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Hockey Stick Slapped Climate change's Bellesiles?
NRO ^ | 3 Nov 03 | — Iain Murray

Posted on 11/03/2003 6:58:59 AM PST by .cnI redruM

One of the pillars on which the alarmist case for doing something about global warming rests is the contention that the 20th century was the warmest in the last thousand years. This proposition is most dramatically expressed in the "hockey stick" graph contained in the Intergovernmental Panel on Climate Change's third assessment report. The graph shows temperatures mostly flat for the last 1,000 years, before a sudden, sharp rise in the 20th century that, on a graph, looks like the blade of a hockey stick. The graph is very persuasive — it caused Sen. John McCain (R., Ariz.) to express alarm when he first saw it in May 2000, and played a part in McCain's bringing to the Senate floor the misguided and economically destructive Climate Stewardship Act, which was defeated last week.

One of the problems with the graph is that its smooth progression through the first 900 years is at variance with established scholarship in the field. We know that the 1600s-1800s saw both a Medieval Warm Period — when the Vikings colonized Greenland — and a Little Ice Age — when the River Thames froze over regularly in London. The graph does not show much variance for either of these occurrences. It was constructed by calibrating many different proxies for temperature, such as tree-ring widths or measurements from ice deposits at the poles. It should also be noted that the blade of the hockey stick consists of actual temperature readings from thermometers, not the proxies, which themselves do not show nearly as great a spike. But the graph's defenders argue that the well-documented temperature swings of history were localized, and only the 20th-century warming is a global phenomenon.

The debate over the graph exploded into new life in late October when two Canadian experts in statistical analysis — Stephen McIntyre and Ross McKitrick (known as "M&M" in discussions of the climate debate) — published what they called an "audit" of the data underlying the hockey-stick graph. Their audit was based on information provided by an associate of Michael Mann, whose articles inspired the hockey-stick graph in the first place. M&M investigated the data underlying the graph with the original source data.

They found numerous and worrying errors. As they put it, the data "for the estimation of temperatures from 1400 to 1980 contains collation errors, unjustifiable truncation or extrapolation of source data, obsolete data, geographical location errors, incorrect calculation of principal components and other quality control defects." They used the original source data to correct these errors, after which they concluded that "the particular 'hockey stick' shape . . . is primarily an artefact of poor data handling, obsolete data, and incorrect calculation of principal components."

If true, this conclusion is devastating to the "hockey stick" argument, and we must conclude that 20th century was not unusual at all. The warming trend could simply be natural phenomenon; support for the greenhouse theory dissipates; and we therefore have little need to enact restrictions on carbon-dioxide emissions (restrictions that, in practice, amount to restrictions on energy use and, therefore, restrictions wealth).

Michael Mann's reaction has so far been dismissive. He attacked the M&M paper as a "political stunt," seemingly before reading it. His retort was transmitted through the website of a sympathetic freelance journalist, and has muddied the debate considerably.

Mann claims that M&M used the wrong data set, and that they only used 112 proxies when 159 were needed. But M&M point out on their web site that Mann's original research paper contained only 112 proxies, and that these were the proxies Mann instructed his associate to provide to them.

Mann also asserts that many other paleoclimatologists have been able to replicate his results closely. But this response does not address the question whether those experts uncovered the same errors in the data that M&M, coming to the issue fresh, were able to find.

The whole affair bears strong resemblance to the recent Bellesiles controversy. Emory University historian Michael Bellesiles won a Bancroft Prize for his argument that gun ownership in early America was not widespread. It took an amateur historian, Clayton Cramer, to point out that this claim could not be substantiated on the basis of actual gun-ownership records. Eventually, an Emory University investigation strongly criticized Bellesiles, and the Bancroft Prize was withdrawn.

So far, it looks like the errors in Mann's data set were accidental. Yet it will be interesting to see how far the proponents of strong action on climate change go to defend the data without addressing the fundamental question: Are the numbers as proposed by M&M right? If they are, then the climate debate will need to change.


TOPICS: Crime/Corruption; Culture/Society; Extended News
KEYWORDS: climatechange; falsestats; globalwarming; gunhomocides; lying
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I've posted a similar argument before, but it's fun to see it taken up by professional media. Gun Control and Climate Change are both political issues where scientific analysis has been corrupted on behalf of special pleading. It's becoming so bad that you pretty much just tell the university or think tank what they are supposed to 'discover' and they then cook the data to produce your desired result. Noone buys science anymore, they just issue the grants to purchase results.
1 posted on 11/03/2003 6:58:59 AM PST by .cnI redruM
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To: .cnI redruM
A related thread was posted here.

This graph was available which shows the fraud in progress:


2 posted on 11/03/2003 7:03:00 AM PST by Damocles (sword of...)
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To: .cnI redruM
So far, it looks like the errors in Mann's data set were accidental.

I need this guy to do my taxes.

3 posted on 11/03/2003 7:04:09 AM PST by Always Right
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To: .cnI redruM
There is no global warming. It's facist land grab and business control propaganda.
4 posted on 11/03/2003 7:04:29 AM PST by concerned about politics ( As a rightous man declarith a thing, so shall it be.)
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To: .cnI redruM
Thanks for my new tag line. SCARY!
5 posted on 11/03/2003 7:05:18 AM PST by Xthe17th (No one buys science anymore. They just issue the grants to purchase results.)
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To: Damocles
That should go up on The Smoking Gun.com.

Mann is clearly singing for his supper and letting the man who pays the trubador call the tune.
6 posted on 11/03/2003 7:06:08 AM PST by .cnI redruM (I ain't sayin' nothin', but that ain't right! - Stewart Scott, ESPN.)
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To: concerned about politics
Correctamente
7 posted on 11/03/2003 7:07:04 AM PST by Eric in the Ozarks
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To: .cnI redruM
I belive there is something to the concept of man raising the temperature of the atmoshpere. On a hot day, stand under some trees, stand on some grass, stand on a black-top road, and stand on a concrete parking lot.

The concrete reflects and amazing amount of heat back up while the trees absorb a lot of heat. As we replace trees with concrete we increase the heat reflected back upward and this warms the atmosphere. No?

8 posted on 11/03/2003 7:07:17 AM PST by Tacis
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To: Tacis
No. Try flying over the United States some time. Look down. How much of that "blacktop" do you see? You can't see any. It is infinitessimal as a % of world-wide surface area. If you honestly think this teeny, virtually unnoticable amount of blacktop is more powerful than, say, sun activity or volcanic activity, then I have property in Florida I want to sell you.
9 posted on 11/03/2003 7:12:08 AM PST by LS
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To: Tacis
No. Try flying over the United States some time. Look down. How much of that "blacktop" do you see? You can't see any. It is infinitessimal as a % of world-wide surface area. If you honestly think this teeny, virtually unnoticable amount of blacktop is more powerful than, say, sun activity or volcanic activity, then I have property in Florida I want to sell you.
10 posted on 11/03/2003 7:13:06 AM PST by LS
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To: Xthe17th
Political Science.
11 posted on 11/03/2003 7:13:39 AM PST by Smokin' Joe
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To: .cnI redruM
They used the original source data to correct these errors, after which they concluded that "the particular 'hockey stick' shape . . . is primarily an artefact of poor data handling, obsolete data, and incorrect calculation of principal components."

Perhaps Messrs. M&M are being charitable here. It's possible that Michael Mann was deliberately lying.

12 posted on 11/03/2003 7:14:00 AM PST by r9etb
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To: r9etb
Charity is a virtue, but there comes a time to call a lying sack of s--- by its proper name.
13 posted on 11/03/2003 7:17:26 AM PST by .cnI redruM (Mouthing support for the workingman is one of the best ways to avoid actually being one.)
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To: r9etb
Charity is a virtue, but there comes a time to call a lying sack of s--- by its proper name.
14 posted on 11/03/2003 7:17:27 AM PST by .cnI redruM (Mouthing support for the workingman is one of the best ways to avoid actually being one.)
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To: Tacis
The concrete reflects and amazing amount of heat back up while the trees absorb a lot of heat. As we replace trees with concrete we increase the heat reflected back upward and this warms the atmosphere. No?

Well, sorta. The so-called "heat island" effect -- the absorption and retention of heat in the concrete and asphalt of cities -- is quite real. But it's local, not global.

15 posted on 11/03/2003 7:17:53 AM PST by r9etb
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To: Tacis
I belive there is something to the concept of man raising the temperature of the atmoshpere. On a hot day, stand under some trees, stand on some grass, stand on a black-top road, and stand on a concrete parking lot.

That's a joke, right? If you put your hand in a campfire, you'll find out that's really hot, too!
Ban campfires!

16 posted on 11/03/2003 7:18:54 AM PST by concerned about politics ( As a rightous man declarith a thing, so shall it be.)
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To: concerned about politics; LS
Suggestion to you guys: engage your brains before engaging your mouths.

As a local phenomenon, the heat island effect of cities is real and well-documented.

It's unlikely that it has any global impact, but your silly political replies were unjustified and technically uninformed.

17 posted on 11/03/2003 7:21:23 AM PST by r9etb
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To: Damocles
And you know what's not quite up front about that chart? It only goes back 500 years. That's like sending a freshman to the sea to measure the tides and after 2 hours he comes screaming back saying that the world's going to be under water in a day.

I'm not sure how you get temperatures from 500 years ago, but one needs to go back 5000 years before looking for trends in the weather.
18 posted on 11/03/2003 7:23:05 AM PST by lelio
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To: lelio
I'm not sure how you get temperatures from 500 years ago, but one needs to go back 5000 years before looking for trends in the weather.

One doesn't go back 500 years for temperatures, which is the root of the problem here. Instead, one uses proxies, such as tree rings, ice cores, and the like. These M&M fellows are saying that Mann's data are not properly correlated to actual temperatures.

Moreover, the dataset itself is not consistent, as it combines actual temperatures since ~1850, with the improperly correlated proxies. A more reasonable plot would show the proxies over the entire time-frame.

19 posted on 11/03/2003 7:27:21 AM PST by r9etb
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To: .cnI redruM
It was constructed by calibrating many different proxies for temperature, such as tree-ring widths or measurements from ice deposits at the poles. It should also be noted that the blade of the hockey stick consists of actual temperature readings from thermometers, not the proxies

In other words, the graph is a lie.

20 posted on 11/03/2003 7:29:27 AM PST by Sloth ("I feel like I'm taking crazy pills!" -- Jacobim Mugatu, 'Zoolander')
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