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!
how do they determine date in this study?
MattN says:
May 26, 2010 at 6:38 pm
So, what exactly does “we are currently at the cold end of the Holocene” mean?
Historically, what’s next? Up or down? The word “end” in that sentence indicates to me the Holocene is about to end. Correct?
___________________________________________________________________________
That is a question open to a lot of debate.
1974 CIA Document on the Global Cooling Scare
Ice Ages are cyclical in nature and consist of approximately a 90,000-year glacial period followed by a relatively brief warming peak for 10,000 to12,500 years, called interglacials… Investigations indicate interglacials never extend beyond 12,500 years nor has the period ever been less than 10,000 years…. That this will occur within the next 2,500 years they are quite positive; that it may occur sooner is open to speculation….”
Ice Ages Confirmed: The Milankovitch theory
NASA: Intervals fell exactly where Milankovitch said they would
Past Climate Cycles: Ice Age Speculations
Sorry to ruin the fun, but an ice age cometh
In the middle of this presentation
is a graph with the current and other interglacials overlaid that is interesting to look at.
From Woods Hole Oceanographic Institution:
Abrupt Climate Change: Should We Be Worried?
Milankovitch Hypothesis Supported by Precise Dating of Coral Reefs and Deep-Sea Sediments
Extremist view:
Physicist Vladimir Paar: mankind needs to start preparing for the ice age
“The reality is that mankind needs to start preparing for the ice age. We are at the end of the global warming period. The ice age is to follow. … [W]e do not know precisely when it could start – but soon.”
The argument is over exactly what is meant by “soon” 10, 100, 1000 years or the 2,500 years max stated in the CIA report. Some reports even suggest we missed the change to an Ice age this time around and the earth will stay warm for another entire cycle.
Richard Hill says:
May 26, 2010 at 7:30 pm
Seems a shame so few southern hemisphere records. WRT Australia, would it be possible for the CSIRO to put more effort into collecting this type of raw data? Perhaps the resources they put into computer modelling could be diverted. The CSIRO might get more original multi-cited papers out of SH data collection, since they have better access to the study areas. In the computer modelling side the CSIRO is competing with huge resources from other countries. Much less chance of ground breaking multi-cited papers. Can anyone suggest a person with influence who could be contacted with these thoughts?
_________________________________________________________________________
I do know that Australia and South Africa have caves since I have been caving with people from both countries. I wonder if speleothem studies could be under taken if suitable caves can be found. Ships logs are another source of information for that area.
“I have posted the data I used, along with the R file that I wrote to analyze the data,”
Willis!!!! That is not the correct method! Someone may try to “Prove your work is incorrect”. Off to the CRU for some lessons in Methodology! 😉
“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.”
Just guessing, but the earth might be susceptible to regular ice ages until Antarctica moves away from the South Pole, millions of years from now. That’s when sea level will rise to higher than it is now. It will drop during the glacial periods, and come back up to about present levels in the interglacials.
O/T apologies but we have missed another bullet:
Kansas City Star: EU Commission backs off on higher CO2 emission goals
Hedegaard was presenting a report indicating that conditions for a 30 percent move “are clearly not met,” a point not included in a draft which was seen by the German news agency dpa on Tuesday…
http://www.kansascity.com/2010/05/26/1972982/eu-commission-backs-off-on-higher.html
yesterday Ben Webster from UK Times jumped the gun:
Australian (from UK Times): Ben Webster: Europe’s bold move on climate
EUROPE was tipped to introduce a new plan overnight to combat global warming, committing it to the world’s most ambitious targets.
The surprise plan proposes a massive increase in the target for cutting greenhouse gas emissions in this decade…
http://www.theaustralian.com.au/news/world/europes-bold-move-on-climate/story-e6frg6so-1225871740545
as did Bloomberg:
Carbon Rises as EU Outlines Steps Toward Tougher Climate Goal by Ewa Krukowska and Mathew Carr
“The EU carbon price may double under a 30 percent target, according to the statement citing Michael Wilkins, S&P’s global head of carbon markets”
http://www.businessweek.com/news/2010-05-26/carbon-rises-as-eu-outlines-steps-toward-tougher-climate-goal.html
phew!
anna v says:
May 26, 2010 at 8:27 pm
Extending the geologic time-frame out another 3 billion years should follow the last 3.5 billion years.
Simple decay of higher order to lower. Another snowball Earth or two in between.
Until the Sun expands and cooks the planet prior to itself conking out some few billion years further.
Nothing to do to prevent geologic-scale climate change…except invent Warp Drive and get outta here.
I have a couple of charts showing the transition out of the ice age from the Greenland and Antarctic ice cores which might help this a little.
http://img38.imageshack.us/img38/9509/transitioniceagegrlndan.png
http://img260.imageshack.us/img260/8371/transitioniceageco2.png
One thing is that the Northern Hemisphere has more up and down variability in the ice ages (the Younger Dryas was only one of about 16 different significant up and/or down events, (the Younger Dryas was not as important as the Older Dryas for example and the Younger Dryas is really being used for its “scare factor” by richard Alley and the like).
The bigger drop in the following chart is actually the Older Dryas at 14,500 years ago, not the Younger at 12,800 (also note that the temperatures are not calibrated properly in this chart, the temp change – from Richard Alley – should only be half as much).
http://www.wunderground.com/education/GISPIItemp.gif
Third, on the dO18 isotopes from the speleotherms, Paul Dennis would note that regional precipitation changes can have a big affect on the isotope measures so that has to be taken into account. I would say we should just use them as they are and say they give us a pretty good measure of temperature changes in this region. The formula used by Willis here of Temp = do18/0.36 is probably off a little and should be more like Temp = do18 / 0.45 for this latitude and the fact that it is not really close to the ocean. For high latitudes like Greenland and Antarctica, one can use 0.90 or so ie, each 1.0%% is close to 1.0C.
Flask says:
May 26, 2010 at 9:09 pm
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?
The blues will be sung on 6 Continents as Global Trade takes it on the chin.
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Hm. Contemplating speleothems and the warm-and-fuzzy Ursus maritimus supposedly drowning in the unforgiving Arctic Ocean as the ice vanishes between his insulated feet, just what the hell happened to despatch the cave bear (Ursus spelaeus) some twenty-seven millennia ago?
No, don’t tell me. It was anthropogenic global real estate development.
Humans competing with them poor, furry, innocent children of Mother Nature for space in those caves.
Doubtless we’ll find evidence of that in analyses of the stalactites and stalagmites. The residua of early, primitive realtors “blockbusting” the poor critters out of their homes….
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stevengoddard says:
May 26, 2010 at 4:02 pm
The Younger Dryas stadial, also referred to as the Big Freeze,[1] was a geologically brief (1,300 ± 70 years) cold climate period between approximately 12,800 and 11,500 years ago (between 10,800 and 9,500 BCE)
That coincides nicely with the dip at 10,000 BCE (12,000 YA); but what about the bigger dip at 13,000 BCE (15,000 YA)?
anna v says:
May 26, 2010 at 8:27 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.
Echenbach’s Hawk is apparently part bat since it flys around in caves.
ps. I like bats, most don’t.
MikeC says:
May 26, 2010 at 8:29 pm
Not sure what your point is here, Mike. Do you have some reason to think that the ratio d18O/T is constant around the world?
w.
bruce says:
May 26, 2010 at 8:30 pm
Good question. The dates were determined by each of the individual investigators of each cave. Typically, this is done by radiation decay. For example, one says:
You can find out more at the NOAA Paleoclimate site.
w.
Willis,
The “dip” following the “hump” actually marks the Younger Dryas. What your chart shows is that the onset of the Holocene was interrupted by the YD and actually delayed by about two thousand years. That period is problematic to paleontologists and archaeologists for several reasons. Massive extinctions are taking place. As Firestone and some others have observed there is a “nanodiamond” horizon marking the beginning of the event, but what is less commonly discussed is that the YD is also marked by an enormous C-14 anomaly which collapses near 2,000 years into an apparent 500 or so. So, in addition to Firestone’s possible extraterrestrial strike there is also a phenomenal radiation event with a large increase in cosmic rays to trigger the formation of excess C-14. The event was apparently very short in duration as well. I have yet to see any convincing hypothesis for the cause.
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Duster writes of “…in addition to Firestone’s possible extraterrestrial strike there is also a phenomenal radiation event with a large increase in cosmic rays to trigger the formation of excess C-14. The event was apparently very short in duration as well. I have yet to see any convincing hypothesis for the cause.”
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?
Roger MacBride Allen and astrophysicist Eric Kotani (Yoji Kondo) published the novel Supernova in 1991 to explore the possible effects of a violent cosmic event within (astronomically) close range of Sol system. Major bad juju. Might something of a like nature have occurred to account for that “enormous C-14 anomaly” in the Younger Dryas?
—
Hi WIllis,
one of the other useful conclusions which can be drawn from speleotherm data, (note spelling, I’m not a grammar nazi but it might save you some embarassment later) is that the MWP was a worldwide phenomenon. Speleotherm data from th southern hemisphere shows an upward blip around the MWP. There are some examples at co2sience.org of papers on New Zealand and South American speleotherms showing it.
Willis, I wonder if these glow worm filaments have any involvement in making stalactites and if so, what effect their delta-O18 might have on the reconstruction?
I have not asked specific permission to use this URL, but do look at
http://www.glowworm.co.nz/photo-gallery.html
Flask says:
May 26, 2010 at 9:09 pm
“Just guessing, but the earth might be susceptible to regular ice ages until Antarctica moves away from the South Pole, millions of years from now. That’s when sea level will rise to higher than it is now. It will drop during the glacial periods, and come back up to about present levels in the interglacials.”
Oh no. Can the UN do anything to stabilize the tectonic plates the way they are going to stabilize the global climate? No more than 2 C and 20 km should be the rallying call to save us. Perhaps a market for continental offsets and related derivatives could achieve this vital goal, with massive investments in research and monitoring by the IPCD. This will require sacrifices from the little people of course, whose sheer weight would clearly be the cause, and more global governance to address this coming global crisis.
But we must do it, for the children and the penguins.
I’m also deeply concerned about the sun. Its just a matter of time, and when it goes, the results could be catastrophic.
Duster says:
May 26, 2010 at 10:42 pm
“Massive extinctions are taking place. As Firestone and some others have observed there is a “nanodiamond” horizon marking the beginning of the event, but what is less commonly discussed is that the YD is also marked by an enormous C-14 anomaly which collapses near 2,000 years into an apparent 500 or so. So, in addition to Firestone’s possible extraterrestrial strike there is also a phenomenal radiation event with a large increase in cosmic rays to trigger the formation of excess C-14.”
It just keeps getting more interesting. But since those massive extinctions were quite selective, I wonder how/if this radiation effect could play into that?
Concerning the Younger Dryas, there was recently a pseudoscientific study from Univ. of New Mexico, linking its temporary fall back to ice age conditions with mammoth extinction, which stopped farting methane. They allegedly produced 10 billions kg CH4/year before. Comparing this tiny amount against the mass of the whole atmosphere with its 5×10^18t, it was clear it is pure nonsense, just to keep the idea of “greenhouse gases” as the main climate driver. Methane probably dropped, since the ice cover expanded and rotting organic matter like grass or plants – the main source of methane – were suddenly limited. Can the author make similar common sense rebuttal like with the Silver lining thing?
http://content.usatoday.com/communities/sciencefair/post/2010/05/mammoth-extinction-triggered-climate-cooling/1
Hi WIllis,
one of the other useful conclusions which can be drawn from speleotherm data, (note spelling, I’m not a grammar nazi but it might save you some embarassment later) is that the MWP was a worldwide phenomenon. Speleotherm data from the southern hemisphere shows an upward blip around the MWP. There are some examples at co2sience.org of papers on New Zealand and South American speleotherms showing it.
Concerning the Younger Dryas dip, there’s a good article on ‘Clovis culture’ in Wikipedia. Has the nanodiamonds and even “high levels of metal and magnetic spherules found deep inside the tusks and skulls of mammoths”.
If you are a mammoth I suppose having a comet land on you would ruin your whole day.
PS. no sign of William ‘Mr 5428’ Connolley in the history page.
tallbloke says:
May 27, 2010 at 12:25 am (Edit)
Thanks, tallbloke. CO2Science, the Idso’s excellent site, does have a variety of information on this subject as it relates to the MWP. I was more interested in a bit longer view of things.
I’m not a grammar nazi either, but I don’t find “speleotherm” in any dictionaries. The Encyclopedia Britannica says:
McGraw-Hill dictionary says:
Finally, the NOAA Paleoclimatology web site I referred to in the original post is headed:
Thanks for the comment,
w.