This is for entertainment only. Given the week we’ve had, I thought it might be interesting to gauge some opinion about dendroclimatology. While we can certainly argue the merits of “who said what” etc. the question on my mind is what do people think of the technique of using tree rings for determining past climatic history?
Readers, please invite others at non skeptical blogs to participate, use the “share this” link. I’ll extend a blanket invitation to anyone to participate, no matter what your view might be.
Since this is a highly polarized issue, I’ll note that the poll code is setup (by WordPress.com) to minimize the possibility of vote stuffing and encourage one vote per person. You’ll know you’ve hit that security feature if certain messages are displayed.
Here’s the poll question:
Of course I should add that no online poll is scientific, it is only an interesting and entertaining exercise in gauging the opinion of people who visit here.
Discover more from Watts Up With That?
Subscribe to get the latest posts sent to your email.
OT. Want talk about something significant? Take a look at this:http://www.guardian.co.uk/technology/2009/sep/30/icann-agreement-us
Alas, the actual poll question, as opposed to the accompanying article, does not reference tree rings. Tree rings I think I could scoff at.
But “tree derived temperature data” generically as stated in the actual poll question? No. The reason is I *do* place value in the various studies that have been done showing where trees grew in the past vs now. That kind of tree temperature data, so far as I know, has not been seriously called into question.
Of course, the studies I’ve seen reported also don’t support the idea that the 20th century is “warmest in the last umpty centuries” either.
I am no statistician, but I am curious as to how Beck’s work would stand up to an audit, …… Would at least show the warmongers a bit of good faith, since the importance of tree proxies has been thoroughly autopsied. Steve, please publish. If peer-review is not done fair and square on your paper, first they will hear the sound of pipes in the highlands, and then, …..
On a similar note, Tom Wigley who? The poor Lamb made way for the wolf, …. that ate the homework. Sorry for the cryptic post,……~~~~~~~~~~~~~~~~~~~ just messin’ ’round, ….. :^]
psi (15:39:50) :
Bravo.
Chris
Norfolk, VA, USA
This from Dr.Keith Biffa’s site at http://www.cru.uea.ac.uk/cru/annrep94/trees
It is fairly general and includes this…..
“By sampling selected trees in carefully chosen locations it is possible to simplify the identification of specific climate information. For example, trees growing at high latitudes or high altitudes are most sensitive to changing temperatures while the growth of trees in semi arid environments responds strongly to changing soil water conditions and so provides information on precipitation. ”
This is interesting and some links to establish the validity that trees at high altitude/latitude are more sensitive to temperature than the other factors would be welcome.
Dendrochronology is great for dates…. Dendroclimatology’s attempt at a temperature record though, is flawed…..
Too many things affect the growth of trees.
…. Then of course there is the government funding of science to justify environmental ideological policies…… The integrity and reputation of Science is at risk of being impugned in the minds of many, if this sad state of affairs continues.
psi (15:39:50) :
Damn fine letter psi. Good job.
Signal to noise ratio. There is no discernable signal of temperature changes in tree rings from year to year, or score to score or century to century, and “discernable” is the correct word. No point in arguing about resolution. The value of signal in the ratio is so tiny that the value of the ratio approaches zero.
[snip]
Jody (19:40:57) :
I vote that someone here or anywhere write a paper that can be published showing how tree rings are not/cannot be indicators of temperature.
Please! Somebody do more than write a post. Publish a Paper about this matter if you are so convinced that trees cannot be used for establishing past temperatures. Otherwise, this is all conjecture. (And please spare all of us the conspiracy theories about peer-reviewed science).
I wrote a paper on this issue. It’s not the definite paper because I have to include some other graphs on raw data compared with solar irradiance, but it gives you the whole panorama about the uselessness of treerings for establishing past temperatures. Please, pay special attention to the last diagram:
http://www.biocab.org/Insolation_Treerings_Growth.html
Oops! Please change “definite” for “definitive”. The phrase corrected is as follows:
It’s not the definitive paper because I have to include…
Sorry… 🙂
What the heck does this chart mean?
http://minnesotansforglobalwarming.com/m4gw/2009/10/03/RisingTemps.jpg
Here is the original source
http://www.pca.state.mn.us/oea/reduce/climatechange.cfm
Was it tree ring data and then instrument or weather station data?
Keith:
“This is interesting and some links to establish the validity that trees at high altitude/latitude are more sensitive to temperature than the other factors would be welcome.”
Someone posted about this on another thread. Trees in a harch cold environment have a very short growing season. Therefore a change in temperature changes the percentage of the growing season by more than trees that have a very long growing season. A larger percentage change in the growing season is more easily recognized in the rings. But unfortunately the whole thing is a waste of time due to the chronology selection methods that I have described here.
http://reallyrealclimate.blogspot.com/2009/10/tree-ring-chronology-selection-problem.html
Keith Minto (21:30:35):
This is interesting and some links to establish the validity that trees at high altitude/latitude are more sensitive to temperature than the other factors would be welcome.
You cannot disconnect photosynthesis from growth, nor from luminosity. We are talking about trees, i.e. photosynthetic organisms.
If insolation goes up beyond the optimal index (0.5 for most cases), the growth would slow. That is the reason by which C3 plants prosper better at high latitudes/altitudes where the insolation index is around 0.5 (Odum. Ecology. 2006. Pp. 47-51).
The big problem is that if the insolation goes up, i.e. above the optimal index, the growth of C3 plants would go down, as if the insolation was low. The same physiological phenomenon occurs with temperature, although the predominant factor is not temperature, but insolation.
Thanks, Tilo (22:37:43)
I would say I’m not sure. Limited usefulness, probably.
Of course, they are not useful at all if you throw out the tree rings that don’t agree with your preconceived conclusions. Well, I guess they are useful, but not scientifically. 😛
ANY gardener would tell a scientist that a tree is a rotten proxy for temperature.
As someone who has held science in reverence for many years I’m still struggling very much with the revelations as to what passes for ‘science’ nowadays. I’m seriously disappointed. When I was a child I discovered that teachers aren’t necessarily intelligent (a shock at the time!). Then I discovered that doctors aren’t necessarily clever either (believing in treatments that are unscientific). Then in my early 20s I discovered that politicians are often liars, and worse, say and do incredibly stupid things. I read many years ago that scientists can be strange characters, and like the great man Isaac Newton himself, display odd behavioral characteristics. But to find out the truth about the scientific process which I have held in very high esteem, and to discover that ‘scientists’ simply do not follow a ‘scientific’ line in many instances has come as a bitter blow from which I will not recover. I no longer trust scientists at all. And neither will I pay any attention to ANY scare story of the future. I’m over halfway through my life, and I’ve heard of everything from a coming ice age to Swine Flu. It’s all nonsense, and I’m bitterly disappointed. I’m a gardener, and I could have told any scientist anywhere that trees grow according to where you plant them. A distance of just 2 metres can have an effect. As a proxy for temperature they’re useless. I’ve grown many trees (too many to count), and I can say that sunlight and water mean everything to a tree.
Is it just me? I am not generally dyslexic, but every time I see the word treering I mis-read it as teetering.
Jody (19:40:57) :
I vote that someone here or anywhere write a paper that can be published showing how tree rings are not/cannot be indicators of temperature.
Please! Somebody do more than write a post. Publish a Paper about this matter if you are so convinced that trees cannot be used for establishing past temperatures.
Jody, the problem with your request at this particular moment is we have good reason to doubt the AGW “peer review” system. For the recent past with respect to any climate related science – the whole system is suspect. Not due to conspiracy but due to hard evidence via Briffa demonstrating lack of oversight, bias, poor attention to detail, faulty research protocols, lack of transparency of data, etc.
Briffa, Mann and likely hundreds of other “peer reviewed” studies attesting to global warming – are now suspect. PR agencies are not substitutes for good science. Your boy has cried wolf one too many times.
I am an AGW skeptic and have been since first starting to hear about AGW in the early 1980s, but I am actually quite open to tree-mometers as evidence of past temperatures. While the growth rings of an individual tree are evidence just of its own unique growing conditions, the only thing a large number of widely scattered trees could share is a global temperature record. So the problem is not the concept of tree-mometers per se, but the vanishingly small sample sizes used. (I have various other problems with the way it is done too, but they’re not worth even mentioning until there are cores from waaaaaaaaaaay more trees from many more widely scattered locations.)
“Are trees an accurate enough recorder of air temperature to accurately determine past temperatures?”
A bit of a stiff test!
Actually, taken literally, they possibly are, a bit like boreholes are, the problem is not in the recording, the problem is in the playing back.
Alex
In Memoriam
HOCKEY STICK
Age 11
So. Farewell then
Hockey Stick
Robust Reconstruction
It would seem that
You are dead
But are you?
You have risen
many times before
So why not now?
But then. Do dendro
Theories really die?
And so eternal.
Remain the doubts
with Us.
(E.J Thribb age 17 ½)
(with apologies to Barry Fantoni and Howard Hughes. In addition, I would also like to add that.. continued page 99)
Keith Minto (21:30:35), thanks for your post. You say:
I’ve heard that claim as well, but I haven’t found the studies to back it up. The problem is that temperature is not a limiting factor by itself. It is always the temperature in relation to how much water the plant has. With enough water, trees can continue to grow at a much higher temperature than when they are water stressed. If trees are short of water, they show the signs of heat stress (e.g. lack of turgor, browning) at a much lower temperature.
The problem with Briffa’s claim is that high elevation sites are often quite arid. They also are often on steep, poor soils with little moisture-holding capacity. As a result, although you would expect trees near the treeline to be “most sensitive to temperature” as Briffa claims, the real issue at the treeline is often not temperature. Extra warmth means nothing if there is not enough water to allow increased growth. In fact, when water is short, extra temperature leads to less growth, not more. And at the treeline, water is often very short.
So although I read that statement a lot, I don’t think it is true in general. It may be true in the wetter parts of the Pacific Northwest, but I believe it is not generally the case. I’d have to see some good studies of the question before I’d believe it, and despite looking, I’ve never found them. However, they may be out there … so let me add my voice to yours in asking for some links to establish the validity of the claim.
Best regards,
w.
jeroen (14:34:21) :
if there is enough rain and lots off sunshine but colder temps then the tree will have a good year.
I’d like to add, if you don’t mind : if there is enough rain and lots of sunshine, plus extra co2 in the air from burning ‘fossil fuels’, but colder temps then the tree will have a good year.
We have enough trouble with being able to achieve accurate long term trend results using modern calibrated thermometers and thermisters. This is evidenced by the data manipulation used to try and nullify environmental and other factors on the raw recorded data.
To quote Cheech and Chong on the different use of a certain tree….
“Far out Mann !!!”