The Finnish "Supra-Long" Chronology #1

Over the past 30 years, Finnish dendrochronologists have developed a “supra-long” tree ring chronology now stretching back (Helama et al 2008) to 7600BP, well into the Holocene Optimum. Earlier versions of this chronology have been reported in many articles (e.g. Helama et al 2002, Eronen et al 2002 and references back into the 1990s plus articles here. Among other things, the chronology has been used to date changes in the treeline, which, in turn, has been used to estimate past temperatures.

We discussed one such study (Kultti et al 2006) at CA here (which estimated MWP temperatures as 0.55 deg C higher than at present) in passing in 2006, but, because of the focus on studies relied upon by IPCC, we haven’t had occasion to consider this data at length.

Y’see, although the Finnish chronology is a long well-dated chronology that would seem to meet any reasonable selection criteria governing Tornetrask or Yamal or bristlecones, this data wasn’t used in any of the AR4 multiproxy studies, nor was it used in Mann et al 2008. Nor was it mentioned in IPCC AR4 (a point that I’ll return to in another post.) Given that Briffa was a co-author of Eronen et al 2002 (one of the key publications), its not as though he was unaware of this data. So its exclusion from earlier studies really requires a little explanation.

We re-encountered this data because it was (long overdue) included in Briffa et al 2008. After 6 months and repeated efforts by Phil Trans B, Briffa finally archived the first tranche of data (a merged version of Swedish and Finnish data.) Not making things easy, Briffa didn’t provide any metadata as to where anything came from. This led to a bit of head-scratching, but I think that we can now be sure that the first 430 items are from Finland (with a few from Norway via the Finnish authors) and the rest from Sweden.

With some effort, I was able to match a few series to archived versions (e.g. one beam form Sodankyla church). Jean S reminded us that Mauri Timonen, one of the architects of the chronology, had commented previously at CA. and urged me to contact him about questions regarding the Finnish component of Briffa et al 2008. This proved to be a very felicitous reminder. I sent an email to Mauri Timonen of METLA a few days ago and received a very cordial reply in which he sent greetings to CA readers and expressed satisfaction that the Finnish timberline pine chronology was being discussed. He mentioned that the 2010 World Dendro Conference was being held in Finland.

He sent me a lot of data, including a listing of the 1087 samples in the supra-long chronology (of which the 430 most recent were used in Briffa et al 2008). Of these 1087 samples, metadata (including UTM northing, easting and altitude) were provided for 1039 trees – there are 3 institutions involved in Finnish sampling: METLA, University of Joensuu (SAIMA) and University of Helsinki and I think that the exclusions pertain to data from other institutions (I’m clarifying this.) He also sent me measurement data for 342 cores, 71 of which were selected into the supra-long chronology. I don’t know who made the selection, why a subset was taken or the criteria for subsetting (I didn’t notice an explanation in Helama et al 2002 or Eronen et al 2002).

It’s nice to contrast the openness of Timonen and METLA, with the surly attitudes that bedevil so many operatives in this field (Santer, Mann, Briffa, Jones, Thompson, Hansen,…) I must say that it affects one’s attitude to the data (and I have to watch out for this), as one inevitably is more critical of data that you have to fight to get.

So I’m a bit swamped with fresh data right now and having a pleasant time with it. I have a couple of posts in the works, one of which will discuss their estimates for the MWP and Holocene Optimum; one will be on IPCC review comments, one on RCS.

Briffa, K. R., V. V. Shishov, T. M. Melvin, E. A. Vaganov, H. Grudd, R. M. Hantemirov, M. Eronen, and M. M. Naurzbaev. 2008. Trends in recent temperature and radial tree growth spanning 2000 years across northwest Eurasia. Philosophical Transactions of the Royal Society B: Biological Sciences 363: 2271-2284.
Eronen, M., P. Zetterberg, K. R. Briffa, M. Lindholm, J. Merilainen, and M. Timonen. 2002. The supra-long Scots pine tree-ring record for Finnish Lapland: Part 1, chronology construction and initial inferences. The Holocene 12, no. 6: 673.
Helama, S., M. Lindholm, M. Timonen, J. Merilainen, and M. Eronen. 2002. The supra-long Scots pine tree-ring record for Finnish Lapland: Part 2, interannual to centennial variability in summer temperatures for 7500 years. The Holocene 12, no. 6: 681.
Timonen, M. Lustia Dendrochronology Project.


  1. kim
    Posted Jan 5, 2009 at 10:32 AM | Permalink

    Bon voyage.

  2. Pierre Gosselin
    Posted Jan 5, 2009 at 10:35 AM | Permalink

    “…one inevitably is more critical of data that you have to fight to get.”
    And it’s the same in police detective work!
    Wishing you lots of fun in the data swamp.

  3. Posted Jan 5, 2009 at 11:49 AM | Permalink

    Some dendros provide a few trees worth of data, looks like you got the whole forest!


  4. Steve McIntyre
    Posted Jan 5, 2009 at 12:21 PM | Permalink

    METLA (the Finnish Forest Research Institute) is part of the Finnish Ministry of Agriculture. Maybe this gives them a different attitude than the climate folk.

  5. Gary Hladik
    Posted Jan 5, 2009 at 2:22 PM | Permalink

    Greetings to Mauri Timonen from this CA reader, and thanks for the data!

    I look forward to the upcoming posts on these data, even though the stats always make my head hurt. 🙂

  6. Posted Jan 5, 2009 at 2:45 PM | Permalink

    R, Steve! R like the wind!

  7. TonyA
    Posted Jan 5, 2009 at 2:47 PM | Permalink

    That Lustia website is very interesting – even for a non-expert.

    This power-point was most enlightening (check out page 8 to see what a Finnish “hockey-stick” looks like):

    Click to access MTP_231007.pdf

    • Mike Rankin
      Posted Jan 5, 2009 at 4:04 PM | Permalink

      Re: TonyA (#7),

      The power point presentation is very educational. Although they carefully do not claim anything except a very long regional temperature proxy, one could surmise that our current temperatures are not unprecedented in the last thousand years. The obvious extention of using the same species in adjacent Eurasian areas to broaden the base should be persued. That this mass of work was ignored by IPCC says much about the IPCC.

    • Chris Wright
      Posted Jan 6, 2009 at 5:55 AM | Permalink

      Re: TonyA (#7),

      That presentation is fascinating.There’s an amazing hockey stick on page 6. Problem is, the blade is on the wrong side!

      Haven’t these Finnish guys heard of the IPCC? Don’t they know the 20th century warming was ‘unprecedented’?

      More seriously, it’s pretty shocking to hear that the IPCC and their followers have ignored this impressive work. It’s not hard to see why. It will be fascinating to see Steve M’s analysis of these reconstructions.

      Something else got my attention. Look at the graph on page 28. This is a temperature plot of the last thousand years. It actually shows the current warming at about 0.2 degree warmer than the MWP. But see what happens around the middle of the 20th century. The temperatures start to fall steeply! This appears to be a perfect example of the divergence problem (assuming Finland became warmer over the second half of the 20th century).
      Unfortunately it could call into question the validity of the whole reconstruction. As Loehle has ably pointed out, it may be that trees are very poor thermometers. Just as in the mid 20th century, the steep falls following the three main peaks in the MWP may have occurred because the temperatures had actually continued to increase!
      The comments about cycles are interesting. I would take their predictions with a pinch of salt, but they appear to be saying that we are in a cycle similar to the MWP that will peak in another decade or so followed by very low temperatures in the mid 21st century. My guess is that they are probably right – except that the warming may already have peaked.


  8. William Newman
    Posted Jan 5, 2009 at 3:11 PM | Permalink

    obvious typo in the introduction: “the chronology has been used to data changes in the treeline” should be “to date changes in the treeline”

    (Maybe I shouldn’t be worrying about it, but I’ve spent enough time puzzling over errors in computer programs in not-my-native-computer-language to sympathize with your readers reading posts in not their native human language.)


  9. Hoi Polloi
    Posted Jan 5, 2009 at 3:35 PM | Permalink

    “It’s nice to contrast the openness of Timonen and METLA, with the surly attitudes that bedevil so many operatives in this field (Santer, Mann, Briffa, Jones, Thompson, Hansen,…

    No secret handshakes with the Fins!

    So this dendro survey clearly shows the MWP that the Mannians are so desperately trying to iron out…

  10. Clark
    Posted Jan 5, 2009 at 11:24 PM | Permalink

    What a refreshing reaction and openness from Mauri Timonen.

  11. bmcburney
    Posted Jan 6, 2009 at 12:49 AM | Permalink

    Did you really mean “supra” (from the Latin for “above”), not “super” (meaning “to an extreme degree”)? Am I missing a tree joke?

  12. Edouard
    Posted Jan 6, 2009 at 1:45 AM | Permalink

    Klimalounge (climate-(science?)

    Maybe you allow me to make this post here:

    Mr Rahmstorf has a famous weblog in Germany called Klimalounge, where until last week, comments were allowed, like on realclimate.

    He wanted to create a german “realclimate” (his own words).

    But from 2009 on comments will no longer be allowed. The comments must have been to sceptical and to accurate for him:

    “Hier werden Autoren und Redaktion künftig stärker auswählen, etwa so wie eine Druckzeitung interessante Leserbriefe für den Abdruck auswählt. Internetforen, in denen alles erdenkliche Sinnige und Unsinnige zum Klima diskutiert wird, gibt es im Netz zuhauf”

    He first explained he couldn’t answer all comments, above all longer comments, because he was to busy. From 2009 on, only comments, like well written readers letters, will be allowed.

    I’m very very very dissappointed about this real censorship by Mr. Rahmstorf. The popularity of the blog isn’t only HIS achievement. We, the sceptical laymen, were part of it.

    Why did he want to make a german “realclimate” and now makes a complete U-turn?????? This is a real climate joke, like so many things in climate science.

    Everyone on this planet should know about this step back and this censorship on Mr Rahmstorfs very own blog!!!! Open minds must have frozen in ower new little iceage?! Are we really living in a free world???

    Best regards


  13. Matti Virtanen
    Posted Jan 6, 2009 at 2:40 AM | Permalink

    In case someone is interested, Mauri Timonen and his boss, professor Kari Mielikäinen featured in a Finnish current affairs documentary I produced two years ago. No video available online, but here’s a transcript of the show: – you’ll find some other familiar names as well.

  14. Matti Virtanen
    Posted Jan 6, 2009 at 7:14 AM | Permalink

    I remember Mauri Timonen saying that, based on the Finnish dendrochronological temperature reconstruction, the (undisputed) current warm period should last another 500 years before it could be labeled as unprecedented in the holocene. But of course, their results apply only to northern Finland, not globally. (Mauri – please correct me if my memory fails here. Maybe it was just 400 years?)

  15. Pierre Gosselin
    Posted Jan 6, 2009 at 10:17 AM | Permalink

    Looking at the thermometer over the last couple of weeks in Germany and Europe, Herr Ramstorf has to be spooked and in a bit of angst.
    The icebreakers are now out in the canals in Europe…something we have not seen in years. The exact opposite of what Ramstorf predicted earlier is now happening. Let’s all recall earlier this year how he bet “Big Money” on continued warming.

  16. Pierre Gosselin
    Posted Jan 6, 2009 at 10:21 AM | Permalink

    As a reminder, please cast your votes for Best Science Blog!

  17. Posted Jan 6, 2009 at 11:48 AM | Permalink


    I know you have a lot to do at the moment but I thought this may be of interest

    Click to access henderson141208.pdf

  18. Posted Jan 6, 2009 at 12:14 PM | Permalink

    The Lustia group have a link to CA (and World Climate Report) on their news page. No wonder they are shunned by the IPCC. On their references web page they list 34 publications, of which 15 include the word climate or climatic. The relevant chapter of IPCC AR4, chapter 6, has approximately 600 references at the end, including exactly zero papers from this Finnish group. For comparison, chapter 6 cites 14 papers by lead author Keith Briffa and 16 by somebody called M. E. Mann. Another nice example of IPCC bias for my web page.

    Steve: I’m going to do a post on the IPCC handling of treeline results. BTW Briffa was a coauthor of Eronen et al 2002, so he wasn’t unaware of the Finnish results.

  19. Posted Jan 6, 2009 at 3:41 PM | Permalink

    Voting for Best Science Blog of 2008 ends Jan. 12 (or maybe Jan. 13). Each IP address may vote once for each category every 24 hours, at

    Watt’s Up With That is way ahead, with Pharyngula second, CA third, Bad Astronomy a close fourth, and RC in distant but still-viable 6th place.

    RC encourages its readers to vote, but cautiously dismisses the outcome should it favor a wrong blog:

  20. Chris Schoneveld
    Posted Jan 6, 2009 at 6:00 PM | Permalink

    Warning: OT. (in a big way)!

    Could you do me a favour and treat the word “data” as a word that stands for multiple bits of information especially if you refer to bristlecone data (as you know the Latin word data is the plural form of datum). So when you say ” …..any reasonable selection criteria governing Tornetrask or Yamal or bristlecones, this data wasn’t used in any of the AR4 multiproxy studies, nor was it used in Mann et al 2008″, it hurts my eyes to read “this data” instead of the correct “these data”. Especially in the scientific arena information always consists of multiple elements and the word data should always be treated as being plural.

    It is already bad enough that the English language mistreats the Latin word “visum” by saying “visa” when they refer to a single entry document. Even worse is the usage of “multiple visas”. That’s like saying “datas”. The English abuse the origin of Latin words also when they say the “the media is” instead of the the “media are”. A single media doesn’t exist; it is by definition plural.

    Sorry for sounding pedantic but it has bothered me for years and I feel relieved to get it off my chest. A blog is indeed the ideal medium (not in a clairvoyant sense!!) for people to vent their frustrations.

  21. Ron
    Posted Jan 6, 2009 at 7:04 PM | Permalink

    I really do agree and share your frustrations. (I’m sure we both grind teeth when assaulted by locutions such as “try and…” instead of “try to…”, or “each person has their pet peeves”, instead of “his pet peeves”.) However, my linguist friends tell me that these Latin words (and associated systems for number, gender, tense, etc.) are really no longer Latin when borrowed by English. Thus they become, especially when they move into mainstream usage, subject to the usual functional conventions of number, gender, tense, etc. of English. So, these linguists argue, data (singular) and datas (plural) may be a small price we pay if English is to continue to become humanity’s best chance to repair the Tower of Babel.

  22. Chris Schoneveld
    Posted Jan 7, 2009 at 1:05 AM | Permalink


    Yet we do say museum/musea etc. So the Englishdo honour the Latin forms regularly. The answer of course is language is not logical. By the way, even your linguist friends would not approve of “datas”.

    • Raven
      Posted Jan 7, 2009 at 2:08 AM | Permalink

      Re: Chris Schoneveld (#27)
      Maybe not. But data has become accepted as noun which is both singular and plural like “moose”. Insisting on the original latin usage is a bit like insisting on “facsimile” instead of “fax”. You may be right but will anyone care?

  23. Edouard
    Posted Jan 7, 2009 at 7:00 AM | Permalink

    @Pierre Gosselin

    Are you french? I’m from Luxemburg and we speak both, french and german 🙂

    Yes, you are right. Maybe Mr Rahmstorf caught a cold, or he was angry that more than 70% of the posters were more or less sceptic about climate science. Some weeks ago he explained to a true AGW-believer, that realclimate started the same way, and had still become what it is today.

    But, it just didn’t work in Germany. I don’t know why. Maybe because the blog was from Mr Rahmstorf?

    Best regards


  24. mick
    Posted Jan 7, 2009 at 12:01 PM | Permalink

    I feel the same Chris & Ron, but in the exactly the opposite regard… it jars my sensibilities seeing a good English collective/group/mass noun like ‘data’ repeatedly being abused with a plural article as it has been of late on the web. Maybe it’s to do with dialect or it’s merely an institutional thing… I don’t know.

    But all that aside, I notice you don’t baulk at using the word ‘information’ in the same, singular, group sense you’re objecting to with ‘data’ when trying to explain why data should be plural, Chris. Surely, if ‘information’ in the scientific arena always consists of multiple elements, the word ‘information’ should always be treated as a plural. These information…? 😉

    It’s good to wield language precisely; it is one of our most valuable tools after all. But we’re supposed to use language rather than let language use us. To my mind, Steve is clearly referring to a group when he writes ‘this data’; but it’s one single group (even though there are many things in it). Which is why it has a singular article.

  25. Steve McIntyre
    Posted Jan 7, 2009 at 1:01 PM | Permalink

    Enough on data/datum. Point made, but I’m not going to change my usage.

  26. James Lindgren
    Posted Jan 7, 2009 at 5:07 PM | Permalink

    You wrote:

    I must say that it affects one’s attitude to the data (and I have to watch out for this), as one inevitably is more critical of data that you have to fight to get.

    I find that people who are willing to share their data with me at least believe their own analyses.

    Those who won’t share their data, or are very reluctant to share, tend not to believe their own work will stand up to careful an analyses.

    Speaking loosely, those of us who work with data do statistical tests to be (for example) 95% confident that a pattern this strong is not just the result of random variation.

    When someone won’t share data, IMO their statistical analyses no longer meet the 95% confidence standard. In my experience, those who won’t share data are likely to have made major errors (or worse), so their work no longer meets even a 50% confidence standard for me, let alone a 95% confidence standard.

    James Lindgren
    Northwestern University

2 Trackbacks

  1. […] reconstructions (as well as how it gets ‘fudged’ at times). Steve McIntyre ( Climate Audit LINK) has a new article up […]

  2. […] […]

%d bloggers like this: