Global Warming Debate: Refuting Common Arguments

[Bored Wombat]

I think you mean prestigious, not respected, and for its peer review process of submitted papers, and not because of its news articles like the one linked here:

Nature News is still respected on the strength of the scientific basis of the organisation.

And given that most people aren't going to read the national academies report, its a good source of the scientific opinion on it.

Other news sources said the same of course:
http://news.bbc.co.uk/2/hi/5109188.stm" .

And the scientific blogosphere had the same analysis. The point is that the national academies report supported the hockey stick graph, and a scientist that read it could tell you that, even the reporters for Nature.

How ever one characterizes the Mann et al 1200 year temperature reconstruction, there is the observable point that it appeared http://www.grida.no/climate/ipcc_tar/wg1/005.htm" to the paleo section and merged in with several other reconstructions that show the medieval period as warm.

The finding of Mann et al, that the little ice age and the medieval warm period where not at the same time over the northern hemisphere is interesting, valid, and still holds now. This is why whole hemisphere reconstructions show it much more weakly than the 1990 IPPC graph from one site in central England. (still used in the denialist literature such as "swindle".)

The national academies said that it was over used, considering at the time it had not yet been reproduced.

Your argument that it "vanished from the summary", therefore it must be considered wrong doesn't follow. The IPCC reports are about the science that has been learned since the last report. The hockey stick was well reported in the 2001 IPCC report. There is no reason to put it in such a prominent place in the 2007 IPCC report.

It is true that it doesn't appear in the summary for policy makers. You are exaggerating your case when you call this the summary. It does appear in the technical summary.

Could you cite one please (obviously one in the last 30 years to be associate w/ AWG)?

I know that from conversations with ecologists, I don't know where or if they have been published. The rainy season in outback east australia has changed time of year. The ecological communities that blossom in the vastly different temperatures are different. (And not the interesting and unique ones). Freshwater communities devastated by the same effect. The rivers are out of water at the wrong time of year.

The damage to the subantarctic is from interviews with those studying it. I'll look one up if you like, but I'll submit this first, as I might not get a chance.

Source?

Common knowledge.

But the first google hit I got was this:
"Dr Claudia Sadoff of The World Bank, said in her
opening address: “The countries in the Himalayan subregion
account for 40% of the world’s population. The
rivers in the region are extreme in terms of population
density, sedimentation and variability. Each river is in
effect many rivers in one; each is an ecosystem in itself. Hence, issues related to
the Himalayan rivers are complicated. These are difficult rivers to understand,
manage and talk about. They are shared rivers, which increases complications.
There has been a lot of talk recently about how these rivers are under threat.
Glaciers are disappearing, rivers are running dry; rivers are overdrawn and
polluted. These rivers are extremely variable in terms of floods and droughts.
They are even more threatened due to climate change. The World Bank has
identified climate change hot-spots. One is over the Himalayas." - http://www.strategicforesight.com/Kathmandu Report.pdf

Will it do? I'm sure I could find something by the IPCC or a NGO about the consequences of climate change in the region if you want.

Science can show consequences, I don't know that estimating costs is also science, certainly not by climate scientists.

I wasn't really meaning financial costs.
But economics is a science of sorts. And an important one for deciding on climate change policy.

 

[mheslep]

Your argument that it "vanished from the summary", therefore it must be considered wrong doesn't follow.

I did not say that.

It is true that it doesn't appear in the summary for policy makers. You are exaggerating your case when you call this the summary. It does appear in the technical summary.

Summary, as in Summary for Policy Makers.

I know that from conversations with ecologists, ...

That's fine, but not appropriate for this forum.
https://www.physicsforums.com/showthread.php?t=280637

 

[Bored Wombat]

I did not say that.

I doubt that I misinterpreted you. If you think that the paraphrase has lost your meaning, could you point out how?

Summary, as in Summary for Policy Makers.

I can see that that's why you must mean, because of the way that it appeared in the Technical Summary. But you should still be specific when claiming something "vanished" from somewhere, and using that to imply that it has lost favour.

That's fine, but not appropriate for this forum.

It's pretty common knowledge, and not at all controversial that ecosystems are being impacted by climate change, and neither that for ecosystems with smaller geographic ranges, (being the unique in especially interesting ones) that impact is more often extinction or increased risk of extinction.

Since its not controversial, its not inappropriate.

 

[heldervelez]

Google for 'Joanne nova' her handbook is very helpfull.
Her 16 pages "The skeptics handbook" can help you.
quoting from her site "Volunteers have translated it into German, French, Norwegian, Finnish, Swedish, Turkish, Portuguese and Danish. (Versions in Dutch, Spanish, and possibly Italian are on the way). "

The translation to pt-br has been done by university teachears that are brasilian climatologists.
Joanne is not a scientist but, as myself and a lot of us, are tracking the inconvenient facts behind all that noise that pervades the media.
And her site has links to helpful sources.

 

[mheslep]

...I can see that that's why you must mean, because of the way that it appeared in the Technical Summary. But you should still be specific when claiming something "vanished" from somewhere, and using that to imply that it has lost favour...

I referred to the exact title in the first part of the sentence; in the same sentence I referenced it again. Sorry for the confusion.

How ever one characterizes the Mann et al 1200 year temperature reconstruction, there is the observable point that it appeared right up front in the 2001 IPCC Summary for Policy Makers almost as an icon, with no medieval warming period, and then in the 2007 third IPCC report after the investigation it vanished from the Summary, was moved to the paleo section and merged in with several other reconstructions that show the medieval period as warm.

And yes I'd say it is fair to say that some of the key ideas reflected in the MBH 98 hockey stick, namely that there was little or no medieval warming period, has indeed lost favour; that this is reflected by its removal from the Summary for Policy Makers and its subsequent embedding in the graph in the Paleo section with several other competing studies that show a substantial medieval warming, comparable with today's warming.

 

[mheslep]

On this other point, I'm referring to this specific claim:

Iam aware of desert ecological communities, and sub antarctic communities that don't exist any more because of climate change

Could you cite one please (obviously one in the last 30 years to be associate w/ AWG)?

I know that from conversations with ecologists, I don't know where or if they have been published.

That's fine, but not appropriate for this forum.
https://www.physicsforums.com/showthread.php?t=280637

It's pretty common knowledge, and not at all controversial that ecosystems are being impacted by climate change, and neither that for ecosystems with smaller geographic ranges, (being the unique in especially interesting ones) that impact is more often extinction or increased risk of extinction...

Perhaps I misunderstood. By 'ecological communities' that 'dont exist anymore' do you mean a species extinction? I took that to mean human communities. This another good reason for cites - in addition to the data, they avoid ambiguity.

 

[Xnn]

The Medieval warm period was only warm in comparison to the 17th century cold.

See Box 6.4 on page 468 to 469 in the following link.

http://www.ipcc.ch/pdf/assessment-report/ar4/wg1/ar4-wg1-chapter6.pdf

The evidence currently available indicates that NH mean temperatures during medieval times (950–1100) were indeed warm in a 2-kyr context and even warmer in relation to the less sparse but still limited evidence of widespread average cool conditions in the 17th century (Osborn and Briff a, 2006). However, the evidence is not sufficient to support a conclusion that hemispheric mean temperatures were as warm, or the extent of warm regions as expansive, as those in the 20th century as a whole, during any period in medieval times (Jones et al., 2001; Bradley et al., 2003a,b; Osborn and Briff a, 2006).

So, the 20th century (1900 to 1999) was warmer than the MWP.

Also, notice the following conclusions:

Centennial-resolution palaeoclimatic records provide
evidence for regional and transient pre-industrial warm
periods over the last 10 kyr, but it is unlikely that any
of these commonly cited periods were globally synchronous.
Similarly, although individual decadal-resolution
interglacial palaeoclimatic records support the existence
of regional quasi-periodic climate variability, it is unlikely
that any of these regional signals were coherent at the
global scale, or are capable of explaining the majority of
global warming of the last 100 years.

• The TAR pointed to the ‘exceptional warmth of the late
20th century, relative to the past 1,000 years’. Subsequent
evidence has strengthened this conclusion. It is very likely
that average Northern Hemisphere temperatures during
the second half of the 20th century were higher than for
any other 50-year period in the last 500 years. It is also
likely that this 50-year period was the warmest Northern
Hemisphere period in the last 1.3 kyr, and that this
warmth was more widespread than during any other 50-
year period in the last 1.3 kyr. These conclusions are most
robust for summer in extratropical land areas, and for
more recent periods because of poor early data coverage.

 

[mheslep]

The Medieval warm period was only warm in comparison to the 17th century cold.

See Box 6.4 on page 468 to 469 in the following link.

http://www.ipcc.ch/pdf/assessment-report/ar4/wg1/ar4-wg1-chapter6.pdf

[my bold] Yes I've been all through it. I think you misread? Your first sentence directly contradicts the box:

The evidence currently available indicates that NH mean temperatures during medieval times (950–1100) were indeed warm in a 2-kyr context and even warmer in relation to the less sparse but still limited evidence of widespread average cool conditions in the 17th century (Osborn and Briff a, 2006).

One can not draw that conclusion from MBH 98, hence its disfavour.

 

[Xnn]

good point mheslep; "only warm" is overstating.

However, the MWP was not as warm as the 19th century, which some people would tend to consider as a baseline.

 

[Bored Wombat]

Google for 'Joanne nova' her handbook is very helpfull.

It looks like a reproduction of some debunked counterscientific fossil fuel pressure group propaganda.

In what was is it "very helpful"?

Off the top of my head, a brief response to her "only four points that matter" are:

1) The greenhouse signature is missing.

No it's not. The greenhouse signature, the cooling of the stratosphere and the exaggerated warming at the poles is unambiguous, measured and real.

The "hot spot" that you are mistaking for a greenhouse signature has nothing to do with the greenhouse effect. It occurs under any warming that causes the air to hold more water vapour, and is caused by the release of the latent heat of vaporisation of that water when it condenses as rising air cools.

2) The strongest evidence was the ice cores, but newer more detailed data turned the theory inside out.

No the strongest evidence is the physics of optics, by which we understand the greenhouse effect, and therefore know that increasing the concentration of greenhouse gasses will make it warmer.

A 600 or 800 year lag in temperature change over 5000 or 6000 years is an 80% co-incidence. The fact that greenhouse feedback drives the switch from a glaciation to interglacial, set of by milankovich cycles, is perfectly in line with all previous theory. The 10 or 12 K temperature change over that time was only ever about 2 or 3 K due to the 50% increase in CO2 that occurs over that time.

The current best estimates for the effect of doubling CO2 is about 3 or 4 K.

3) Temperatures are not rising.

No they're not.

"In a blind test, the AP gave temperature data to four independent statisticians and asked them to look for trends, without telling them what the numbers represented. The experts found no true temperature declines over time." http://news.yahoo.com/s/ap/20091026/ap_on_bi_ge/us_sci_global_cooling"

4) Carbon dioxide is doing almost all the warming it can do.

No. The current best estimates for the effect of doubling CO2 is about 3 or 4 K.

And that's the top four points.

So I'm at a loss as to what help we've got from them, especially on a physics board, where people probably have some basic scientific understanding.

 

[Bored Wombat]

I referred to the exact title in the first part of the sentence; in the same sentence I referenced it again. Sorry for the confusion.

Well, I'm big enough to accept the apology, but I still suspect that you were trying to overstate your case. If you use an abbreviation for a term you should use it when you first use the term. But in this case it would look better for full disclosure if you explicitly mentioned that it did appear in the technical summary. Or at least that the term "summary" wasn't a good description for the summary for policy makers, especially to an audience interested in physics, who would be more familiar with the other summary.

And yes I'd say it is fair to say that some of the key ideas reflected in the MBH 98 hockey stick, namely that there was little or no medieval warming period, has indeed lost favour;

Well other northern hemisphere reconstuctions can have a slight bump around 1000 AD, but certainly not all of them.

The consensus is that it is certainly not as pronounced as might have been suspected from early, one site based studies. And the suspicion is that this would be further ameliorated if the southern hemisphere were included.

But the National Academies review found nothing wrong with Mann et al's treatment of the data at that time. It was the very recent end that they found that the statistical mistreatment resulted in Mann et al. under-reporting the expected error.

In what way do you mean "fallen out of favour"? Probably we can agree that any medieval warm period was likely at least half a degree cooler than temperatures this decade if we are talking about global mean surface temperature?

that this is reflected by its removal from the Summary for Policy Makers and its subsequent embedding in the graph in the Paleo section with several other competing studies that show a substantial medieval warming, comparable with today's warming.

Disagree. It's removal from the report was because it wasn't new, and had been covered in the 2001 report.

It speaks volumes for the respect that it is still held in that it nevertheless occurred twice in a report that is supposed to be about the findings since the previous report.

 

[Bored Wombat]

Perhaps I misunderstood. By 'ecological communities' that 'dont exist anymore' do you mean a species extinction? I took that to mean human communities. This another good reason for cites - in addition to the data, they avoid ambiguity.

Population extinction of many species, sometimes including total extinction.

No, I wasn't talking about human communities. I don't even know what a sub antarctic human community might mean. And we're talking about global warming, not Godzilla.

I will endeavour to cite more, but I have spoken in the last few years to ecologists looking at Australian freshwater communities, Australian desert communities, European amphibians, and Australian wetlands affected by dry land salinity, and only the last one did not speak with grief of the destruction of their studied area.

And the devastation of various sub-Antarctic communities by invasion by temperate species is now, I am told, well represented in the scientific literature. The concern seems to be now that Antarctic communities may soon fall by the same mechanism.

 

[Bored Wombat]

[my bold] Yes I've been all through it. I think you misread? Your first sentence directly contradicts the box:
One can not draw that conclusion from MBH 98, hence its disfavour.

Please cite a source for this claimed "disfavour".

 

[Andre]

One can not draw that conclusion from MBH 98

Please cite a source for this claimed "disfavour".

The http://republicans.energycommerce.house.gov/108/home/07142006_Wegman_Report.pdf

Overall, our committee believes that Mann’s assessments that the decade of the 1990s was the hottest decade of the millennium and that 1998 was the hottest year of the millennium cannot be supported by his analysis.

 

[Andre]

Population extinction of many species, sometimes including total extinction.

No, I wasn't talking about human communities. I don't even know what a sub antarctic human community might mean. And we're talking about global warming, not Godzilla.

I will endeavour to cite more, but I have spoken in the last few years to ecologists looking at Australian freshwater communities, Australian desert communities, European amphibians, and Australian wetlands affected by dry land salinity, and only the last one did not speak with grief of the destruction of their studied area.

And the devastation of various sub-Antarctic communities by invasion by temperate species is now, I am told, well represented in the scientific literature. The concern seems to be now that Antarctic communities may soon fall by the same mechanism.

Where is the peer reviewed source?

 

[Bored Wombat]

The http://republicans.energycommerce.house.gov/108/home/07142006_Wegman_Report.pdf

The Wegman report raised some issues, and was certainly harsher than the more transparent and peer reviewed National Academies report.

It doesn't really stand for scientific opinion though. Do you have a peer reviewed source?

 

[Andre]

The Wegman report raised some issues, but and was certainly harsher than the more transparent and peer reviewed National Academies report.

What is your peer review resource to make that assessment?

 

[Bored Wombat]

Where is the peer reviewed source?

"The future problem these animals face is via displacement by alien species from lower latitudes. Such invasions are now well documented from sub-Antarctic sites." - http://www.frontiersinzoology.com/content/2/1/9" , Peck, Frontiers in Zoology 2005, 2:9 doi:10.1186/1742-9994-2-9

Perhaps for example: "Warming is likely to remove
physiological barriers on lithodid crabs that currently place a
limit on the invasion of shallow waters of the high Antarctic;
a scenario that is especially likely for waters oV the Antarctic
Peninsula" - http://epic.awi.de/Publications/Tha2008c.pdf"
Thatje et al, Polar Biol (2008) 31:1143–1148 DOI 10.1007/s00300-008-0457-5

(http://www.independent.co.uk/enviro...life-threatened-by-crab-invasion-782989.html", as the popular press put it)

http://www.telegraph.co.uk/science/science-news/3325543/Antarctic-seabed-ecosystems-invasion-threat.html" is another popular press write up, this time about a presentation at the AAAS conference in 2008:
"Unique Antarctic seabed ecosystems are under threat from invasions of species taking advantage of global warming, scientists have warned.

Predatory giant crabs, sharks and other fish are poised to make a return to the rapidly warming shallow waters around the South Pole for the first time in tens of millions of years.

Their come-back will disrupt the make-up of ancient communities of unusual animals such as sea spiders, brightly-coloured brittle stars, thin-shelled muscles and giant relatives of the woodlouse called isopods."

But, again, this is hardly controversial. The fact that species range changes is contributing to the 30% biodiversity drop over the past few decades is well marked in ecology.

 

[Bored Wombat]

What is your peer review resource to make that assessment?

It's not controversial that the National Academies Report's peer review process was transparent and the Wegman reports wasn't.

I have provided the news at nature's article that Mann et al. was vindicated. That is also what was reported in the popular press, and it was also the response of scientists. It is you who are making the controversial claims that needs peer reviewed support.

 

[mheslep]

Well, I'm big enough to accept the apology, but I still suspect that you were trying to overstate your case.

Im little interested in what you suspect about me.

If you use an abbreviation for a term you should use it when you first use the term. But in this case it would look better for full disclosure if you explicitly mentioned that it did appear in the technical summary. Or at least that the term "summary" wasn't a good description for the summary for policy makers, especially to an audience interested in physics, who would be more familiar with the other summary. Well other northern hemisphere reconstuctions can have a slight bump around 1000 AD, but certainly not all of them.

[...]

The consensus is that it is certainly not as pronounced as might have been suspected from early, one site based studies. And the suspicion is that this would be further ameliorated if the southern hemisphere were included.

But the National Academies review found nothing wrong with Mann et al's treatment of the data at that time. It was the very recent end that they found that the statistical mistreatment resulted in Mann et al. under-reporting the expected error.

In what way do you mean "fallen out of favour"? Probably we can agree that any medieval warm period was likely at least half a degree cooler than temperatures this decade if we are talking about global mean surface temperature?
Disagree. It's removal from the report was because it wasn't new, and had been covered in the 2001 report.

It speaks volumes for the respect that it is still held in that it nevertheless occurred twice in a report that is supposed to be about the findings since the previous report.

By disfavour I only refer to MBH 98/Mann99, not any broader topic in AGW, or paleo reconstruction. Perhaps I should say instead that it has been updated in 2007 w/ reconstructions considered more accurate? Anyway I see Vanesch has spoken more clearly here on the subject.
https://www.physicsforums.com/showpost.php?p=1926328&postcount=11

 

[mheslep]

The http://republicans.energycommerce.house.gov/108/home/07142006_Wegman_Report.pdf

Thanks Andre, though I think the National Academies report itself, when read in detail also does a good job of pointing out limitations.
Edit: In particular, I mean what the Academy has to say about:

...the 1990s are likely the warmest decade, and 1998 the warmest year, in at least a millennium.

from

• Mann, M.E and Bradley, R.S. (1999), Northern Hemisphere Temperatures During the Past Millennium: Inferences, Uncertainties, and Limitations, in Geophysical Research Letters, Vol. 26, No. 6, p.759

...Even less confidence can be placed in the original conclusions by Mann et al. (1999) that “the 1990s are likely the warmest decade, and 1998 the warmest year, in at least a millennium” because the uncertainties inherent in temperature reconstructions for individual years and decades are larger than those for longer time periods, and because not all of the available proxies record temperature information on such short timescales.

from

• Surface Temperature Reconstructions for the Last 2,000 Years, Report in Brief, The National Academies, June 22, 2006

http://dels.nas.edu/dels/rpt_briefs/Surface_Temps_final.pdf

 

[Andre]

It's not controversial that the National Academies Report's peer review process was transparent and the Wegman reports wasn't.

I have provided the news at nature's article that Mann et al. was vindicated. That is also what was reported in the popular press, and it was also the response of scientists. It is you who are making the controversial claims that needs peer reviewed support.

Really amazing, anyway, apparently the transcripts to the senate hearings of Oliver North seem to have disappeared; however his exact answer in testimony was recorded on numerous places, -when asked if he disputed the methodology conclusions of Wegman's report- he said:

No, we don’t. We don’t disagree with their criticism

 

[Monique]

The http://republicans.energycommerce.house.gov/108/home/07142006_Wegman_Report.pdf

This is a link to policy makers, but not to the real science. We all know political parties are colored, that's why there's an objection to the source.

 

[Andre]

It would be nice if examples can be given in the Wegman report to demonstrate that the sciencific conclusion is not supported by rigid unbiased reproduceable science especially when the NAS committee agreed with that conclusion as I showed in my previous post.

 

[Andre]

Anyway, let's do a quick recap. So here was the hockeystick in the Third Asssesment report of the IPCC of Mann Bradley and Hughes form 1999 (MBH99) which showed a flat temperature from 1000 Bc up intil about 1850 AD with suddenly rising temperatures. McIntyre and McKitrick demonstrated that MBH had used improper statistic methodologies.

So it was asked to the NAS and to http://www.galaxy.gmu.edu/stats/faculty/wegman.html to verify the critisism of McIntyre and McKitrick. Wegman confirmed that. The NAS with Oliver North in the chair had a more subtle approach. They had misgivings about the procedures of MBH but it would not matter because they stated that other research came to similar conclusions.

So in this thread it is now assumed that Wegman wrote something politcal (which seems to be threated here as biased/spin/fraud) while it also is assumed that the NAS endorsed MBH99. They did not. Because in the hearings of the Committee on Energy and Commerce of the House of Representatives, these were some of the statements of members of the NAS:

CHAIRMAN BARTON. I understand that. It looks like my time
is expired, so I want to ask one more question. Dr. North, do you
dispute the conclusions or the methodology of Dr. Wegman's report?
DR. NORTH. No, we don't. We don't disagree with their
criticism. In fact, pretty much the same thing is said in our
report. But again, just because the claims are made, doesn't
mean they are false.
CHAIRMAN BARTON. I understand that you can have the right
conclusion and that it not be--
DR. NORTH. It happens all the time in science.
CHAIRMAN BARTON. Yes, and not be substantiated by what you
purport to be the facts but have we established--we know that
Dr. Wegman has said that Dr. Mann's methodology is incorrect. Do
you agree with that? I mean, it doesn't mean Dr. Mann's
conclusions are wrong, but we can stipulate now that we have--and if
you want to ask your statistician expert from North Carolina that
Dr. Mann's methodology cannot be documented and cannot be verified
by independent review.
DR. NORTH. Do you mind if he speaks?
CHAIRMAN BARTON. Yes, if he would like to come to the
microphone.
MR. BLOOMFIELD. Thank you. Yes, Peter Bloomfield. Our
committee reviewed the methodology used by Dr. Mann and his coworkers
and we felt that some of the choices they made were inappropriate.
We had much the same misgivings about his work that was documented
at much greater length by Dr. Wegman.

Now what to say about the discussion/allegations in this thread? like:

It's not controversial that the National Academies Report's peer review process was transparent and the Wegman reports wasn't.

I have provided the news at nature's article that Mann et al. was vindicated. That is also what was reported in the popular press, and it was also the response of scientists. It is you who are making the controversial claims that needs peer reviewed support.

I leave the conclusions to the readers.

 

[mheslep]

This is a link to policy makers, but not to the real science. We all know political parties are colored, that's why there's an objection to the source.

Edit:
The Wegman report in this link happens to be hosted on a policy maker's website.
Wegman is a scientific report, non-peer reviewed unless one counts the publicly documented statements on Wegman by the authors of the National Academies North report. On the other hand, the Nature News report post https://www.physicsforums.com/showpost.php?p=2419819&postcount=58" up thread on the subject is not peer reviewed material either.

 

[Xnn]

Of course science marches on and these past reports and reconstructions did not have the following available:

http://www.ucar.edu/news/releases/2009/arctic2k.jsp

https://www.physicsforums.com/attachment.php?attachmentid=21606&stc=1&d=1257469597

From the above perspective, it appears that the MWP (950 to 1100) was only minor warming period superimposed on a 1900 year cooling trend that was distinctly interrupted around 1900.

 

[Xnn]

Notice, that now we can say the following authority:

Arctic temperatures in the 1990s reached their warmest level of any decade in at least 2,000 years, new research indicates.

and it has nothing to do with tree rings or Michael Mann.

 

[Bored Wombat]

Im little interested in what you suspect about me.

You miss the point if you think I was discussing our personal relationship.

MBH 99 appeared in what most people here would consider the summary of the IPCC 2007 WG1 report.

By using the term "Summary" to refer to the SPM, you misrepresent the respect in which MBH is held.

By disfavour I only refer to MBH 98/Mann99, not any broader topic in AGW, or paleo reconstruction. Perhaps I should say instead that it has been updated in 2007 w/ reconstructions considered more accurate? Anyway I see Vanesch has spoken more clearly here on the subject.
https://www.physicsforums.com/showpost.php?p=1926328&postcount=11

I certainly agree that there is more data out there now, and that that increased the confidence that we have in these reconstructions. And that the more modern ones have had a many more datasets included in the analysis, and this also increases confidence in the results.

But MBH 1999 is not an outlier amongst reconstructions, and certainly the current view is nearer the MBH view than the pre-MBH view. So I don't think that it has fallen into any "disfavour".

 

[Bored Wombat]

...Even less confidence can be placed in the original conclusions by Mann et al. (1999) that “the 1990s are likely the warmest decade, and 1998 the warmest year, in at least a millennium” because the uncertainties inherent in temperature reconstructions for individual years and decades are larger than those for longer time periods, and because not all of the available proxies record temperature information on such short timescales.

from

* Surface Temperature Reconstructions for the Last 2,000 Years, Report in Brief, The National Academies, June 22, 2006

Less confidence than the confidence that we have that the "Northern Hemisphere was warmer during the last few decades of the 20th century than during any comparable period over the preceding millennium."

That's a fairly complete vindication of MBH, which has the average for the 20th century to be within the error bars on the temperature reconstruction for most of the time prior to about 1600.
http://en.wikipedia.org/wiki/File:Hockey_stick_chart_ipcc_large.jpg"

So, despite the phrase "even less confidence" this is exactly in line with the findings of the MBH 99 paper, for someone who has understood the error analysis in MBH 99.