"Mann Hockey Stick" demolished, IPCC in disarray

[Rob Lister]

Anyone with access to BBC Radio 4 should maybe switch on. The World Tonight just announced that they would be discussing "global warming sceptics" after the main news. That means some time between now and 10.45 pm GMT (about 35 minutes from now).

Rolfe.

On a related note I've heard (read) a rumor that Nature plans a retraction of the Mann paper for the March issue. No, no links. Just a rumor. If it were not for the very serious debate regarding the M&M paper, I'd discount such a rumor. As it stands, I give it a 50/50 chance of happening.

 

[a_unique_person]

Furthermore, and more to the point, nothing in M&M's paper has been debunked. I'm not knowledgable enough in the field to know what's real and what's not but I know a series of ad homs when I read them.

From a totally novice POV, it appears that Mann's paper detailing the hockey stick has been debunked and that debunking is not only 'sticking' but causing some serious discussion/whispering/backpeddling/ad homming by the GW 'believers. I'm not really sure what that means in terms of the whole Kyoto thing but I suspect it doesn't mean much given that the whole Kyoto thing was dead/useless well before the debunking of the Mann article.

So, A_U_P suggests that Mann is only one piece of the puzzle and that the GW theory is strong without it. What other peices of the puzzle are there that do not rely on or reference the same dataset/process that Mann used?

Edit to fix quote error.

I asked my scientist friend, (who researchs AGW for the CSIRO), and his reply was that Mann has nothing to do with the current research. It is interesting as an historical record for comparison with the past, but it has never been used as the basis for the science. It is something what was done in response to the research, to try to recreate an historical record of temperature.

That is, the modelling is based on known records as a base, and computed from that base. The work of Mann would constitute about 1% of the AGW work. You can look at the IPCC website. Mann is referenced there, but the actual modelling work is not dependent on it at all. The actual rapid rise in temperature is not dependent on it, the increase in CO2 in the atmosphere is not dependent on it.

 

[EvilYeti]

But, the site you linked to is Mann's site. So it's Mann debunking M&M's debunking of Mann. Not exactly an unbiased source. [/B]

Neither is McKintrick, he works for ExxonMobill. So it comes down to two potenially biased sources, one a well respected climate scientist and the other statistician whom works for the petroleum industry. I know who my money's on!

Here's an article from USA today with some quotes from other scientists defending Mann.

http://www.usatoday.com/weather/climate/2003-11-18-warming-debate_x.htm

Some tidbits

Climate researcher Tom Wigley of the National Center for Atmospheric Research. in Boulder, Colo., calls the critics' complaints "seriously flawed" and "silly."

In addition to the Nature paper, about a dozen independent studies suggest the 20th century was warmer than normal, Wigley points out.

From a statistical viewpoint, "I lean in favor of Mann," says statistician George Shambaugh. of Georgetown University. "There is an increase in the 20th century that is greater than the cyclical patterns found by either group since 1550. And since the early 1900s, we have been hotter than any time since then."

Princeton geoscientist Michael Oppenheimer. compares climate skeptics to tobacco industry scientists who sought for decades to obscure the link between smoking and lung cancer. Arguing over whether man-made global warming exists obscures a more important debate over what steps are possible to moderate its effects, he says.

 

[EvilYeti]

Furthermore, and more to the point, nothing in M&M's paper has been debunked. I'm not knowledgable enough in the field to know what's real and what's not but I know a series of ad homs when I read them.

Oh, so M&M is right because I said McKitrick is a tool?

I also think John Edwards is a douchebag, so you must think he can talk to dead people now as well, eh?

From a totally novice POV, it appears that Mann's paper detailing the hockey stick has been debunked and that debunking is not only 'sticking' but causing some serious discussion/whispering/backpeddling/ad homming by the GW 'believers. I'm not really sure what that means in terms of the whole Kyoto thing but I suspect it doesn't mean much given that the whole Kyoto thing was dead/useless well before the debunking of the Mann article.

And like many with novice opinions on complex subjects, you are completely wrong.

The science journal "Nature", where MH98 was originally published, have already REJECTED M&M's research for publication, based on negative appraisals by reviewers and the editor.

Are you suggesting, that you, an admitted novice, are better qualified to assess the veracity of M&M's work than the editor and reviewers of one of the most respected science journals in the world? I'm skeptical.

So, A_U_P suggests that Mann is only one piece of the puzzle and that the GW theory is strong without it. What other peices of the puzzle are there that do not rely on or reference the same dataset/process that Mann used?

There are many independent temperature reconstructions that show the warming of the last century to be anomolous. The ExxonMobil funded disinformation campaign chooses to focus on MH98 as its one of the more common ones to reference, as well as being mentioned by the IPCC. It has nothing to do with datasets/process or science for that matter.

 

[Rob Lister]

There are many independent temperature reconstructions that show the warming of the last century to be anomolous. The ExxonMobil funded disinformation campaign chooses to focus on MH98 as its one of the more common ones to reference, as well as being mentioned by the IPCC. It has nothing to do with datasets/process or science for that matter.

Please point to a couple of those reconstructions that show the warming of the last century to be anomolous.

Regarding your other comments which, given the method you used to respond did not carry over in the quote, I can only wonder why it is you feel you need to attack. I fully admit that I don't know who is right. My point is that if M&M are not correct then why are their points being responded to with ad homs instead of explainations. That makes me think there really is something to what they are saying. I also read the referee responses to their original submission to nature (provided by them) as well as natures stated reasons for not publishing the data. So unless they are lying (which for all I know they may well be) then it doesn't seem reasonable that their submission was rejected.

Is McKitrick is a tool? I don't know, nor do care because I don't see what possible difference it makes one way or the other.

 

[DaChew]

Climate researcher Tom Wigley of the National Center for Atmospheric Research. in Boulder, Colo

Has advanced degrees in math and physics. His only formal training regarding the climate was a 15 month meteorology course he took in 1961.


From a statistical viewpoint, "I lean in favor of Mann," says statistician George Shambaugh. of Georgetown University.

Has degrees in political science and physics and advanced degrees in political science and government affairs. He teaches the uses of statistics in politics but is not a statistician.


Princeton geoscientist Michael Oppenheimer.

One of the originators of the Kyoto Protocol. Has a degree in chemistry and advanced degrees in physics and astrophysics. One of the lead authors for IPCC and has received a lot of money from the UN over the years. McKitrick isn't the only one being paid for his opinion on climate.

[/B]

 

[Anders]

No, I won’t say it, no, no no…..I can’t…please.....Argumentum ad hominem……there it is….sorry! Referring to the above post that is.

 

[DaChew]

No, I won’t say it, no, no no…..I can’t…please.....Argumentum ad hominem……there it is….sorry! Referring to the above post that is.

You're referring, of course, to where EvilYeti says this:

Neither is McKintrick, he works for ExxonMobill.

and this

Yes, McKitrick is such a complete, utter, tool

You couldn't be referring to anything I posted because, as I'm sure you realize, all I did was list the formal training credentials of each of three people as taken from their own websites. I made no argument therefore no ad hominem. If it is somehow significant that McKintrick works for ExxonMobil, how is it not significant who these other folks work for?

 

[Anders]

You're referring, of course, to where EvilYeti says this:



and this



You couldn't be referring to anything I posted because, as I'm sure you realize, all I did was list the formal training credentials of each of three people as taken from their own websites. I made no argument therefore no ad hominem. If it is somehow significant that McKintrick works for ExxonMobil, how is it not significant who these other folks work for?

Goes for anyone on either side that uses Ad Hominem. It really doesn't matter where the money comes from or at which university he or she works at. If it’s good science, than everything is ok, if it’s bad science, then we can attack the bad science, not the person behind it.

 

[DavidJames]

If it’s good science, than everything is ok, if it’s bad science, then we can attack the bad science, not the person behind it.

From a pure logical perspective I agree 100%. Reality, however, prevents me from being able to intelligently dissect the science behind all the various claims out there. So I need to make some compromises. So I hope you will excuse me if I look a bit more skeptical at the ID science as espoused by creation scientists or the tobacco is not harmful claims from the tobacco industry scientists or the global warming is nonsense claims from the oil industry scientists.

Maybe that makes me a less "pure" skeptic, so be it.

It really doesn't matter where the money comes from or at which university he or she works at.

I'm not sure what I can say about that except is sure would be nice to see how many studies paid for by the aforementioned organizations produced results unflattering towards their sponsors.

 

[EvilYeti]

Please point to a couple of those reconstructions that show the warming of the last century to be anomolous.


Here is a listing of all the research that went into the famous "Hockey Stick". I've included Mann for the sake of completeness.

Bauer, E., M., Claussen, and V. Brovkin, Assessing climate forcings of the earth system for the past millennium, Geophys. Res. Lett., 30 (6), doi: 10.1029/2002GL016639, 2003.

Bertrand C., M.F. Loutre, M. Crucifix, and A. Berger, Climate of the Last millennium: a sensitivity study, Tellus, 54(A), 221-244, 2002.

Briffa, K.R., and T J. Osborn, Blowing Hot and Cold, Science, 295 2227-2228, 2002.

Briffa, K.R., T.J. Osborn, F.H. Schweingruber, I.C. Harris, P.D. Jones, S.G. Shiyatov and E.A. Vaganov, Low-frequency temperature variations from a northern tree-ring density network. J. Geophys. Res., 106, 2929 2941, 2001.

Cook, E.R., J. Esper, and R.D. D'Arrigo, Extra-tropical Northern Hemisphere land temperature variability over the past 1000 years, Quat. Sci. Rev., 23, 2063-2074, 2004.

Crowley, T.J., Causes of Climate Change over the Past 1000 Years, Science, 289, 270-277, 2000.

Crowley, T.J., and T. Lowery, How Warm Was the Medieval Warm Period?, Ambio, 29, 51-54, 2000.

Esper, J., E.R. Cook and F.H. Schweingruber, Low-frequency signals in long tree-line chronologies for reconstructing past temperature
variability, Science, 295, 2250-2253, 2002.

Gerber, S., F. Joos, P. Brügger, T. F. Stocker, M. E. Mann, S. Sitch, and M. Scholze, Constraining temperature variations over the last millennium by comparing simulated and observed atmospheric CO2, Climate Dynamics, 20, 281-299, 2003.

Gonzalez-Rouco, F., H. von Storch, and E. Zorita, Deep soil temperature as proxy for surface air-temperature in a coupled model simulation of the last thousand years, Geophys. Res. Lett., 30, 2116, doi:10.1029/2003GL018264, 2003.

Huang, S., H. N.Pollack and P.-Y. Shen, Temperature Trends Over the Past Five Centuries Reconstructed from Borehole Temperature, Nature 403, 756-758, 2000.

Jones, P.D., K.R. Briffa, T.P. Barnett and S.F.B. Tett, High-resolution palaeoclimatic records for the last millennium: Integration, interpretation and comparison with General Circulation Model control run temperatures, Holocene, 8, 455-471, 1998.

Jones, P.D., M. New, D.E. Parker, S. Martin, and I.G. Rigor, Surface air temperature and its changes over the past 150 years, Reviews of Geophysics, 37, 173-199, 1999.

Jones, P.D., T.J. Osborn, and K.R. Briffa, The Evolution of Climate Over the Last Millennium, Science, 292, 662-667, 2001.

Mann, M.E., R.S. Bradley, and M.K. Hughes, Northern Hemisphere Temperatures During the Past Millennium: Inferences, Uncertainties, and Limitations, Geophysical Research Letters, 26, 759-762,
1999.

Mann, M.E., Jones, P.D., Global surface temperature over the past two millennia, Geophysical Research Letters, 30 (15), 1820, doi: 10.1029/2003GL017814, 2003.

Mann, M.E., Rutherford, S., Bradley, R.S., Hughes, M.K., Keimig, F.T., Optimal Surface Temperature Reconstructions Using Terrestrial Borehole Data, Journal of Geophysical Research, 108 (D7), doi: 10.1029/2002JD002532, 2003.

Regarding your other comments which, given the method you used to respond did not carry over in the quote, I can only wonder why it is you feel you need to attack.

This is the science sub-fora of a message board devoted to critical thinking. You can expect junk science (and those that endorse it) to be attacked.

I fully admit that I don't know who is right. My point is that if M&M are not correct then why are their points being responded to with ad homs instead of explainations. That makes me think there really is something to what they are saying.

I think John Edward is a douchebag, do you think he can talk to dead people now too?

I also read the referee responses to their original submission to nature (provided by them) as well as natures stated reasons for not publishing the data. So unless they are lying (which for all I know they may well be) then it doesn't seem reasonable that their submission was rejected.

Well, I trust the opinion of the editors of Nature over a couple industry wonks with no science education.

Is McKitrick is a tool? I don't know, nor do care because I don't see what possible difference it makes one way or the other.

He makes bombastic claims that he has invalidated legitimate research and uses error-ridden analyses. When legitmate journals refuse to publish his results and explain why, instead of checking his work he submits to journals with weaker review policies. He also refuses to withdraw papers with absolutely glaring mistakes, like confusing degrees with radians. So he is, IN MY OPINION, a completey, total and utter tool.

 

[Drooper]

When legitmate journals refuse to publish his results and explain why, instead of checking his work he submits to journals with weaker review policies.

He may or may not be a tool as you claim. But the long and short of it is that this tool appears to have revealed that an extensively peer reviewed work, that held a central place in the IPCC TAR (the scientific basis) is nothing more than an artefact of poor statistics and scientific method.

Surely that is the issue here.

 

[JamesM]

extensively peer reviewed work, that held a central place in the IPCC TAR (the scientific basis) is nothing more than an artefact of poor statistics and scientific method.

Yes, this is the question. The way I see it, there are three questions, in fact:

1. Is it ok to use non-centered Principal Component Analysis?
2. What stopping criteria should be used when extracting the components?
3. How often does random data produce a hockey-stick shape with PCA?

I use PCA a fair bit, but not the non-centered version. I am also not familiar with the model selection criteria used by either Mann or McIntyre & McKitrick. Nonetheless, it appears that they used different methods, and extracted different numbers of components. This could have a major effect on the results.

 

[DaChew]

From a pure logical perspective I agree 100%. Reality, however, prevents me from being able to intelligently dissect the science behind all the various claims out there. So I need to make some compromises. So I hope you will excuse me if I look a bit more skeptical at the ID science as espoused by creation scientists or the tobacco is not harmful claims from the tobacco industry scientists or the global warming is nonsense claims from the oil industry scientists.

Maybe that makes me a less "pure" skeptic, so be it.

I'm not sure what I can say about that except is sure would be nice to see how many studies paid for by the aforementioned organizations produced results unflattering towards their sponsors.

I agree. I'd also like to see how many studies paid for by politicians with vested or ideological interest in slowing down the growth of western economies produced results unsupportive of those agendas.

 

[anonimouse]

From a pure logical perspective I agree 100%. Reality, however, prevents me from being able to intelligently dissect the science behind all the various claims out there. So I need to make some compromises. So I hope you will excuse me if I look a bit more skeptical at the ID science as espoused by creation scientists or the tobacco is not harmful claims from the tobacco industry scientists or the global warming is nonsense claims from the oil industry scientists.

Maybe that makes me a less "pure" skeptic, so be it.

I'm not sure what I can say about that except is sure would be nice to see how many studies paid for by the aforementioned organizations produced results unflattering towards their sponsors.

But you can take that to extremes, though - I mean, should we skeptical at the science with regards to vaccination because the pharmaceutical companies support it? Should we skeptical with regards to the safety research wrt cars because automobile companies support it? There's only so far you can go with the "vested interests taint the science" argument before it becomes silly, IMO.

 

[Drooper]

Yes, this is the question. The way I see it, there are three questions, in fact:

1. Is it ok to use non-centered Principal Component Analysis?
2. What stopping criteria should be used when extracting the components?
3. How often does random data produce a hockey-stick shape with PCA?

I use PCA a fair bit, but not the non-centered version. I am also not familiar with the model selection criteria used by either Mann or McIntyre & McKitrick. Nonetheless, it appears that they used different methods, and extracted different numbers of components. This could have a major effect on the results.

from what I have read the following appear very likely:

3. extremely often.
1. yes, with proper consideration for the leverage of the components (in this case massive loeverage is apparently attributable to a spurious pine cone series that even Mann doesn't claim represent a temperature proxy). Also, there seem to be issues with the way it was applied (shifting around the normalisation periods).

 

[Diamond]

I'm on vacation, but thought I'd drop in to say hello!

Why am I not surprised that EvilYeti repeats Michael Mann's lies and distortions?

When I return:

1. The real extent of the fossil fuel industry's funding of McIntyre and McKitrick.
2. The results of my correspondance with climatologists, if any...
3. Geophysical Research Letters' "weak peer review" of MM05.

 

[Diamond]

Sir John Houghton is obviously a devout Christian, but if you're trying to suggest that he is a creationist then I think you're very far from the mark:

http://www.aaas.org/spp/dser/beyond/perspectives/warming.shtml

soph·is·try

1. Plausible but fallacious argumentation.
2. A plausible but misleading or fallacious argument.

An incredibly desperate attempt to ignore that which is clear. Sir John Houghton referred to the second of the Genesis creation myths (the "Garden of Eden" myth) in order to claim that "we were once gardeners". Nowhere did Sir John root his argument in scientific theory (the theory of evolution) but instead sought refuge in the Genesis creation myth. According to evolutionary theory and the fossil record, we were not originally gardeners - "hunter-gatherers", yes, gardeners, nope.

For that reason, "creationism" is not too strong a term for it. Would you like to ask Sir John whether Adam and Eve actually existed and we are all their descendents?

Sir John may find creationism "an incredible pain in the neck" but does not exactly enhance his scientific credibility with direct references to the Genesis myth and from Brian's quote"..physicist Houghton, who has written articles on the value of prayer" does not exactly qualify for scientific article of the month (but may qualify for the $1 million JREF prize).

 

[Diamond]

Yes, this is the question. The way I see it, there are three questions, in fact:

1. Is it ok to use non-centered Principal Component Analysis?
2. What stopping criteria should be used when extracting the components?
3. How often does random data produce a hockey-stick shape with PCA?

I use PCA a fair bit, but not the non-centered version. I am also not familiar with the model selection criteria used by either Mann or McIntyre & McKitrick. Nonetheless, it appears that they used different methods, and extracted different numbers of components. This could have a major effect on the results.

Those are good and fair questions. You could try sending a comment to Steve McIntyre on his weblog http://www.climateaudit.org and see what he says...