You know, in science, there was once this thing we called the Theory of Multiple Working Hypotheses. Anathema (a formal ecclesiastical curse accompanied by excommunication) in modern climate science. So, in juxtaposition to the hypothesis of future global climate disruption from CO2, a scientist might well consider an antithesis or two in order to maintain ones objectivity.
One such antithesis, which happens to be a long running debate in paleoclimate science, concerns the end Holocene. Or just how long the present interglacial will last.
Looking at orbital mechanics and model results, Loutre and Berger (2003) in a landmark paper (meaning a widely quoted and discussed paper) for the time predicted that the current interglacial, the Holocene, might very well last another 50,000 years, particularly if CO2 were factored in. This would make the Holocene the longest lived interglacial since the onset of the Northern Hemisphere Glaciations some 2.8 million years ago. Five of the last 6 interglacials have each lasted about half of a precession cycle. The precession cycle varies from 19-23k years, and we are at the 23kyr part of the range now, making 11,500 years half, which is also the present age of the Holocene.
Which is why this discussion has relevance.
But what about that 6th interglacial, the one that wasn’t on the half-precessional “clock”. That would be MIS-11 (or the Holsteinian) which according to the most recently published estimate may have lasted on the order of 20-22kyrs, with the longest estimate ranging up to 32kyrs.
Loutre and Berger’s 2003 paper was soon followed by another landmark paper by Lisieki and Raymo (Oceanography, 2005), an exhaustive look at 57 globally distributed deep Ocean Drilling Project (and other) cores (Figure 1), which stated:
“Recent research has focused on MIS 11 as a possible analog for the present interglacial [e.g., Loutre and Berger, 2003; EPICA community members, 2004] because both occur during times of low eccentricity. The LR04 age model establishes that MIS 11 spans two precession cycles, with 18O values below 3.6o/oo for 20 kyr, from 398-418 ka. In comparison, stages 9 and 5 remained below 3.6o/oo for 13 and 12 kyr, respectively, and the Holocene interglacial has lasted 11 kyr so far. In the LR04 age model, the average LSR of 29 sites is the same from 398-418 ka as from 250-650 ka; consequently, stage 11 is unlikely to be artificially stretched. However, the June 21 insolation minimum at 65N during MIS 11 is only 489 W/m2, much less pronounced than the present minimum of 474 W/m2. In addition, current insolation values are not predicted to return to the high values of late MIS 11 for another 65 kyr. We propose that this effectively precludes a ‘double precession-cycle’ interglacial [e.g., Raymo, 1997] in the Holocene without human influence.”
Figure 1. The past 5 million years of climate from 57 globally distributed sediment cores. (a general definition of an interglacial since the MPT is the oxygen 18/oxygen 16 isotope ratio must drop to 3.6 parts per mil)
To bring this discussion up to date, Tzedakis (Figure 2, his figure 3), in perhaps the most open peer review process currently being practiced in the world today (The European Geosciences Union website Climate of the Past Discussions) published a quite thorough examination of the state of the science related to the two most recent interglacials, which like the present one, the Holocene (or MIS-1) is compared to MIS-19 and MIS-11, the other two interglacials which have occurred since the Mid Pleistocene Transition (MPT) and also occurred at eccentricity minimums. Since its initial publication in 2009, and its republication after the open online peer review process again in March of this year (2010), this paper is now also considered a landmark review of the state of paleoclimate science. In it he also considers Ruddiman’s Early Anthropogenic Hypothesis, with Ruddiman a part of the online review. Tzedakis’ concluding remarks are enlightening:
“On balance, what emerges is that projections on the natural duration of the current interglacial depend on the choice of analogue, while corroboration or refutation of the “early anthropogenic hypothesis” on the basis of comparisons with earlier interglacials remains irritatingly inconclusive.”
An astute reader might have gleaned that even on things which have happened, the science is not that particularly well settled. Which makes consideration of the science being settled on things which have not yet happened dubious at best.
As we move further towards the construction of the antithetic argument, we will take a closer look at the post-MPT end interglacials and the last glacial for some clues.
Higher resolution proxy studies from many parts of the planet suggest that the end interglacials may be quite the wild climate ride from the perspective of global climate disruption.
Boettger, et al (Quaternary International 207 [2009] 137–144) abstract it:
“In terrestrial records from Central and Eastern Europe the end of the Last Interglacial seems to be characterized by evident climatic and environmental instabilities recorded by geochemical and vegetation indicators. The transition (MIS 5e/5d) from the Last Interglacial (Eemian, Mikulino) to the Early Last Glacial (Early Weichselian, Early Valdai) is marked by at least two warming events as observed in geochemical data on the lake sediment profiles of Central (Gro¨bern, Neumark–Nord, Klinge) and of Eastern Europe (Ples). Results of palynological studies of all these sequences indicate simultaneously a strong increase of environmental oscillations during the very end of the Last Interglacial and the beginning of the Last Glaciation. This paper discusses possible correlations of these events between regions in Central and Eastern Europe. The pronounced climate and environment instability during the interglacial/glacial transition could be consistent with the assumption that it is about a natural phenomenon, characteristic for transitional stages. Taking into consideration that currently observed ‘‘human-induced’’ global warming coincides with the natural trend to cooling, the study of such transitional stages is important for understanding the underlying processes of the climate changes.”
Hearty and Neumann (Quaternary Science Reviews 20 [2001] 1881–1895) abstracting their work in the Bahamas state:
“The geology of the Last Interglaciation (sensu stricto, marine isotope substage (MIS) 5e) in the Bahamas records the nature of sea level and climate change. After a period of quasi-stability for most of the interglaciation, during which reefs grew to +2.5 m, sea level rose rapidly at the end of the period, incising notches in older limestone. After brief stillstands at +6 and perhaps +8.5 m, sea level fell with apparent speed to the MIS 5d lowstand and much cooler climatic conditions. It was during this regression from the MIS 5e highstand that the North Atlantic suffered an oceanographic ‘‘reorganization’’ about 118.73 ka ago. During this same interval, massive dune-building greatly enlarged the Bahama Islands. Giant waves reshaped exposed lowlands into chevron-shaped beach ridges, ran up on older coastal ridges, and also broke off and threw megaboulders onto and over 20 m-high cliffs. The oolitic rocks recording these features yield concordant whole-rock amino acid ratios across the archipelago. Whether or not the Last Interglaciation serves as an appropriate analog for our ‘‘greenhouse’’ world, it nonetheless reveals the intricate details of climatic transitions between warm interglaciations and near glacial conditions.”
See Figure 3 (also figure 3 in their study)
and Figure 4 (figure 5 in their study).
- Figure 4. The MIS-5e notch (photo A) and modern notch (photo B) (Hearty and Neumann, 2001, figure 5).
The picture which emerges is that the post-MPT end interglacials appear to be populated with dramatic, abrupt global climate disruptions which appear to have occurred on decadal to centennial time scales. Given that the Holocene, one of at least 3, perhaps 4 post-MPT “extreme” interglacials, may not be immune to this repetitive phenomena, and as it is half a precession cycle old now, and perhaps unlikely to grow that much older, this could very well be the natural climate “noise” from which we must discern our anthropogenic “signal” from.
If we take a stroll between this interglacial and the last one back, the Eemian, we find in the Greenland ice cores that there were 24 Dansgaard-Oeschger oscillations (Figure 5, originally figure 1. Sole et al, 2007), or abrupt warmings that occurred from just a few years to mere decades that average between 8-10C rises (D-O 19 scored 16C). The nominal difference between earth’s cold (glacial) and warm (interglacial) states being on the order of 20C. D-O events average 1470 years, the range being 1-4kyrs.
Sole, Turiel and Llebot writing in Physics Letters A (366 [2007] 184–189) identified three classes of D-O oscillations in the Greenland GISP2 ice cores A (brief), B (medium) and C (long), reflecting the speed at which the warming relaxes back to the cold glacial state:
“In this work ice-core CO2 time evolution in the period going from 20 to 60 kyr BP [15] has been qualitatively compared to our temperature cycles, according to the class they belong to. It can be observed in Fig. 6 that class A cycles are completely unrelated to changes in CO2 concentration. We have observed some correlation between B and C cycles and CO2 concentration, but of the opposite sign to the one expected: maxima in atmospheric CO2 concentration tend to correspond to the middle part or the end the cooling period. The role of CO2 in the oscillation phenomena seems to be more related to extend the duration of the cooling phase than to trigger warming. This could explain why cycles not coincident in time with maxima of CO2 (A cycles) rapidly decay back to the cold state. ”
“Nor CO2 concentration either the astronomical cycle change the way in which the warming phase takes place. The coincidence in this phase is strong among all the characterized cycles; also, we have been able to recognize the presence of a similar warming phase in the early stages of the transition from glacial to interglacial age. Our analysis of the warming phase seems to indicate a universal triggering mechanism, what has been related with the possible existence of stochastic resonance [1,13, 21]. It has also been argued that a possible cause for the repetitive sequence of D/O events could be found in the change in the thermohaline Atlantic circulation [2,8,22,25]. However, a cause for this regular arrangement of cycles, together with a justification on the abruptness of the warming phase, is still absent in the scientific literature.”
In their work, at least 13 of the 24 D-O oscillations (indeed other workers suggest the same for them all), CO2 was not the agent provocateur of the warmings but served to ameliorate the relaxation back to the cold glacial state, something which might have import whenever we finally do reach the end Holocene. Instead of triggering the abrupt warmings it appears to function as somewhat of a climate “security blanket”, if you will.
Therefore in constructing the antithesis, and taking into consideration the precautionary principle, we are left to ponder if reducing CO2’s concentration in the late Holocene atmosphere might actually be the wrong thing to do.
The possibility consequently exists that at perhaps precisely the right moment near the end-Holocene, the latest iteration of the genus Homo unwittingly stumbled on the correct atmospheric GHG recipe to perhaps ease or delay the transition into the next glacial. Under the antithesis “Skeptics” and “Warmists” thus find themselves on the mutual, chaotic climate ground where the efficacy of CO2 as a GHG had better be right.
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William reckons
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we are left to ponder if reducing CO2’s concentration in the late Holocene atmosphere might actually be the wrong thing to do.
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This is kind of misleading. It is not proposed to reduce CO2, it is proposed to not allow it to increase without limit.
William, you have presented evidence that the subtle change in Solar insolation leading into the next ice age will produce extremely variable climate. I already understood that the climate can do some pretty wild things for no known reason.
On that basis you reckon that a bunch of monkeys playing with the levers on a climate machine that they don’t understand, is an OK thing and might even be beneficial.
I take it you enjoy playing Russian Roulette???
Take into account that with the new founding of the age of the homo sapiens race having existed for about twice as long “we” have gone through twice as many “MIS’s” or all the five MIS’s in fig 3.
Amazing what happens with time and better equipment and the higher, and more accurate, resolutions it all gives. Every time is like it has never happened before and that’s what’s amazing.
@Gary Young Pearse says:
December 30, 2010 at 2:44 pm
“…the problem with modern climate science is that it was invented by astrophysicists…”
Unfortunately for your hypothesis, most of these AGW proponents that we’re dealing with in this arena are in fact geologists (Mann also has a degree in physics, but his highest and most recent are in geology). Perhaps I’m mistaken, but I believe most degrees in climatology are awarded in the departments of earth sciences at the several universities. These people should know better.
William claims
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n their work, at least 13 of the 24 D-O oscillations (indeed other workers suggest the same for them all), CO2 was not the agent provocateur of the warmings
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William it looks like you are trying to fly the popular but bogus argument that: CO2 increases did not trigger warming in the past therefore CO2 cannot trigger warming now.
That was then this is now. Large changes in atmospheric CO2 are rather rare in the past and typically cause by massive volcanic eruptions. The rise of an intelligent species that generates a lot of CO2 should be considered a very special event in the earth’s history.
Excellent post. Geological time certainly does put things in perspective.
So not unprecedented then, eh?
Overall it is refreshing to read people discussing what we do not yet know, rather than claiming that they already know everything and drawing extremely dubious conclusions from ‘thin air’.
For a long time I’ve concluded that the CO2 paradigm is a monumental red herring- a miniscule influence on climate- trivial efffect on temperature- but substantial serendipitous benefic in crop yield and plant growth rate. The tragic aspect is that most ‘climate scientists’ have no geological perspective at all, and do not study the causes and controls of the glacial/interglacial cycles. The next step change inevitably is the switch down to the next full glaciation, just when?
JimF says:
December 30, 2010 at 2:41 pm
@Brian H says:
December 30, 2010 at 12:33 pm
The verbal form is:
anathematize |əˈnaθəməˌtīz|
verb [ trans. ]
curse; condemn : she anathematized Tom as the despoiler of a helpless widow.
ORIGIN mid 16th cent.: from French anathématiser, from Latin anathematizare, from Greek anathematizein, from anathema (see anathema ).
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On the other hand even etymology has its antitheses:
anathemize
verb
1. wish harm upon; invoke evil upon; “The bad witch cursed the child” [syn: curse] [ant: bless]
2. curse or declare to be evil or anathema or threaten with divine punishment [syn: accurse]
WordNet® 3.0, © 2006 by Princeton University.
I can just imagine the anguished cries we would hear from the CAGW proponents if we were in a glacial period right now, adding CO2. The mastodons are dying out! The Appalachian mountains will lose their permanent snow cover! Our crops will wilt in the hot summers! and best of all: Sea levels will rise hundreds of feet!!
LazyTeenager says:
December 30, 2010 at 3:11 pm
This is kind of misleading. It is not proposed to reduce CO2, it is proposed to not allow it to increase without limit.
Not so fast, Lazy,
http://www.columbia.edu/~jeh1/2008/TargetCO2_20080407.pdf
Title: Target Atmospheric CO2: Where Should Humanity Aim?
Date: not given
1st author: James Hansen [+8 others]
Target:
CO2 will need to be reduced from its current 385 ppm to at most 350 ppm
William says:
“An astute reader might have gleaned that even on things which have happened, the science is not that particularly well settled. Which makes consideration of the science being settled on things which have not yet happened dubious at best.”
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Well said.
@LazyTeenager says:
December 30, 2010 at 3:22 pm
“…That was then this is now. Large changes in atmospheric CO2 are rather rare in the past and typically cause by massive volcanic eruptions. The rise of an intelligent species that generates a lot of CO2 should be considered a very special event in the earth’s history….”
That may the most unintelligent comment I’ve ever seen posted here at WUWT. There’s no accounting for silliness.
The Anti-[CO2]thesis = understanding the:
– poorly defined Carbon Cycle
– poorly defined Water Cycle
– poorly understood Solar Cycle
– poorly managed data
– lack of key factors: salinity, fresh water Ocean input, chemical input, etc.
– lack of holistic thinking
– lack of appropriate tools
– lack of structured logic in programming
– lack of Global standards and structured metadata
this could go on for quite a while but thanks for the post : )
Vince Causey says:
December 30, 2010 at 1:25 pm
Bill Illis,
“Insolation is not only the product of orbital configurations, but also of albedo, which is in great part a dependent on clouds. I think it optimistic to declare the longevity of our interglacial on orbitals alone.”
Actually, you are quite right that it is Albedo that controls the glacial cycles – it is not solar insolation at 65N or 75N. If fact, in most of the ice ages, the total global solar irradiance is actually higher than it is today. Cloudiness is also lower in the ice ages than it is today.
The ice ages are driven by Ice-Albedo feedback, which starts initially at 75N. That is is where the snow and ice currently melts in the summer and farther north than this, it doesn’t really melt back much at all in the summer.
When the solar insolation at 75N in the summer falls low enough so that Arctic sea ice and the snow on Ellesmere Island and north Greenland doesn’t melt completely in the summer, the glaciers build up, more sunlight is reflected, the Earth cools off very slightly and then the Albedo-feedback kicks in and 30,000 years later, there are glaciers in Chicago.
Right now, the winter snow (except for high elevations) melts on Ellesmere Island and northern Greenland in the summer. The Arctic sea ice melts back at 75N in the summer. If the summer solar insolation is not going decline very much at this latitude for at least 50,000 years, the ice-Albedo-feedback will not kick in. The forecasts say it is not going to happen for probably 170,000 years. The summer sunshine will be warm enough to melt the winter snow and no additional glaciers will build up.
I’ve long tried to see in the charts where we stood on the Milankovich cycles and when the Holocene would end, and not been able to come to any conclusions. This post has broadened my understanding of the topic to the point where I now know why I don’t know when.
The info on the interglacials prior to the Eemian is very helpful. Thanks.
I shall suppress the grammar n*zi in me screaming to weigh in on some of the above comments.
cal says:
December 30, 2010 at 2:20 pm
“However I have some doubt about the 100K cycles. It seems that in counting the peaks and troughs in the last million years some of them have been ignored. When I count them all I find that there are about 50 reversals in every million years just the same as before. It looks like the underlying forcing is still there.”
It looks the 41kyr cycle is still present in the 100kyr sequence, and the 41kyr sequence is in the 100kyr signal, but weak. The 41kyr sequence also looks like it has other frequencies in it. I find it hard to believe such saw toothed signals could be produced by orbital variations. It`s all very much based on the idea that TSI variation is the issue, if it happens to be the strength of the solar wind that matters instead, then the orbital variations could well be not too important.
From the 41k/100k beats, I would be looking at a repeat of the end of inter-glacial`s 11 and 19.
December 30, 2010 at 4:55 pm
typo, that was “100k in the 41k” {2nd line}
LazyTeenager says:
December 30, 2010 at 3:22 pm
William it looks like you are trying to fly the popular but bogus argument that: CO2 increases did not trigger warming in the past therefore CO2 cannot trigger warming now.
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The latest science says that CO2 causes cold and snow
“If the summer solar insolation is not going decline very much at this latitude for at least 50,000 years, the ice-Albedo-feedback will not kick in. The forecasts say it is not going to happen for probably 170,000 years. The summer sunshine will be warm enough to melt the winter snow and no additional glaciers will build up.”
_____________________________________________________________
The” joker in the pack” however, would be large-scale volcanic activity. An eruption the size of Toba (c.75,000 BP) thought to be 100x larger than Pinatubo, MAY be enough to cool the summers for long enough for the ice-albedo effect to kick in after the dust has (literally) settled.
Such events are totally unpredictable of course, but if I were a bookmaker I would not lay long odds on getting through the next 170,000 years without one.
OT, but take a look this over at FOX News:
“NASA Scientist Publishes ‘Colonizing the Red Planet,’ a How-To Guide”
Read more: http://www.foxnews.com/scitech/2010/12/30/nasa-scientist-publishes-colonizing-red-planet-guide/#ixzz19eQ4iPGh
Having successfully manipulated the climate of the Earth, the folks over at NASA are ready to terraform the Red Planet! Perhaps they can profitably apply their proven CO2 reduction schemes to that atmosphere. But a lot of funding will be required. Maybe a new carbon tax? (LOL) This project will be a good task for the new Muslim scientists that Obama will be bringing on board at NASA in the future.
Using words such as abrupt and extreme to describe earth events that can only be measured over geologic time only highlights the problem facing humans. At the one extreme we attempt to attribute single events to climate change. But at the other we mistakingly think humans are affected – even interested – in climatic changes that take thousands of years to manafest. How many generations can you trace back your ancestry. Your interest in climate will not extend back much further.
Professor Nir Shaviv’s (Jerusalem University) research could help answer some of the questions raised about ice age cycles. It also provides a ready explanation for the “climate instability” noticed.
I understand the Solar System’s present galactic position is just inside the boundary of the Orion spur spiral arm (preparing to cross: please have all woollies and extreme winter wear ready). If Shaviv is right, the next ice age could start real soon now and be a humdinger … but before it does, we can expect a lot of ups and downs in warming/cooling.
JimF says:
December 30, 2010 at 3:19 pm
@Gary Young Pearse says:
December 30, 2010 at 2:44 pm
“…the problem with modern climate science is that it was invented by astrophysicists…”
Yes a lot of new “geoscientists” were created by the theory, many moving in from biology, astrophysics (Hansen – astrofizz can be said to be one of the founding fathers – hence my remarks about telescopes and Venus), members of the anachronistic pseudo-science geography (you remember learning in geog that coffee grows in brazil and that the capital of Ecuador is Quito). Oh and how about another founding father: a british diplomat:
http://blogs.telegraph.co.uk/news/jamesdelingpole/100069775/the-man-who-invented-global-warming/
Virtually all geologists of the calibre of this post’s author that I know agree that CAGW is not demonstrated by the flawed work of its proponents. All the same folks also KNOW that the climate has changed radically throughout its 4+Byr history. Jim be impressed. This is a superb paper delivered in a very well mannered and compelling way.
I can remember being taught that the Theory of Multiple Working Hypotheses was a viable exercise as long as you didn’t let one hypothesis become dominant. It would appear that with AGW, CO2 warming has taken the dominant position and drowned out everything else.
alan says:
December 30, 2010 at 6:27 pm
Spot the risible oxymoron in your post! 😉