Talk:Temperature record of the past 1000 years/Archive 3

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Archive 2 Archive 3


We seem now to be arguing over:

Although temperature reconstructions from proxy data help us understand the character of natural climate variability, they play only a small and indirect part in attribution of recent climate change [1] [2]

with TS and FtF preferring "significant" to "small".

If you look at the exec summary of the D+A chapter, you'll find vert little about the palaeo reconstructions [3]. If you look within the D+A chapter, you'll find One of the most important applications of this palaeo-climate data is as a check on the estimates of internal variability from coupled climate models, to ensure that the latter are not underestimating the level of internal variability on 50 to 100 year time-scales (see below). The limitations of the instrumental and palaeo-records leave few alternatives to using long “control” simulations with coupled models (see Figure 12.1) to estimate the detailed structure of internal climate variability. [4] which explicitly downplays their role. If you continue through that chapter, you'll find pages and pages of stuff, but you won't find the HS there at all, at least as far as I can see. So the idea that the HS is "significant" is unsupported.

Against this is set the SPM [5]. But even there, the HS only appears in 1 of 7 paras.

The HS has clearly appeared a lot in public discussion; but reading the actual report makes it clear that it has *not* played a major role in D+A. Hence small is correct; significant just reflects wishfull thinking and/or inability to distinguish the science and politics William M. Connolley 13:23, 21 November 2006 (UTC)

If you are trying to claim that the hockey stick did not have significance in the SPM, then you and I are reading different SPMs.  TheSeven 13:42, 21 November 2006 (UTC)
This article isn't about the SPM. Its about the temperature record. The particular piece in dispute is *how the palaeo record is used in attribution*. If you think its about how the HS is used in the SPM, then that may well explain the problems we're having. Now thats been made clear, how about you go round again and examine the actual point at issue, using the links I've helpfully provided above? William M. Connolley 14:08, 21 November 2006 (UTC)
The paleoclimatology was seen as so important that it is on the first page of the summary of the IPCC report. IPCC said that comparing recent changes with previous variability was part of attribution (1 of 3 or 4 parts of the attribution argument). They did not say it was minor; your blog did. Your analysis of numbers of paragraphs is original research. But while you insist in having your playing down of the temperature record in the introduction and on playing with words to mean what you want them to mean rather than the impression given to readers, you see no dispute. If this article is not about how the IPCC used the temperature record, don't include that bit at all. --Facethefacts 17:58, 21 November 2006 (UTC)
The palaeo stuff was new and interesting, so it got featured. But you are failing to see past the headlines to the science, even though I've pointed you to it several times. Its only a minor part of D+A, as you can see from looking at the chapter. Your bit about OR is funny; apparently you're allowed to assess it as "sig" (even though IPCC nowhere says this) but anyone else may not analyse to the opposite. Fact the Facts old fruit (you have it in your name but aren't very good at doing it): the HS doesn't even appear in the D+A chapter. Putting the HS into perspective is a valuable part of the argument, which is why it appear on the page, especially as misunderstandings like yours are so common William M. Connolley 19:05, 21 November 2006 (UTC)
Either you are lying or playing with words again. Mann's work is mentioned in [6] in Chapter 12, with a link to figure 2.21 [7]. --Facethefacts 20:17, 21 November 2006 (UTC)
How gracious of you. I'll take that as an implicit acceptance that the HS does indeed not appear - certainly I haven't seen it. And form the link provided the following quote is rather revealing: However, a number of difficulties, including limited coverage, temporal inhomogeneity, possible biases due to the palaeo-reconstruction process, uncertainty regarding the strength of the relationships between climatic and proxy indices, and the likely but unknown influence of external forcings inhibit the estimation of internal climate variability directly from palaeo-climate data. We expect, however, that the reconstructions will continue to improve and that palaeo-data will become increasingly important for assessing natural variability of the climate system. One of the most important applications of this palaeo-climate data is as a check on the estimates of internal variability from coupled climate models, to ensure that the latter are not underestimating the level of internal variability on 50 to 100 year time-scales (see below). The limitations of the instrumental and palaeo-records leave few alternatives to using long “control” simulations with coupled models (see Figure 12.1) to estimate the detailed structure of internal climate variability. I think that quote, to which you were kind enough to link, rather makes my point: that as far as D+A is concerned, the HS et al are of limited importance William M. Connolley 23:16, 21 November 2006 (UTC)
That is a deliberate deception and twisting of what I said. You left out the earlier lines "Palaeo-reconstructions provide an additional source of information on climate variability that strengthens our qualitative assessment of recent climate change. There has been considerable progress in the reconstruction of past temperatures. New reconstructions with annual or seasonal resolution, back to 1000 AD, and some spatial resolution have become available (Briffa et al., 1998; Jones et al., 1998; Mann et al., 1998, 2000; Briffa et al., 2000; Crowley and Lowery, 2000; see also Chapter 2, Figure 2.21)." That is the hockey stick and more, and you know it. And I read the words you quote as saying the temperature record of the past 1000 years is important but the reconstructions have been weak. If you honestly don't think that is what is being said then you are deluding yourself; otherwise you are deluding everybody else. --Facethefacts 00:57, 22 November 2006 (UTC)
The fact that the hockey stick appeared in SPM doesn't imply that it's central to the science as such. Remember, SPM is the abbreviation for "Summary for Policymakers." The SPM an attempt to frame the science in a way that is accessible to non-scientists. Such folks don't understand the finer points of radiative forcing and ice-albedo feedback, but they can (maybe) understand a graph of temperature trends. Raymond Arritt 19:57, 21 November 2006 (UTC)
Very patronising: non-scientists don't understand, so let's amuse them with pictures. No - the summary has the key and significant points. --Facethefacts 20:17, 21 November 2006 (UTC)
Not patronizing at all -- it's simply making the point that the SPM is expressed in terms that the intended audience is able to understand. Few policymakers are trained in physical science or numerical methods so they aren't equipped to handle the nuts and bolts of Gibbs fringes, ice-phase parameterizations, and the like. (Conversely, scientists tend to zone out when the subject turns to organization charts.) If the SPM was written in technical language it wouldn't be an effective summary. Again, the fact that a particular figure is included in the SPM means that it's effective in illustrative terms, not necessarily that it's central to the scientific underpinnings. Raymond Arritt 20:47, 21 November 2006 (UTC)
Still patronising, and still wrong. --Facethefacts 00:57, 22 November 2006 (UTC)

MBH, M&M usage

The article has a lot of confusion between the alternative names for each group of scientists. May I suggest that after the first mention that "Mann, Bradley, Hughes (1998) becomes simply "MBH98" and that the usage of "Mann et al (1998)" is dropped.Sparkzilla 06:04, 26 November 2006 (UTC)

Update:, I tried to work the above into an edit, but I abandoned it as it was harder than I first thought ;( It may be easier just to refer to the study (after initial mention) as "Mann's report", "Mann's study" and "Mann's hockey stick" In any case there needs to be some more consistency to the way the report is presented through the articleSparkzilla 06:35, 26 November 2006 (UTC)

I'm all in favour of consistency, but it's not just Mann's. Correctness is more important than convenience...--Stephan Schulz 07:21, 26 November 2006 (UTC)
I agree that this needs to be more consistent. As Stephan motes, simply using "Mann" isn't correct; there were two co-authors. The alternatives are "MBH98" and "Mann et al. (1998)". I prefer the latter as it's an accepted format in scientific journals and is less jargonish. Comments; or shall I be bold? Raymond Arritt 17:04, 26 November 2006 (UTC)

new evidence from Stieglitz

This weeks new scientist has an article on Climate change sceptics lose vital argument. Reporting on work of Stiegltz in Nature (vol 444, p601)[8](subscription required). Stiegltz seems to have a better model of the gulf stream which explains the little ice age and why its not reported in the hocky stick graph. Should something about this go in? --Salix alba (talk) 18:43, 4 December 2006 (UTC)

Article is badly POV and needs cleanup

After some recent cleanup and entries to achieve NPOV, WMC has reverted my edits and those of others. I have reverted. Both sides of the debate have to be presented. It is wikipedia policy. RonCram 15:48, 31 December 2006 (UTC)

I didn't blanket-rv your edits; unlike (sadly) you. I moved NRC out of the political bit, since it wasn't: that was science. I reverted your promotion of CA in the ext refs: I see no reason given for that, indeed you hid it. Well, we shall see what others say William M. Connolley 16:05, 31 December 2006 (UTC)

Time for a "Hockey stick controversy" page?

This page (and some others; notably McI and Mann biogs) are getting cluttered with the Hockey stick wars. They need to be mentioned here, but they shouldn't dominate the page. So I suggest creating a Hockey stick controversy page to move most of that stuff (NSC, Wegman, etc) into. Comments? William M. Connolley 22:03, 7 January 2007 (UTC)

I agree, as I first got involved in this page when trying to find out about said controversy and think it would be far better for the average reader if the controversy was made seperate Sparkzilla 00:05, 8 January 2007 (UTC)
Nuts. "Hockey stick" gets caught in my website blocker at work, since it's obviously sports related ;) and it would be too much of a pain to get an exception. Is there a redirect available without the work Hockey? (it's the URL, not the text, that matters.) --Spiffy sperry 15:26, 10 January 2007 (UTC)
You can make your own easily enough! William M. Connolley 16:13, 10 January 2007 (UTC)

Hi. I've tried to follow this discussion here. It is very long and perhaps I have overlooked something. Nevertheless, from what I have read about climate during the Medieval Warm Period, for both Northern Scotland and Greenland, it seems impossible to me that the graph(s) being discused can possibly be accurate, since they indicate the climate today as being significantly warmer than at that time. So I must agree that the page in question gives an impression of temperature over the past 1000 years that seems implausible. If that means it lacks NPOV in its current form, so be it! Joe da Silva ... about 13:50, 26 May 2007 (UTC).

There is a difference between local or hemispherical temperature, and global temperature. Several papers have described a seesaw effect, where typically northern and southern hemispheres experience opposite effects of natural variability. --Stephan Schulz 20:32, 26 May 2007 (UTC)
OK, I'll accept that for the moment, in which case the obvious question is - to what extent does the temperature proxy data originate from the northern hemisphere? If the answer is that much of it does, then that should still show a higher average temperature for the Medieval Warm Period than for today. OTOH, if the proxy data is not biased toward the northern hemisphere, then what you suggest might be a plausible explanation. However, since many people are suggesting a "red shift" bias in the data or the methodology, it seems we already have sufficient doubt about these curves, and therefore the page as it stands is misleading. Joe da Silva ... about 7:30, 30 May 2007 UTC.
PS - Actually, the page states that the data relates to the northern hemisphere (which is what I thought, although I was in a rush, so I failed to double-check at the time). So that's that! Given what we know about the climate during the Medieval Warm Period in the northern hemisphere, how can the graph(s) possibly be correct, since they show this period as being significantly cooler than today? For me, this is compelling evidence that the graph(s) are wrong, without even debating the role of CO2 or any other factor. Joe da Silva ... about 4:50, 31 May 2007 UTC.
If you "know" by mystical revelation that the NH was warmer than today in the MWP then I guess you do "know" that the graphs are wrong. The rest of us only have the data to go by. It would be nice, perhaps, to have on the page a discussion of why various things we "know" (European MWP, for example) don't contradict this. Grapes, for example :-) William M. Connolley 08:49, 31 May 2007 (UTC)
William, the only graphs that show the NH warmer now than in the MWP are graphs made after MBH98. Mann photoshopped the proxy record to do away with the MWP and he got caught. His graphs are not valid. RonCram 11:57, 26 September 2007 (UTC)


I removed:

However, recent research suggests that present day warmth has been equaled in the year 1000 CE.[1]

This is misleadingly presented. Its a comment on the Briffa et al stuff, and has an answering comment by Briffa. Presenting it without Briffa (which we should probably add) makes no sense William M. Connolley 11:18, 26 September 2007 (UTC)

Removing it while adding Briffa would be POV and contrary to Wikipedia policy. RonCram 11:53, 26 September 2007 (UTC)
If it's a comment on the research and not the research itself (that "suggests that present day warmth has been equaled in the year 1000 CE"), then the statement is incorrect, right? Ben Hocking (talk|contribs) 12:42, 26 September 2007 (UTC)
Indeed, its a comment, not a paper. And its inaccurately paraphrased too William M. Connolley 12:45, 26 September 2007 (UTC)

Loehle paper

The US National Academy of Sciences looked into the Hockey Stick controversy and advised that strip bark trees are not temperature proxies. Since all trees more than 600 years old are strip bark trees, Loehle reconstructed temperature going back 2,000 without using tree ring data. He found the MWP to be consistent at the 18 sites he studied all over the globe and found the MWP was 0.3C warmer than the late 200th century. [9] RonCram (talk) 01:36, 18 November 2007 (UTC)

He published this "result" in Energy and Environment, which means it is utterly unreliable. --Stephan Schulz (talk) 01:39, 18 November 2007 (UTC)
It's unfortunate that this went to E&E because the basic approach seems like a good idea. It is also worth noting that the record he publishes ends in 1980. Adjusting for that fact, makes the MWP and the end of the 20th century about equal. Dragons flight (talk) 02:15, 18 November 2007 (UTC)

Article name

I've been nitpicky lately, and I think the article name should be "... past 1,000 years" (with a comma) (unless some guideline suggests not using commas). ~ UBeR (talk) 17:57, 8 February 2008 (UTC)

The plot is pretty suspicious

1000 Year Temperature Comparison.png

I cannot believe that 1000-year old data have lower dispersion than 400-year old ones. Please note, how the charts diverge and converge. --Javalenok (talk) 11:54, 26 February 2008 (UTC)

The figure does not show the associated uncertainties, just the best reconstruction. The apparent spread is caused by one paper only, and reflects Northern Hemisphere tree ring data only. See [10]. --Stephan Schulz (talk) 12:14, 26 February 2008 (UTC)
Neither the uncertainties nor the North impose any doubt. Speaking about them I consider an attempt to chatter the issue. The issue is why the chats,which pretty agree in 1000..1100, disagree in the 1100..1900, which is closer to our time. Different measurements in the period 1000..1100 have the same level of matching as the modern century. It looks implausible because the further you travel the larger must be the error the higher the divergence must be. I do not understand the argument "based on a paper". --Javalenok (talk) 14:19, 26 February 2008 (UTC)
"because the further you travel the larger must be the error the higher the divergence must be": Why? The farther back in time you go, the fewer records are available and the more everyone is looking at the same small pool of data, and hence the more likely they are to reach the same "consensus". That consensus may be wrong due to an incomplete picture, but that possibility of error doesn't necessarily manifest as divergence. Dragons flight (talk) 17:55, 26 February 2008 (UTC)

Blogs et al

Regarding the Bishop Hill piece:

I fail to see how a summary of the Wahl and Ammann papers on a blog is any more or less appropriate than references using papers that are "in press" by the two parties, press releases from them, and web pages from them. Or how the references to Real Climate blog articles by Wikipedia editors carry more weight than a summarized sequence of events by a disinterested third party. Blogs, unpublished materials, and press releases by one half of the dispute and none by the other is hardly neutral. Balance (as I've tried to do, including tagging the dead links) or remove.Sln3412 (talk) 17:12, 20 August 2008 (UTC)

Thanks for tagging the dead links. I fixed one of them and there should be also a link to the IPCC AR4. I realized in general that this section is poorly written and does not give a good overview of the hockey stick controversy. So, it may be better to replace it with some condensed material of the (quite extensive) Hockey stick controversy article. Splette :) How's my driving? 19:58, 20 August 2008 (UTC)
Please check WP:SPS and the exceptions to it. Both M&M and W&A have published papers in this particular area, and at least for W&A it can be said that they are experts commenting on the area of their expertise. Bishop Hill on the other hand is a completely anonymous self-published source, with no prior publication records, or any expertise claims on the subject. --Kim D. Petersen (talk) 21:06, 20 August 2008 (UTC)
I don't disagree. Press releases and papers in press aside, it would just be nice to have a less confusing timeline/summarization. Sln3412 (talk) 21:05, 22 August 2008 (UTC)

Climate change: 'Hockey stick' holds up

Just setting the section header to wind the skeptics up :-). I don't think there is any hurry to add this new piece, but for info:

Nature 455, 140 (11 September 2008) | doi:10.1038/455140b; Published online 10 September 2008

Climate change: 'Hockey stick' holds up [1]Proc. Natl Acad. Sci. USA 105, 13252-13257 (2008)

A fresh analysis of climate indicators shows that the Northern Hemisphereis warmer now than it has been in at least 1,300 years.

Previous analyses of climatic history by Michael Mann of Pennsylvania State University in University Park and his colleagues produced a distinctive 'hockey stick' shape; but some of this analysis, and the tree-ring data it used, came under attack.

The latest work by Mann and his co-workers involves various climate proxies, including corals, ice cores, historical records and marine sediments. The authors show that current warming is anomalous even if all tree-ring data are eschewed

William M. Connolley (talk) 09:25, 12 September 2008 (UTC)

One aspect of this new article is that the analysis extends back 2000 years. In consequence I propose an equivalent change of this article's title. Gabriel Kielland (talk) 09:44, 12 September 2008 (UTC)


[Trolling removed - WMC] Still, to show I'm not just trolling, I would propose that McIntyre's thesis be presented, perhaps under its own subheading, with reference to his recent work published on More specifically, he has shown that the stastical methods used are not, all denials notwithstanding, "robust," as that term is usually used in statistics. To the contrary, with a couple of exceptions, these reconstructions fall into one of three categories: (1) those in which the "hockey stick" shape is caused by the defective Yamal data; (2) those in which the "hockey stick" shape is caused by the strip bark bristlecones; and (3) those in which the "hockey stick" shape is caused by either or both. (Accorind to McIntyre, the "couple of exceptions" suffer from different, more debatable defects in their methodology.)

Incidentally, and for the record, not even McIntrye would agree with my characterization of the reconstruction as a hoax. He, himself, pointed out that there may turn out to be some at least colorable justification for the cherry-picking of data in the Yamal set. But the extraordinary efforts to conceal the data from skeptical eyes sure suggests otherwise.

User:QBeam 29 September 2009 —Preceding unsigned comment added by (talk) 21:30, 29 September 2009 (UTC)

If McIntyre gets something published in a real journal, i.e. not on his blog, we can start to consider it. Even then, its usually valuable to wait a few months to see the reactions. --Stephan Schulz (talk) 22:23, 29 September 2009 (UTC)
Ok, then, how about a section that describes the various violations of accepted scientific protocol by the (alleged) scientists who produced the results upon which this article is based? The cherry-picking of data and refusal to archive and publish the data and methodologies that produced these results is well documented, and highly material to the credibility of these results. An overt acknowledgement of the obvious and inevitable conclusion--that the "hockey stick" exists only as a consequence of these practices--can wait for McIntyre's eventual publication of a technical article that quantifies the impact of the cherry-picking. —Preceding unsigned comment added by (talk) 15:51, 1 October 2009 (UTC)
I've removed the more blatant trolling. The answer to your second post is the same as to your first William M. Connolley (talk) 17:21, 1 October 2009 (UTC)

POV label

I've added the POV label. It's especially the introduction - the first paragraph - whose current form is unacceptable. The papers by Mann et al. are increasingly problematic. Many errors have been pointed out by many authors, and Mann et al. had to publish an extensive list of errors in Nature. The method itself was recently shown to produce highly biased results - see September 30th issue of Science (Hans Von Storch). [11] [12] [13]

Many scientists would agree that we have a lot of material that is more reliable than Mann et al. This page in its current form is a piece of propaganda produced by the alarmists, and Wikipedia deserves a better page. --Lumidek 16:44, 6 Nov 2004 (UTC)

(William M. Connolley 17:19, 6 Nov 2004 (UTC)) Lumideks assertions above are inaccurate. The NPOV header is spurious. The Mann et al reconstructions are widely accepted by the climatology community, whereas the criticisms are not. To assert that "many authors" have pointed out errors is wrong: M&M have published a little-regarded critique; the von S paper is far more sensible but very new. Muller is merely parroting M&M, and L is wrong to imply that Muller is saying anything related to von S. Also, von S doesn't say the hockey stick is biased: just that it underestimates long-term variance: which is a very different thing. MBH indeed published a corrigendum in nature but that was a corrigendum to the methods and sources: not to the results. The Nature corrigendum explicitly states that the results are unaltered. This is stark contrast to McK, who recently managed to confuse degrees and radians and hence get the wrong results. And finally... as the article points out... the results of other authors agree with MBH, thus providing independent verification [14].
Adding long term variance to the temperature graph has the effect to eliminate the conjectures about the extraordinary warming in the 20th century - and it is exactly this unjustified conjecture that is promoted so much in this article, which is why this article is a POV. If the temperature fluctuated a lot, as other papers than those MBH-like claim, then the results of MBH are not true, and their promotion in most of this article is unjustifiable.
(William M. Connolley 19:40, 6 Nov 2004 (UTC)) The page shows results other than MBH, which produce similar results. If you know of reconstructions that differ substanitally from MBH, you haven't troubled to ref them.
As I understand well, you have not found any problems with Von Storch's paper in Science.
(19:40, 6 Nov 2004 (UTC)) Von S is a sensible chap. But his paper doesn't support the interpretation you've given. And the von S paper is very new.
Incidentally, this is the first time I am writing the name "Richard Muller" - so far, I consider Richard Muller to be a Slovak musician. ;-) Sure, I know the physicist, but I thought that he only wrote a semi-popular article explaining why global warming science is not hard science; has he done some actual piece of research?
(William M. Connolley 19:40, 6 Nov 2004 (UTC)) The RM I'm talking about is the author of the second link that you inserted above. Do you not bother read the stuff you link to?
When you say that "the results of other authors agree with MBH", you should also say that the results of yet other authors disagree with MBH.
(William M. Connolley 19:40, 6 Nov 2004 (UTC)) You keep saying this. When, one day, you actually provide a ref then maybe I'll take you seriously.
MBH was published to overthrow the old belief - or theory - that there has been intense medieval warm period, followed by little ice age, and so forth.
(William M. Connolley 19:40, 6 Nov 2004 (UTC)) This too is inaccurate and unhistorical. Before MBH, there were no long reconstructions of hemispheric T. Thats why it gets so much attention - it was the first (or one of the very first) quantitative estimates of hemi T.
There are just too many people who call the MBH-like texts "junk science", and I encourage you to consider these people seriously. The Russian Academy of Science labeled Kyoto, for example, as "scientifically unfounded nonsense". --Lumidek 18:06, 6 Nov 2004 (UTC)
(William M. Connolley 19:40, 6 Nov 2004 (UTC)) Ah yes, the ever reliable RAS. A point worth talking about. Clearly, tehy aren't influential - Putin rejected their foolish advice. More interestingly though, how did they reach their advice. Can you point to an authoritative position paper from them - or are you just quoting press releases from a few members? And can you point to any reports on what they based their opinions on?

I don't think there's any question that this article is POV - it actually links to someone's blog as if it were a continuation of the article itself! More importantly it tails off very badly. For some reason as the article progresses it concentrates more and more on Mann et al's work (specifically one work, for some reason). Then every work that criticises Mann's work is listed, but a specific criticism is made of each of these works. Then we launch into a whole section criticising Mann's main critics - McIntyre et al. Then we look at the Wegmann report, criticise the Wegmann report and give Mann and McIntyre's blog addresses - under an "Updates" section. This is a wiki - if it needs updating, we can update it easily. References should go in the references section - the presence of two of the protagonists blogs in the main article suggests, at least to me, a serious absence of NPOV. What other sources exist apart from Mann et al? Can someone include the findings of these? Otherwise we may as well rename the article "Mann and McIntyre" --Dilaudid 21:03, 4 December 2006 (UTC)

As a first step to pruning this debate down - can we cut the "he said" "she said" below?

McIntyre and McKitrick only audited the work of Mann et al. (1998), and made no assessment of the other studies that are broadly consistent with the results of Mann (1998). However, the findings from the Wegman report suggest that authors in the area of paleoclimate studies are closely connected and thus ‘independent studies’ may not be as independent as they might appear on the surface.

I don't think the Wegman report is relevant to M&M, I don't think that there is any suggestion that M&M audited other studies. Is there a more recent Mann et al so we can perhaps day M&M audited 1998 but have not looked at later reports? Worst of all this alludes to the existence of "other sources", and without specifying who they are it criticises them. It seems a bit strange! --Dilaudid 21:03, 4 December 2006 (UTC)

There is a big issue in balancing this article between temperature record, and MBH in particular. There is probably a lot to be said for an article dedicated to "the hockey stick controversy", but that would then gut this article of most of its criticism. As to your specific points above: Wegman adds nothing of value to the debate and might as well be removed entirely (but I doubt the skeptics would wear that). You are correct that M&M haven't published on other studies: but this is a good point to make; because even if you simply delete MBH from the picture, nothing changes William M. Connolley 23:02, 4 December 2006 (UTC)

LOL even in the wikipedia lemma Hockey stick controversy an external link to an overview of recent developments on Wahl and Ammann is censored out. VERY POV IMHO. Hans Erren (talk) 08:59, 17 August 2008 (UTC)

Considering the serious appearance of bias on the part of Connolly on this topic, he is the LAST person that should be allowed to edit any of it. —Preceding unsigned comment added by (talk) 05:29, 20 December 2009 (UTC)

This is a real "eye opener" regarding the extent that people are willing to twist science and still call it legitimate. Given the issues surrounding the CRU, and the head stepping down whilst an investigation is going on, I recommend that this be removed until the investigation is complete. After the review, it could be reviewed and reposted. —Preceding unsigned comment added by (talk) 03:47, 21 December 2009 (UTC)

Borehole Proxy Temperatures

Borehole proxy temperatures are a major independent temperature method not yet mentioned in the article. Accordingly I summarized the National Academy of Sciences publication that borehole temperatures show: “a warming over the last 150 years of approximately 1°C ± 0.2°C preceded by a few centuries of cool conditions. Preceding this was a warm period centered around A.D. 1000, which was warmer than the late 20th century by approximately 1°C.” [2] DLH (talk) 04:10, 22 December 2009 (UTC)

Perhaps you should try to read the context? You may also want to note that the NAS specifically states that this is local conditions and not representative of global? You are doing a synthesis here by cherry-picking specifics in the NAS report, and ignoring the conclusions. If this had been a section on Greenland or Antarctica, with a discussion on the local conditions and their relation to global conditions, then it might have had weight - here it is out of place and seems to be pushing a POV. [Not to mention that amount of ice boreholes are minute compared to regular boreholes - so weight is a problem there as well] --Kim D. Petersen (talk) 07:51, 22 December 2009 (UTC)
In principle, mentionning boreholes is fine. But Kim indeed points out some problems with your use William M. Connolley (talk) 10:47, 22 December 2009 (UTC)
  1. ^ Bürger, G., 2007. Comment on “The Spatial Extent of 20th-Century Warmth in the Context of the Past 1200 Years”. Science, 316, 1844a.
  2. ^ BOREHOLES IN GLACIAL ICE Surface Temperature Reconstructions for the Last 2,000 Years (2006), pp 81,82 Board on Atmospheric Sciences and Climate (BASC), National Academy of Science,ISBN: 978-0-309-10225-4

Why was this article renamed? While the other title may not have ...

...been entirely correct, the new one precludes some of the content. There is no reason that 3rd millenium temperatures shouldn't be here. It is simply the amount of time (1000 years) into the past where we have reasonable records. I suggest that the name be changed back, especially since there hasn't been any discussion about a name-change. --Kim D. Petersen (talk) 01:20, 17 January 2010 (UTC)

I was wondering the same myself. I've reverted the move and if somebody thinks it was a good idea we can discuss it here. --TS 01:28, 17 January 2010 (UTC)
For more suitable names, perhaps something like "Millennial temperature reconstructions." --TS 01:43, 17 January 2010 (UTC)
The idea is that as the 3rd millennium progresses, "the past 1000 years" will make the article sound like the figures it discusses go back to a later and later starting point, when the actual starting point is still 1000 CE. (And of course, if it remains unchanged at the end of 3000 CE, the title will no longer be relevant to any of its subject matter.) How about "Temperature record since 1000 CE"? I feel it's important to have titles that will never date as long as a clock keeps running, since Wikipedia could easily become part of the record humanity leaves for a future civilization (on Earth or elsewhere, by accident or by design). NeonMerlin 03:44, 23 January 2010 (UTC)

Plase *don't* make controversial moves like this without discussing them first. And please don't discuss them without looking back over the *long* talk page history of attempts to rename this article. Only if you're prepared to dredge through that and deal with the arguments should you raise the matter again William M. Connolley (talk) 08:17, 23 January 2010 (UTC)

Un-verified claim

I have deleted this from the introduction: "... but the graph is overall acknowledged by the scientific community."

Someone have RV this with the accusation of POV and the claim that it is supported in the text body. But it is not supported there. The only you can find is: "In turn, Michael E. Mann (supported by Tim Osborn, Keith Briffa and Phil Jones of the Climatic Research Unit) has disputed the claims made by McIntyre and McKitrick [14][15]. The IPCC Fourth Assessment Report says that McIntyre and McKitrick "may have some theoretical foundation, but Wahl and Ammann (2006)[16] also show that the impact on the amplitude of the final reconstruction is very small."[17]"

This is certainly not in support with the claim in the introduction. (talk) 07:01, 14 February 2010 (UTC)

Let me also point out the way the user KimDabelsteinPetersen to forbid me from edit the article: "(Reverted to revision 341565102 by ClueBot; rv POV, and the "un-verified" is sourced in the body of the text.. using TW)" - TW is used to report vandalism.
This is not a honest and serious behavior. (talk) 07:34, 14 February 2010 (UTC)
TW is a tool, not only used for vandalism. If i had reverted as vandalism it would have been clearly marked as suck. --Kim D. Petersen (talk) 07:43, 14 February 2010 (UTC)
Please notice that we have a complete article on the controversies surrounding the graph: Hockey stick controversy. The overall acknowledged part is entirely correct, since (afaik) no later reconstruction has disagreed with the results. The critique is on methodology not on the results. --Kim D. Petersen (talk) 07:43, 14 February 2010 (UTC)

Please, there is nothing in support for the claim in that article either. Instead, the article explain very much about why the hockey stick is dubious... It is still an un-versified claim, and please do not make any more changes before this discussion is settled! (talk) 07:51, 14 February 2010 (UTC)
Sorry, but that is incorrect. Both the NAS panel, IPCC, US CCSP as well as the scientific literature in general are in support of the graph. You will need to separate methodology from results. And the MBH98 reconstruction from all the other reconstructions that have been made. --Kim D. Petersen (talk) 08:14, 14 February 2010 (UTC)
We can attact this ref to the sentence if you really want one: Brumfiel, G. (2006). "Academy affirms hockey-stick graph". Nature. 441 (7097): 1032–1033. Bibcode:2006Natur.441.1032B. doi:10.1038/4411032a. PMID 16810211.  --Kim D. Petersen (talk) 08:19, 14 February 2010 (UTC)

please do not make any more changes before this discussion is settled! - I think that is good advice, anon, and you should take it yourself. The text has been stable: why do you expect to show up and suddenly remove it? Your arguments are not persuasive William M. Connolley (talk) 11:15, 14 February 2010 (UTC)

Reconstructed Temperature graph is OR and misleading

The Reconstructed Temperature graph is OR and is misleading. The misleading item is the 2004 end marker which is a non-smoothed data point (see, unlike the rest of the graph which has been decadally smoothed. The graph should be corrected or replaced by a graph from a reliable source. Cadae (talk) 08:56, 5 April 2010 (UTC)

Agree, this Graph is now used for articles on how to not make a graph. Or better yet how to artificially create a hockey stick. Here: An illustration where the single year 2004 for observed temperature data explicitly is used in comparison with the super averaged medieval temperature data. I know the classical Connolley reply is that these articles are not peer reviewed but neither is this graph. Please address the issues raised in the article or move the graph to the art section of wikipedia, where this globalwarmingart belongs. LucVC (talk) 19:37, 6 April 2010 (UTC)

Article needs to examine claims that temperature proxies are unreliable in more depth

Has anyone as yet come right out and asked Dr. Mann (along these lines): "Dr. Mann, you substituted actual recorded temperatures in recent times (which constitutes the sharply upward spike which is the ‘blade’ of your graph) for the tree ring proxies that you used for the remainder of the graph (the ‘shaft’ that shows relatively stable temperatures prior to the advent of the industrial age). You did this because had you continued to use the tree ring proxies they would have diverged from the actual recorded temperatures and would have evidenced significantly lower temperatures for the blade portion of your graph. Seeing how the proxies have proven unreliable in more contemporary times as approximations of actual temperatures, how can you be certain they are reliable for past times and that they hadn’t diverged many times previously during the shaft portion of your graph? If there is no such certainty, then of what use is your entire graph?”

This article needs more examination of arguments that temperature proxies are unreliable. Without a reliable historical estimate of temperatures prior to 1850, then the theory of man-made global warming is simply not tenable because it cannot be proven as yet. (Which doesn’t necessarily mean it is incorrect.) This is an extremely important consideration regarding this entire subject and controversy. HistoryBuff14 (talkcontribs) 18:10, 27 May 2010 (UTC)

Stripped of the rhetoric, you have a point, which I've attempted to answer on the article page. Note that during the period of historical temperature record (approximately since 1850) the thermometer records are more accurate and so are preferred; I hope you now understand how Mann et al. constructed their reconstruction William M. Connolley (talk) 20:09, 27 May 2010 (UTC)

--Well, thank you, William. But what I don’t understand is how scientists determine whether various available proxies for temperatures before recorded ones are reasonably accurate. For example, I assume that radiocarbon dating was first tested on objects in which there is no doubt of how old they are. In the case of the tree ring proxies that Dr. Mann used (or for that matter, any prospective proxy), the only test available would seem to be for more modern times when there are recorded temperatures and they (at least Dr. Mann’s proxies) have been proven not to be accurate as approximations of temperatures. So why then assume they were accurate prior to recorded times? This make no sense to me.````

There are two parts to that, and I'd guess Proxies ought to cover it, but who knows. First, that there can be theoretical reasons for believing in the proxy-temperature relationship (delta-o-18 in ice cores for example; tree ring widths). And then you have the calibration phase. Due to the divergence problem - meaning, we don't really know why - tree ring proxies diverge from the temperature record (read: when using the normal calibration) after about 1960. But that still leaves you 1850-1960 to calibrate against William M. Connolley (talk) 21:57, 27 May 2010 (UTC)

--William, thank you for the link. I did read the Wiki article concerning temperature proxies per your suggestion. Also, I found a fairly comprehensive article that addresses this issue head on:

A rebuttal by “jmath” (under “comments” below the article) is worth reading as well. I read somewhere that many scientists “privately” doubt whether an accurate rendering of past temperatures can really be given. I don’t know if this is true or not. I just thought that if there are credible climate scientists who feel as such, their views could be explored within the article in an objective manner, as without an accurate rendering of past temperatures, the theory of man-made global warming can’t really be proved except on an empirical basis. If the theory is true, by then it might be too late as proponents argue.

I have no problem with Dr. Mann’s methodology per se. I just think his assumptions about past temperatures are open to legitimate skepticism. Indeed, he himself noted such uncertainties, something his most vicious critics fail to credit him with.

Thanks again.HistoryBuff14 (talk) 14:05, 28 May 2010 (UTC)

When you plot both delta-Deuterium and delta-O-18 from Vostok, the first series shows 4 interglacials and the second shows 8 to 12. Therefore, I don't think that delta-O-18 is a good example. Q Science (talk) 05:42, 28 May 2010 (UTC)
I'm not following you. Which pic do you mean? William M. Connolley (talk) 07:40, 28 May 2010 (UTC)
Plot delta-Deuterium vs Depth and delta-O-18 vs depth (description) on the same graph. Q Science (talk) 16:04, 28 May 2010 (UTC)
Errm, well if you've done so (and I presume you have, otherwise you wouldn't be saying stuff) couldn't you just upload the pic? William M. Connolley (talk) 16:18, 28 May 2010 (UTC)
Sorry, I figured that you would prefer "reliable" data :) Note that the δ18O data is inverted, I really don't know if that is correct, but it appears to be. (If you just want a link here, please edit this post as appropriate.) Q Science (talk) 19:46, 28 May 2010 (UTC)
Plot of Delta Deuterium and Delta 18O verses deepth for Vostok Antarctica
OK, thanks. Yes i think you're right - I don't think I'd ever realised that. Hmm, that means proxy (climate) really ought to be updated, as should Paleothermometer William M. Connolley (talk) 20:18, 28 May 2010 (UTC)
I'm a bit confused (and a layman) but i think that Petit et al(1999) might help here? Page 431 "Climate and atmospheric trends". If there wasn't a difference between d18O and dD, then we couldn't calculate a temp could we? --Kim D. Petersen (talk) 22:16, 28 May 2010 (UTC)
Thanks. That verifies that I was correct to invert the δ18O data. As far as your comment on the "difference between d18O and dD", even though there is a minus sign, it is not clear if the values are added or subtracted because dD is typically a negative number and d18O is a positive number. Personally, I think that the minus simply means that the δ18O data should be plotted inverted (like Petit shows) and then the 2 values are summed. However, I am not sure what the double delta (Δδ) means. Q Science (talk) 07:52, 29 May 2010 (UTC)

Oops, I think I was wrong. I don't have a convenient way to check right now but: D-O-18 from ice should be about the same as D-D from ice. Haven't you got D-O-18 from air? William M. Connolley (talk) 10:28, 1 June 2010 (UTC)

Yes, I plotted δ18Oair. Unfortunately, I do not have δ18Oice which is described as an "ice volume proxy" in Petit et al(1999), Figure 2c. Please note that neither δ18O series agrees with δD. In the case of sea cores, δ18O is considered to be a salinity proxy and not a temperature proxy. Presumably, more ice means less water and saltier oceans. Q Science (talk) 17:56, 1 June 2010 (UTC)
D-D and D-O18-ice should be very similar (as Petit et al. say, "Temperature. As a result of fractionation processes, the isotopic content of snow in East Antarctica (dD or d18O) is linearly related to the temperature above the inversion level,"). Are you sure about D-O18-ice? They should both be fractionation, maybe with a correction for global ice volume. It would be different in sea water, of course William M. Connolley (talk) 18:29, 1 June 2010 (UTC)
He doesn't say which inversion layer he is referring to. Specifically, there is no polar inversion layer during the polar summer. During the polar winter, there is a permanent inversion layer (at 5,000 meters), but I don't think the precipiation forms there (because, at -35C, it is warmer than the air above and below it). Instead, the precipiation is blown in from warmer (more moist) climates. One interpretaion of the paper is that δ18Oice is not dependent on the surface temperature (even though the paper says otherwise). Q Science (talk) 22:22, 1 June 2010 (UTC)
He means the semi-permanent inversion layer above Antarctica. I.e, conditions in the free atmosphere. Check my prior job :-) and list of papers William M. Connolley (talk) 07:33, 2 June 2010 (UTC)

Rv: why

The tag was pointless; see the article body William M. Connolley (talk) 18:09, 15 June 2010 (UTC)