Climate Change

[mdettweiler]

Originally Posted by cheesehead

No it isn't a key factor in that ... because there's been no plateau in global warming, which is what the article I linked to is saying!

You, like many AGW-deniers recently, seem to be confusing a decadal variation with a multi-decadal trend.

To illustrate, consider the function y = 0.6t + sin t.

(The 0.6t part represents a long-term trend and the sin t part represents a period-3.1 oscillation imposed on the long-term trend, just as the 11-year solar-cycle oscillation is imposed on the long-term global warming trend.)

t = 0.0, y = 0.
t = 0.4, y = 0.63
t = 0.8, y = 1.20
t = 1.2, y = 1.65
t = 1.6, y = 1.96
t = 2.0, y = 2.11
t = 2.4, y = 2.12
t = 2.8, y = 2.01
t = 3.2, y = 1.86
t = 3.6, y = 1.72
t = 4.0, y = 1.64

t = 4.4, y = 1.69
t = 4.8, y = 1.88
t = 5.2, y = 2.24
t = 5.6, y = 2.73
t = 6.0, y = 3.32
. . .

Suppose we were sitting at t = 4.0 and didn't know any future values of y at larger values of t yet. Did the drop in y between t = 2.8 and t = 4.0 mean that the long-term trend had ended? No.

It's not that the solar cycle has been ignored by mainstream climatologists. It's the anti-AGWers who keep ignoring or overlooking factors, usually because of their own incomplete understanding of science. What's being overlooked by folks claiming that the apparent pause in temperature rise for the past decade means that global warming has ceased is that oscillations imposed on the long-term trend don't mean the long-term trend has ended.

... because you've not understood what the article is saying in the rest of the context. It's saying that there has been no plateau in the long-term trend. So the conclusion that the solar-cycle oscillation means that the long-term global warming trend has plateaued is wrong. Anti-AGWers are the ones who haven't yet taken all factors into account.

Anti-AGWers are not denying that there are temperature changes going on; rather, they simply maintain that they are of natural causes and thus there's nothing we can (or would really want to) do about it. An overall upward trend like the one you showed is perfectly consistent with this.

No, they don't. The solar cycle is an 11-year oscillation, just like the sin x part of the function above. The argument for AGW is that there is a larger, longer trend that has not disappeared just because of a short-term oscillation.

No, it seems to show that you have an incomplete understanding of science, you want to ignore part of the data, and you impose your bias on what you read.

But what you've shown is only that the debate with anti-AGWers who are ill-informed and don't have a complete understanding of climatology is ongoing. The debate between fully-informed competent climatologists _is_ over.

If you want to convince us that there are still well-informed, valid arguments aginst AGW, then present them instead of presenting us with articles written by anti-AGWers who are by your own criteria NOT doing good science!!

That's only because you apparently can't tell the difference between "real" science and the faulty scientific understanding presented in the Spiegel article.

But the point you actually made is just the opposite!

The discussion, regarding whether AGW exists, between scientists who actually know what they're talking about _is_ over. The remaining not-over discussion is being perpetuated by people who _don't_ know what they're talking about -- which is exactly, precisely what you have just shown us!

Okay, so it seems then that you're saying the climatologists interviewed in the Spiegel article are not fully informed and competent. Then how come they're still employed by big, respected research laboratories? And, may I point out that most of the people interviewed seemed to still be full-on AGW believers, though they are nonetheless being responsible scientists and investigating a possible problem with their theory.

[ewmayer]

Originally Posted by __HRB__

http://blogs.news.com.au/heraldsun/a...hadley_hacked/
http://blogs.telegraph.co.uk/news/ja...lobal-warming/
http://www.guardian.co.uk/environmen...-leaked-emails
http://www.examiner.com/x-28973-Esse...ocs-and-emails
http://www.nature.com/news/2009/0911...2009.1101.html
http://news.bbc.co.uk/2/hi/science/nature/8370282.stm
http://www.foxnews.com/story/0,2933,576009,00.html

Hacked E-Mail Is New Fodder for Climate Dispute: Private messages hacked from a British university are causing a stir among global warming skeptics.

Hundreds of private e-mail messages and documents hacked from a computer server at a British university are causing a stir among global warming skeptics, who say they show that climate scientists conspired to overstate the case for a human influence on climate change.

The e-mail messages, attributed to prominent American and British climate researchers, include discussions of scientific data and whether it should be released, exchanges about how best to combat the arguments of skeptics, and casual comments — in some cases derisive — about specific people known for their skeptical views. Drafts of scientific papers and a photo collage that portrays climate skeptics on an ice floe were also among the hacked data, some of which dates back 13 years.

In one e-mail exchange, a scientist writes of using a statistical “trick” in a chart illustrating a recent sharp warming trend. In another, a scientist refers to climate skeptics as “idiots.”

Some skeptics asserted Friday that the correspondence revealed an effort to withhold scientific information. “This is not a smoking gun; this is a mushroom cloud,” said Patrick J. Michaels, a climatologist who has long faulted evidence pointing to human-driven warming and is criticized in the documents.

Some of the correspondence portrays the scientists as feeling under siege by the skeptics’ camp and worried that any stray comment or data glitch could be turned against them.

The evidence pointing to a growing human contribution to global warming is so widely accepted that the hacked material is unlikely to erode the overall argument. However, the documents will undoubtedly raise questions about the quality of research on some specific questions and the actions of some scientists.

In several e-mail exchanges, Kevin Trenberth, a climatologist at the National Center for Atmospheric Research, and other scientists discuss gaps in understanding of recent variations in temperature. Skeptic Web sites pointed out one line in particular: “The fact is that we can’t account for the lack of warming at the moment and it is a travesty that we can’t,” Dr. Trenberth wrote.

The cache of e-mail messages also includes references to journalists, including this reporter, and queries from journalists related to articles they were reporting.

Officials at the University of East Anglia confirmed in a statement on Friday that files had been stolen from a university server and that the police had been brought in to investigate the breach. They added, however, that they could not confirm that all the material circulating on the Internet was authentic.

But several scientists and others contacted by The New York Times confirmed that they were the authors or recipients of specific e-mail messages included in the file. The revelations are bound to inflame the public debate as hundreds of negotiators prepare to negotiate an international climate accord at meetings in Copenhagen next month, and at least one scientist speculated that the timing was not coincidental.

Dr. Trenberth said Friday that he was appalled at the release of the e-mail messages.

But he added that he thought the revelations might backfire against climate skeptics. He said that he thought that the messages showed “the integrity of scientists.” Still, some of the comments might lend themselves to being interpreted as sinister.

In a 1999 e-mail exchange about charts showing climate patterns over the last two millenniums, Phil Jones, a longtime climate researcher at the East Anglia Climate Research Unit, said he had used a “trick” employed by another scientist, Michael Mann, to “hide the decline” in temperatures.

Dr. Mann, a professor at Pennsylvania State University, confirmed in an interview that the e-mail message was real. He said the choice of words by his colleague was poor but noted that scientists often used the word “trick” to refer to a good way to solve a problem, “and not something secret.”

At issue were sets of data, both employed in two studies. One data set showed long-term temperature effects on tree rings; the other, thermometer readings for the past 100 years.

Through the last century, tree rings and thermometers show a consistent rise in temperature until 1960, when some tree rings, for unknown reasons, no longer show that rise, while the thermometers continue to do so until the present.

Dr. Mann explained that the reliability of the tree-ring data was called into question, so they were no longer used to track temperature fluctuations. But he said dropping the use of the tree rings was never something that was hidden, and had been in the scientific literature for more than a decade. “It sounds incriminating, but when you look at what you’re talking about, there’s nothing there,” Dr. Mann said.

In addition, other independent but indirect measurements of temperature fluctuations in the studies broadly agreed with the thermometer data showing rising temperatures.

Dr. Jones, writing in an e-mail message, declined to be interviewed.

Much more to come, I'm sure.

[cheesehead]

Originally Posted by mdettweiler

Actually, in the Spiegel article it didn't seem to be even necessary to point out about ocean heat content or global heat content.

You still seem to be missing the point of http://www.skepticalscience.com/glob...ed-in-1998.htm : surface and air temperatures are not the whole story. Because there is heat exchange between ocean surface and ocean depths, one has also to consider subsurface ocean temperatures.

When one considers that the ocean waters have a much greater heat-holding capacity than atmosphere and air, it becomes even more important not to leave out subsurface ocean temperatures.

You have not yet shown that you understand that.

The Spiegel article never ever made that distinction. All its references to temperature are evidently surface temperatures. E.g., "temperatures declined in large areas of North America, the western Pacific and the Arabian Peninsula. Europe, including Germany, remains slightly in positive warming territory." Clearly, the references to North American, Arabian Peninsula, and Europe are about surface temperatures, and clearly there is no distinction made that the western Pacific temperatures are anything except surface temperatures also.

The article at http://www.skepticalscience.com/glob...ed-in-1998.htm explains why it is "necessary to point out about ocean heat content or global heat content", as you put it. You show no sign of understanding that. Please acknowledge that you understand this basic point, because until you do, all of the rest of your argument is meaningless because it's based on the false idea that the global warming trend can be measured by surface and air temperatures alone.

Once you understand why the subsurface ocean temperatures are important, you will also understand, I hope, that as long as the ocean depths are still warming, the plateau in surface temperatures does not mean that global warming has paused. Once you admit that, the whole Spiegel article's premise (that global warming has plateaued) falls apart.

After all, if the theory being presented is that global warming cycles are caused by changes in the sun's activity,

First, regarding only sunspots (that's what "sun's activity" sometimes means -- sunspot cycle):

If that were true, why haven't we seen 11-year cycles dominating the global warming trend?

The absence of significant 11-year cycles in the global warming trend means that solar sunspot cycles cannot be a significant cause of global warming.

Next, regarding whether there has been a long-term (longer than 11 years, not related to sunspot cycle) overall solar increase:

That extremely obvious possibility has been explicitly and thoroughly considered by climatologists before they ever declared that we have a global warming trend. Perhaps you're unaware that astronomers have been measuring the rate of solar energy reaching Earth for well over a century (from the ground, and for multiple decades from space satellites). It hasn't varied significantly, aside from the 11-year sunspot cycle.

Thus, climatologists already have solid evidence that the warming was not significantly due to solar output increase. The notion that they've ignored or overlooked this effect would be proposed only by people who are ignorant about climatology.

then there'd be no argument against the fact that the planet's heat content would increase because of that.

... which is exactly why climatologists have already considered that, not ignored or overlooked it!!

Also, I am by no means claiming that the guy who wrote the article is himself a "good scientist". After all, he's just a news reporter, writing about what actual scientists have said, and such were quoted throughout the article.

My complaint was about the supposedly scientific evidence and statement presented in the article. Consider all my criticisms about the writing to be criticisms of the ideas presented, not the precise identity of the author.

You presented the article to us by writing:

"Here's an example of one article presenting some convincing anti-global-warming evidence that had the amazing fortune of being allowed to surface:
http://www.spiegel.de/international/...662092,00.html"

By saying that, you endorsed the content of the article as being a good-enough representation of "convincing" "evidence".

This quibble about journalist versus scientist is clearly an effort to avoid answering the gist of my criticisms. Consider all my references to be to the people who originated the ideas.

You wouldn't be trying to backtrack away from your endorsement by saying that the journalist who wrote the article didn't write accurately, would you?

You presented the article as containing evidence, not just a journalist's perhaps-mistaken interpretation of evidence. Do you wish to make a change in your endorsement?

all of whom seemed to be well-respected,

Do you equate "well-respected" to "competent and knowledgable in climatology"?

concluded completely opposite things from the evidence presented: some that global warming was caused by sunspot cycles

... which is shown not to be the case by absence of 11-year effects ...

and had stagnated,

The sunspot cycle has not stagnated; it continues to operate with its historic characteristics (some astronomers keep track of this).

This fits perfectly well with the point I was trying to make, which was not about the validity of the article itself,

Oh ... so you are backtracking on your endorsement of "presenting some convincing anti-global-warming evidence", aren't you?

but rather that debate is still continuing in earnest between well-respected scientists..

Again, do you equate "well-respected" to "competent and knowledgable in climatology"? If so, what evidence can you present that the scientists still debating are competent and knowledgable in climatology?

[cheesehead]

Originally Posted by mdettweiler

Anti-AGWers are not denying that there are temperature changes going on; rather, they simply maintain that they are of natural causes and thus there's nothing we can (or would really want to) do about it.

In other words, they're either (a) denying the greenhouse effect of carbon dioxide, (b) denying that the atmosphere's carbon dioxide content has been steadily increasing for over a century, (c) denying that the carbon dioxide increase matches anthropogenic carbon dioxide emissions plus natural emissions minus known carbon dioxide sinks, as far as is known, or (d) denying that we can do anything significant about anthropogenic carbon dioxide emissions?

How much of that do you think is simply resistance to behavioral change - the desire to keep doing things the way we've been doing them? ("Change is painful.")

An overall upward trend like the one you showed is perfectly consistent with this.

Do you get the point that a cyclic factor imposed on a monotonic upward trend can produce a temporary dip or plateau, such as the recent pause in surface temperatures?

Do you acknowledge that that possibility means that the recent pause cannot be taken to be any proof that the warming trend has stopped?

Okay, so it seems then that you're saying the climatologists interviewed in the Spiegel article are not fully informed and competent. Then how come they're still employed by big, respected research laboratories?

I've had co-workers with long company seniority who were incompetent or ignorant in some respect.

And, may I point out that most of the people interviewed seemed to still be full-on AGW believers, though they are nonetheless being responsible scientists and investigating a possible problem with their theory.

Fine. But the "possible problems" mentioned in the article are bogus. The quotes in the article may not accurately represent the full opinions of the people quoted. Can you demonstrate that the quotations were not taken out of context or are otherwise misleading?

If you want to present "convincing" evidence, you'll have to do a lot better than the Spiegel article. It would have been much more convincing if you had presented an article written by established climatologists and published in a peer-reviewed journal or at least in a science-oriented magazine with a history of scientific accuracy (such as Scientific American) rather than an article written by a journalist for a general-audience publication.

By presenting a popular-audience article written by a journalist with such obvious scientific flaws, you've only confirmed my contention that the only debate still going on is not between competent climatologists, and that the actual scientific debate is over.

[__HRB__]

Originally Posted by mdettweiler

[...]the point I was trying to make [...] was not about the validity of the article itself, but rather that debate is still continuing in earnest between well-respected scientists.

As you can see, for GW-alarmists even meta-statements to the effect that their alarmism might be unjustified are pure blasphemy (note that the thread title presupposes that GW cannot be "real, but not a threat"). While I admire your efforts to remain objective, I fear that you will only become increasingly frustrated. Unfortunately the forum-moderators do not allow the natural methods for humans to relieve stress, so I invite you to openly speculate a little about why especially liberal-socialists have embraced GW-alarmism (OT: conservative-nationalists embrace terrorist-alarmism).

As a starting point I'll argue that GW-alarmism is an especially attractive position for people one can comfortably classify as losers, because the failure to to have achieved anything of significance in their life makes them assets, whereas the winners, who have become wealthy by making it possible for everybody to own a car (or live an extra ten years in spite of high cholesterol), are actually liabilities because they are destroying the planet.

[philmoore]

Here's another point of view:

www.guardian.co.uk

Again, a journalist, not a scientist, but interesting never-the-less.

[__HRB__]

Originally Posted by philmoore

Here's another point of view:

www.guardian.co.uk

Again, a journalist, not a scientist, but interesting never-the-less.

Actually, it is much more interesting to read the comments. I followed a couple of the links, and it is likely that some of the allegations are in fact quite serious. Specifically, some of the filtering (smoothing) techniques used, weigh data points at the end of the time-series more heavily than intermediate points, as data was frequently smoothed using averages of the previous 25 and following 25 years. There is nothing wrong with this technique as long as one stops 25 years in the past and if one doesn't want to stop 25 years in the past, one could simply use averages of the last 50 years, which would simply shift the smoothed graph 25 years to the right.

Apparently the authors created an extra 25 data points so they could keep on smoothing until the last measured sample. The issue is that the authors deliberately chose not the last available average but zero (which was significantly above the last average), the overall effect being that the graph goes sharply upward in the last 25 years. According to the hacked correspondence, this was not the honest error of bad scientists, but deception with malicious afterthought by dishonest pseudo-scientists.

I doubt that public media will be able to whitewash this (like the quote Guardian article), so hopefully GW-alarmism is over, and we can hopefully discuss effects of possible "Global Lukewarming" without us monkeys going completely apeshit.

[philmoore]

I read a number of the comments, and found most of them not particularly interesting, so I must have missed what you found. Care to post the particular links that you found relevant? It is not unusual to weigh later data points more highly if the accuracy is considerably higher than the earlier data points, but of course, this can be problematic if one is attempting to demonstrate a systematic change over time. If the earlier data is not that reliable, any such change would be reliably demonstrated.

[__HRB__]

Originally Posted by philmoore

I read a number of the comments, and found most of them not particularly interesting, so I must have missed what you found. Care to post the particular links that you found relevant? It is not unusual to weigh later data points more highly if the accuracy is considerably higher than the earlier data points, but of course, this can be problematic if one is attempting to demonstrate a systematic change over time. If the earlier data is not that reliable, any such change would be reliably demonstrated.

Maybe there was no link. My browser (Konqueror) has a couple extra highlighting/search features, so that I eventually stumbled upon:

http://www.climateaudit.org/?p=7810

UPDATE: The files are now also on:
http://wikileaks.org/wiki/Climatic_R...els,_1996-2009

If stuff like the following turns out to be real...

From: Phil Jones
To: "Michael E. Mann"
Subject: IPCC & FOI
Date: Thu May 29 11:04:11 2008
Mike,
Can you delete any emails you may have had with Keith re AR4?
Keith will do likewise. He's not in at the moment - minor family crisis.
Can you also email Gene and get him to do the same? I don't
have his new email address.
We will be getting Caspar to do likewise.
I see that CA claim they discovered the 1945 problem in the Nature paper!!
Cheers
Phil
Prof. Phil Jones
Climatic Research Unit Telephone +44 (0) **** 592090

>> > At 04:30 PM 1/20/2005, Tom Wigley wrote:
>> >
>> > Mike,
>> >
>> >
>> >
>> > This is truly awful. GRL has gone downhill rapidly in recent years.
>> > I
>> >
>> > think the decline began before Saiers. I have had some unhelpful
>> >
>> > dealings with him recently with regard to a paper Sarah and I have
>> >
>> > on glaciers — it was well received by the referees, and so is in
>> > the
>> >
>> > publication pipeline. However, I got the impression that Saiers was
>> >
>> > trying to keep it from being published.
>> >
>> >
>> > Proving bad behavior here is very difficult. If you think that
>> > Saiers
>> >
>> > is in the greenhouse skeptics camp, then, if we can find
>> > documentary
>> >
>> > evidence of this, we could go through official AGU channels to get
>> >
>> > him ousted. Even this would be difficult.
>> >
>> >
>> > How different is the GRL paper from the Nature paper? Did the
>> >
>> > authors counter any of the criticisms? My experience with Douglass
>> >
>> > is that the identical (bar format changes) paper to one previously
>> >
>> > rejected was submitted to GRL.
>> >
>> >
>> > Tom.
>> >
>> > ===============

Lagniappe (careful, this IS a hoax):

From: George Soros
To: Al Gore ,fat@xxxxx.xxx, t.boone.pickens@xxxx.xxx
Subject: Socialist plan to take over the World
Date: Mon., 16 Nov 2009 13:31:15 +0000
Cc: w.buffett@xxx.xx.xx

Dear Al and T.,

After all this time and money spent, we can finally say that our view is aired consistently by the MSM. We now own The Washington Post editorial board (except for Will, who still insists on publishing the truth about AGW), and at the New York Times we just added Friedman to our payroll; but Rich and Kristof have been doing fairly well for us there. In short, climatofascism can now enter its next stage. With the help of the liberal noise machine at MSNBC and the blogs, we can now delude the rest of the American public into taking "action." Romm, Revkin, Dave Roberts, Zimmer are all fighting hard to keep the message fresh. We're a little concerned with Oolius at the moment. He might be going rogue in which case we'll have to terminate his contract. Otherwise we're in good shape. Once this catches on, we'll be making trillions of dollars in so-called "alternative" energy. I know you are, T-Bone, but Al, are you fully invested in this yet? I know you've been busy with your book cover, but it's really time *now* to leverage the equity in your mansion. [...]

[ewmayer]

Originally Posted by philmoore

I read a number of the comments, and found most of them not particularly interesting, so I must have missed what you found. Care to post the particular links that you found relevant? It is not unusual to weigh later data points more highly if the accuracy is considerably higher than the earlier data points, but of course, this can be problematic if one is attempting to demonstrate a systematic change over time. If the earlier data is not that reliable, any such change would be reliably demonstrated.

I don`t see so much the alleged "mushroom cloud" (i.e. a vast pro-AGW conspiracy theory) - though I reserve the right to change my opinion as more facts emerge - as evidence of a systemic and coordinated attempt to manipulate away "inconvenient data" not fitting the preferred hypothesis. For instance:

From: Phil Jones
To: ray bradley ,mann@virginia.edu, mhughes@ltrr.arizona.edu
Subject: Diagram for WMO Statement
Date: Tue, 16 Nov 1999 13:31:15 +0000
Cc: k.briffa@uea.ac.uk,t.osborn@uea.ac.uk

Dear Ray, Mike and Malcolm,
Once Tim's got a diagram here we'll send that either later today or first thing tomorrow. I've just completed Mike's Nature trick of adding in the real temps to each series for the last 20 years (ie from 1981 onwards) amd from 1961 for Keith's to hide the decline. Mike's series got the annual land and marine values while the other two got April-Sept for NH land N of 20N. The latter two are real for 1999, while the estimate for 1999 for NH combined is +0.44C wrt 61-90. The Global estimate for 1999 with data through Oct is +0.35C cf. 0.57 for 1998. Thanks for the comments, Ray.

Cheers
Phil

Prof. Phil Jones
Climatic Research Unit Telephone +44 (0) 1603 592090
School of Environmental Sciences Fax +44 (0) 1603 507784
University of East Anglia
Norwich Email p.jones@uea.ac.uk
NR4 7TJ
UK

My Comment: The NYT article I referenced above has AGW proponent Michael Mann attempting to explain this benignly this way: "scientists often used the word 'trick' to refer to a good way to solve a problem, 'and not something secret'" ... but in the above e-mail (assuming it is authentic), the word 'trick' is closely followed by 'hide the decline', which makes it seem that this particular 'trick' was used to solve the 'problem' of data not fitting the hypothesis. Even if the rumors of a vast conspiracy prove to be overblown, it is indicative of scientific misconduct and pervasive bias. Another example ... we know that the "reputable scientists" in the AGW camp misused tree ring data to to make their case for the "Mann hockey stick" warming curve (see my separate post below on that), and this e-mail supports that there was active data manipulation going on in that regard:

From: Gary Funkhouser
To: k.briffa@uea.ac.uk
Subject: kyrgyzstan and siberian data
Date: Thu, 19 Sep 1996 15:37:09 -0700

Keith,

Thanks for your consideration. Once I get a draft of the central and southern siberian data and talk to Stepan and Eugene I'll send it to you.

I really wish I could be more positive about the Kyrgyzstan material, but I swear I pulled every trick out of my sleeve trying to milk something out of that. It was pretty funny though - I told Malcolm what you said about my possibly being too Graybill-like in evaluating the response functions - he laughed and said that's what he thought at first also. The data's tempting but there's too much variation even within stands. I don't think it'd be productive to try and juggle the chronology statistics any more than I already have - they just are what they are (that does sound Graybillian). I think I'll have to look for an option where I can let this little story go as it is.

Not having seen the sites I can only speculate, but I'd be optimistic if someone could get back there and spend more time collecting samples, particularly at the upper elevations.

Yeah, I doubt I'll be over your way anytime soon. Too bad, I'd like to get together with you and Ed for a beer or two. Probably someday though.

Cheers, Gary
Gary Funkhouser
Lab. of Tree-Ring Research
The University of Arizona
Tucson, Arizona 85721 USA
phone: (520) 621-2946
fax: (520) 621-8229
e-mail: gary@ltrr.arizona.edu

[ewmayer]

Here is an article detailing the alleged "tree ring conspiracy" - besides the (alleged) data manipulation, the note about incestuous staffing on certain key IPCC panels is interesting. The article (of which I only reprint the first portion) features the same Keith Briffa to whom the 2nd e-mail reproduced in my post above is addressed:

Beginning in 2003, I worked with Stephen McIntyre to replicate a famous result in paleoclimatology known as the Hockey Stick graph. Developed by a U.S. climatologist named Michael Mann, it was a statistical compilation of tree ring data supposedly proving that air temperatures had been stable for 900 years, then soared off the charts in the 20th century. Prior to the publication of the Hockey Stick, scientists had held that the medieval-era was warmer than the present, making the scale of 20th century global warming seem relatively unimportant. The dramatic revision to this view occasioned by the Hockey Stick’s publication made it the poster child of the global warming movement. It was featured prominently in a 2001 report of the U.N. Intergovernmental Panel on Climate Change (IPCC), as well as government websites and countless review reports.

Steve and I showed that the mathematics behind the Mann Hockey Stick were badly flawed, such that its shape was determined by suspect bristlecone tree ring data. Controversies quickly piled up: Two expert panels involving the U.S. National Academy of Sciences were asked to investigate, the U.S. Congress held a hearing, and the media followed the story around the world.

The expert reports upheld all of our criticisms of the Mann Hockey Stick, both of the mathematics and of its reliance on flawed bristlecone pine data. One of the panels, however, argued that while the Mann Hockey Stick itself was flawed, a series of other studies published since 1998 had similar shapes, thus providing support for the view that the late 20th century is unusually warm. The IPCC also made this argument in its 2007 report. But the second expert panel, led by statistician Edward Wegman, pointed out that the other studies are not independent. They are written by the same small circle of authors, only the names are in different orders, and they reuse the same few data climate proxy series over and over.

Most of the proxy data does not show anything unusual about the 20th century. But two data series have reappeared over and over that do have a hockey stick shape. One was the flawed bristlecone data that the National Academy of Sciences panel said should not be used, so the studies using it can be set aside. The second was a tree ring curve from the Yamal Peninsula in Siberia, compiled by UK scientist Keith Briffa.

Briffa had published a paper in 1995 claiming that the medieval period actually contained the coldest year of the millennium. But this claim depended on just three tree ring records (called cores) from the Polar Urals. Later, a colleague of his named F. H. Schweingruber produced a much larger sample from the Polar Urals, but it told a very different story: The medieval era was actually quite warm and the late 20th century was unexceptional. Briffa and Schweingruber never published those data, instead they dropped the Polar Urals altogether from their climate reconstruction papers.

In its place they used a new series that Briffa had calculated from tree ring data from the nearby Yamal Peninsula that had a pronounced Hockey Stick shape: relatively flat for 900 years then sharply rising in the 20th century. This Yamal series was a composite of an undisclosed number of individual tree cores. In order to check the steps involved in producing the composite, it would be necessary to have the individual tree ring measurements themselves. But Briffa didn’t release his raw data.

Over the next nine years, at least one paper per year appeared in prominent journals using Briffa’s Yamal composite to support a hockey stick-like result. The IPCC relied on these studies to defend the Hockey Stick view, and since it had appointed Briffa himself to be the IPCC Lead Author for this topic, there was no chance it would question the Yamal data.

Despite the fact that these papers appeared in top journals like Nature and Science, none of the journal reviewers or editors ever required Briffa to release his Yamal data. Steve McIntyre’s repeated requests for them to uphold their own data disclosure rules were ignored.

Then in 2008 Briffa, Schweingruber and some colleagues published a paper using the Yamal series (again) in a journal called the Philosophical Transactions of the Royal Society, which has very strict data-sharing rules. Steve sent in his customary request for the data, and this time an editor stepped up to the plate, ordering the authors to release their data. A short while ago the data appeared on the Internet. Steve could finally begin to unpack the Yamal composite.

It turns out that many of the samples were taken from dead (partially fossilized) trees and they have no particular trend. The sharp uptrend in the late 20th century came from cores of 10 living trees alive as of 1990, and five living trees alive as of 1995. Based on scientific standards, this is too small a sample on which to produce a publication-grade proxy composite. The 18th and 19th century portion of the sample, for instance, contains at least 30 trees per year. But that portion doesn’t show a warming spike. The only segment that does is the late 20th century, where the sample size collapses. Once again a dramatic hockey stick shape turns out to depend on the least reliable portion of a dataset.

But an even more disquieting discovery soon came to light. Steve searched a paleoclimate data archive to see if there were other tree ring cores from at or near the Yamal site that could have been used to increase the sample size. He quickly found a large set of 34 up-to-date core samples, taken from living trees in Yamal by none other than Schweingruber himself! Had these been added to Briffa’s small group the 20th century would simply be flat. It would appear completely unexceptional compared to the rest of the millennium.