Tom Nelson spots a gem in the Climategate 2 emails:
Hockey stick co-author Ray Bradley:
“it may be that Mann et al simply don’t have the long-term trend right”;
“I hedge my bets on whether there were any periods in Medieval times that might have been “warm”, to the irritation of my co-authors!”
…
Sorry this kept you awake…but I have also found it a rather alarming graph. First, a disclaimer/explanation. The graph patches together 3 things: Mann et al NH mean annual temps + 2 sigma standard error for AD1000-1980, + instrumental data for 1981-1998 + IPCC (“do not quote, do not cite” projections for GLOBAL temperature for the next 100 years, relative to 1998. The range of shading represents several models of projected emissions scenarios as input to GCMs, but the GCM mean global temperature output (as I understand it) was then reproduced by Sarah Raper’s energy balance model, and it is those values that are plotted. Keith pointed this out to me; I need to go back & read the IPCC TAR to understand why they did that, but it makes no difference to the first order result….neither does it matter that the projection is global rather than NH….the important point is that the range of estimates far exceeds the range estimated by Mann et al in their reconstruction. Keith also said that the Hadley Center GCM runs are being archived at CRU, so it ought to be possible to get that data and simply compute the NH variability for the projected period & add that to the figure, but it will not add much real information. However, getting such data would allow us to extract (say) a summer regional series for the Arctic and to then plot it versus the Holocene melt record from Agassiz ice cap….or….well, you can see other possiblities.
[……At this point Keith Alverson throws up his hands in despair at the ignorance of non-model amateurs…]
But there are real questions to be asked of the paleo reconstruction. First, I should point out that we calibrated versus 1902-1980, then “verified” the approach using an independent data set for 1854-1901. The results were good, giving me confidence that if we had a comparable proxy data set for post-1980 (we don’t!) our proxy-based reconstruction would capture that period well. Unfortunately, the proxy network we used has not been updated, and furthermore there are many/some/ tree ring sites where there has been a “decoupling” between the long-term relationship between climate and tree growth, so that things fall apart in recent decades….this makes it very difficult to demonstrate what I just claimed. We can only call on evidence from many other proxies for “unprecedented” states in recent years (e.g. glaciers, isotopes in tropical ice etc..). But there are (at least) two other problems — Keith Briffa points out that the very strong trend in the 20th century calibration period accounts for much of the success of our calibration and makes it unlikely that we would be able be able to reconstruct such an extraordinary period as the 1990s with much success (I may be mis-quoting him somewhat, but that is the general thrust of his criticism). Indeed, in the verification period, the biggest “miss” was an apparently very warm year in the late 19th century that we did not get right at all. This makes criticisms of the “antis” difficult to respond to (they have not yet risen to this level of sophistication, but they are “on the scent”). Furthermore, it may be that Mann et al simply don’t have the long-term trend right, due to underestimation of low frequency info. in the (very few) proxies that we used. We tried to demonstrate that this was not a problem of the tree ring data we used by re-running the reconstruction with & without tree rings, and indeed the two efforts were very similar — but we could only do this back to about 1700. Whether we have the 1000 year trend right is far less certain (& one reason why I hedge my bets on whether there were any periods in Medieval times that might have been “warm”, to the irritation of my co-authors!). So, possibly if you crank up the trend over 1000 years, you find that the envelope of uncertainty is comparable with at least some of the future scenarios, which of course begs the question as to what the likely forcing was 1000 years ago. (My money is firmly on an increase in solar irradiance, based on the 10-Be data..). Another issue is whether we have estimated the totality of uncertainty in the long-term data set used — maybe the envelope is really much larger, due to inherent characteristics of the proxy data themselves….again this would cause the past and future envelopes to overlap.
…Ray [Bradley]
At 01:34 PM 7/10/00 +0200, you wrote: Salut mes amis,
I’ve lost sleep fussing about the figure coupling Mann et al. (or any alternative climate-history time series) to the IPCC scenarios. It seems to me to encapsulate the whole past-future philosophical dilemma that bugs me on and off (Ray – don’t stop reading just yet!), to provide potentially the most powerful peg to hang much of PAGES future on, at least in the eyes of funding agents, and, by the same token, to offer more hostages to fortune for the politically motivated and malicious. It also links closely to the concept of being inside or outside ‘the envelope’ – which begs all kinds of notions of definition. Given what I see as its its prime importance, I therefore feel the need to understand the whole thing better. I don’t know how to help move things forward and my ideas, if they have any effect at all, will probably do the reverse. At least I might get more sleep having unloaded them, so here goes……[Frank Oldenfield]
==============================================================
But wait, there’s more
Hockey stick co-author claims that after 1850, critical trees lost their alleged ability to record temperature
If you examine my Fig 1 closely you will see that the Campito record and Keith’s reconstruction from wood density are extraordinarily similar until 1850. After that they differ not only in the lack of long-term trend in Keith’s record, but in every other respect – the decadal-scale correlation breaks down. I tried to imply in my e-mail, but will now say it directly, that although a direct carbon dioxide effect is still the best candidate to explain this effect, it is far from proven. In any case, the relevant point is that there is no meaningful correlation with local temperature. Not all high-elevation tree-ring records from the West that might reflect temperature show this upward trend. It is only clear in the driest parts (western) of the region (the Great Basin), above about 3150 meters elevation, in trees old enough (>~800 years) to have lost most of their bark – ‘stripbark’ trees. As luck would have it, these are precisely the trees that give the chance to build temperature records for most of the Holocene. I am confident that, before AD1850, they do contain a record of decadal-scale growth season temperature variability. I am equally confident that, after that date, they are recording something else. [Malcolm Hughes]
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RockyRoad says:
December 25, 2011 at 8:11 am
@ur momisugly Steve Garcia RE “a physicist”. Yeah, I’ve noticed that too. Anthony should place a list of trolls on the right sidebar for reference before anybody attempts to respond to such nefarious mis-direction.
============================================
Yeh, but, if you let them talk/write long enough, they will talk/write themselves into a circle of fail. There’s some good entertainment value in that.
The acid rain farce is nearly identical to the ozone farce. Scientists observed a phenomenon they didn’t understand. Blamed it on man’s activity, passed laws, and then something changed. They claimed victory and still don’t understand what happened.
This stems from a prevailing ideological precept and conviction mixed with an undeniable truism. The truism is that mankind has continually advanced. The precept and conviction is: Any activity on man’s part to improve his life, works to the detriment of nature. Hence, any change in nature is perceived as a malady caused by mankind’s continued advancement.
It is a horrible form of misanthropy.
Paul Homewood says:
December 25, 2011 at 3:02 am
I hedge my bets on whether there were any periods in Medieval times that might have been “warm”, to the irritation of my co-authors!).
“Now why should Mann have been irritated? Surely an objective scientist should search for knowlege as an end in itself, and not want it to lead to a predetermined outcome.”
Mann “outed” himself in his December 5 editorial in the WSJ. In that editorial he claimed that he should receive the high level of respect that other scientists received for achievements such as finding “the” link between smoking and cancer or “the” link between lead in gasoline and brain damage in children. Hiding behind analogies, he asks to be judged by the standards of medical science rather than those of pure science.
Medical science serves medicine and the goal of medicine is relief of suffering not satisfaction of curiosity. In fact, medical science struggles to catch medical practice. Those irrepressible people known as surgeons are quite happy to carve your body to relief your suffering and they do so on the basis of their trained intuition. The science comes later.
Mann’s request should be roundly rejected. To become a science, climate science must pursue understanding of Earth’s climate systems. To substitute the goal of relieving suffering that can be “associated with” climate, though not yet as a matter of pure science, is to adopt the medical model for evaluation of peer reviewed articles. Such an approach can only delay the pure science that can provide us with genuine understanding of our climate systems.
Steven Wilde,
While I’m glad you agree that tree rings are not capable of being a proxy for temperature, a lot of your other arguments just don’t add up.
SW
Tress grow best and fastest where the local combination of temperature and precipitation suit them best>>>>
CO2 levels alter that equation considerably. An change in CO2 levels alters the optimum combination considerably. Where the tree is growing within itz preferred temperature range, hours of sunshine are a major factor. Further, fastest isn’t the only governing issue. As I attempted to explain above, how much snow arrives in the winter can dramaticaly alter how early spring arrives, and hence the LENGTH of the growing season which will also affect tree ring thickness.
SW
So if one shifts the climate zones poleward or equatorwatd different trees will benefit or suffer depending on their individual locations relative to the climate zones.>>>
As I’ve suggested above, you’ve focused on precipitation and temperature as the critical variables. In fact, the list of critical variables is much larger and the ones that I’ve pointed out not only affect tree ring growth, they may affect the limits otherwise imposed by precipitation and temperature.
SW
It must be self evident that temperature and rainfall on average overall are by far the most dominant factors influencing tree or plant success>>>
But it isn’t. Consider the single example of the vast North American prairie region which is well within the temperature and precipitation ranges to support forest growth, yet no forests grew there for thousands of years. Yet today, we see that the tree line is in fact encroaching agressively upon the prairies. Why? Answer: No more prairie grass fires. Before farms and highways and such, grass fires could roar through hundreds of miles in a day or two, and they happened regularly. Grass grows back in days or weeks, but the tree seedlings, even if they were several years old, were toast. Similarly, conditions conducive to pine tree growth may also be conducive to pine beetles. The range that the trees thrive in is broader than that of the pine beetle, but UNLESS the conditions outside of the pine beetle’s range occur from time to time, the pine beetle will wipe out a pine forest over a period of years. In other words, if the climate does NOT stray to the very edges of the pine forest’s limits from time to time, the pine forest will be wiped out despite existing in conditions of optimum precitpitation and temperature.
SW
To show that null hypothesis to be false one would have to propose permanently fixed climate zones >>>
I believe I have falsified your null hypothesis.
Steve Garcia says:
December 25, 2011 at 7:37 am
JUST TO GIVE A HEADS UP TO EVERYONE: “A PHYSICIST” IS A TROLL.
I recommend to all to ignore him. His being here is an attempt to hijack the thread.>>>
Engaging him and debunking him is of tremendous value for those who are just beginning their own personal quest for information on climate change. If we ignore the voices of dissent, then we are just preaching to the choir. By debunking the trolls, we both demonstrate to the casual reader that we embrace debate rather than hide from it, and we have arguments that are well thought out and factual that speak to the exact same issues on smear blogs like RC where the same comments are made, but no skeptic gets to answer them.
A fake physicist;
2003 is hardly recent by current standards, and onnly a single paper out of many, but to heck with papers, lets talk real life.
In the early 80’s I got thrown out of a university lecture by a guest speaker talking about acid rain. He had a large map of southern Ontario displayed showing all the lakes that had turned acidic and their proximity to nearby industrial activity. I had the temerity to ask this question:
“If the source of the acid rain is the areas of industrial activity, why are the acidified lakes mostly north and south of the industrial areas instead of east, which would be downwind of the prevailing winds?”
In the ensuing argument, the speaker dismissed me out of hand and a couple of professors asked me to shut up and leave. Which I did.
Years later the truth came out, and I was vindicated. The establishment of of industrial centres was altering the migratory paths of geese. The geese were flying around the major centres rather than over them, and as a result, were landing on different lakes for rest stops than they would otherwise. Lakes immediately north and south of the industrial centres were no longer getting the same levels of geese.
What does that have to do with it? Glad you asked. Goose poo is highly alkaline. Pine tree resin is highly acidic. Every year rain washes acidic debris from the pine trees into the lakes. Every year the geese were making a pit stop in spring and fall and neutralizing the acid with their poo. No more geese landing on the lake, acid level sky rockets.
Now that I think about it, I actually got thrown out of that lecture on question 2, which was “did you back up your theory by actually measuring the ph of rainfall in the area to see of it was in fact acidic?” That’s when the lecturer grew angry, demanded to know if I was there to learn something or just be disruptive, and I was asked to leave.
davidmhoffer says:
December 25, 2011 at 9:19 am
“As I’ve suggested above, you’ve focused on precipitation and temperature as the critical variables. In fact, the list of critical variables is much larger and the ones that I’ve pointed out not only affect tree ring growth, they may affect the limits otherwise imposed by precipitation and temperature.”
Spot on, David. You have that “instinct for the empirical” that is critical for all scientists.
Sunshine is a very important variable. For trees, the relative amount of sunshine received is subject to several local variables. The most prominent is type of forest. A young tree in an old deciduous forest faces a very different struggle for sunshine than it would face in a forest dominated by Fir trees.
I really like your example of prairie fires. In the USA, and most of the world, nearly all of the land has been subject to intense human management for some time. Much of the land east of the Mississippi River has been under the plow for more than a century and the forests that rest on that land today suffer from soil that has been depleted of several minerals. The land was first cleared by “slash and burn” practices. I do not see how there can be sweeping generalizations about tree growth.
A science of tree growth is possible. But one must select environments and do empirical research on tree growth in each. The same environment might occur at many locations across the USA or the world but the scientist must justify the claim that the several locations are in fact “instances” of the same environment.
What climate science has done is take records of tree growth that extend centuries into the past and treated them as comparable to one another. In other words, they have taken all old records at face value. There is no scientific justification for such practice. Such a practice amounts to a non-empirical, “a priori,” assumption about tree growth.
Just to be clear here: when a Real Peer-Reviewed Climate Scientist® says, “Temperatures may warm as much as 7°C over the next century, leading to widespread flooding, and the deaths of millions in low lying areas.” it means that those people are as good as dead right now. But when a Real Peer-Reviewed Climate Scientist® says, “it may be that Mann et al simply don’t have the long-term trend right” it clearly means that the long term trend is definitely correct and that the Real Peer-Reviewed Climate Scientist® did not have a sufficient lack of evidence to see that Mann et al were not only spot on, but actually eternally acknowledged in all of science by Consensus, Peer-Review, and the Holy Gaia (PBUH).
RockyRoad says:
December 25, 2011 at 8:11 am
“@ur momisugly Steve Garcia RE “a physicist”. Yeah, I’ve noticed that too. Anthony should place a list of trolls on the right sidebar for reference before anybody attempts to respond to such nefarious mis-direction.”
I am a very liberal thinker, classical liberal along the lines of John Stuart Mill. I think there should be an annotated list of trolls. Along with the annotations would go a ranking. Anyone who cited Wendell Berry for anything, including Berry’s poetic imagination, should receive the highest troll ranking of Munchkin. Responding to Munchkins would be forbidden. Doubly so for those who call themselves “A Physicist.” One cannot be a physicist and cite Wendell Berry. /sarc
I think this article on http://strata-sphere.com/blog/index.php/archives/17772 entitled “The Third Nail In The CRU/IPCC AGW Coffin” regarding “Hide the Decline” ought to get more exposure.
data4alps.pro dated Aug 2008
printf,1,’IMPORTANT NOTE:’
printf,1,’The data after 1960 should not be used. The tree-ring density‘
printf,1,’records tend to show a decline after 1960 relative to the summer‘
printf,1,’temperature in many high-latitude locations. In this data set‘
printf,1,’this “decline” has been artificially removed in an ad-hoc way, and‘
printf,1,’this means that data after 1960 no longer represent tree-ring
printf,1,’density variations, but have been modified to look more like the
printf,1,’observed temperatures.’
Which of the following is true concerning Mann and the hockey stick?
There was a missjudgment in using the data.
There was a deliberate manipulation of data to fit a desired outcome.
Fraud was committed in presenting manipulated and known problamatic data.
The first one seems to be a given. The second finds support in the politics of the IPCC and in the acquesence of the players to allow the graph to stand.
The question of fraud stands and needs to be answered. A lot of funding was generated based on that graph.
davidmhoffer
I note the points you make and do not disagree as regards the examples of exceptions to the general rule that you cite.
However, on average and globally, temperature and water supply are the primary factors.
“As I’ve suggested above, you’ve focused on precipitation and temperature as the critical variables. In fact, the list of critical variables is much larger and the ones that I’ve pointed out not only affect tree ring growth, they may affect the limits otherwise imposed by precipitation and temperature.”
I don’t disagree but every such additional variable will be modified as regards its effect on growth by the availability of water and warmth.
You have to look at the species population in its entirety and not just local variants.
A Physicist-
That you cited this links shows you understand nothing about the acid rain issue. The Adirondack lakes had been historically acid with very little productivity as a result. (diatom cores show this to be the case) Adirondack in the native language means bark eater– an example of how little terrestrial food was grown in either the terrestrial or the aquatic environment on these poor soils over the granitic shield bedrock. Some of the early cultivation raised the pH- which really jumped after the Great Adirondack Fire’s alkaline ash caused productivity to explode and fish populations to markedly expand. Fire suppression and the governments decision to re-plant conifers have caused a slow and steady decline in pH as a result of organic acids from forest regrowth.
The chemistries were always BS- the acidity in the rain was never anywhere near as powerful as the organic acids created by the forests and bogs. Here’s your chance to wow me with your science Physicist- show me how water percolating through peat bogs (pH approx 3.5) and pine forest soil (pH 4.5-5.0) flowing over granitic bedrock can produce anything other than highly acid water. Even acid tolerant Brook trout can’t survive at this pH- yet the public was told that the lakes no longer teemed with 5 lb brook trout because of acid rain is an absolute lie. (Give me some lime or fire and you’ll have big brookies again- but no air quality controls can ever bring this about.)
And there is no non-partisan environmental group left representing hunters or fishermen- I used to be an officer of one of them so am more than up to speed on this subject.
Some of the best scientists the environmental field ever produced had their careers shattered by acid rain ideology- and the restoration of the Atlantic Salmon (a subject very near and dear to me) is still held hostage to this BS. You remind me of the vile people who orchestrated this tragedy- so in the interest of maintaining the spirit of the holiday season- I will refrain from further engagement with you.
Stephen Wilde;
I don’t disagree but every such additional variable will be modified as regards its effect on growth by the availability of water and warmth.>>>
No. Increased CO2 for example CHANGES the range AND mix of temperature and precipitation that maximizes growth. So, an increase or decrease in CO2 would have a dramatic effect on tree growth across the entire population without ANY change in temperature and precipitation. To complicate matters further, any given tree will have a different response to the exact same change in CO2 depending on it being at the top, bottom, or middle of the range of maximum growth before the CO2 changed.
Similarly, as zones move north or south, their “average” temperature and precipitation may remain constant while “order” in which they arrive changes. A cool wet spring followed by a hot dry summer has a completely different growth pattern than the reverse, though their averages may well be the same on an annual basis.
To those who think the truth of this sort of thing will get out – how many people have you met who are aware of this? How often have you seen these sorts of issues reported in the general media? In my experience, the answers to those questions are “none” and “never”. The complicity between the media and the politicians will keep all of this sort of thing covered up. After all, exposing the data falsifications and lies of the warmistas is doubleplusungood.
Stephen Wilde says:
December 25, 2011 at 12:23 pm
“I don’t disagree but every such additional variable will be modified as regards its effect on growth by the availability of water and warmth.”
Yes, but you have to assign a portion of that growth to each factor. To insist that water and warmth are so important that the rest can be ignored is “a priori” reasoning. You have no empirical evidence to present to support your case.
“You have to look at the species population in its entirety and not just local variants.”
You seem to be unable to take your eye off the trees themselves and put your eye on the measurement techniques that are being used. You must first have measurements that are done in accordance with scientific method and, necessarily, those measurements must be done with regard to the local environment. You cannot just run around the world assuming all environments for tree variety “X” are the same. Once the you the matter of measurement is settled then you can start thinking about species populations. Reverse the order and you have species measurements that are based on no empirical validation of measurement techniques whatsoever. You might as well be asking Grandma Betsy how much the trees grew that year.
Dudley Robertson says:
December 25, 2011 at 11:56 am
“The question of fraud stands and needs to be answered. A lot of funding was generated based on that graph.”
Excellent point. The question of fraud must be investigated. Horner and Cuccinelli have been trying to do that for months but the University of Virginia stands squarely and stupidly in their way. The University of Virginia will never live this down.
Tad says:
December 25, 2011 at 1:06 pm
“To those who think the truth of this sort of thing will get out – ”
Good points…but…google Al Gore Enron…or “Google AGW Bias”…Google spellchecks your search, and redirects it to AGE bias but click on AGW Bias… kinda cool huh!
Try a few other combo’s it’s kinda fun…however I am sure Obama, Biden and Joe Romm don’t think its funny. Nor does Google board member Al Gore.
Merry Christmas
Andrew
Following the low sulfur coal law, I spent a lucrative time programming and installing in electrical generating plants new sulfer burning equipment to introduce charged particles enabling the electrostatic ash precipitators to work again!
Excess cold will kill growth stone dead as will inadequate water.
All else is chaff.
I agree that many other variables are in play but one cannot overcome lack of warmth or lack of water so taking a species as a whole on average globally the most important parameters are water and warmth.
Now if one needs to go further to diagnose the growth factors for each individual tree or group of treees then you are both correct.
But we do not need to do that for the purpose of simply discrediting trees as adequate thermometers.
Tree rings grow less despite increasing warmth if accompanied by a reduced supply of water so tree rings can never be an adequate indicator for temperature because as the climate zones drift poleward temperatures may rise but growth will decline due to reduced rainfall.
There is no logical need to complicate the issue further than that. There is plenty of empirical evidence that drought reduces tree growth as does cold and drought is also associated with higher temperatures so tree ring width becomes an unreliable indicator for warmth.
Keep it simple.
The way my fellow science teachers and I found to break the ‘mass synching bias’ of students, to believe before they perceive, was a simple ad hominem logic questions in their class work:
We all observe when trees lose their leaves (every) fall, it snows shortly thereafter;
However, down in the tropics, where the trees don’t lose their leaves, it never snows;
This correlation between leaves and snow is perfect, and so is lead-lag ‘causation’.
Therefore, we can say *falling leaves ’causes’ it to snow*. Then if we chop down all
trees, we can reduce global warming. Please write a counter-argument to the above.
The ‘hidden message’ of course, is that *global deforestation is the real cause*, and it’s always great to see the ‘aha’ moment when students ‘get it’, except the real indoctrinated ones, although it’s prolly not worth getting terminated for challenging the ‘Alternate Given Wisdom’ in textbooks.
What did Mao say? Give me your children, and I will give you an International Carbon Caliphate!
Crosspatch wrote: It would be rather difficult to find trees where temperature was the dominant constraint on growth.
Such trees are the Polar Urals and Yamal ones (studied by Briffa, Schweingruber, Hantemirov, and Shiyatov) – mainly Siberian larches.
They grow at river banks, therefore water is not a problem. They are shielded from polar winds by the fact, that they grow in the shallow river valleys under the level of the Yamal peninsula tundra. The rivers also warm a bit the valleys as to enable these trees to grow as trees and not as shrubs.
Therefore summer temperature should be their main variable, and it is only few weeks between July and August, when they are able to grow.
Interestingly, Hantemirov and Shiyatov write about these trees in Russian as “summer temp proxies”, evading carefully all mentions about their “global context”.
EW says:
December 25, 2011 at 4:50 pm
…………
Therefore summer temperature should be their main variable, and it is only few weeks between July and August, when they are able to grow.
Interestingly, Hantemirov and Shiyatov write about these trees in Russian as “summer temp proxies”, evading carefully all mentions about their “global context”.
===============================================================
Thanks EW, but let us take it to the proper position.
In my view, it is fantastic that anyone who thinks about this for a moment or two doesn’t understand this simple concept. What is the low temp? What is the low temp for the seasons outside the growing season? The only way any period of time correlates with temperatures is through a manipulation of my first love. (Numbers) And, that manipulation is more deplorable and obscene than any drug dealer/pimp could ever imagine. This sick perversion of science and numbers these bastards do is tantamount to numerical buggery.
THERE IS ABSOLUTELY NO WAY ONE CAN GAIN HISTORICAL TEMPERATURES AT ANY POINT IN TIME THROUGHOUT HISTORY, BY LOOKING AT SOME OR MANY SILLY TREE RINGS!!!
We’ve gone beyond lending that vapid thought any credence. The only thing left if to decide if indictments should be handed out only in this nation, (the U.S.) or should INTERPOL be involved. They should have never engaged. It won’t just be me, there will be many, many more, but, I’ll be the “Simon Wiesenthal” of climatphrenology. Those stupid bastards knew this was crap!! Their harm is uncalculable.
@davidmhoffer December 25, 2011 at 9:42 am:
Good story, David.
In 2000, I attended a conference at which an engineer was presenting his ideas on the Great Pyramid. His ideas stood the entire subject on its ear, and it was the first time I’d had a chance to hear it all. I asked quite a few direct questions like you did about acid rain. The speaker answered all of them and seemed to be thriving on them. At one point someone in the audience said they didn’t think it was right that I ask so many pointed questions, but the speaker disagreed with the audience member, saying mine were exactly the kind of questions he wanted someone to ask. His answers were as direct as my questions were.
As the conference wore on, the speaker and I became fast friends. It isn’t everyone who is afraid of direct questions. If they aren’t ready for them, and especially if they become hostile, it basically shows they are insecure about what they are talking about, IMHO. I think that gives extra reason to doubt the truth of what they are presenting. No one who knows their subject could get hot and bothered about direct questions; that should be their opportunity to really show they know their stuff.