From the Telegraph:
The ‘hockey stick’ that became emblematic of the threat posed by climate change exaggerated the rise in temperature because it was created using ‘inappropriate’ methods, according to the head of the Royal Statistical Society.
By Louise Gray, Environment Correspondent
Professor David Hand said that the research – led by US scientist Michael Mann – would have shown less dramatic results if more reliable techniques had been used to analyse the data.
Prof Hand was among a group of experts charged with investigating the “climategate” email scandal that engulfed the University of East Anglia’s Climatic Research Unit (CRU) last year.
Sceptics claimed that the hacked messages showed scientists were manipulating data to support a theory of man-made global warming.
However the review, led by Lord Oxburgh into the research carried out by the centre, found no evidence of ”deliberate scientific malpractice”.
Lord Oxburgh said the scientists at the research unit arrived at their conclusions ”honestly and sensibly”.
But the reviewers found that the scientists could have used better statistical methods in analysing some of their data, although it was unlikely to have made much difference to their results.
That was not the case with some previous climate change reports, where “inappropriate methods” had exaggerated the global warming phenomenon.
Prof Hand singled out a 1998 paper by Prof Mann of Pennsylvania State University, a constant target for climate change sceptics, as an example of this.
He said the graph, that showed global temperature records going back 1,000 years, was exaggerated – although any reproduction using improved techniques is likely to also show a sharp rise in global warming. He agreed the graph would be more like a field hockey stick than the ice hockey blade it was originally compared to.
“The particular technique they used exaggerated the size of the blade at the end of the hockey stick. Had they used an appropriate technique the size of the blade of the hockey stick would have been smaller,” he said. “The change in temperature is not as great over the 20th century compared to the past as suggested by the Mann paper.”
…
Prof Hand praised the blogger Steve McIntyre of Climate Audit for uncovering the fact that inappropriate methods were used which could produce misleading results.
======================
Complete article here
Smokey (21:19:03) :
“It’s legit, and it’s still used.”
Not in the new UN/IPCC Assessment Reports. Why? Because it’s been debunked.
Explanation here: click
Nah !
Check here:
http://www.ipcc.ch/publications_and_data/ar4/wg1/en/ch6s6-6.html
The Mann Hockey stick graph is an urban legend… It keeps popping up here and there and only the gullible and the true believers embrace it…. maybe some small birds also flutter happily as the hockey stick is displayed…
Wren:
Wegman’s response was “the fact that the answer may have been correct does not justify the use of an incorrect method in the first place”
That’s a generic statement, Wren, not a confirmation of Mann’s answer, which alleged to erase the MWP. Was Wegman saying it did not exist, and that he knew it by some other investigation? Which one?
It applies to a case where you already pretty much know the correct answer because of the prior use and replication of correct methods, according to the rules of the Scientific Method. No amount of incorrect methods will make the answer any more correct = bad science.
I wonder what Wegman thinks Method Correct + Answer Wrong equals?
It means that either the answer might actually be wrong or else some previously unknown factor has affected the Method. So you look carefully at the situation to see what might be going on, and you repeat the Method. You might have just got onto something big.
It’s really not that difficult.
J.Peden, perhaps you know where there’s a graph constructed using the same data used by Mann but also using the appropriate technique that Wegman advocated?
No?
Are you aware that subsequent studies both using and not using the tree proxies have confirmed the hockey stick shaped graph?
Are you aware that the MWP and LIA are evident in the MBH98 graph, despite lies that MBH98 erased these climate periods (surely the ultimate strawman)?
Yes, let’s take the famous graph from 1972 again 🙂
I realise Louise Grey only asserts this in her article, but I have not been able to find any source where Prof Hand is actually quoted. I only can find other blog sites repeating this assertion.
Wren (20:06:57) :
Wegman on Mann’s Hockey Stick:
“The fact that the answer may have been correct does not justify
the use of an incorrect method in the first place.”
Note the context – one of the toughest multi-phased critical
examination of a single article ever? Wegman goes overboard
in severity. And was it even his final deliberated conclusion;
he retorted in a live session?
The scientific method does not assume that an original article should
get everything right. On the contrary, it assumes the opposite and bets
on subsequent contributions to point out flaws and evaluate the conclusions.
Of course there is a responsibility to not peddle crude mistakes
and crazy ideas: the peer review is meant to filter out such drafts –
Mann et al 1998 passed, right?
Shouldn’t a balanced evaluation consider positive outcomes also:
although the idea to somehow make a synthesis of paleo proxies
was probaly in the air at the time; it was Mann et al who did it, you
can’t take that away from him.
Sceptics are perhaps good at criticizing work done (which is necessary,
no question), but really don’t give enough thought to the creativity
side, which absolutely drives the science process.
It seems Mann could have done better, the statistics at least, been
more cooperative etc. But, the article probably, at the time, was not
seen by authors as something definitive.
So if the hockey stick is as dead as proclaimed, we will see a commonly
accepted successor with a significantly different shape gain ground
in the next years. It is fully possible, but let’s not go ahead of times.
Wren (21:45:54),
You folks keep trying to claim that Mann’s Hokey Schtick chart, which shows no MWP, is still used by the UN/IPCC.
That is false.
Here is the Mann chart that was debunked by McIntyre & McKittrick: click
You think I don’t know my charts? Here’s a corrected chart, showing the MWP: click
The IPCC loved Michael Mann’s chart! It was visually excellent propaganda. No other chart has the visual impact of Mann’s. It was so pretty. And SCARY! The IPCC would have never given it up if they weren’t forced to.
So you won’t be seeing Michael Mann’s debunked hokey stick chart in any new IPCC Assessment Reports. Only sad, pale imitations. Because Mann’s chart is debunked.
Smokey (04:35:31) :
Wren (21:45:54),
You folks keep trying to claim that Mann’s Hokey Schtick chart, which shows no MWP, is still used by the UN/IPCC.
That is false.
——————-
On the surface of it, looks like you are right – but the one in IPCC 2007
is titled MBH 1999. So, did M&M debunk this one? I thought they came
in much later?
In the MBH 1999 article text it looks like MBH were just continuing
there work? In that case is ‘debunked’ justified?
I find it hard to believe that the Mann hockey stick is still being debated. At the outset, a wealth of geologic data (including glacial fluctuations, oxygen isotopes from ice cores, pollen, historic data, crop fluctuations, ………) show that Mann’s concept of no Midieval Warm Period or Little Ice is ridiculous. Just take a look at hundreds and hundreds of papers in the literature! When I first saw Mann’s hockey stick I said either the trees he used weren’t sensitive enough to show the well-established global warming and cooling or else the data is fraudulent. After Climategate, we now know which of these was correct.
McIntyre and others have done an admirable job of exposing the misuse of data, but the AGW people are still using the hockey stick as proof of CO2 warming as if it was credible. They obviously haven’t read the literature (and yes, it’s peer reviewed and peer reviewed when that meant something) and I can’t for the life of me understand why anyone who call themselves scientists subscribe to the idea that just because climate warms (which it has done over and over for millenia), that somehow proves it is due to CO2 (especially when the warmings occur BEFORE CO2 began to escalate.
Just compare Mann & Jones (2003) “improved” hockey stick to Esper (2003), Moberg (2005) with Alley (2004)…
Alley, Esper, Mann & Moberg
Guess which reconstruction looks the least like the ice core d18O temperature data?
For the FT Article: http://www.ft.com/cms/s/0/b942edba-47f6-11df-b998-00144feab49a.html
Try BreakthePaywall:
BreakthePaywall! is a free add-on for Internet Explorer (Firefox coming soon!) that simplifies using the various methods for circumventing website paywall restrictions.
Smokey (04:35:31) :
Wren (21:45:54),
You folks keep trying to claim that Mann’s Hokey Schtick chart, which shows no MWP, is still used by the UN/IPCC.
That is false.
Here is the Mann chart that was debunked by McIntyre & McKittrick: click
You think I don’t know my charts? Here’s a corrected chart, showing the MWP: click
The IPCC loved Michael Mann’s chart! It was visually excellent propaganda. No other chart has the visual impact of Mann’s. It was so pretty. And SCARY! The IPCC would have never given it up if they weren’t forced to.
So you won’t be seeing Michael Mann’s debunked hokey stick chart in any new IPCC Assessment Reports. Only sad, pale imitations. Because Mann’s chart is debunked.
=========
Smokey, you are wrong. Mann’s hokey stick is in the most recent IPCC report. See MBH 1999 in the second chart in Figure 6.10:
http://www.ipcc.ch/publications_and_data/ar4/wg1/en/figure-6-10.html
Wren (08:48:59),
As I explained, imitations don’t count.
Wake me when you find this Michael Mann hokey stick chart in a recent or new IPCC AR: click
Mann’s wonderful, scary looking chart that catapulted him to fame and fortune was debunked by M&M, so the IPCC dare not use it even though they would dearly love to plaster it all over AR-5. Sorry about that. But it was based on BS data, and Mann knew it. In fact, he’s still at it. Here’s the correction: click
Smokey (09:23:00) :
“Mann’s wonderful looking chart was debunked by M&M, so the IPCC dare not use it even though they would dearly love to plaster it all over AR-5.”
You are fixed on Mann or the MBR 1998 graph. Just a year later
MBR 1999 produced a new one, which is still in the IPCC 2007 report.
So Mann self-debunked? Or, as most of us would conclude: continued
working scientifically, applying self-criticism and taking into
consideration criticism from Briffa, Jones. Correct me if I am wrong
Macintyre debunking came in later chronologically, at least after 2001?
These are Professor Hands own words:
“Prof Hand said his criticisms should not be seen as invalidating climate science. He pointed out that although the hockey stick graph
– which dates from a study led by US climate scientist Michael Mann
in 1998 – exaggerates some effects, the underlying data show a clear
warming signal.
He accused sceptics of “identifying a few particular issues and
blowing them up” to distort the true picture. The handful of errors
found so far, including the exaggerated hockey stick graph and a
mistaken claim by the Intergovernmental Panel on Climate Change that Himalayan glaciers would disappear by 2035, were “isolated incidents”,
he said. “If you look at any area of science, you would be able to find odd examples like this. It doesn’t detract from the vast bulk of the conclusions,”
he said.
http://www.ft.com/cms/s/0/162b0c58-47f5-11df-b998-00144feab49a.html
Smokey (09:23:00) :
Wren (08:48:59),
As I explained, imitations don’t count.
Wake me when you find this Michael Mann hokey stick chart in a recent or new IPCC AR: click
Mann’s wonderful, scary looking chart that catapulted him to fame and fortune was debunked by M&M, so the IPCC dare not use it even though they would dearly love to plaster it all over AR-5. Sorry about that. But it was based on BS data, and Mann knew it. In fact, he’s still at it. Here’s the correction: click
======
MBH 1999 is the Hockey Stick. See MBH 1999 in the See MBH 1999 in the second chart in Figure 6.10:
http://www.ipcc.ch/publications_and_data/ar4/wg1/en/figure-6-10.html
It’s as plain as day. Why do you persist with the fiction that it’s not in the report?
mikael pihlström (09:55:51) :
“You are fixed on Mann or the MBR 1998 graph.”
No, that is projection. It is you and Wren who are fixated on Mann’s Hokey Stick graph. When Wren first brought it up, I pointed out:
“If Mann’s Hokey Stick was legit, it would still be used. It’s not.”
Wren responded:
“It’s legit, and it’s still used.”
It must be due to cognitive dissonance [Orwell’s “doublethink”] that is making both of you deliberately misunderstand the issue: Michael Mann’s scary looking chart was debunked by McIntyre & McKittrick.
That particular chart — by far the best of the bunch — can no longer be used by the IPCC. They would love to use it, but now they must use pale imitations [which are also bogus, but M&M debunked the Mann chart; the other copycat charts came out after the Mann debunking].
If that were not so, the IPCC would continue to use Mann’s original chart, because it is by far the best, most visually arresting, scary propaganda showing [falsely] that modern temperatures have risen to unprecedented levels. [They have not; and global temperatures during the earlier Greek optimum and the Roman optimum were warmer than current global temperatures, which are not unusual.]
The original argument is not as you are now trying to re-frame it. The IPCC’s use of inferior hokey stick charts is another issue. I simply pointed out that Michael Mann’s chart can no longer be used by the IPCC because the data Mann used to create it has been debunked, and I stand by that.
If you decide to pick more nits, show that the IPCC is still using this particular chart: click. You know they want to.
“”” Gilbert (16:02:14) :
bob (09:13:00) :
Has McIntyre shown that the statistical methods did indeed produce different results, rather than could have produced misleading results.
In other words, any evidence that the hockey stick graph is wrong?
Anyway MBH98 is obsolete anyway, and maybe it is time to stop arguing that it is faulty or misleading, as there is better data in more recent publications.
Michael Mann pioneered the use of bad proxies, and others rapidly piled on. Briffa’s stick even uses dead trees that show it was never warm enough for the trees to exist.
I’ve been thinking of an analogy.
Say law enforcement has solid evidence that a body is buried in a field. So they dig 1000 holes and one hole has a body, thus confirming the evidence.
Then, along comes Mann and uses the 999 empty holes to prove that no body was really there after all. Others pile on and viola!!!
Lots of studies showing no body.
Only one study showing there was a body.
Overwhelming evidence!!!! “””
Actually, you missed the proper analogy:-
In the usual case, somebody randomly digs a hole in a field, and finds a body. Law enforcement officials then jump to the conclusion that they have stumbled upon a whole field full of bodies.
Or more dramatically, you might have bored a hole into the ground on a farm called Elandsfontein, about 20 miles north east of Pretoria, SA; perhaps an 18 foot deep hole lokking for water. Instead of water you came up with a broken piece of diamond weighing about 21 or so ounces; obviously broken off an even larger piece.
So you jump to the conclusion that 18 feet below you is a whole sheet of diamond. In reality; you just accidently stumbled on the Cullinan Diamond; the largest gem qualitydiamond ever found.
It’s called a failure to observe the Nyquist sampling theorem, which lays down the rules for taking samples of any continuous function.
So include Biffra’s infamous tree rings, and ice cores or sediment cores, as examples of where a single sample is considered representative of the real situation.
Well that’s what happens when you use the Temperature measured at some Urban Heat Island to represent the Temperature 1200 km away from there; you get “aliassing noise”; and you get it for quite modest violations of the Nyquist Criterion; it’s what makes the wagon wheels go backwards in TV or movie horse operas.
And to be pedantic; the Cullinan Diamond was not actually discovered by a random bore in the ground. It was found in 1905 by Frederick Wells, the superintendent of the “Premier Mine” in SA while doing a routine inspection. But it was 18 feet below the earth surface, sticking out of a wall of the mine. (3106 Carats actual weight). The other missing piece, that was presumed to exist because of the large cleavage face; has never been found; and it is believed it also would not have been crushed in mining operations. Cullinan of course was the owner of the Premier Mine.
And no; don’t ask how I know all this stuff. My guess is you could probably find much more details by googling; I wouldn’t know; I never tried it.
But as for tree rings; a tree is a three dimensional object; it has a height, and a (roughly) circular crossection. When you core bore a tree, you get a one dimensional sample of that three dimensional object. It tells you nothing about what you might see if you bore a second hole at a different height or in a different radial direction; well other than the age from ring counting. That’s probably why they call it “dendrochronology.”
There is also (I am told) some sort of “general theorem of pattern recognition”; which basically says that pattern recognition is impossible. Well it really says something like:- given a finite set of N-dimensional projections (images) of an N+1 dimensional object; it is always possible to construct a counterfeit (different) , N+1 dimensional object that yields the same set of N dimensional projections. It is important in camouflage strategies and similar problems. Well it also is the reason for the “face on Mars”; which really doesn’t exist. Counterfeiting is relatively easy, for two dimension projections of real 3-D objects; well at least the usual three view engineering projections. The error rate goes down rapidly as the number of N-D projections increases.
Myth: the hockey stick graph has been proven wrong
http://www.newscientist.com/article/dn11646-climate-myths-the-hockey-stick-graph-has-been-proven-wrong.html
Arguments based on myths are phony.
Andrew W (00:13:36) :
Andrew:
1] I was analyzing Wegman’s statement per se, which I still don’t think was an endorsement of Mann’s Hockey Stick. But I was willing to entertain that I was wrong, if Wegman did think there were some valid studies showing the “correct answer” as the same thing Mann’s “bad method” study gave. If so, I was also asking what these studies were.
2] I believe Mann’s own “Team” refers to themselves as the “Hockey Team”, but at any rate everyone else refers to Mann’s reconstruction as in effect a “Hockey Stick”.
3] A Hockey Stick has a level shaft.
4] No, I am not aware of any proxy reconstruction which validly establishes or suggests, at the least according to statistical methods regardless of the physical meaning of the proxy data, an essentially level MWP – which would also contradict a massive amount of geologic evidence for a significant MWP, which even the ipcc admitted in its 1995 graph. I believe McIntyre has shown that these invalid proxy studies, including Gore’s Thompson’s Thermometer, always rely upon Mann’s stripbark bristlecones, or else have some other problem.
Anyway, what are the allegedly valid studies which show an essentially flat shaft MWP?
5] In that regard, I do know that Craig Loehle’s multi-proxy analysis, which used only proxies having a verification period of some duration, did show a MWP, and nothing resembling a level shaft from there on, either.
Wren (10:40:17),
You keep avoiding the point I’ve repeatedly made: that the IPCC can no longer use Michael Mann’s scary chart. THIS particular chart: click
I understand exactly why you avoid answering: if you admit the IPCC can no longer use Mann’s chart linked above, your response to my original point – the only point I made – fails.
Instead of digging a deeper hole, if you can’t admit to the fact that Mann’s hokey stick chart was debunked, then moving on to another subject would be your best course of action.
Unless, of course, you can show that the IPCC used Mann’s chart after it was debunked by M&M. Because you know they would love to keep on using it, rather than its inferior imitations.
Please post something that answers my original point, instead of responding with your own strawman arguments, or MoveOn. Fair enough?
The shape of Mann’s graphs aren’t identical, if that’s what you mean, but both swing upward on the right like a hockey stick’s blade. Incidentally, none of the graphs were ever smooth lines like an actual hockey stick.
Why do you continue to mischaracterize McIntyre’s and Wegman’s criticism of the hockey stick as “debunking” ?
Webster’s defines debunk as “to expose the sham or falseness.”
Has McIntyre or Wegman said the hockey stick is false?
George E. Smith (10:34:31) :
“But as for tree rings; a tree is a three dimensional object; it has a height, and a (roughly) circular crossection. When you core bore a tree, you get a one dimensional sample of that three dimensional object. It tells you nothing about what you might see if you bore a second hole at a different height or in a different radial direction; well other than the age from ring counting. That’s probably why they call it “dendrochronology.”
Quite right, but not entirely. Tree boring is primarily good for age
determination (dendrochronology), but the 3-D problem is not so
grave as you might think. Having bored hundreds of trees (killed some)
my intuition is that although one side of the tree can grow slower than the other the relative diffs in yearly growth on any side will not be disturbed.
If something happenson one side of the tree and not the other, for
instance a neighbour tree outgrows ‘our’ tree, your theory holds. But, since
a set would be a number of trees locally, these ‘anomalies’ tend to even out.
However, the stand history: silvicultural actions, draining, fertilization and
natural fertility distributed unevenly over time, could disturb any climate warming signal.
Scaling up, at landscape or even regional level tree rings would react to
a specific regional climate. If warming occurs, steadily increasing
temperature is reproduced in thicker tree rings, only if precipitation is
constant or co-increasing and serious nutrient limitation will not set in
in aged stands. Also, in any landscape there would be cooler and warmer
spots due to topography.
So, THERE IS NO REASON?, why tree rings should be a good proxy for
climate. But they seem to be and dominantly support warming theory.
What Mann did cleverly, was to not rely only on tree rings. You often
seem to forget that his are multi-proxy studies, which can be tricky
to handle methodologically I guess. Another clever thing was to expand
geographically to get nearer a global average. But, this got him into
trouble with sceptics, who distinctly remember sunbathing on Greenland.
Smoky, my previous post is a reply to you, but I forgot to address it to you. But you probably have surmised it’s for you.
Wren (11:33:02) :
“The shape of Mann’s graphs aren’t identical, if that’s what you mean…”
No, that is not what I stated or mean, which was: that particular Michael Mann Hokey Stick chart – the best one by far for the IPCC’s purposes, and the chart that catapulted Mann to stardom and grant heaven – was debunked, and that is why the IPCC can no longer use that chart. You’re doing everything possible to avoid facing that fact.
Keep digging that hole deeper.