by Dr Roger Pielke, Sr.
With the McShane and Wyler paper examining and questioning the method, this look at the proxy data and its problems seems like a relevant issue to review.
Comment On Tree Ring Proxy Data and Thermometer Type Surface Temperature Anomalies And Trends
There was an interesting conclusion in a New York Times article on the relationship between tree ring proxy temperature trend analyses and thermometer type measures of temperature anomalies and trends. The article is
British Panel Clears Scientists by Justin Gillis published on July 7, 2010
The relevant text is on page 2 it is written
“But they were dogged by a problem: Since around 1960, for mysterious reasons, trees have stopped responding to temperature increases in the same way they apparently did in previous centuries. If plotted on a chart, tree rings from 1960 forward appear to show declining temperatures, something that scientists know from thermometer readings is not accurate.”
There are, however, problems with this conclusion. Since the thermometers are not coincident in location with the tree ring data (in the same local area), it would not be surprising that they are different. Indeed, this is yet another example that implies unresolved biases and uncertainties in the surface temperature thermometer type data as we discussed in several of our papers (see and see), as the thermometers are measuring elsewhere then where the proxy tree data is obtained. This obvious issue has been ignored in the assessment of this so-called divergence between the two methods to evaluate temperature anomalies and trends.
It is possible, of course, that the trees are responding differently due to the biogeochemical effect of added carbon dioxide and/or nitrogen deposition. Nonetheless, to accept the thermometer record as the more robust measurement of spatial representative temperatures is premature.
I have discussed this issue further in the posts
Comments On The Tree Ring Proxy and Thermometer Surface Temperature Trend Data
December 2007 Session ‘The “Divergence Problem’ In Northern Forests
“Since the thermometers are not coincident in location with the tree ring data (in the same local area), it would not be surprising that they are different.”
If I read this right, I would disagree with this statement. It is not the DATA itself, but the TREND in the data that is at issue.
Using this logic, we can’t compare temps in any place with ones in any other place. But, of course, we do. Heck, we let Kola tree rings represent the whole planet, for God’s sake.
Was this the real intent of this sentence? To say we can’t compare the tree rings to instruments? What am I missing?
Absolutely. As earthdog says, uniformitarianism DICTATES that the overlap period GOVERNS. Therefore, all past tree ring proxies must be re-calibrated to match the overlap period – the post 1960 period. This is the only period when we can compare them. If not individual trees, then at least the overall trends.
As per Jim Hogg — But there SHOULD be thermometers placed right AT the trees. This is such a basic scientific method! Why has it not been done?
Dr. Pielke? On both co-locating trees and thermometers? Has it been done? And on the overlap period being the governing/calibrating period?
@James Baldwin Patterson –
Briefly OT:
THANKS for pointing out the paleontological circular reasoning. YES, so many sites around the world have inverted geologic columns, and YES, the theories are all ad hoc affairs, none of which cover all the bases.
Archeologists do the same kind of thing. They are still wedded to the same chronology that was pegged to ceramics and paleography, the ones dreamed up long before C14 and radiometric dating. The latter truly scientific dating methods were calibrated against the less scientific methods, as I understand it all – the exact opposite of real scientific methodology would dictate.
And, BTW, for any that don’t know it, C14 does NOT diminish linearly. That was a VERY early assumption, and one that is still the public’s understanding of it.
End of slight OT there. Sorry…
I think Keith Briffa lies awake at night, wondering how much he screwed up.
Did any of those tree rings happen to confirm Noah and his great flood..? [wide grin]
Pielke didn’t quote the best part. Gillis in NYT:
“Grafting,” not “splicing”!
Rob Dawg says:
August 21, 2010 at 10:28 pm
Excellent snark sir. May I suggest that the supremacy of trees be vetted by an unbiased panel of Druids?
Wow. That’s hilarious! But hey, why stop stop there?
“Talk with a rock, a plant or a tree at least once a week. They have heard and seen everything and have much to teach you about patience, reliability and age old wisdom.” Maya Magee Sutton, Ph.D.
http://www.dwij.org/forum/cerritomni/r3_maya.html
rofl..!
I submit that even if this proxy theory were valid in the first place, this mechanism breaks down over the years no matter what. You see, the theory is that only certain trees respond well to temperature, as opposed to other things. They do it while they are at the timberline, right on the edge, starved for basically everything else, such as water, nutrients, and sunshine. If the other factors wiggle a bit, the trees respond weakly, because they are still pretty much starved. But if the temperature goes up, the trees respond to that.
Now here’s the problem. This theory only works as long as the trees remain right on the ragged edge for centuries, never falling off in either direction. They never get happy about anything, they never get dead, and they never get very warm. They never get much more or less water, and so on. If they ever got happy about any of the the other factors, they would start responding strongly to those factors instead.
So the entire proxy theory requires that while the trees stay in place near the timber line (remember trees outside Middle Earth can’t move themselves), the timber line itself never, ever moves. Never. For centuries.
How unlikely is this?
Mr Hide-the-Decline Briffa found that tree rings show falling temeratures from 1945.
http://eas8001.eas.gatech.edu/papers/Briffa_et_al_PTRS_98.pdf
Page 69, fig 6.
Perhaps the trees rings are correct and the temperature record has been contaminated … most likely by UHI,
Tree rings growth responds to several environmental factors, true; especially, to incident solar radiation upon the Earth’s surface (insolation). Tree rings growth width is a weak proxy to represent ancient atmospheric temperatures:
http://www.biocab.org/Insolation_Treerings_Growth.html
Next, a subtext from my article:
“Notice that the width of the treerings is primarily a response to insolation rather than temperature. The reason being that Siberian Larch Trees are C3 plants, whose growth is more closely linked with insolation than it is with environmental temperature.
It is clear that C3 plants achieve better growth when the proportion of insolation does not exceed 50% of the total insolation; for values above 50%, the growth of Siberian larch trees, which are C3 plants, is slowed progressively as solar luminosity increases.”
Of course, as a biome evolves, its productivity decreases. The extinction of a local species means an increase in the biodiversity of bioma in the long term by competitive post-extinction replacement, in this case, of the coniferous forest. Therefore, each individual in that biome is put under higher interspecific and intraspecific competitive stress, which reduces its production. The latter also confirms that, to wide biodiversity, minor productivity in the biome.
The quote of Daly says it all (thanks Ian W) and Pielke sen. makes it complete.
There is no science close to being settled, if the tree ring technique is science at all.
Unbelievable how this is used to cheat the whole world.
Btw., German Prof. Schellnhuber, Chief Climate Change Advisor to chancellor Merkel in a recent interview: “One third of Hawaiian beaches are already endangered by sea level rise.” (http://www.spiegel.de/international/world/0,1518,712113,00.html)
Any alarming signals from the Hawaiians?
And, has Al Gore already bought beach front property there?
How could any Warmist possibly respond to this scene:
It’s mid January, we’re sitting in a ski vacation lodge, by the fire, looking out at the snow & ice covered floria… & I ask… “Why don’t we go outside & take a core & see what the winter was like here last year?!” “What was the weather like here then?”
Are Warmist’s really that thoughtless, that uncreative, that uninquisitive? Really?
If plotted on a chart, tree rings from 1960 forward appear to show declining temperatures, something that scientists know from thermometer readings is not accurate.
Hey, guess what started around 1960? Urban sprawl.
So, what’s more likely, that trees suddenly stopped responding to temperature or the UHI proportion of the signal increased?
Jimmy Haigh says:
August 21, 2010 at 11:55 pm
I was born in 1960 and I deliberately caused the divergence problem because I thought it might be fun.
BEAUTIFUL! HAH!
tree rings from 1960 forward appear to show declining temperatures
The trees tells us temperatures are falling…
The peer review gang tells us temperatures are rising…
So we are probably somewhere in the middle… business as usual… natural variability.
But if you put a gun to my head and asked me to choose between TREE and MANN then I would go with the trees… because trees don’t lie… they can only be misunderstood… which reminds me of a song from the 60s by the ANIMALS 🙂
We could get a good feel for the tree ring/temp relationship by doing a serious tree ring study in the English Midlands, where we have the CET record going back to the 1600’s. Those temps are from several sources, but the study could core trees from the neighborhoods, many species, many locations. The data set could be enlarged over time, somewhat like the SurfaceStations.org data set. Other researchers could use the data for their own papers (also somewhat like SurfaceStations.org, ouch!)
Other records might show rainfall/drought/stresses. Tax records might show crop yields as a general indication of growing conditions for a year.
Then we could do a real PCA, and see what counts with tree rings.
Should we be asking why did the trees for a short time happen to track with temperature. Is there an environmental reason or a problem with the data collection and analysis?
It should be obvious that tree-ring width is primarily an indicator of the overall optimization of growing conditions in any given year. Narrow rings can be caused by conditions being too dark, too dry or too hot, as well as being too cold. Thus the use of these ring-widths to indicate average annual temperatures must be highly speculative without other independent corroborating evidence. Perhaps a detailed isotopic or chemical analysis of the material in each ring might give better results.
I am now convinced that tree rings provide a better measure of temperature than thermometers.
I hope I am there next time Mike Mann needs his temperature taken for a medical check up.
“Bend over please sir…”
Personaly I am really impressed with some scientists. Using a very small sample he has produced vast funding streams from a few wood shavings, he is pure magic!
It may be that some forest ranger stations have a record of thermometer readings that could be co-related to tree-rings adjacent. These rangers would be pretty disciplined in taking down the data, but not necessarily trained in standards of thermometer siting. Yet, providing the instruments are not simply hung on the outside wall, the data might still work to compare tree-trends with thermometer trends.
ps. So where’s my grant?
pps. Logging companies, too. When I went a-logging at Franklin River here in British Columbia, I had to take a thermometer reading and relative humidity calculation every morning at 10:00am, or as close to that as I could possibly get. But in this case I was there only in the summer, and the purpose of the readings was to determine if the woods were too dry for safe logging. I don’t know if the readings were continued in winter, but maybe they’ve been done elsewhere.
I don’t see how you can infer temperature from tree rings. Tree rings vary with a lot of variables including rainfall, the fertility of the soil, the amount of sunlight (numbers of cludy days) and the amount of carbon available to soak up.
Derryman says:
August 22, 2010 at 8:12 am
Thermometers, when they first appeared as an instrument, were calibrated against the triple point of water as 0C and the boiling point of water, all at 1 atmosphere. These two points set the scale which was divided by 100.
Even on a desert island with no contact to the rest of the world one can construct a thermometer compatible with the rest of the world because of this definition.
from wikipedia:
From 1744 until 1954, 0 °C was defined as the freezing point of water and 100 °C was defined as the boiling point of water, both at a pressure of one standard atmosphere.[citation needed] Although these defining correlations are commonly taught in schools today, by international agreement the unit “degree Celsius” and the Celsius scale are currently defined by two different points: absolute zero, and the triple point of VSMOW (specially prepared water). This definition also precisely relates the Celsius scale to the Kelvin scale, which defines the SI base unit of thermodynamic temperature (symbol: K).
It was the need for precision in relating the Kelvin an Celsius scales that changed the definition in international standards, certainly not a precision relate to tree rings as thermometers.