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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Very interesting. Most studies cite the beginning of this interglacial period as starting at the end of the Younger Dryas cooling -11,550+ years ago. Other studies and papers indicate the end of the last interglacial occured prior to the Younger Dryas period. See Figure 2. Climate changes in the past 17,000 years for the GISP2 Greenland ice core.
http://www.globalresearch.ca/index.php?context=va&aid=10783
bubbagyro,
I think the point flew right over your head.
3 out of every 10,000 molecules in 1900 where CO2. Today 4 out of every 10,000 molecules are CO2. And they say it’s caused horrific things to planet Earth.
Which molecule has CO2 been replacing? H2, O2, CH4, H2O, etc
So the $64,000 question remains: Is our children learning what snow is?
bubbagyro says:
December 30, 2010 at 12:04 pm
Anything is possible says:
December 30, 2010 at 11:08 am
You mistake cause and effect—an epidemic these days.
____________________________________________________________
Why do the two have to be mutually exclusive?
Cannot something that is an effect of changing climate today wind up as being a cause of (non)-changing climate tomorrow?
That would certainly help to explain why the science is so darned complicated……
“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”.
You must be a great lover of fairy tails.
Jared says:
December 30, 2010 at 11:15 am
re; jar with 10,000 molecules in it
The best vacuum attainable in a lab still has 100 particles per cubic centimeter.
You might want to change the specification for your experiment from 10,000 molecules to some practical number like 10,000,000,000,000. Or better yet specify partial pressures of the different gases.
Brian H says:
December 30, 2010 at 12:33 pm
The existing word is anathematize.
Brian H says:
December 30, 2010 at 12:33 pm
jorge;
One might speculate how best to verb-ize “anathema”. Anathemate? Anathmetize?
😉
In greek it is “anathematizo” so it should be “anathematize”.
Where I live, another Ice Age like the last would mean only one month–July–would have average lows above freezing. And that would be by a measly 1 or 2 degrees F. How could anybody expect to grow ANYTHING with a growing season measured in days or weeks, rather than months? They flat out couldn’t. And as horendous as the prospects of the next Ice Age might be, I believe it has a far higher probability of happening than any catastrophic event the AGW people can dream up.
Bill Illis says:
December 30, 2010 at 11:09 am
On what basis are we so sure that insolation by itself is the only factor in interglacial termination? Is insolation the new CO2? I thought that climate was a complex system – maybe this is naive (its certainly politically incorrect).
Thanks for this post. Lots of interesting information.
~ ~ ~ ~ ~~ ~ ~ ~ ~ ~ ~ ~
From the 3rd paragraph: since the onset of the Northern Hemisphere Glaciations some 2.8 million years ago.
The Isthmus of Panama came into being at about 3 million years ago. The timing regarding the information in this post follows the closure of the “Central American Seaway”, so some may want to read about it.
Without getting into the argument of how it came to be, consider the Isthmus of Panama; http://en.wikipedia.org/wiki/Isthmus_of_Panama
Before that land came to be there was a “Central American Seaway” between the now-Atlantic and the now-Pacific Oceans. See this site for an explanation, maps, and a discussion of why this is important:
http://www.whoi.edu/oceanus/viewArticle.do?id=2508
Convergence of the of the Pacific, North American, and Caribbean tectonic plates was sufficiently well along by about 5 million years ago and the closure was likely in place about 3 million years ago.
The title of the last linked-to paper is:
How the Isthmus of Panama Put Ice in the Arctic:
Drifting continents open and close gateways between oceans and shift Earth’s climate
Here is a quote: “ The gradual shoaling of the Central American Seaway began to restrict the exchange of water between the Pacific and Atlantic, and their salinities diverged. . . . As a result of the Seaway closure, the Gulf Stream intensified. It transported more warm, salty water masses to high northern latitudes, where Arctic winds cooled them until they became dense enough to sink to the ocean floor. ”
This is an informative report with nice graphics.
———-
At 11:08 Anything is possible says: . . . the changes in surface topography which are an inevitable consequence of the building and disintegration of continental ice sheets . . .
I’ll restate this as Earth is dynamic. Some of the research dollars being thrown at the AGW concept might better be applied toward a better understanding of the transitions described in the McClenney Antithesis.
Doug in Seattle says:
December 30, 2010 at 11:19 am
It would be the ultimate climate irony . . .
As the effect of CO2 is logarithmic one gets a stronger response from the removal than one does from the addition but in the opposite direction.
Bill Illis,
“If you extend this forecast out now for 200,000 years, it looks like we do not fall below the magic 470 watts/m2 for 50,000 years, 130,000 years or even 170,000 years. So, this interglacial should be by far the longest one since the ice ages started.”
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.
[banzai voice]
It’s the great glaciation guesswork gamble! Will we freeze our fundaments off in:
a) 500 years?
b)1500 years?
c)50000 years?
Place bets NOW!!!
Great article by the way.
Amazingly excellent post…thank you!
William McClenney,
I found your article excellent in providing perspective on the natural variation in the current natural climate processes that could show an ending of the current interglacial (our beloved Holocene).
AGW theory has some significant competing hypotheses to contend with. : )
John
I found the charts in this post really interesting. It is the clearest picture I have seen of how the ice ages have evolved. Looking at Fig 1 the world’s climate clearly started to cool about 3 million years ago but maintained its sinusoidal pattern with a 41K year cycle. Then about 1 million years ago there was a sudden and (so far) irreversable change to a 100K cycles with each one characterised by a slow cooling and then a sudden brief warming.
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. Superimposed on this is a continuation of the overall cooling and an additional sudden and brief warming every 100K which I personally think looks like some sort of terrestial resonance effect linked to the ice formation. That is an overshoot and bounce back.
It seems bizarre to me that some are predicting that the current warm period will last for another 50000 years when none of the last 10 cycles have anything like this pattern. They appear to use Milankovitch type arguments. However everyone knows that whilst the Milankovitch patterns fit the data the mechanisms when translated to changes in insolation don’t make sense. Clearly the mechanisms are not yet understood so how can you make predictions. I’m for betting that history will repeat itself and that it is going to get colder pretty soon.
Fascinating.
From 5 million years ago to 1 million years ago, warm periods were at the frequency of one every 40,000 years or so. From 1 million years ago up to the present time, the frequency has been one every 100,000 years or so. Even more interesting is the very steady descent into overall cooling these last 5 million years. The Ice Age threshold was only regularly crossed from about 2.5 million years ago and since then things have got steadily worse (=colder, with bigger swings) although things might, just might have bottomed out.
I had to redo the Lisieki-Raymo chart and put it all on one line, to see all this clearly.
Lots of good stuff here that I’ll have to think about. Always good to see the geological perspective on climate change. Thanks for a very thought-provoking post.
Best for 2011, Pete Tillman
Consulting Geologist, Arizona and New Mexico (USA)
@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 ).
Wonderful stuff! Geology is the beautiful science. I think it is clear that the problem with modern climate science is that it was invented by astrophysicists who were ignorant of the venerable and considerable body of paleoclimatological work. Much of the past 30 years of modern climatology has been spent in fighting a rearguard action against prior paleoclimatological findings as they (the physicists) inevitably came to discover their existence and the inconvenient story they presented. They even put down their telescopes which were trained on Venus and took up the tools of the paleoclimatologist to re-jigger that science. The craziness of physicists studying tree rings! Geologists, who tend to be quiet genial types in the main, first off didn’t bother to join the discussion, busy as they always are, and ultimately were essentially shut out of the mainstream of a science to which they had the most to offer. Thankfully, for the wellbeing of humankind and other species put at risk by armageddon zealots, geologists are coming forward in the authoritative and gentleperson manner of their kind to quash the expensive silliness that has been let rage on far too long.
John from CA says:
December 30, 2010 at 11:53 am
=====
Sorry, I was wrong — I was referring to 25kyr BP to present (though I’m still having trouble with the megaboulder tossing).
Based on the following study (see figure 1), projected Pacific sea level at the Bering Strait ˜120kyr BP was above current levels. It seems reasonable to conclude that Atlantic Sea Level could have been 5-6 meters higher in the Bahamas during this period.
Influence of Bering Strait flow and North Atlantic circulation on glacial sea-level changes
PUBLISHED ONLINE: 10 JANUARY 2010 | DOI: 10.1038/NGEO729
Study: http://www.cgd.ucar.edu/ccr/publications/ngeo729.pdf
Figure 1: http://www.nature.com/ngeo/journal/v3/n2/fig_tab/ngeo729_F1.html
Excellent. Thanks. We need more stories like this. It is good to see the idea that AGW is probably not C getting discussed.
In taking a skeptical view of CAGW there are lots of people who will jump up to immediately dispute the AGW part who never get to discussing the C. From my point of view C is the most interesting letter and the evidence for Catastrophe is the weakest part of the entire CAGW story.
Great post, William.
I fully concur with:
John F. Hultquist says:
December 30, 2010 at 1:14 pm
“…I’ll restate this as Earth is dynamic. Some of the research dollars being thrown at the AGW concept might better be applied toward a better understanding of the transitions described in the McClenney Antithesis….”
These data and interpretations are very disturbing. It appears that in these latter days the Earth is being jerked around something fierce, if the data actually are meaningful. If this: “…abrupt warmings {or to put it another way, and much more ominously, coolings} that occurred from just a few years to mere decades that average between 8-10C rises (D-O 19 scored 16C)…” were to begin to happen to us now, I would imagine that millions would perish and all hell would break loose.
We should be spending our taxpayer dollars – if at all – on science without an agenda – science to understand our planet. Maybe the AGW folks are right, and maybe they’re wrong, but the focus of tax-payer funded science should be knowledge, period. We should ask our politicians to review and alter the governmental funding of science (and I think the new Republican majority in the House would be disposed to see it thus). Meanwhile we should withdraw funding from political purposes such as the IPCC (and much of anything else the United Nations does).
tallbloke says:
December 30, 2010 at 1:34 pm
[banzai voice]
It’s the great glaciation guesswork gamble! Will we freeze our fundaments off in:
a) 500 years?
b)1500 years?
c)50000 years?
Place bets NOW!!!
What I’m bothered about are:
a) 5 years
b) 15 years
c) 50 years
Everything else is someone else’s problem. Now if it did come to pass that we had an glacial period in
ourmy lifetime, then I will be very upset.I may even write a snotty letter to the Guardian.