Guest Post by Willis Eschenbach
In my usual peripatetic wandering around the web, I came across an interesting paper called “Millennial- and orbital-scale changes in the East Asian monsoon over the past 224,000 years”, in Nature Magazine (subscription required), 28 Feb. 2008 , with Supplementary Online Information.
The paper uses “speleothems” to estimate past climate conditions. Speleothems are secondary mineral deposits formed in caves. Stalactites and stalgmites are speleothems, and they come in a wide variety of sizes and shapes. Here’s a photo of some speleothems:
Figure 1. Speleothems in a New Zealand Cave.
What can we learn from the speleothems?
The authors used the speleothem data from two caves in China to investigate the climate changes over the last two glacial periods, a quarter million years or so. Being more interested in the recent past, and noticing that one of the datasets extended up to the year 1490, I decided to see what speleothems could tell us about the temperature changes in more recent times. So I got a large group of speleothem records from the NOAA Paleoclimatology web site.
I wasn’t interested in what happened thousands and thousands of years ago, so I got all of the long records that covered all or part of the period from the end of the last ice age to the present. This gave me 20 records.
The speleothems give us a record of what is called the “delta oxygen 18” (∂18O) value. This value is related to the temperature. The paper does not give the associated temperature values, so I converted them using the relationship described here as:
This is based on the average d[delta]18O/dT relation in modern precipitation (~0.6‰ °C-1), and the water-calcite fractionation that accompanies speleothem deposition (~-0.24‰ °C-1).
Decoded, this means that the change in temperature is equal to the change in ∂18O divided by (0.6 – 0.24), or ∂18O/0.36. Using that relationship, I calculated the temperatures from the various speleothems, and graphed them all with no further adjustment.
Figure 2. Raw data from 20 speleothem records. All of them have been converted from ∂18O using the relationship Temperature = ∂18O/-0.36. Black line is a 200-point Gaussian average. Different records are different colors.
While this was interesting, it appeared to me that the various records were likely not vertically aligned quite properly. After all, there is no a priori reason to think that they would all fit together, since they were simple anomalies (data minus average of that data) over different time periods.
So how to adjust them? There are several methods that are used to make this kind of adjustment to temperature anomalies for the global temperature records. GISS takes an average of two records in the area where they overlap, and adjusts on that basis. That was possible here, but seemed inaccurate. GHCN, on the other hand, uses one type of “first difference” method. However, their method requires that all of the datasets be on the same basis (annual, monthly, etc.), where in this case the measurements are at various random times that differ between datasets.
After some thought, I realized that I could use “first differences” in another way. The “first difference” is a new dataset that is made by calculating the difference between successive datasets. For example, if the dataset is {1, 2, 4, 8, 10}, then the first difference of that dataset is {(2-1), (4-2), (8-4), (10-8)}, or {1, 2, 4, 2}. This represents the differences between the points in the original dataset.
I realized that the standard deviation of the first difference is a measure of how well the various datasets fit together. (Standard deviation, “SD”, is a measure of how scattered the data is.)
So to adjust them, I first combined all of the 20 speleothem datasets into one single large dataset. Then I took the first difference of that single dataset. I measured the SD of the first difference data.
Then I adjusted each of the individual speleothem records by moving it slightly upwards and downwards, and used the increase or decrease of the SD to indicate which way it should be moved. I repeated this until the match was not improved by further testing and moving of the individual datasets. The result is shown in Figure 3.
Figure 3. Adjusted data from the same 20 speleothem records. All of them have been adjusted vertically to give the best fit. Black line is a 200-point Gaussian average.
This has improved the accuracy of the reconstruction. This is shown by the greater vertical range of the Gaussian average line.
So, what does all this mean? Heck, I don’t know, I’m investigating, not drawing conclusions. A few comments, in no particular order:
• As is shown in the Greenland ice core records, we are currently at the cold end of the Holocene (the current interglacial).
• Recent phenomena (Roman Warm Period, Medieval Warm Period, Current Warm Period) are scarcely visible at this scale. So much for the “uprecedented” nature of the recent rise.
• The polar bears are not in any danger from the recent rise.
• What’s up with the big jump and drop about 12000 years ago? I have not seen that in the ice core records, but it is present in these speleothem records from around the planet. [Update] A number of people have pointed out that this is almost certainly the “Younger Dryas” event. I hadn’t noticed it in the Vostok record, but a closeup of that record shows it.
• The amount of the temperature change depends on the coefficient used to translate from d18O to temperature. So the numbers are likely in the right range, but may be somewhat too large or too small.
Anyhow, that’s my thoughts about what I’ve found out, I welcome yours. I continue with the investigation. It strikes me that I may be able to adjust the conversion factor (d18O/T) to see if that improves the fit of the data … should be interesting. Onwards …
DATA:
The caves used in this study were:
Cave, Location
Borneo_sch01, Borneo
Borneo_sch02, Borneo
Buckeye, Central US
Chilibrillo, Panama
Cold_Air, South Africa
Crystal, Midwest USA
Dayu, Central China
Dongge, Eastern China
Dongge04, Eastern China
Dongge05a, Eastern China
Heshang, Central China
Liang_Luar, Indonesia
Lianhua, Southern China
Lynds, Tasmania
Mystery, Midwest USA
Sanbao08, Central China
Sanbao10, Central China
Soreq_Bar, Israel
Spannagel, Austria
Venado, Costa Rica
In two cases, where there were several speleothem records from the same cave analysed by the same investigators, I have combined them into a single longer record. Data from different studies of the same cave have a year (e.g. “08”,”10″) appended to the name.
I have posted the data I used, along with the R file that I wrote to analyze the data, as a zip file here. Enjoy!
What do you see wrong with Younger Dryas event showing up in this data?
The whole thing seems to match existing dO18 studies elsewhere, although Antarctic cores seems less sensitive than both this data and GRIP (Greenland).
http://en.wikipedia.org/wiki/File:Epica-vostok-grip-40kyr.png
(I don’t trust wikipedia, especially posts by Connelly who is a AGW crusader who got defrocked as wiki admin for abusing his admin right, but this does seem representative and is the first link I found.)
This is an interesting corroboration of GRIP data from a physically and geographically different medium.
E. R. Thomas et al 2009
doi:10.1029/2009GL040104, 2009
We are using a temporal gradient of 0.5 ± 0.1 ‰ per °C to convert δ18O to temperature, based on the calibration between the δ18O with site temperatures from the European Centre for Medium Range Weather Forecasts (ECMWF) (1980–2005).
Seems to match your convertion , where do you get your water-calcite fractionation figure?
I don’t understand the temperature projections into the future. Am I missing something?
Thanks WIllis. You’re right, it seems to get spelled both ways, but there are about 10 times as many google hits for your spelling and only around 13000 for mine. I’ll use speleothem in future.
Cheers
“Thought about the onset of the next glacial and the attendant sea-level drop.
The Alarmists have not even stopped to consider the effects of that one.
How much of a global temp drop would it take to sufficiently lower the sea level to incapacitate the Suez & Panama Canals?”
If global trade were to be significantly effected by this, then they would dig a channel however deep as would be required to keep that shipping lane open.
They are already increasing the capacity of this canal by making it wider.
J Midgley says:
May 27, 2010 at 1:39 am
Minus is BC, above 0 is AD.
Technically incorrect, in fact, because there never was a zero year. The calendar (retrospectively) goes from -1 to +1. Innumerate popes, and all that.
In that case, since you understand it, perhaps you can tell us what the change was, about a million years ago, that started the current series of regular ice ages. That way, we’ll know what to look at for what might end the current series.
AnnaV has probably her own idea .
.
My take on it is that we don’t know that anything significant changed 1 million years ago .
It is just an artefact because more or less reliable “climatic” data are younger than 1 million years and most of those that are used are actually even shorter (100s thousands of years) .
1 million years is really nothing at the geological scales .
What happened between 79 millions and 78 millions years ago ?
Were there glaciation cycles ? How many and how strong ?
In some kind of vaguely defined average this randomly chosen short period looks like relatively warm but would a .04 or even .1 ky oscilating signal be visible at all at a 100 million year scale ? At a billion year scale ?
Would there be much of it left at all anyway ?
Certainly not .
If we talk temperature , the only way to maintain a parameter in a narrow band of variation (what is what we observe since the Earth exists and here I talk billions of years) is to make it oscillate or to make it constant .
As a chaotic system is never in equilibrium and can’t be constant , the system must oscillate .
The frequencies may vary with time and they surely do but there certainly were pseudo periodical Ice age oscillations since the day when temperatures at the poles allowed formation of ice and that happened billions of years ago .
So yes , the next Ice Age is a certainty unless one supposes that the climate system suddenly stopped to oscillate and went in a divergent , non chaotic , unbounded mode what would be unprecedented in 4 billions of years .
If one expects that the principal frequencies vary smoothly with time , the next occurence will happen with a similar frequency like the last one – that is the argument AnnaV used and I tend to think the same thing too .
Hi Willis,
Good work, but I notice that if I look at the Vostok ice-core data which Joanne Nove has kindly expanded on her website:
http://joannenova.com.au/global-warming/ice-core-graph/
You get excellent correlation of the graph shape but your graph is shifted some 2000 years to the right. This means that if the two graphs are at all coincident, then your graphs actually stop 2000 years before the ice-core data (which in itself stops some 2500 years before the present day. This means that your most recent data is actually not showing todays climate, but is in fact showing the climate from 5000 years ago. I would presume that this is because the water percolating into these caves from the surface actually takes thousands of years to make the journey.
What is interesting about your grpahs is they show a 2Celsius decline in temperature since the end of the last glacial. This is much more in line with the ice-core data of previous inter-glacials which show a gradual decline in temperature to the start fo the next glacial.
RE:
Willis Eschenbach says:
May 26, 2010 at 7:44 pm
rbateman says:
May 26, 2010 at 7:19 pm
“The end of the Holocene is inevitable if one draws on full geologic history as a guide, Smokey.”
Well, there was a time when there were no regular ice ages. Then regular ice ages started. Someday, I assume that regular ice ages will end … so I would hardly call another ice age “inevitable”. “Very probable”, sure, but inevitable, no.
Willis,
The explanation usually given for the beginning of ice ages is the closing of the gap between North and South America, restricting interchange between the Atlantic and Pacific Oceans.
So, unless someone blows up the Isthmus of Panama, it would seem that Ice Ages will continue 🙂
Mike
tallbloke says:May 26, 2010 at 11:09 pm
. . . one of the other useful conclusions which can be drawn from speleotherm data. . .
We might christen the temperature curves derived from speleothems “speleotherms.”
Perhaps we should enter Willis’ chart into Wikipedia. It’s every bit as colorful (and therefore authoritative) as their current Holocene temperature chart.
Willis,
Nice posting but I have one significant issue with it. This is that the Vostok Ice Core does not contain a Younger Dryas aged reversal. The reversal in d180, temperature, and trace elements found in various Antarctic cores (much more detaiol is available from the Taylor Dome, Byrd, Dronning Maud Land, Dome Conchordia, Siple Dome and Dome Fuji cores) during the glacial-Holocene transition has been dated accurately. The event is officially known as the “Antarctic Cold Reversal (ACR). There is a heap of detailed work on this and I can provide references if you are interested.
If you go back further into the isotopic records from Greenland and Antarctica you will find that millenial-scale climate events over the respective ice sheets are out of phase (by about 1500 yrs or so) through almost the entire glacial period from about 100,000 BP to 10,000 BP. Antarctic events appear to take the lead in terms of timing. This pattern is also found in sea surface temperatures when the Southern Ocean is compared to the North Atlantic. The causes of this general pattern are still being hotly debated. The effects stretch to the periodic penetration of Antarctic bottom water as far north as Portugal in the North Atlantic.
If you wish to follow up on this field of study I would suggest you start with:
Ahn, J.; Brook, E.J. 2008. Atmospheric CO2 and climate on millennial time scales during the last glacial period. Science 322: 83-85.
Schmittner, A.; Saenko, O.A.; Weaver, A.J. 2003. Coupling of the hemispheres in observations and simulations of glacial climate change. Quaternary Science Reviews 22: 659-671.
Blunier, T.; Brook, E.J. 2001. Timing of millennial-scale climate change in Antarctica and Greenland during the last glacial period. Science 291: 109-112.
*Monin, E. et al 2001. Atmospheric CO2 concentrations over the last glacial termination. Science 291: 112-114.
The last gives a very nice comparison of the relative timing of the Antarctic Cold Reversal and the Younger Dryas. NB there is a fairly large literature relevant to the relative timing and intenssity of millennial-scale climatic events for both hemispheres.
Note that in the last few years the presence of the Younger Dryas has largely been debunked as far as the climate record in New Zealand is concerned, whereas (unsurprisingly) there is clear evidence for a cold event associated with the ACR in NZ (from speleothem records).
By the way I seem to recall reading a paper (from the Journal Geology I think) on widespread charcoal in North America relating to a potential comet or asteroid strike at the initiation of the Younger Dryas.
Cheers
Rob R
“Okay, so we may be looking at an event occurring outside our residential star system. Any residua of something cosmically catastrophic in the stellar neighborhood at that time? ”
Unless the comet strike changed the atmospheric properties to become more transparent to cosmic rays until the world could get itself back together?
Willis Eschenbach says:
May 26, 2010 at 10:33 pm
In that case, since you understand it, perhaps you can tell us what the change was, about a million years ago, that started the current series of regular ice ages. That way, we’ll know what to look at for what might end the current series.
I will go back to my dynamical analogy of the waves on the shore.
In that analogy, as a physicist, could I answer “what would end the current series of wavefronts”?
The answer is : a change in the energy inputs. For the wave fronts this change could take many ways: change in wind, change in cloud cover , change in currents.
In the case of the planetary system and earth itself, a change in orbits due to energetic interactions: getting into the range of different gravitational fields, a rogue planet entering the system, an asteroid hitting the earth, the sun turning nova, tectonic effects from internal energy changes, etc.
Your question reminded me of a Hodja story.
Hodja is an anatolian judge/mufti ( sometimes a clown) common in the folklore of Turks and Greeks who have originated in Anatolia.
Hodja was walking by a forest when he saw a man sitting on a thick branch of a tree and sowing it off on the wrong side. He spoke up: “my good fellow, be careful, you will have a bad fall” .
Before he reached the village he heard running footfalls and the wood cutter ran up to him and said: “Hodja, you are a great prophet, can you tell me when I will die”?
My answer would be, inevitably in the next eighty years.
Very interesting data. It compares well with oxygen isotope data (for a much more accurate chronology, compare it with the GISP2 data (Stuiver and Grootes, 2000) rather than the Vostock data which is not well dated. You can view the isotope curve for the past 17,000 years developed by Cuffy and Clow (1997) in the paper posted on my website– http://myweb.wwu.edu/dbunny/research/global/index.htm.
For a detailed view of the isotope record at the GISP2 data for the past 500 years, look at Fig. 33 in the same paper.
The big warming at about 15,000 years is the sudden, intense climate shift that marked the beginning of the end of the last Ice Age, and the cooling at 12,800 is certainly the Younger Dryas (12,800 to 11,500 years ago). The curve also captures the sudden cooling and warming from about 8200 to 8500 years ago. Note the large differences in the magnitude of the warming/cooling episodes compared to recent warming/cooling. The ice cores show huge changes in very short time periods (largest noted by other authors is warming of about 15 degrees F in only 40 years at the end of the Younger Dryas as compared to modern warmnig of 0.8 degrees per century.
The GISP2 core shows that the first 7,000 years of the Holocene (last 10,000 years) were warmer than present (but the polar bears survived it quite well) with cooling over the past 3,000 years. The past 500 years are particularly interesting because the isotope records shows a persistent cyclic of warming and cooling with an average 27 years (the same as the periodicity of the Pacific Decadal Oscillation).
Cave isotope records in Oman show an interesting correlation between delta 14C (which is a measure of production of radiocarbon in the upper atmospheric by incoming radiation) and oxygen isotope ratios between about 6,000 and 9,000 years ago (see figure 38 in the web paper). Looks like a strong solar influence of climate.
About the southern Hemisphere climate record—the Vostok core is not well dated so detailed correlations are difficult at best. However, the land record in New Zealand is very clear. Glaciers there responded to the Younger Dryas and left moraines dated at Younger Dryas at Birch Hill, Prospect Hills, and several other valleys. The idea that the Southern Hemisphere was out of phase with the Northern Hemisphere is at odds with this very real data. A paper now in press will detail all of this data.
Sorry, this Oxygen 18/Temperature correlation is “The King’s New Clothes”.
There is absolutely NO proof that this correlates with either “global energy balance” nor temperature.
Tropical thunderstorms increase the amount of O18, particularily along costal outfall areas.
This is about the only known “fact”. Extending it to “global temperature” or even atmospheric energy (overall) is a “stretch” or a “jump” which has no good basis.
“Tell a lie..often enough, loud enough…long enough..” You know the rest.
Max
we made a cave with speleothems for science. We used the crystal growing recipe on the bottle of Mrs. Stewart’s bluing, and we made several and layered them. We made them on alum foil with holes pricked in it, and we could shape the aluminum foil to resemble layers of rock. Every now and then we added new solution, and sometimes we added food coloring. That kind of showed when the application was made. We got stalagtites and stalagmites, some as big as a half inch. We had so much fun with that project we kept it around the house for the better part of a year, messing with it. We followed up with a trip to California Caverns up near Sonora – WHOA! We found that we had made a pretty good model in the kitchen.
Have a nice day Anthony – ttfn Juanita
Here’s some amazing pictures of speleothems
http://www.crystalinks.com/mexicocrystals.html
Mod- Unsure of how to code my link, quick tip?please
Willis,
Thanks for this very interesting work.
One thing that surprised me was that even though the data from different sites tells the same basic story, there does seem to be quite a bit difference in the range of temperature variation for different sites. I have read that the glacial/interglacial difference in temperature is expected to be much larger at high latitudes than in the tropics. Since the cave sites cover a range of latitudes, might the differences in temperature be related to the differences in latitude (with high latitude sites showing greater temperature variations than tropical sites)?
“Okay, so we may be looking at an event occurring outside our residential star system. Any residua of something cosmically catastrophic in the stellar neighborhood at that time? ”
What about an unprecedented Solar event? Collision with a large object possibly creating a massive flare?
Its worse than we thought, man caused the Younger Dryas… bad man, bad, bad bad, you shmuck!
http://www.cosmosmagazine.com/news/3460/did-megafauna-extinction-cool-planet
I think its highly possible there was a planet size comet captured in our solar system that came apart 25,000 years ago and it could have been producing the glacials by gravitational pull. Now that it came apart we might not have any more. Research the Taurids complex and surviving comet P2Enki. Harvard has a lot…
http://articles.adsabs.harvard.edu/full/seri/MNRAS/0251/0000636.000.html
http://stevepace.intuitwebsites.com/
I see that people here are “quick” learners. Not about actual science, mind you. This is the same type of “trick” that Michael Mann uses. To blindly say that the d18O signal in a speleothem is purely temperature is WRONG. I’ll give you the benefit of the doubt and chalk it up to ignorance, as opposed to a devious ploy. Many [snip] were up in arms about the tree rings and precipitation changing tree ring width – not just temperature – and now you’re doing it here!!! Too funny.
Your observation that the early Holocene was much warmer than present is seriously flawed based on your transfer function.
Readers here should be aware of the terrible science being employed here. Don’t blindly accept it.
Surely we are looking at what happened x years ago? We need to find out how long it takes water to filter through the rock to know when x actually was and then everything before that can be related to dated ice cores.
tonyb
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stan stendera says:
May 26, 2010 at 10:33 pm
Echenbach’s Hawk is apparently part bat since it flys around in caves.
ps. I like bats, most don’t.
_________________________________________________________________________
Bats eat mosquitoes, so whats not to like?
Perhaps Dr Mann should be spending that 1.8 million building and distributing bat houses to malaria ridden areas. At least that way someone would get some good out of the money. It would provide Green ECO jobs too!
William Roberts says:
May 27, 2010 at 9:00 am
I see that people here are “quick” learners. Not about actual science, mind you. This is the same type of “trick” that Michael Mann uses. To blindly say that the d18O signal in a speleothem is purely temperature is WRONG. I’ll give you the benefit of the doubt and chalk it up to ignorance, as opposed to a devious ploy. Many deniers were up in arms about the tree rings and precipitation changing tree ring width – not just temperature – and now you’re doing it here!!! Too funny.
Your observation that the early Holocene was much warmer than present is seriously flawed based on your transfer function.
Readers here should be aware of the terrible science being employed here. Don’t blindly accept it.
_______________________________________________________________________
Willis is not asking us to “blindly accept it” He has an inquiring mind, took some already published data and had a look at it, and played with it for a bit. He thought it looked interesting and put it up at this website for the rest of us to look at, comment and critique. Seems pretty close to what science is supposed to be like, an open discussion about the data and given, time, money, equipment and expertise, reproduction of the results.
Willis even said:
“…So, what does all this mean? Heck, I don’t know, I’m investigating, not drawing conclusions…..
The amount of the temperature change depends on the coefficient used to translate from d18O to temperature. So the numbers are likely in the right range, but may be somewhat too large or too small.
Anyhow, that’s my thoughts about what I’ve found out, I welcome yours. I continue with the investigation. It strikes me that I may be able to adjust the conversion factor (d18O/T) to see if that improves the fit of the data … should be interesting. Onwards …”
You say the O18 should not be used to estimate temp. How about giving us some studies/papers that show it is a poor proxy???
This shows O18 used for sea temp studies: http://www.physics.ohio-state.edu/~wilkins/energy/Companion/E16.3.pdf.xpdf
Yes I know that is based on living animals sequestering the O18. So here is a paper that
seems to be using O18 in climate studies using speleothems.
“…Abstract
‘Clumped isotope’ thermometry is based on analyzing mass 47 in CO2 extracted from carbonates and uses the tracer mass 47 anomaly (Δ47). Δ47 is defined as the deviation of R47 from that expected for a random distribution of isotopologues and reflects a temperature dependent preference of 13C and 18O to create a bond with each other in CO2 or in the carbonate lattice. Being an internal characteristic of the carbonate mineral, it is independent of the isotopic composition of the water in which equilibrium precipitation of the carbonate occurs and can therefore be used to independently determine carbonate growth temperatures. This work provides a first examination of the applicability of ‘clumped isotopes’ thermometry to reconstructing the growth temperatures of speleothems, by examining the glacial/interglacial variations of the Δ47 values of speleothem carbonates from Soreq cave, Israel. The results indicate that the last glacial maximum temperatures were 6–7 °C colder than modern day temperature and a sample at 56 Ky BP was 3 °C colder than the modern…” Glacial/interglacial temperature variations in Soreq cave speleothems as recorded by ‘clumped isotope’ thermometry
Dear Willis, I am afraid William Roberts is right on this. I am doing a PhD on speleothems and climate. The interpretation of d18O depends on many factors, and primarily on cave location. For instance, in monsoon regions, d18O usually shows precipitation amount through the “amount effect”: when there is more rainfall, your d18O values will be more negative, because the heavier isotopes rain out first… If you plot, for instance, Dongge cave record individually, you will see that the most negative values of the record (which you interpret as lower temperatures) will coincide with the Early Holocene, when it was really wet and warm.
Please don’t get me wrong. I support scepticism and open science. However, doing a bit more research before you start your analysis will dramatically enhance your credibility. I hope you see my point.
And, check climategate e-mails. Michael Mann is condemned even by his allies because of doing such poor analysis – like the one you did above. He used monsoon records as temperature proxies, in a very similar fashion.