dendro matching

September 29th, 2009 at 7:55 pm
Can I see if I have this correct?

1. We have a number of tree ring samples from different areas
2. Briffa has selected only rings that match valid local temperature records.
3. Briffa assumes that these trees stay in sync with temperature to an early time in their life.
4. Briffa matches older dead(?) trees to those that match local temperatures and says that these must therefore also be in sync with local temp.
5. repeat 4. and until tree rings are available at the required earliest age.
6. Statistics does not allow matching of tree ring temperature proxy to real temperature because this is cherry picking and will always produce a hockey stick

I agree that extending backwards from multiple overlapped records must produce greater deviations from reality.
I agree that a single tree ring record can deviate once away from the matched record.

However, thinking as an engineer trying to find an accurate reading of for example a time series of a voltage supply to a building monitored with inaccurate chart recorders over various lengths of cable (= added noise). if one recorder is known to have been calibrated (to national standards) over recent part of that record, then I would look at the other recorders over this calibrated period and throw out all the outlier readings (they are wrong now, and I do not know if they were ever correct so there is no reason to include them in my determination. Some of the more accurate recorders may have read high before the calibrated range and some may have read low. Some will be recording significant noise compared to the majority and so these could be ignored if sufficient others remain to determine this fact. I would then average the remainder and suggest that this average record is the most likely record of voltage.
As a statistician are you suggesting that all recorder outputs should be averaged including those reading zero and those reading full scale and those whose readings deviate grossly from the mean.
This seems wrong and certainly will give a invalid result. Am I wrong?

But then we need to look at the tree sampling.
Were the trees sampled totally at random - trees in water, trees in bogs, trees scraping by on a solid rock, trees near to death, young trees etc?
Were they at the tree line or sea level?
Were they all the same "make"?

I would suggest that the actual sampling was not random. Altitude, health, species, etc. are all non randomly chosen (cherry picked)

If this is the case what is the point suggesting that they should not be further chosen to best represent temperature? what would be the point for example choosing a tree that fell over during its life but continued to grow with diminished root function? What would be the point in chosing a tree with growth limited by water/nutrients. What would be the point in including a tree 100skm further north than the rest? Would your statistical methods require that these be included in the sequence?

Steve McIntyre:
September 29th, 2009 at 9:28 pm
Re: thefordprefect (#244),

Some of your premises are not yet demonstrated. There are a couple of different levels of consolidation: at a "site", multiple cores are taken, usually within fairly close proximity to one another. These are composited into a "site chronology". Briffa unusually composites samples from areas not at all close to one another in Avam-Taimyr and Tornetrask-Finland. At Yamal, for some reason, he has not composited samples from Polar Urals, which is closer to Yamal than Avam is to Taimyr.

2. Briffa has selected only rings that match valid local temperature records.
[There are two issues: selection of trees at a site e.g. Yamal and selection of sites, e.g. Avam and a nearby Schweingruber site into Taimyr. The procedures are not described. It is not known how Yamal core selection decisions were made and which were made before CRU and which at CRU].

3. Briffa assumes that these trees stay in sync with temperature to an early time in their life.
[Not necessarily. WE don't know what was done. It is possible that trees with elevated growth rates were preferentially selected, but we don't know that for sure.]

4. Briffa matches older dead(?) trees to those that match local temperatures and says that these must therefore also be in sync with local temp.
[ no. crossdating is done by pattern matching.]

5. repeat 4. and until tree rings are available at the required earliest age.
6. Statistics does not allow matching of tree ring temperature proxy to real temperature because this is cherry picking and will always produce a hockey stick.
[this is a different issue.]

FP, I don't have time to provide personal education to everyone trying to get up to speed. I've asked people who don't have specialist viewpoints to comment on Unthreaded.


Climate primer refs


interesting links

effect of snow and grass on cooling
effect of cloud and wind on cooling
tree rings briffa
tree rinkg yamal
Here’s another interesting dissertation with descriptions of the Yamal trees and environment:

Good descriptions of the environment and the trees sampled.

Unfortunately (???) he ends up with yet another hockey stick:
See figure 18
Figure 18- of change in the mean temperature of summer (deviations from the average), smoothed by 50-year filter, and the dynamics of polar timber line


How HADCRUT temp adjustments are made


water vapour and GHGs

anna v (20:43:39) :
CO2 is a trace greenhouse element . period. the tail does not wag the dog.

BUT consider ozone. Even less than a trace gas. But if it were reduced by a few percent globally UVb would be playing hell with our genes, plant growth, plankton survivability. 1% change in O3==2% increase in UV.
From Wiki O3 gives 3-7% of the GHG effect from only 0.00006 percent of the atmosphere (0.6ppm)
Is this not a case of the hair on the flea in the tail wagging the dog? CO2 could be similar?

Stephen Wilde (23:50:41) :
The composition of the air is merely an enabler. Once it has served it’s function in permitting the creation of liquid oceans and a hydrological cycle it’s significance becomes marginal.

You are making some really wild leaps here.
As you said energy balance is everything. The earth is a "grey" body radiator and if the atmosphere were suddenly lost radiation away would be determined by the various emissivities of the different terrain. And temperature will stabilise when grey body radiation out = radiation in. This would bottom out at about -18C.

Adding atmosphere makes it more complex so lets assume all GHGs are removed but the same atmospheric pressure were present (O2, N2, H2 are non GHGs). Without GHGs thermal radiation from the grey body will not be absorbed so only conduction and thence convection will heat the air. With no absorption by GHGs the grey body + atmosphere will still loose the same amount of radiation as if the atmosphere were not present (possibly more as the conducted heat to air will also radiate from the air).
So without any GHGs but with an amosphere the earth will radiate as before - as a grey body.

Major GHG effect (wiki)
water vapor, which contributes 36–72%
carbon dioxide, which contributes 9–26%
methane, which contributes 4–9%
ozone, which contributes 3–7%
Water vapor accounts for the largest percentage of the greenhouse effect, between 36% and 66% for water vapor alone, and between 66% and 85% when factoring in clouds.[8] ...
The Clausius-Clapeyron relation establishes that air can hold more water vapor per unit volume when it warms.

If we now add only normal concentration of water vapour to an earth without other GHGs assuming it starts at the average of 13-15degC However this is with a full compliment of GHGs. Water vapour only provides 72-85% of the GHG effect so the temperature will fall. Falling temperature will reduce the water vapour content of air which will lower the GHG effect and the temperature will fall. Falling temperature will reduce the water vapour content of air which will lower the GHG effect an the temperature will fall etc. - a positive feedback that will eventually lead to very low levels of water vapour and hence we will be back at near grey body temperature.

If we now add the other GHGs into the atmosphere then the grey body radiation is reduced and temperature rises. Rising temperature leads to more water vapour which leads to higher temperature etc. We then end up with a warming grey body. At some point the grey body radiation out will equal the incoming radiation and we have temperature "stasis".

water in the atmosphere


Ozone Hole

Reference stuff


After the Antarctic Ozone Hole was discovered, some scientists took the view that it might be a natural event caused by volcanic chlorine emissions from Mount Erebus rather than manufactured chlorinated chemicals. Eventually, however, Mount Erebus was exonerated (Zredna-Gostynska et al., 1993). Most of the chlorine Mount Erebus throws up takes the form of hydrogen chloride (HCl), which (like other chlorine from natural sources) readily dissolves in the water vapour of the lower atmosphere well before it can reach the stratosphere.
For Mount Erebus to affect the ozone layer, the volcano would have to inject a large proportion of its hydrogen chloride directly into the stratosphere, above a height of about 10 km. Mount Erebus has been active since it was first observed by James Ross in 1840, but appears never to have erupted with the force necessary to send chlorine directly into the stratosphere. The mountain itself is almost 4,000 m high (3,794 m), but the volcanic plume seldom rises above 5,000 m. The amount of gas Mount Erebus emits also bears no relation to the size of the ozone hole. In the summer of 1983, chlorine emissions from Mount Erebus were about 170 tonnes a day. In the following seven summers, when ozone depletion was even more severe, the chlorine emissions ranged from one-tenth to one-quarter of the 1983 figure (Zreda-Gostynska et al., 1993).


Greenland and North Atlantic climatic conditions


Jørgen Peder Steffensen stuff

Of interest:

Some interestinfg stuff from Jørgen Peder Steffensen
and links on left
Climate change is man-made shows arctic research
New research shows that the temperature of the arctic region fell steadily from over 2000 years ago all the way up to a 100 years ago. The cooling was caused by less solar radiation during the summer and the cold temperatures would have continued undisturbed. But around the year 1900 there occured a dramatic increase in temperature and the new research results therefore provide further evidence of man’s influence on the climate. The results are published in the scientific journal, Science.

NPI stuff

Unprecedented low twentieth century winter sea ice extent in the Western Nordic Seas since A.D. 1200

Abstract We reconstructed decadal to centennial variability of maximum sea ice extent in the Western Nordic Seas for A.D. 1200–1997 using a combination of a regional tree-ring chronology from the timberline area in Fennoscandia and δ18O from the Lomonosovfonna ice core in Svalbard. The reconstruction successfully explained 59% of the variance in sea ice extent based on the calibration period 1864–1997. The significance of the reconstruction statistics (reduction of error, coefficient of efficiency) is computed for the first time against a realistic noise background. The twentieth century sustained the lowest sea ice extent values since A.D. 1200: low sea ice extent also occurred before (mid-seventeenth and mid-eighteenth centuries, early fifteenth and late thirteenth centuries), but these periods were in no case as persistent as in the twentieth century. Largest sea ice extent values occurred from the seventeenth to the nineteenth centuries, during the Little Ice Age (LIA), with relatively smaller sea ice-covered area during the sixteenth century. Moderate sea ice extent occurred during thirteenth–fifteenth centuries. Reconstructed sea ice extent variability is dominated by decadal oscillations, frequently associated with decadal components of the North Atlantic Oscillation/Arctic Oscillation (NAO/AO), and multi-decadal lower frequency oscillations operating at ~50–120 year. Sea ice extent and NAO showed a non-stationary relationship during the observational period. The present low sea ice extent is unique over the last 800 years, and results from a decline started in late-nineteenth century after the LIA.


Short vs long term temperature events

from WUWT
anna v (00:36:51) :
Proof is in the pudding: the existing CO2 ,though growing ,has not managed to stop a cooling PDO and it will stop the ice age
IFF radiation input/output to the earth is BALANCED (in=out) global warming/cooling will not happen. There will be weather, seasons, PDOs etc. but IFF in=out the averaged temperature over decades will be constant. Short term Temperatures will fluctuate!!!!!!!
If in is not equal to out then temperatures averaged over decades will show a rise/fall. If in-out difference is small then average temperature change will be small compared to weather, seasons, PDO etc. BUT there is still a trend up or down which will be obvious when temperatures are averaged over long enough periods. This is where we are. Weather, seasons, PDOs happen giving wandering temperature but do not negate small continuous changes to the in/out balance.
The flip from ice age to temperate will be caused by a long term in/out balance change not by weather, seasons, PDO or other transient events.

Sad reflection on a scientist (Plimmer)

masonmart (23:49:30) :
Monbiot refused to debate the issues with Plimer (as all AGW proponents refuse debate with knowledgeable skeptics) and I, who know nothing, would gladly debate Climate change with Monbiot.

Monbiot has stated that he will not debate unless written answers are provided to his questions. These answers have not been provided therefore no debate.

As you have read Plimers book from which all answers may be obtained (according to Plimer) Perhaps you could answer both Plimer and Monbiots questions here?
Q to Plimer
1. The first graph in your book (Figure 1, page 11). How do you explain the discrepancy between the HadCRUT3 figure and your claim?
2. Figure 3 (page 25) is a graph purporting to show that most of the warming in the 20th Century took place before 1945 closely resembles the global temperature graph in the first edition of Martin Durkin’s film The Great Global Warming Swindle - since retracted as false. What is the source for the graph you used?
3. You maintain that “the last two years of global cooling have erased nearly thirty years of temperature increase.” (page 25)
a. Please give the source for your claim.
b. How do you reconcile it with the published data?
In your discussion of global temperature trends, you maintain that “NASA now states that […] the warmest year was 1934.” (p99)
a. Are you aware that this applies only to the United States?
b. Was this a mistake or did you deliberately confuse these two datasets?
5. Discussing climate trends in the Arctic, you state that “the sea ice has expanded” (p198). Again, you give no reference.
a. Please give a source for this claim.
b. How do you explain the discrepancy between this claim and the published data? http://nsidc.org/arcticseaicenews/
6. You state that “If the current atmospheric CO2 content of 380 ppmv were doubled to 760 ppmv […] [a]n increase of 0.5C is likely” (p366). Again you give no source. Please provide a reference for this claim.
7. You claim that “About 98% of the greenhouse effect in the atmosphere is due to water vapour.” (p370). Ian Enting says “In some cases the numbers given by Plimer are exaggerated to such an extent as to imply that without water vapour, Earth’s temperature would be below absolute zero - a physical impossibility.”
a. Please provide a reference for your claim about water vapour.
b. Please explain how your two statements (98% of the greenhouse effect is caused by water vapour and 18C can be attributed to CO2) can both be true
8. You cite a paper by Charles F Keller as the source of your claim that “satellites and radiosondes show that there is no global warming.” (p382)
a. How did you manage to reverse the findings of this paper?
b. Was it a mistake or was it deliberate misrepresentation?
9. You state “The Hadley Centre in the UK has shown that warming stopped in 1998″ (p391). Again you produce no reference.
a. Please give a reference for your claim.
b. How do you explain the discrepancy between your account of what the Hadley Centre says and theirs?
10. You state that “Volcanoes produce more CO2 than the world’s cars and industries combined.” (p413)
a. Please provide a reference for your claim.
b. How do you explain the discrepancy between this claim and the published data?
11. You maintain that “termite methane emissions are 20 times potent than human CO2 emissions”. (p472) Please provide a source for this claim.

Plimer to Monbiot
1. From the distribution of the vines, olives, citrus and grain crops in Europe, UK and Greenland, calculate the temperature in the Roman and Medieval Warmings and the required atmospheric CO2 content at sea level to drive such warmings. What are the errors in your calculation? Reconcile your calculations with at least five atmospheric CO2 proxies. Show all calculations and justify all assumptions.

2. Tabulate the CO2 exhalation rates over the last 15,000 years from (i) terrestrial and submarine volcanism (including maars, gas vents, geysers and springs) and calc-silicate mineral formation, and (ii) CH4 oxidation to CO2 derived from CH4 exhalation by terrestrial and submarine volcanism, natural hydrocarbon leakage from sediments and sedimentary rocks, methane hydrates, soils, microbiological decay of plant material, arthropods, ruminants and terrestrial methanogenic bacteria to a depth of 4 km. From these data, what is the C12, C13 and C14 content of atmospheric CO2 each thousand years over the last 15,000 years and what are the resultant atmospheric CO2 residence times? All assumptions need to be documented and justified.

3. From first principles, calculate the effects on atmospheric temperature at sea level by changes in cloudiness of 0.5%, 1% and 2% at 0%, 20%, 40%, 60% and 80% humidity. What changes in cloudiness would have been necessary to drive the Roman Warming, Dark Ages, Medieval Warming and Little Ice Age? Show all calculations and justify all assumptions.

4. Calculate the changes in atmospheric C12 and C13 content of CO2 and CH4 from crack-seal deformation. What is the influence of this source of gases on atmospheric CO2 residence time since 1850? Validate assumptions and show all calculations.

5. From CO2 proxies, carbonate rock and mineral volumes and stable isotopes, calculate the CO2 forcing of temperature in the Huronian, Neoproterozoic, Ordovician, Permo-Carboniferous and Jurassic ice ages. Why is the “faint Sun paradox” inapplicable to the Phanerozoic ice ages in the light of your calculations? All assumptions must be validated and calculations and sources of information must be shown.

6. From ocean current velocity, palaeotemperature and atmosphere measurements of ice cores and stable and radiogenic isotopes of seawater, atmospheric CO2 and fluid inclusions in ice and using atmospheric CO2 residence times of 4, 12, 50 and 400 years, numerically demonstrate that the modern increase in atmospheric CO2 could not derive from the Medieval Warming.

7. Calculate the changes in the atmospheric transmissivity of radiant energy over the last 2,000 years derived from a variable ingress of stellar, meteoritic and cometary dust, terrestrial dust, terrestrial volcanic aerosols and industrial aerosols. How can your calculations show whether atmospheric temperature changes are related to aerosols? All assumptions must be justified and calculations and sources of information must be shown.

8. Calculate 10 Ma time flitches using W/R ratios of 10, 100 and 500 for the heat addition to the oceans, oceanic pH changes and CO2 additions to bottom waters by alteration of sea floor rocks to greenschist and amphibolite facies assemblages, the cooling of new submarine volcanic rocks (including MORBs) and the heat, CO2 and CH4 additions from springs and gas vents since the opening of the Atlantic Ocean. From your calculations, relate the heat balance to global climate over these 10 Ma flitches. What are the errors in your calculations? Show all calculations and discuss the validity of any assumptions made.

9. Calculate the rate of isostatic sinking of the Pacific Ocean floor resulting from post LGM loading by water, the rate of compensatory land level rise, the rate of gravitationally-induced sea level rise and sea level changes from morphological changes to the ocean floor. Numerically reconcile your answer with the post LGM sea level rise, oceanic thermal expansion and coral atoll drilling in the South Pacific Ocean. What are the relative proportions of sea level change derived from your calculations?

10. From atmospheric CO2 measurements, stable isotopes, radiogenic Kr and hemispheric transport of volcanic aerosols, calculate the rate of mixing of CO2 between the hemispheres of planet Earth and reconcile this mixing with CO2 solubility, CO2 chemical kinetic data, CO2 stable and cosmogenic isotopes, the natural sequestration rates of CO2 from the atmosphere into plankton, oceans, carbonate sediments and cements, hydrothermal alteration, soils, bacteria and plants for each continent and ocean. All assumptions must be justified and calculations and sources of information must be shown. Calculations may need to be corrected for differences in 12CO2, 13CO2 and 14CO2 kinetic adsorption and/or molecular variations in oceanic dissolution rates.

11. Calculate from first principles the variability of climate, the warming and cooling rates and global sea level changes from the Bölling to the present and compare and contrast the variability, maximum warming and maximum sea level change rates over this time period to that from 1850 to the present. Using your calculations, how can natural and human-induced changes be differentiated? All assumptions must be justified and calculations and sources of information must be shown.

12. Calculate the volume of particulate and sulphurous aerosols and CO2 and CH4 coeval with the last three major mass extinctions of life. Use the figures derived from these calculations to numerically demonstrate the effects of terrestrial, deep submarine, hot spot and mid ocean ridge volcanism on planktonic and terrestrial life on Earth. What are the errors in your calculations?

13. From the annual average burning of hydrocarbons, lignite, bituminous coal and natural and coal gas, smelting, production of cement, cropping, irrigation and deforestation, use the 25µm, 7µm and 2.5µm wavelengths to calculate the effect that gaseous, liquid and solid H2O have on atmospheric temperature at sea level and at 5 km altitude at latitudes of 20º, 40º, 60º and 80ºS. How does the effect of H2O compare with the effect of CO2 derived from the same sources? All assumptions must be justified and calculations and sources of information must be shown.

Remember Plimer says his questions' answers can be found in his books.

So we have Monbiot mainly requesting sources of Plimer's eronious statements (surely a simple request to answer?) and Plimer requesting a journalist to provide original scientific research and to derive models from first principles. As Monbiot admits - he is not a research scientist so the questions are outside his knowledge.
Some of Monbiots questions (have now been answered on realclimate)

Oh dear!!!!!!!!!!!
Rabett Run


Arctic Temps posting on WUWT

Arctic Temperatures – What Hockey Stick?

Circling the Arctic

What sudden recent warming? What Hockey Stick? I don’t see any.

By Lucy Skywalker Green World Trust


Not impressed with the title here.
I have now gone through the GISS data (homogenised) and differenced the monthly figures of each station then averaged over the locations in the above map. It may not be classical hockey stick but its very close:
Over 2 degC difference between 1882 and 2008
A steady rise from 1966 onwards rising to greater than 0.5C higer than 1936 temp