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Thanks for starting this, guys. I'll contribute a bit as time permits. Cheers, Pete Tillman ( talk) 19:50, 18 December 2009 (UTC)
I've removed, for now, the reference to the CRU hacking. This is an article on science, not a gossip column. The context-free quote of a statement by Phil Jones raises serious biographies of living persons (BLP) problems, as the same form of words anywhere else on Wikipedia would. -- TS 20:35, 2 January 2010 (UTC)
Please note that, by a decision of the Wikipedia community, this article and others relating to climate change (broadly construed) has been placed under article probation. Editors making disruptive edits may be blocked temporarily from editing the encyclopedia, or subject to other administrative remedies, according to standards that may be higher than elsewhere on Wikipedia. Please see Wikipedia:General sanctions/Climate change probation for full information and to review the decision. -- TS 20:38, 2 January 2010 (UTC)
This is also wrong [1].
Needs citation: who is supposed to have said this. What does "much more" mean?
but is then backed up by a ref to just one region (the Sargasso). We *know* already that temperatures vary by region - see the MWP article itself. Nor does the ref support "there is evidence that the current CO2 induced warming is significantly less than normal climate variability" - what it actually says is the very differnent "at least some of the warming since the Little Ice Age appears to be part of a natural oscillation".
William M. Connolley ( talk) 20:20, 7 January 2010 (UTC)
So, combined with the use of data that hides the MWP (the hockey stick plot), I think that these quotes capture the general thinking in the IPCC documents. (I am surprised that you needed a reference for this.) As for mentioning Gore, I agree that the issue was known long before his movie. I mentioned him as a counter to WMC's suggestion that only "the right-wing blogosphere" is discussing the MWP. The fact that making a joke of the MWP was a critical point in the movie indicates the importance of determining exactly how warm it was. Q Science ( talk) 08:46, 8 January 2010 (UTC)
If tree rings no longer correlate to temperature, in the current environment where we have an abundance of evidence, why do we assume that they are correlating in the past, where we have much more limited evidence? For example the title of Briffa's paper is "Trees tell of past climates - but are they speaking less clearly today?" - essentially I am asking, what evidence is there that tree rings are correlated to global temperatures at all? -- Dilaudid ( talk) 10:16, 3 February 2010 (UTC)
I don't see this one discussed here: full text online. Esper & Frank suggest that some reported divergences arise from data-handling errors, and might go away if the data were handled properly. The paper is labeled as an editorial and is pretty arm-wavy. I haven't yet read it carefully, and won't have time to do so for awhile -- so I'm posting it in case someone like WMC has digested it and can say if it's worth mentioning in our article, or not. Should get a line or so, I'd think:
It's not really suitable for "Further reading" by the general public, but does have a good, up-to-date bibliography on the topic. Thanks, Pete Tillman ( talk) 19:41, 4 October 2010 (UTC)
It seems a shame that such an interesting topic is treated in such a superficial manner. The article is riddled with inaccuracies and omissions - from the first two sentences alone: it is clumsy to describe the divergence problem as an "anomoly" and it is not a phenomenon affecting just ring width e.g. maximum latewood density is also affected. Many significant features of the issue are ignored e.g. there are problems in detecting if this is an in the issue in the first place in many chronologies where it apparently appears, and the fact that the issue can affect whole chronologies, subsets of chronologies and in some cases individual trees. The problem is observed on a decadal timescale, which is hugely significant for climate reconstructions, yet this is not mentioned anywhere in the article. There are also many possible explanations that are not touched on here e.g. the assumptions of a linear growth response to temperature when in fact the response in non-linear (e.g Craig Loehle's work) and the affect of regional curve standardisation (discussed by Keith Briffa, in many places), and many more.
Even the primary significance of the divergence problem for dendroclimatology is not mentioned - the "uniformitarianism" assumption, upon which all of dendroclimatology is based, is in fact called into question by the divergence problem. This is the assumption that the relationship between the environmental variable (more complex than simply "temperature" - not made clear in this article) we are considering and observed tree ring growth in recent times, also holds true for the past which we are attempting to reconstruct.
I would be willing to spend a bit of time reworking the article (I have spent some time studying this area in the past), but would prefer to start the article from scratch - this would mean replacing all the work currently on here. Is that acceptable? (somewhat of a wiki newbie...) — Preceding unsigned comment added by 82.22.196.56 ( talk) 22:59, 25 May 2011 (UTC)
Taubes 1995 certainly shouldn't be the first cite for this -- it was just a "Research News" article summarizing Jacoby & d'Arrigo (1995) , which should be the primary cite. — Preceding unsigned comment added by Krabapple ( talk • contribs) 18:01, 5 February 2014 (UTC)
This is the widespread forestry observation that tree growth can decline if it's too warm or too cold -- with obvious implications for interpreting tree rings as "treemometers". See Loehle, C. 2009. A Mathematical Analysis of the Divergence Problem in Dendroclimatology. Climatic Change 94:233-245. He argues that tree rings can only be used for climatology going back the length of the local climate record, 100 yrs or so -- not the longer 1000+ years often attempted. Any comment from knowledgeable readers? -- Pete Tillman ( talk) 15:08, 18 November 2014 (UTC)
![]() | This article is rated C-class on Wikipedia's
content assessment scale. It is of interest to the following WikiProjects: | |||||||||||||||||||||||
|
![]() | The
contentious topics procedure applies to this page. This page is related to
climate change, which has been
designated as a contentious topic. Editors who repeatedly or seriously fail to adhere to the purpose of Wikipedia, any expected standards of behaviour, or any normal editorial process may be blocked or restricted by an administrator. Editors are advised to familiarise themselves with the contentious topics procedures before editing this page. |
Thanks for starting this, guys. I'll contribute a bit as time permits. Cheers, Pete Tillman ( talk) 19:50, 18 December 2009 (UTC)
I've removed, for now, the reference to the CRU hacking. This is an article on science, not a gossip column. The context-free quote of a statement by Phil Jones raises serious biographies of living persons (BLP) problems, as the same form of words anywhere else on Wikipedia would. -- TS 20:35, 2 January 2010 (UTC)
Please note that, by a decision of the Wikipedia community, this article and others relating to climate change (broadly construed) has been placed under article probation. Editors making disruptive edits may be blocked temporarily from editing the encyclopedia, or subject to other administrative remedies, according to standards that may be higher than elsewhere on Wikipedia. Please see Wikipedia:General sanctions/Climate change probation for full information and to review the decision. -- TS 20:38, 2 January 2010 (UTC)
This is also wrong [1].
Needs citation: who is supposed to have said this. What does "much more" mean?
but is then backed up by a ref to just one region (the Sargasso). We *know* already that temperatures vary by region - see the MWP article itself. Nor does the ref support "there is evidence that the current CO2 induced warming is significantly less than normal climate variability" - what it actually says is the very differnent "at least some of the warming since the Little Ice Age appears to be part of a natural oscillation".
William M. Connolley ( talk) 20:20, 7 January 2010 (UTC)
So, combined with the use of data that hides the MWP (the hockey stick plot), I think that these quotes capture the general thinking in the IPCC documents. (I am surprised that you needed a reference for this.) As for mentioning Gore, I agree that the issue was known long before his movie. I mentioned him as a counter to WMC's suggestion that only "the right-wing blogosphere" is discussing the MWP. The fact that making a joke of the MWP was a critical point in the movie indicates the importance of determining exactly how warm it was. Q Science ( talk) 08:46, 8 January 2010 (UTC)
If tree rings no longer correlate to temperature, in the current environment where we have an abundance of evidence, why do we assume that they are correlating in the past, where we have much more limited evidence? For example the title of Briffa's paper is "Trees tell of past climates - but are they speaking less clearly today?" - essentially I am asking, what evidence is there that tree rings are correlated to global temperatures at all? -- Dilaudid ( talk) 10:16, 3 February 2010 (UTC)
I don't see this one discussed here: full text online. Esper & Frank suggest that some reported divergences arise from data-handling errors, and might go away if the data were handled properly. The paper is labeled as an editorial and is pretty arm-wavy. I haven't yet read it carefully, and won't have time to do so for awhile -- so I'm posting it in case someone like WMC has digested it and can say if it's worth mentioning in our article, or not. Should get a line or so, I'd think:
It's not really suitable for "Further reading" by the general public, but does have a good, up-to-date bibliography on the topic. Thanks, Pete Tillman ( talk) 19:41, 4 October 2010 (UTC)
It seems a shame that such an interesting topic is treated in such a superficial manner. The article is riddled with inaccuracies and omissions - from the first two sentences alone: it is clumsy to describe the divergence problem as an "anomoly" and it is not a phenomenon affecting just ring width e.g. maximum latewood density is also affected. Many significant features of the issue are ignored e.g. there are problems in detecting if this is an in the issue in the first place in many chronologies where it apparently appears, and the fact that the issue can affect whole chronologies, subsets of chronologies and in some cases individual trees. The problem is observed on a decadal timescale, which is hugely significant for climate reconstructions, yet this is not mentioned anywhere in the article. There are also many possible explanations that are not touched on here e.g. the assumptions of a linear growth response to temperature when in fact the response in non-linear (e.g Craig Loehle's work) and the affect of regional curve standardisation (discussed by Keith Briffa, in many places), and many more.
Even the primary significance of the divergence problem for dendroclimatology is not mentioned - the "uniformitarianism" assumption, upon which all of dendroclimatology is based, is in fact called into question by the divergence problem. This is the assumption that the relationship between the environmental variable (more complex than simply "temperature" - not made clear in this article) we are considering and observed tree ring growth in recent times, also holds true for the past which we are attempting to reconstruct.
I would be willing to spend a bit of time reworking the article (I have spent some time studying this area in the past), but would prefer to start the article from scratch - this would mean replacing all the work currently on here. Is that acceptable? (somewhat of a wiki newbie...) — Preceding unsigned comment added by 82.22.196.56 ( talk) 22:59, 25 May 2011 (UTC)
Taubes 1995 certainly shouldn't be the first cite for this -- it was just a "Research News" article summarizing Jacoby & d'Arrigo (1995) , which should be the primary cite. — Preceding unsigned comment added by Krabapple ( talk • contribs) 18:01, 5 February 2014 (UTC)
This is the widespread forestry observation that tree growth can decline if it's too warm or too cold -- with obvious implications for interpreting tree rings as "treemometers". See Loehle, C. 2009. A Mathematical Analysis of the Divergence Problem in Dendroclimatology. Climatic Change 94:233-245. He argues that tree rings can only be used for climatology going back the length of the local climate record, 100 yrs or so -- not the longer 1000+ years often attempted. Any comment from knowledgeable readers? -- Pete Tillman ( talk) 15:08, 18 November 2014 (UTC)