Talk:Hockey stick controversy

Graph

The aim of this page (or at least my aim in starting it) is to take material from Temperature record of the past 1000 years, and Michael Mann (scientist) and Stephen McIntyre and Ross McKitrick (curiously little there) and put it into a central place to avoid duplication and mess. And to allow the other articles to focus on their substance William M. Connolley 12:26, 9 January 2007 (UTC)

Congratulations, this is a great idea. TheronJ 15:49, 10 January 2007 (UTC)

The graph used on this page should be the graph at issue (i.e. Mann's graph). As it is, Mann's graph is the blue line in the current muli-line graph. The bold black line in the current graph is even more extreme than Mann's blue line, and I question why this graph is used when it is the original work of a Wiki user. There are plenty of graphs from peer reviewed journals available, and the obvious choice for this page would be the so-called hockey stick graph itself as it appeared in the ITCC.Bdell555 14:14, 20 January 2007 (UTC)

Errrm, graphs in PR journals tend to be copyright. The *data* in the graph is sourced from the given PR sources, so what is the problem? William M. Connolley 14:27, 20 January 2007 (UTC)

Graphs in US Government sources could be used and would be an improvement. The current graph invites readers to compare the bold black line against that data FROM OTHER SOURCES AND METHODOLOGIES for dates prior to the beginning of that line. Again, this is comparing apples to oranges. For what it is worth, that black line data disagrees with the anomaly temperature data recognized by the IPCC, the World Meteorological Organization, etc. Finally, that most problematic line is boldened to obscure the other lines, a technique no respectable peer reviewed journal would engage in. But this is all beside the point that this is not the graph that this article is about anyway.Bdell555 15:50, 20 January 2007 (UTC)

If you care to point to a possible replacement, we could consider it. Otherwise its all a bit vague. I very much doubt that the black line disagrees. Please point to something is disgrees with William M. Connolley 18:53, 20 January 2007 (UTC)

The graph which gave rase to this "hockey stick controversy" could be cut from

http://www.usgcrp.gov/usgcrp/Library/nationalassessment/LargerImages/OverviewGraphics/1000YrRecords.jpg

That is a .gov source which I believe gives rise to no copyright issues under Wiki policy.

Actually, not everything on a .gov server is public domain. Only works performed by US federal gouvernment employees as part of their official duty are. Images prepared by others on behalf of the gouvernment will be under copyright (which can be held by either the creator, a third party, or, somewhat suprising, even the US gouvernment). Unless we have an explicit statement about that image, we probably cannot use it. Also, there is no good legend with the image - it looks like it contains unsmoothed data without any confidence intervals. We can replot the same from the original data. I'm fine with having the bare hockey stick in addition to the image with all the reconstructions. We need the other, though, because it gives a very succinct statement about part of the debate. --Stephan Schulz 20:00, 20 January 2007 (UTC)

I don't believe it is Wiki policy to have to ask for permission to use images from US Government publications. In any case, for a complete "debate", the IPCC graph which Mann's graph replaces should also be provided.Bdell555 20:28, 20 January 2007 (UTC)

On your user page you claim that you do not believe much... See WP:Copyrights#Image_guidelines for the Wikipedia policy on images. Images need to be either freely usable (with possible attribution requirement) (e.g. PD, GFDL, Creative Commons Attribution-Share Alike licenses are ok), or a specific fair use case has to be made. Making a fair use case here would be hard, as an equivalent image can be easily created from the available data.

I also suggest we build a Wiki article based on the facts as opposed to your "doubts", and the facts are that the party supplying the temperature anomaly data for the bold black line themselves concede that their numbers disagree with other sources. They say that it is because "the global and hemispheric anomalies used by IPCC and in the World Meteorological Organization and Met Office news releases were calculated using optimal averaging" (http://www.cru.uea.ac.uk/cru/data/temperature/).

Actually, they say "The more elementary technique (used here) produces no estimates of uncertainties, but our results generally lie within the ranges estimated by optimum averaging", i.e. there is no statistically significant difference. --Stephan Schulz 20:00, 20 January 2007 (UTC)

OK, then, why not present the IPCC and/or WMO temperatures instead of or as well?Bdell555 20:28, 20 January 2007 (UTC)

Create a plot. If it sigificantly differs from the current one, we can talk. If not, this is just hot air. --Stephan Schulz 21:07, 20 January 2007 (UTC)

The issue is not creating a plot using sources you select or sources I select. The issue is creating a plot at all that combines hemispheric studies with global studies and short term studies with long term studies while dismissing "local" studies as if the hemispheric and global studies are not themselves aggregations of local studies.Bdell555 21:49, 20 January 2007 (UTC)

Well, they are not. Glad that that is solved now. --Stephan Schulz 23:04, 20 January 2007 (UTC)

2 paras cut

I removed:

'Among the charges against Mann et al. is that the graph grafts the surface temperature record of the 1900s (which in Mann's graph was shown in red) onto the pre-1900 tree ring record. It has been argued that two data series representing such different variables as temperature and tree rings simply cannot be credibly grafted together into a single series.

Another criticism is that the surface record differs significantly from the satellite temperature record [1] and the surface record has been claimed by some to be the product of urban heat islands.

The second is about the instrumental temperature record; crit of it belongs there, not here. The first doesn't really make sense (and the records aren't all tree rings). The pre-1900 reconstruction is supposed to be temperature, and has been calibrated against the instrumental record; so it makes perfect sense to graft them together William M. Connolley 14:35, 20 January 2007 (UTC)

1) This article is about a graph that uses the surface temperature record as its input for its 20th century data points and using other instrument sources would have produced a different result. Some reference should be made to that. Why not use the satellite temperature record?

The various sfc records are essentially all the same. You can argue that there should be different ones more to your liking, I suppose. But any dicussion of that belongs on the ITR page. The satellite record is (a) too short to calibrate the longer records and (b) doesn't differ significantly from the sfc and (c) exists in multiple versions. You did know point (c), didn't you? William M. Connolley 18:47, 20 January 2007 (UTC)

I don't prefer "different ones". What I prefer is more than one, while you apparently want readers to remain ignorant of any issues concerning the surface temperature record which Mann relies upon, and thereby constitutes part of the "hockey stick controversy".Bdell555 20:28, 20 January 2007 (UTC)

2) The primary source of the pre-1900 data is tree rings. The primary source for the post-1900 data is the surface temperature record. This is comparing apples to oranges. At a bare minimum it should be acknowledged that the two periods are coming from different sources. Moreover, calibrating recently laid rings against known temperatures that existed at the time could mean using a temperature series seriously contaminated by heat island and other local errors. If the calibrating temperatures are wrong, the whole tree ring temperature reconstruction for the distant past is also compromised.Bdell555 15:30, 20 January 2007 (UTC)

Its from 1860 rather than 1900. There aren't a lot of heat islands in the forests. You are pushing far too much you own personal views here. If you can find some nice refs about the problem of calibration, then feel free to add them William M. Connolley 18:47, 20 January 2007 (UTC)

You are very correct that there "aren't a lot of heat islands in the forests"! That's why when you want to conclude that the earth was cooler, use tree ring data, and when you want to conclude the earth is comparatively warmer, use surface temperature data that is influenced by heat islands!! I dare say you are every bit as shrewd as Professor Mann!Bdell555 20:34, 20 January 2007 (UTC)

For my part I have removed

"However a number of other reconstructions, shown in the graph, produce broadly the same result especially around the Medieval Warm Period.

This sentence essentially suggests the scientific consensus agrees with Mann's implication that there was no MWP or LIA. Just because some Wiki-user has made a dubious graph which suggests there was no MWP or LIA does not make it the professional consensus.

You septicism is showing through now. The graph is excellent; it shows all the reconstructions fairly. You don't like the *fact* that none show a warmer MWP, but it remains a fact. William M. Connolley 18:47, 20 January 2007 (UTC)

As a matter of fact, I am not a global warming skeptic. I don't think the skeptics have made adequately made their case. What I take issue with is not global warming but the number of people out there like yourself who do not want both sides of the argument presented to the general public. As for the facts, you are the one who has reverted my citations of studies supporting a MWP without explanation or argument.Bdell555 20:41, 20 January 2007 (UTC)

If you want to mention studies that have concluded there was no MWP or LIA then fine, go ahead. But it should also be stated in the interest of informing the reader that previous IPCC reports clearly indicated a MWP and LIA and that Mann's graph represented a divergence from that. I fail to see why it was necessary to delete that fact in particular.Bdell555 16:05, 20 January 2007 (UTC)

"Some Wiki user" has gone to the considerable trouble of integrating all available peer-reviewed studies into a comparison graph. If you don't like it, show where he failed. I'm also sure Robert (aka Dragon's Flight) will integrate any other peer-reviewed study from a reliable source that you can offer. IPCC reports before the 2001 TAR did not offer any temperature reconstruction, but just a qualitative graph of what was back then the best guess. --Stephan Schulz 16:15, 20 January 2007 (UTC)

Are "all" studies included on this graph or just the ones that support a particular point of view? If, with no small indulgence, we say that it is perfectly reasonable to compare recent data to data from 1000 years ago gathered by another method, then there are MANY studies which could have been used instead of or in addition to that bold black line. It just so happens that bold black line goes straight up whereas satellite data, to take just one example, does not. A "qualitative graph" that reflects "best guess" is, in fact, more respectable that a quantitative graph that claims greater accuracy than is available, especially when that new graph stands in contradiction to accepted knowledge at the time.Bdell555 16:43, 20 January 2007 (UTC)

As you can see from the image page, Robert used all studies for the relevant time period listed at [2], except for repetitive ones and one that did not supply the data in replottable form. Again, if you are aware of any other quantitative temperature reconstruction for the time in question that was published in a reputable scientific publication, bring the source, and we will integate it. I'm not aware of any conflicting studies. As for the satellite temperature record, you are a few years to late. The satellite data has been revised a couple of times as more and more problems were detected, and is now in good agreement with the surface record and model predictions. See e.g. the final report of the US Climate Change Science Program to congress[3], which states in the abstract; "Specifically, surface data showed substantial global-average warming, while early versions of satellite and radiosonde data showed little or no warming above the surface. This significant discrepancy no longer exists because errors in the satellite and radiosonde data have been identified and corrected. New data sets have also been developed that do not show such discrepancies." (emphasis added) --Stephan Schulz 17:29, 20 January 2007 (UTC)

An article at http://adsabs.harvard.edu/abs/1999GeoRL..26.1445B supplies replottable data for 858 years, data which indicates that "Neither instrumental nor proxy data in Idaho northeast valleys show unusual warming during the twentieth century." Perhaps you could explain to me again why that is not worthy of inclusion but that bold black line which only goes back a few decades is.

The study you reference is not a global or hemispherical temperature reconstruction, but only a local one. And the "bold black line" is the actual instrumental surface temperature record, which, in contrast to the satellite data, has held up very well over the years. Several studies have e.g. shown that the urban heat island effect has no discernable influence on it. --Stephan Schulz 18:37, 20 January 2007 (UTC)

So the creator of the graph believes it legitimate to globalize selected hemispherical temperature reconstructions, but no such expansion can occur to a study that doesn't support the warming hypothesis? The cited source for that bold black line (the Climate Research Unit at the University of East Anglia) also found that global average temperature did not increase between 1998 and 2005 and yet I cannot perceive that from your graph.Bdell555 20:54, 20 January 2007 (UTC)

If you cannot see the difference between a hemispheric reconstruction and a local one, discussion becomes somewhat pointless. Most reconstructions are northern hemisphere, as there are more proxies available there. As the graph ends in 2000 and the temperature is smoothed, it's no surprise you cannot see short-term trends after 2000....--Stephan Schulz 22:33, 20 January 2007 (UTC)

What I cannot see is how a hemispheric (or global) reconstruction can be made without looking at any locations. A local study is evidently junk science to you, but if you repeat junk science over enough times in different locations it turns into real science? Meanwhile my opened eyes are supposed to be blind to any difference between a hemispheric study and a global one. Last time I lost a silver dollar on the sidewalk I searched for it on the sidewalk on the other side of the street because more light was "available there". Was that logical? If you are prepared to defend this graph that uses sub-global studies to support global conclusions then in the name of consistency I take it you are not one of the many who reject a MWP and/or LIA by arguing that any such thing was merely a hemispheric phenomenon. If the "graph ends in 2000" I take it you are prepared to to concede that 2004 should not be so prominently stamped in the top right?Bdell555 23:02, 20 January 2007 (UTC)

You obviously have no idea what you are talking about. A local study is not necessarily junk science, but it gives information about local climate only. A hemispheric study given information about changes of temperature at all latitudes from the equator to the pole. It's not as good as a global study, but it is a lot better than a local study. And no, I do not reject MWP and LIA. I find evidence for the LIA more convincing than for the MWP, but neither is completely settled. And, btw, both are compatible with the Mann et al reconstructions if you allow for the confidence interval. The graph is clearly labelled, and it is clearly stated that the 2004 data point is there for comparison only. --Stephan Schulz 23:39, 20 January 2007 (UTC)

You cannot simultaneously claim that information from a particular location gives information about "local climate only" while claiming that the information provided by a particular location as part of a larger area study provides information about more than just its local climate. Moreover, the studies you cite as hemispheric do not provide data "at all latitudes" from zero to 90. The fact of the matter is that BOTH contribute information about the global climate. I have cited 5 studies from different areas of the world to start with and your reaction is not to challenge the validity of their procedures but instead to simply dismiss them by saying they could not possibly say anything about global climate. If "you allow for the confidence interval" then you have to allow that the Mann graph may say nothing and may support nothing. You rejected the alternative graph I suggested on the grounds that it has no error bars while simultaneously having no problems at all with the original research graph which includes Mann's graph without error bars! Finally, it looked to me that that 2004 data point was from the bold black line series data. If you are now claming that 2004 data point comes from some other source then what is that source? 01:03, 21 January 2007 (UTC)

I might add that the issue relevant to the "hockey stick controversy" was whether Mann was justified in ignoring satellite data in 1998, not 2007.

In 1998, the satellite data was available for 19 years only. Moreover, it does not show surface temperatures (which Mann et all reconstructed), but temperatures from a broad stretch of the atmosphere. Why should he compare apples and oranges?--Stephan Schulz 18:37, 20 January 2007 (UTC)

He shouldn't, but given his willingness to switch from tree ring data to surface temperatures, I think one can ask why switch to oranges instead of bananas. The data used for that bold black line does not use air temperatures over the oceans as it does for land, either.Bdell555 21:04, 20 January 2007 (UTC)

By the way, I cut this line from the article,

"This is a curious comment, because the borehole data suggest cold temperatures early on (http://www.grida.no/climate/ipcc_tar/wg1/fig2-19.htm) and (as shown by the figure above) other studies find the MWP to be no warmer than in MBH."

I am reluctant to cut rather than change or expand but I don't see how to revise this one. The citation shows warming from AD 1500, which argues in favour of a LIA that our infamous hockey stick graph does not recognize (so why the editorial comment?) It also mentions "other studies" which supposedly contradict what is said just prior to "This is a curious comment..." but does not list them. I should think one could provide some evidence these studies exist (aside from referring to our "bold black line" graph, which by the way includes our "hockey stick graph" and thereby begs the question).Bdell555 17:59, 20 January 2007 (UTC)

Yes, the borehole data does suggest a cool LIA. So the borehole data makes the 20th C even more exceptional - the warming is greater. So McK's comment makes no sense William M. Connolley 18:47, 20 January 2007 (UTC)

McKitrick is comparing the 20th century to the MWP, not the LIA, to conclude that the 20th century is not exceptional. The citation you gives provides no data prior to 1500, so is irrelevent to that particular point. In any case, it is for the reader to decide what "makes no sense" or is "curious". Also, why do you refuse to list these other sources you speak of? Bdell555 19:45, 20 January 2007 (UTC)

I'm not aware of any borehole data suggesting a warm MWP. Which are you (or McK) thinking of? I'm not quite sure how to interpret these other sources you speak of - if you mean other temperature reconstructions, they are listed on the graph. You have looked at the graph and noticed that none show a warm MWP, haven't you? Or are you still asserting that disenting studies have been suppressed? In which case you need to understand the difference between individual locations and hemispheric averages William M. Connolley 20:17, 20 January 2007 (UTC)

You are straw manning McKitrick here by claiming his contention is that there was a MWP clearly warmer than today when in fact he is instead claiming that today's warmth is not drastically different, and therefore not exceptional, relative to the MWP. And although it is hard to read because the bold black propaganda line is obscuring the others, I'd say the red line, and possibly others, support McKitrick's contention. Also, one of the lines is Mann's own graph, so you are essentially saying, look, Mann's implication that there was no MWP or LIA is proven because Mann implies that. This is a logical fallacy called begging the question.Bdell555 21:43, 20 January 2007 (UTC)

It becomes increasingly clear that you don't know what you are talking about. AFAIK, the borehole temperatures support *colder* earlier times, not warmer. The link I provided supports this. McK is claiming... who knows what (aside: McK is very much a minor partner in all this: McI is the one that has done all the work: just look at climate audit). McK, however, does not cite his borehole evidence, and neither do you. Please tell us exactly which evidence you are thinking of William M. Connolley 23:50, 20 January 2007 (UTC)

To repeat myself, the evidence relevant to McK's comments here is pre-1500 data, not post, and you citing post-1500 AD data. If you want to consider post-1500 AD bornhole evidence perhaps you would not object to adding this link to your article as well: http://epw.senate.gov/hearing_statements.cfm?id=266543 —The preceding unsigned comment was added by Bdell555 (talk • contribs) 23:59, 20 January 2007 (UTC).

But McK has not provided this early borehole data, and nor have you. Where is it? William M. Connolley 12:51, 21 January 2007 (UTC)

Note to Article Readers

I have attempted to provide more balance to this article but my edits have been reverted wholesale and I fail to see the point of extended revert war. So I would just caution you that a critical criticism of Mann's graph is that it implies no Medieval Warming Period or Little Ice Age and these phenomena are well documented in other sources. For example, studies in support of a global MWP and/or LIA include those that looked at

- radiocarbon dating of marine organisms in sediments of the Sargasso sea bed (LD Keigwin, "The Little Ice Age and Medieval Warm Period in the Sargasso Sea", Science, v.274, 1996, pp. 1504-1508)

- extractions from Kenyan lake bed sediments (D Verschuren, "Rainfall and Drought in Equatorial East Africa during the past 1 100 Years", Nature, v.403(6768), Jan 27 2000, pp. 410-414)

- oxygen 18 isotopes from Peruvian glaciers [4] and a well-dated stalagmite in a South African cave (Tyson, P.D. et al., "The Little Ice Age and Medieval Warming in South Africa". South African Journal of Science, v.96, 2000, pp. 121-126)

- sea levels over the last 1400 years [5]

Instead of adding a criticism to the citation of such studies the mention of them is simply reverted wholesale, apparently to protect your innocence from the conclusions of scientists. Apparently you are also not supposed to know that Mann used tree ring data for the part of his graph that is flat and what the limitations of tree ring data are. Finally, you are evidently also not supposed to know that the US National Assessment nonetheless reproduced Mann's graph without error bars and described it as applying globally [6], although I can't imagine why that was reverted as well. I suppose it might cause you to have an excessively inquiring mind concerning the conclusions of the US National Asssessment as well!Bdell555 21:43, 20 January 2007 (UTC)

why is this not Mann's graph?

OK let's start a fresh para here. This is too long.

In a nutshell this article purports to deal with the controversy over Mann's "hockey stick" analysis. So why is the only thing I see NOT Mann's graph?

This is absurd. The entry claims to discuss the contoversy but displays someone elses graph in place of the one in question!

Much of the controversy is that the graph was so widely published by the UN , IPCC , the Canadian gov. and half the media outlets of the planet that it has become widely accepted by many as a true representation.

Are we really to believe that it is now impossible to get any copy of this widely published graph to place on Wikipedia?

Willaim Connerly, you seem to the self appointed guardian of your version of the truth on climate topics here and it is you doing your typical "slash and burn" editorial on any content that does not fit your personal world view.

You started this topic, and have spent considerable effort argueing why you cant post Mann's graph for copyright reasons.

Why dont you ask your close collaborator and co-author on "realclimate" Micheal Mann ?

Unless of course your real motive for starting this page was misrepresent the record on this issue.

If you have not already done so could you please ask Micheal Mann to add his graph to this page or give you permission to do so. That will end all copyright arguements and excuses. —The preceding unsigned comment was added by 90.144.113.77 (talk) 11:28, 12 February 2007 (UTC).