern Hemisphere instrumental record, Ljungqvist’s 2010 Nothern Hemisphere reconstruction and Alley’s 2000 Central Greenland reconstruction for Central Greenland… Alley, Ljungqvist, HadCRUT3 – 3.5 kya. I calibrated Alley’s Greenland reconstruction to Ljungqvist. What caused the “fevers” from 1450 BC to 1350 BC and 320 BC to 120 BC?

    Here’s the same reconstruction expanded to cover most of the Holocene: Alley, Ljungqvist, HadCRUT3 – 3.5 kya. What caused the “fevers” from 6300 BC to 5900 BC, 5250 BC to 4980 BC, 4300 BC to 3700 BC, 3480 BC to 3250 BC, 2820 BC to 2300 BC and 2000 BC to 1680 BC?

  74. David,

    The HADCRUT3 1911-1944 +0.5 C increase started out a whopping 0.4 C below the +0.5 C increase since 1975, and global temperaures thus went up almost a full degree C over the 20th century. That (long-term increase) is the fever that one would expect from antropogenic GHG forcing.

    And the graph that you show since the start of the Holocene essentially shows only the GISP2 record. May I remind you that that is a single ice core in one spot in Greenland ? That graph really makes my point that some people cherry-pick ONE location and then feel that it has any meaning for the global temperature record.

    At least in the following graph there are 8 proxies combined (from various places on Earth),

    This shows again that Greenland (or any other local record) is not representative for the average of this planet. It also shows (again) that temperatures right now are unprecedented as seen over the entire Holocene record.

    Why is this so hard for you (and Anthony) to accept ? Why do you guys keep cherry-picking locations (or time intervals) and pretend that such cerry-picking has any meaning in the global picture ?

  75. Rob says:
    November 28, 2010 at 1:28 am
    David,

    The HADCRUT3 1911-1944 +0.5 C increase started out a whopping 0.4 C below the +0.5 C increase since 1975, and global temperaures thus went up almost a full degree C over the 20th century. That (long-term increase) is the fever that one would expect from antropogenic GHG forcing.

    And the graph that you show since the start of the Holocene essentially shows only the GISP2 record. May I remind you that that is a single ice core in one spot in Greenland ? That graph really makes my point that some people cherry-pick ONE location and then feel that it has any meaning for the global temperature record.

    At least in the following graph there are 8 proxies combined (from various places on Earth),

    This shows again that Greenland (or any other local record) is not representative for the average of this planet. It also shows (again) that temperatures right now are unprecedented as seen over the entire Holocene record.

    Why is this so hard for you (and Anthony) to accept ? Why do you guys keep cherry-picking locations (or time intervals) and pretend that such cerry-picking has any meaning in the global picture ?

    Rob,
    Your Wikipedia source says that “there is no scientific consensus on how to reconstruct global temperature variations during the Holocene.” If there was such a consensus, it certainly would not be to simply average together 8 global proxies. Most paleo climate reconstructions of the Upper Holocene are limited to the Northern Hemisphere. Antarctic ice cores show very little in the way of stadial/interstadial climatic fluctuations. Greenland ice cores, sediment cores, speleothems, etc show quite a lot of stadial/interstadial climatic fluctuations. Antarctic ice cores are not used for Northern Hemisphere reconstructions. Two of the eight proxies are Antarctic ice cores. Most Northern Hemisphere reconstructions are extra-tropical. Three of the eight proxies are from tropical locations.
    So, five of the eight proxies would probably not be used in a Northern Hemisphere reconstruction over the entire Holocene.
    Despite the flaws of the Wiki-reconstruction, it basically shows the same pattern as the GISP2 reconstruction. The heavy black curve is the average of the 8 proxies. It shows the modern warming to be comparable to the Medieval Warm Period and the Little Ice Age to be the coldest part of the Holocene. It shows a steadily cooling climate since the Holocene Climatic Optimum with a super-imposed millennial warming and cooling cycle. There is nothing unprecedented about the modern warming on the Wiki-reconstruction.

  76. David,
    I posted the wiki reconstruction (with 8 proxies) just as an example of how irrelevant single-location / single-proxy samples are in the global record.
    Even with just 8 proxies, the picture (of the previous “unprecedented” warming periods that you mentioned) looks entirely different. Regardless of the weight by which each proxy is measured, a large sample of proxies irons out the extreme (“unprecedented”) random/weather anomalies of single samples, and reveals the low-frequency climate trends that climate science is interested in.

    From signal theory, we know that for N channels (each with uncorrelated, “local” noise) signal to noise ratio for common signals is SQRT(N) better than for a single channel. Meanwhile, local temperature extremes are moderated by a factor of N. From that we know that more (and more physically widespread) samples are quantifiably better than small number of samples if we are interested in ‘global’ or ‘common’ trends.

    Even with just 8 proxies on this Holocene record, the long, slow term down trend since the Holocene Climatic Optimum becomes apparent (which is very well explained with the Milankovitch cycles) and the global (+0.7 C in 100 years) climate anomaly of the 20th Century starts to come out of the noise as well.

    In that light, I find it mystifying why you throw out 5 of the 8 reconstructions (because they are not in the extra-tropic Northern Hemisphere).
    As you very well know, that just increases the noise, and makes it more difficult to recognize climate trends.

    Ljungqvist already reduced the number of proxies that he considered (by separating regions, and then again even for the individual regions as well). Then Anthony used the local noise in the Greenland record and the noise that Ljungqvist created by reducing proxies to somehow imply that 20th Century warming is not unprecedented.
    And now you are doing the same thing with the Holocene record.

    I start to see the pattern that Ljungqvist (at least in this non-peer-reviewed pdf story), Anthony and you are using :

    Reduce the number of samples (preferably by cherry-picking) to the point where the local weather noise is greater than the 20th century warming (or to sample size 1, whichever comes first), and then use that to claim that “therefore” the 20th Century warming is not unprecedented or AGW is in doubt.

    Of course, you are just fooling yourself (and some readers here) with noise that you created yourself.

    Question is, again : WHY are you guys doing that ? Why not find MORE proxies and combine them with the 1000+ proxies (dating back to many different past times) that we already have ? Why reduce the set, create noise, and then imply statistically irrelevant conclusions ?

    Why ?

Comments are closed.