The Antithesis

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.”

Figure 2. Tzedakis (2010) comparing the Holocene with the previous 4 interglacials.

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)

Figure 3. Rapid Sea Level Spike at the end of MIS-5, the Eemian.

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.

Figure 5. Dansgaard-Oeschger oscillations with their cycle designations. (Sole et al, 2007)

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.”

Figure 6. Sole et al (2007) D/O oscillation classes.

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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112 thoughts on “The Antithesis

  1. The second sentence of the post is:
    Anathema (a formal ecclesiastical curse accompanied by excommunication) in modern climate science.
    Removing the parenthetical clause yields:
    Anathema in modern climate science.
    Where is the verb that could help me understand the point? What is the anathema? Do you mean that alternate hypotheses are anathemas to the Warmists?

  2. Newt Love says:
    December 30, 2010 at 10:08 am

    “The second sentence of the post is:
    Anathema (a formal ecclesiastical curse accompanied by excommunication) in modern climate science.
    Removing the parenthetical clause yields:
    Anathema in modern climate science.
    Where is the verb that could help me understand the point? What is the anathema? Do you mean that alternate hypotheses are anathemas to the Warmists?”

    I’d assumed that the previous period should’ve been a hyphen, but I do tend to overuse such punctuation.

  3. 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.
    =========================================================

    One of the many skeptical perspectives is that warming is a good thing. Many of us have been saying this for years. I very seriously doubt ACO2 emissions have much to do with anything, but if it were to be a cause of warmth, we should do more of it.

  4. A VERY thought provoking article. Thank you, this certainly was one worth reading. (even if some of the jargon is a bit beyond my comprehension)

    @Newt: Any hypothesis (or evidence even!) that disagrees with AGW is an anathema to the Warmista’s – after all, such theories would undermine their funding and alarmism.

  5. This article is a good illustration of why geologists, by and large, have not been invited into the CAGW discussion. An understanding of past climate variations inconveniences those who claim current warming is CO2 induced and unprecedented.

  6. Two other conditions must occur to create the interglacials. Obliquity must be approaching maximum and perihelion must be in NH summer. These conditions all lined up about 10 -12000 years ago. Back of the envelope calculations indicate this condition, where all come together, occurs about every 100,000 years.

  7. An excellent post!
    It highlights the science that motivates the better informed AGW zealots.
    It is a fact that the global climate has repeatedly flipped by 10 degrees or more on a dime, in a few decades or less, maybe much less.
    We do not know why, but we do know it has happened often in relatively recent times, geologically speaking..
    The AGW crowd, imo, knows this and is terrified that such an excursion could result from our GHG emissions. The atmosphere is so poorly understood that it is equally possible that the result would be a sharp drop in global temperature, but that is not the propaganda path they chose.
    The heart of their message is that this is the only environment we have, it is pretty good, but it is pretty unstable, so let’s not mess with it. Lots of other elements will anyways.
    I for one would see this as a credible message.Too bad it has gotten lost in the scuffle.

  8. It’s curious how scientists have clung to the reductionist view that carbon and only carbon is a factor in global warming. Possible effects of the precessional cycle, activity on the sun’s surface and other possibly very relevant factors such as deforestation which only began about 5000 years ago don’t seem to attract any interest.

    But then I have always suspected scientists don’y much care for the complexity of problems that do not offer prospects of immediate and generous research grants. I mean who is going to care about a problem that needs 23k years research?

  9. Why is it that the biggest feedback mechanism of all – the changes in surface topography which are an inevitable consequence of the building and disintegration of continental ice sheets – gets nary a mention in the discussion of glacial/inter-glacial cycles?

    At the height of the last glaciation, the ice sheets over North America and Europe were 3-4km thick. Simply by applying Environmental Lapse Rates (ELR), we can deduce that the surface temperatures in these regions would have been 20-25C cooler than today, merely because of their increased height above sea level.

    Additionally, when an area is covered with ice, it is subject to both erosion – vast quantities of material are transported out of the region – and glacio-isostatic depression, meaning that when the ice is removed, the topography would be considerably different – and different in a way that would serve to ameliorate subsequent surface temperatures – than before glaciation took place.

    I’m sorry, but I don’t see how any discussion of how the Earth’s climate switches between glacial and inter-glacial cycles can exclude this effect and hope to tell the full story.

  10. If you look at the forecast June insolation at 65N, it is going to decline (very, very slightly, just a few watts/m2) from today for another 1,000 years before starting back up again.

    The magic insolation number is something like 450 to 470 watts/m2 (the summer sunshine at about 9:00 am if you live at 40N, the centre latitude of the US) so this is high enough to melt all the snow during the summer in the far north (especially since there are more hours of it in the summer). The forecast shows it staying above the 480 watts/m2 at the peak low period in about 1,000 years.

    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.

  11. It might be worth noting that the sudden sea-level spike at the end of MIS 5e (and a supposedly even higher at about 15 meter near the end of MIS 11) are extremely dubious.

    Neither is visible in the isotope record and the interpretation of features in Bahamas and Bermuda as indicating those extremely high sea levels is controversal, to put things mildly. They are not based on indisputable coastline features, and isolated finds and patches of marine deposits at high level mean very little in areas where hurricanes are common.
    Even the endlessly repeated figure of 6 meter sea level rise during the last interglacial is very doubtful. The best data from the most tectonically stable coasts such as the Gawler craton and the Coorong coastal plain in Australia makes a figure of about 2 meters for both MIS 5e and MIS 11 more likely.

    The reason for the popularity of the high sea-level figures is that they support the catastrophy scenarios about collapses of the Greenland and West Antarctic ice caps. As a matter of fact the 6 meter figure seems to have been originally postulated based on how much the sea-level should rise if the WAIS collapsed!
    That all drill-holes in Greenland (including even the small Renland icecap) has found ice of last interglacial age is simply ignored, as is the evidence from the AND-1B drilling in the Ross Sea that shows that the ice in the Ross embayment has never been appreciably smaller than at present since the MIS 31 “super-interglacial” more than a million years ago.

    Here is a couple of more interesting conundrums in the Pleistocene record.

    MIS 13 is a very “wimpy” interglacial in the marine isotope record when apparently a large proportion of glacial ice never melted. However in the continental record in Eurasia (loess profiles and animal and plant fossils) it was a very major interglacial, quite possibly the longest and warmest of all. The only reasonable explanation seems to be that it was an “unipolar” interglacial when much of the ice in Antarctica never melted. However nobody has a clue how this would work.

    Neither does anybody really know why glacial cycles shifted from 40,000 year length to 100,000 year length about a million years ago. This, the Mid Pleistocene Transition (MPT) was a major shift that did not only affect the length of ice-ages, but also had major effect on a multitude of other things. For example it seems that really large coral reefs did not exist before the MPT.

  12. Could James Hansen do this experiment for me?

    - Make 7 jars with exactly 10,000 molecules in each and make it a sample of 1900 air with 3 molecules of CO2 out of the 10,000 molecules.
    - Leave one jar as a Constant
    - Take jar #2 and take out a Methane Molecule and add a CO2 molecule in it’s place (today’s CO2 content)
    - Take jar #3 and take out 4 Methane Molecules and add 4 CO2 molecules in it’s place (doubling of CO2)
    - Take jar #4 and take out an Oxygen Molecule and add a CO2 molecule in it’s place (today’s CO2 content)
    - Take jar #5 and take out 4 Oxygen Molecules and add 4 CO2 molecules in it’s place (doubling of CO2)
    - Take jar #6 and take out a Hydrogen Molecule and add a CO2 molecule in it’s place (today’s CO2 content)
    - Take jar #7 and take out 4 Hydrogen Molecules and add 4 CO2 molecules in it’s place (doubling of CO2)

    - Which jar gets the warmest? Oxygen replaced by CO2? Hydrogen replaced by CO2? Or Methane replaced by CO2? And which one of these is closest to the type of warming we are getting.

    Do not pump in CO2 to unrealistic conditions. If going from 3 CO2 molecules out of 10,000 to 4 CO2 Molecules out of 10,000 is so horrible as you claim, then your test should be horrific.

    Please Jimmy do the experiment and report back.

  13. Good to see some geoscience oriented MWH analysis applied to such a highly complex subject. Something I have been beating the drum for since my undergraduate days. (A long, long time ago) Lots of good information much new to me so I will need to think about it and probably spend some time at the library.

    Not only do we have more questions then answers generated but you have provided a good example of what we do not know. Knowing what we do not know is ultimately the most important part of any scientific understanding of anything. To be a practitioner of the Philosophy of Science is to approach the world with a questioning and skeptical mind set. The only settled part of anything is the understanding that nothing ever is. The only absolute is their probably aren’t any.

  14. It would be the ultimate climate irony if lowering CO2 forced an ice age. This would of course only be possible if CO2 is the great powerful heat trapping gas it is reputed to be by the alarmists – something that has yet to be established.

  15. Newt Love – In normal usage of the English language, sentences (the set of words between full stops), don’t always contain verbs. The trick (if I can use that word here) is to interpret from context. In such cases, either the meaning is obvious anyway, or it typically relates to the previous sentence or last part of same. What you have done in your comment is to drop the previous sentence, thus leaving the cited sentence without context. Not clever.

    Putting it back in, we get: You know, in science, there was once this thing we called the Theory of Multiple Working Hypotheses. Anathema in modern climate science. Clearly, what is being said is that the Theory of Multiple Working Hypotheses is anathema in modern climate science.

    I have no difficulty in accepting that the way it was expressed, while maybe not grammatically perfect, was at least as effective and economical as, for example:
    “You know, in science, there was once this thing we called the Theory of Multiple Working Hypotheses. The Theory of Multiple Working Hypotheses is anathema in modern climate science.”
    or:
    “You know, in science, there was once this thing we called the Theory of Multiple Working Hypotheses, which is anathema in modern climate science.”
    particularly as the author did include the parenthetical clause.

    To me, English as she is is fascinating. There is no correct pronunciation or spelling of any word (lexicographers simply record actual usage), and new words appear in the language without authority while other words disappear without any official pronouncement (NPI). Grammar similarly. Yet one of the worst things that schools can do is fail to teach correct spelling, pronunciation and grammar. So there is no correct form, yet the correct form must be taught. A paradox indeed.

  16. Of course we should have realized it; there is good science being practiced in the climate science community.

    Perhaps it should be the focus of climate science to better clarify just how long we’ve got before descending into another ice age. Anything else (CAGW, for instance) is a major distraction from this goal.

  17. Jared says:
    December 30, 2010 at 11:15 am
    Could James Hansen do this experiment for me?

    JH: Do you mean a Model?. Please clarify: What the heck “experiment” is?

  18. Great post, fascinating, confusing, and disturbing all in one.

    “It was during this regression from the MIS 5e highstand that the North Atlantic suffered an oceanographic ‘‘reorganization’’ about 11873 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.”

    from prior studies:
    14k BP we had human migration across the Bering land bridge and hunting settlements along Eastern Siberia and Alaska.

    As the Oceans rose, Bering Strait is 49 meters deep at its lowest and the Oceans fell 120-150 meters during the glacial, the Strait reopened and altered Atlantic currents. This reopening gradually occurred ˜12-10k BP.

    The Bahamas are in hurricane alley but hurricanes aren’t capable of tossing “megaboulders onto and over 20 m-high cliffs”. Tidal waves from calving east coast glaciers? The ice sheets stopped in and around the NYC area. The scale of ocean displacement required to create tidal waves on this scale seems unlikely given east coast shoreline depth.

    About the only thing that seems to makes sense within the time frames mentioned in the post is tsunami as the crust rebounded or icebergs crashing into the islands. I can easily buy the massive dune-building but the tossing “megaboulders onto and over 20 m-high cliffs” is pretty hard to explain.

  19. The Antithesis is possibly the most significant posting on WUWT since I’ve been visiting here.
    A real eye opener

  20. Anything is possible says:
    December 30, 2010 at 11:08 am

    You mistake cause and effect—an epidemic these days.

    Jared says:
    December 30, 2010 at 11:15 am

    10,000 molecules in a jar would produce a vacuum lower than anywhere now known in the universe, and a much lower vacuum than man is able to generate in the laboratory (at the size of a jar).

  21. James, Bill;
    From your lips(es) to the Climate God(s)’s ears! More Warming = More Life. More Cooling = More Death!

    tty;
    Yes, cherry-picking seems to relate to more than trendline start-stop dates, doesn’t it?

  22. 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

  23. 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

  24. 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……

  25. “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.

  26. 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.

  27. 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”.

  28. 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.

  29. 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).

  30. 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.

  31. 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.

  32. 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.

  33. [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.

  34. 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

  35. 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.

  36. 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.

  37. 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)

  38. @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 ).

  39. 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.

  40. 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

  41. 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.

  42. 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).

  43. 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 our my lifetime, then I will be very upset.

    I may even write a snotty letter to the Guardian.

  44. William reckons
    ———–
    we are left to ponder if reducing CO2’s concentration in the late Holocene atmosphere might actually be the wrong thing to do.
    ———–
    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???

  45. 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.

  46. @Gary 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.

  47. William claims
    ————-
    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
    ————
    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.

  48. 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).

    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’.

  49. 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?

  50. 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 ).

    =============================================================

    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.

  51. 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!!

  52. 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

  53. 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.”
    ==========
    Well said.

  54. @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.

  55. 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 : )

  56. 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.

  57. 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.

  58. 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.

  59. 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.
    ============================================================
    The latest science says that CO2 causes cold and snow

  60. “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.

  61. 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.

  62. 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.

  63. 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.

  64. JimF says:
    December 30, 2010 at 3:19 pm
    @Gary 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.

  65. 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.

  66. R. de Haan wrote on December 30, 2010 at 1:00 pm
    QUOTE
    You must be a great lover of fairy tails.
    UNQUOTE

    RdeH – I am such a bad speller and typist that I rarely get to correct other’s work.

    I think you meant “fairy TALES” as in stories, not tails as in monkeys’ tails.
    If you are not aware, then I will advise you.
    As faries are part of the genus Homus MakeItUptus, fairies no longer have tails but are expert at spinning stories such as the tale of the bad demon CO2.

  67. Could be another 2-4kyrs. We are most similar from an orbital perspective to the 420kyr interglacial (eccentricity and obliquity in phase).

    I’d say we’ve been entering the glacial period for about 3500yrs…the green line is the average of GISP2 and Vostok…we may get another hump in the NH, but I don’t think it will reach the norm for the Holocene. Getting harder to stay at the upper rail for the NH.

    Question is…will we get another 1168yr peak. 3 is very common, but not 4. If the sun is at 1959 levels for SC26/27 I’d say yes. If not, some definite cold coming our way IMO.

  68. A big problem is not having GISP2 data (or equivalent) that goes back to 420kyrs. I have a feeling the phasing is critical, which hemisphere starts the interglacial first, etc…. It’s difficult to judge interglacial length with only a southern hemisphere proxy, as it is not a global proxy, only a SH proxy.

    Judging by the comparison of the GISP2 and Vostok, the two hemispheres behave quite differently, looking at the 550oyr cycle which has a long term opposing trend for the two hemispheres. NH tried first (DO event), the SH ramped up and stayed up at 11150yrs (while the NH cooled back down), followed by the NH ramping and staying up at 9750yrs (with a slight cooling trend in the SH), whereby they both opposed eachother, especially so with the LIA (NH nulled, SH peaked) with the next opposing trend continuing today, albeit with a potential third long term hump for the NH (probably the last gasp IMO).

    And yes, before you say it, I CAN read tea leaves too…

    [URL already fixed. ~dbs, mod.]

  69. “sophocles says:
    December 30, 2010 at 7:06 pm
    Professor Nir Shaviv’s (Jerusalem University) research could help answer some of the questions raised about ice age cycles. 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.”

    I believe we are already in the Ice Age (occurs roughly every 100 million years, which I believe Shaviv’s theory tries to address, please correct me if I’m wrong). Now the timescale is really the Glacial and Interglacial within the Ice Age we are currently in. And of course all of the high frequency noise we’re all hung up on with the climate debate in general.

  70. I think in general ( as moronic as it sounds) that the Earth “prefers” the upper rail for temperature, hence the unequal rate for entering either the Interglacial or the Glacial period. You could guess CO2 though my hunch is Water in it’s various forms as the main culrpit (can you say Ocean?). During the non-ice age eras (previous to the last few million years, between this and the previous Ice Age), the Earth stayed at an upper rail. During the Interglacials of our current Ice Age Epoch, the Earth stays at the upper rails during the interglacials. It enters or tries to, the upper rails rather quickly, but descends into the glacial periods much more slowly (even with CO2 attempting to hold it up there, or Water, whatever your God). As for a runaway scenario…poppycock! We’d have been fried long ago with this upper rail preference. Much too consistent of an upper rail at least for the last 5 interglacials (with very different orbital phasings), and I’d guess outside of the Ice Age epochs, it’s pretty consistent as well. Otherwise, we little primates wouldn’t be sitting here contemplating this high frequency noise we call Climate.

  71. Really, the Earth’s climate is mostly regulated by which phase the planet’s water is in. The physics are 100% different between glacials and interglacials. One reason that Hansen’s derivation of climate sensitivity during the LGM is silly and misguided. Think it through and you’ll see what I mean (hint: water vapor is a GHG and water on Earth is finite)

    Ok, so, given all the physics that goes into the equations, it is obvious that the Earth in its current state is impossible. Negative feedbacks should nail Earth down into an Ice Age, and positive feedbacks should have all of us collecting condensation on the inside.

  72. Since the Chixulub cometary/meteorite impact some 60 – 65 million years-before-present (YBP), six geological eras averaging a diffuse 12 – 16-million years have preceded our current Pleistocene Era of about 2.6-million years’ duration. Characterized by recurring glaciations averaging some 102,000 years, interspersed with median 12,250-year remissions of continental ice-sheets, cyclical Pleistocene temperature-patterns should persist another 12 – 14+ million years. Pending long-term plate tectonic shifts separating North and South American land-masses, restoring global atmospheric circulation between eastern and western hemispheres, recurrent Pleistocene glaciations will no doubt run true-to-form.

    Geophysical evidence indicates that continental glaciers began retreating worldwide from c. 14,400 YBP, abruptly vanishing by c. 12,700 YBP (1,700 years). If not for a 1,500-year “cold shock” called the Younger Dryas, due to astronomical impacts rather than climatological factors, Earth’s present Holocene Interglacial Epoch would likely have ended about AD 450, coincident with termination of the so-called Roman Warm. As it stands, despite a diminishing rebound from a 500-year Little Ice Age lasting c. 1375 – 1875, since about AD 1950 the Holocene’s “long summer” has been fading fast.

    In context and perspective, then, climate research conducted with integrity serves mainly to confirm the obvious: For whatever reasons, however humanity may wish otherwise, Ice Time looms again. As a decades-long “dead sun” phase diminishes Total Solar Irradiation (TSI) amid reinforcing Milankovich and other cycles, radical climatic shifts may well bring catastrophic cooling that reduces 80% of Earth’s arable land-area to frozen waste by 2100 if not well before.

  73. A somewhat crude compilation of several images and data sets – but it does show a lot of the different contributors and their relationships

  74. Two minor glitches in the post:

    “Figure 2. Tzedakis (2010) comparing the Holocene with the previous 4 interglacials” is not appearing in the larger image format (tzedakis-2010-fig-31.jpg), and

    “about 11873 ka ago” should read 118point73 ka (the “ago” is redundant).

    Those minor typos do not detract from an otherwise excellent post. Thank you, Mr. McClenney.

    Bill Illis says: 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.

    That hypothesis assumes that SSI-75N is the only driver (and/or trigger) of initial ice build-up and that some value less than 470 watts/m2 SSI-65N is the trigger point. But ice build-up has apparently been triggered at SSI values greater than that previously during the Pleistocene. Or am I wrong about that? Please explain.

  75. Global warming was over with over 8,000 years ago and it has been a roller coaster ride down since. The only question is , is there an up after the down that we are starting on now. At some point the snow cover on the northern parts of the land masses forgets to melt completely and starts to build up. CO2 has nothing to do with it. pg

  76. Z says:
    December 30, 2010 at 3:08 pm
    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

    [Donald Sutherland voice]

    Don’t give me the negative waves!

  77. Doug in Seattle [December 30, 2010 at 11:19 am] says:

    “It would be the ultimate climate irony if lowering CO2 forced an ice age. This would of course only be possible if CO2 is the great powerful heat trapping gas it is reputed to be by the alarmists – something that has yet to be established.”

    About that irony, yes it certainly would. In fact, let’s see what the Godfather of the AGW crime syndicate himself had to say about this VERY recently:

    Therefore, it is foolish to demand that policy makers reduce CO2 to 280 ppm. Indeed, if, with a magic wand, we reduced CO2 from today’s 389 ppm to 280 ppm that change would increase Earth’s heat radiation to space by almost 2 watts (per square meter). The planet would rapidly move toward a colder climate, probably colder than the Little Ice Age. Whoever wielded the magic wand might receive a Middle Ages punishment, such as being drawn and quartered. – James Hansen, from ‘Conversation with Bill McKibben‘ dated December 12, 2010. [see: PDF from Columbia.edu], [also see: Discussion at WUWT].

    These fools would send us into an ice age without blinking an eye if we let them. Sure, some places are very safe like Hawaii, Florida, Mexico, Central America and Australia, but Europe, USA, Canada, lower South America and Asia have a bullseye painted on them. But the AGW cabal cares about neither, proven as we have recently witnessed escalating deaths from severe cold in Europe. Many more of those human sacrifices on the altar of AGW paganism can be expected.

    So, taking these fools at their word that CO2 will cook the atmosphere, I vote for a large CO2 cushion to be in place ASAP (before the Day after Tomorrow ;-). I’m thinking 600 to 1000ppm (a little more than a doubling) is do-able. That should require us approximately 300 to 500 years time, during which we can hopefully develop and perfect a workable non-steam nuclear or fusion based replacement for electricity generation.

    In the meantime we are using quite a few more incandescents than usual. This is completely out of necessity. Heat!

  78. An interesting synthesis ……… outside my area of expertise. Wish I had time to read the literature. The type of studies discussed are never mentioned in the MSM or considered when defining uncertainty in global warming dogma.

  79. Hindsight & Foresight – Study the period from the apex of the MWP to the depth of the LIA to see the likely immediate future. (None of us will “see” much of this future happen, but it gives more insight than anything we can imagine today with or without all that beautiful O-C-O we’ve been creating.)

  80. Good post.

    Unfortunately, with my level of knowledge concerning geology, it only succeeded in anesthetizing me. ;~P

  81. “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. ”

    And all man has done is to use the energy resources stored here by ages past.
    How many W/m2 does man release each day?
    Are we really prepared to accept an icy consequential outcome that may result if man interferes with the C02 content of Earth’s atmosphere? Climapolicy has already been unleashed in selected places with an iron fist, much to the distress of those downhill from the proclamtion.

  82. “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. ”

    Right on, Mr. McClenney!! Since modern, global man has risen to his current social and productive state in this current interglacial, it would seem wise to extend this period for as long as possible. The consequences of another iteration of the proven glaciation/interglaciation cycle being played to its end-game of sure destruction is incomprehensible. The horror of the Earths’s teeming masses crowded onto the remaining equatorial land masses as the ice sheet advances must be avoided at all cost.

    The best solution to this problem is in the institution of a carbon reward system, the coating of all snow and ice covered parts of the planet with powdered carbon, the change of all existing rooftops to black materials, wholesale interference with all of Earth’s known cooling mechanisms. Primary among those interferences should be to build enough windmills to harness up to 25% of the available wind energy and to develop a technology that would harness a significant amount of the ocean current energy. We may even have time to wrap the Moon in wire and create a large induction system and use the resultant energy to power directional heating elements to warm the Earth.

    These initiatives must be accomplished post-haste and will require hundreds of trillions of dollars. No time to think…must act…oh, the humanity…mumble…mumble…

  83. Brian H says:
    December 30, 2010 at 7:27 pm
    alan says:
    December 30, 2010 at 6:27 pm

    Spot the risible oxymoron in your post! ;)
    alan says:
    Yes! Also consider this: Terraform = bringing “terror” to the Red Planet. Perhaps they can hijack a rocket that will get them there. It probably won’t be a NASA vehicle though!

  84. 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.

    Yeah, “we” sceptics are left to actually think. Because on the other hand, ipcc CO2CAGW “Climate Science” has only selected the precaution to not ask itself what’s wrong with what it is saying, proposing, or doing……obviously because it might find out that it is wrong, which sounds pretty reasonable to the Climate Scientists.

    And – just coincidentally, I’m sure – being wrong is also a possibility that no respectable Propaganda Op. should ever allow! Of course, if you are one of Kealey’s “great scientists” there is no reason or urge to ask yourself anything about what you think, because you automatically never “feel falsified” to begin with.

  85. Pascvaks says:
    December 31, 2010 at 4:57 am

    Hindsight & Foresight – Study the period from the apex of the MWP to the depth of the LIA to see the likely immediate future. (None of us will “see” much of this future happen, but it gives more insight than anything we can imagine today with or without all that beautiful O-C-O we’ve been creating.)

    —————-

    Pascvaks,

    Yes, I completely agree with you. There is very little need for concern about any imminent catastrophic/end-of-the-world style doom and gloom regarding the descent of this interglacial into the next glacial. The past descent from interglacial to glacial, based on papers, show a very slow gradual decline spanning hundreds/thousands of years in transition.

    A Happy New Year to you.

    John

  86. Hansen: “Therefore, it is foolish to demand that policy makers reduce CO2 to 280 ppm. Indeed, if, with a magic wand, we reduced CO2 from today’s 389 ppm to 280 ppm that change would increase Earth’s heat radiation to space by almost 2 watts (per square meter). The planet would rapidly move toward a colder climate, probably colder than the Little Ice Age.”

    Does Hansen realize that he’s saying that fossil fuel CO2 which, according to him, is supposed to produce “the destruction of creation”, has already prevented a LIA?

    By this time the Muslim nations must already be dancing in the street, probably even without the Obama Adm.’s transformative prime directive to NASA that its main mission is to help the Muslim nations increase their self-esteem – even though the President seems to think that their “historic” achievements in the areas of math, science, and engineering are still only historic – apparently by making U.S. science look really stupid. But I guess it probably does help to make Hansen’s valiant efforts in this regard “official”.

  87. Fascinating. The implication of Fig3 is quite interesting. Some theories say that the Arctic ocean “needs” to become ice-free for most of the yr (that would imply Greenland might melt significantly, too) to produce the necessary snow-amounts to last thru summer, to end an interglacial period. At present, there isn’t enough precipitation up there (~5 inches liquid/yr) to make enough snow.

  88. Lucy Skywalker says: (December 30, 2010 at 2:33 pm)

    I had to redo the Lisieki-Raymo chart and put it all on one line, to see all this clearly.

    Already available on Wikipedia.

  89. A few quick comments:

    * As you say, Lisieki and Raymo in Paleoceanography (not Oceanography), propose that the current NH summer insolation minimum of 474 W/m2 is too low to allow for a “‘double precession-cycle’ interglacial” when compared to MIS-11. But Archer and Ganopolski (2005) conclude that an increase in pCO2 results in a deeper minimum in summertime insolation being required to initiate glaciation.

    * Your digression into D-O events seems to be off-topic as they occurred during a glacial period and were most likely caused by energy oscillations within the ocean-climate (cycles in deep water circulation patterns and ice-shelf building) rather than responses to external forcing (orbital or otherwise).

  90. It is quite clear to me that a whole lot of “scientists” need to repeat grade school arithmetic. There is a problem of notation, since there is no notation to distinguish a rounded up number from an integer, but treating rounded up numbers as if they were all integers is arithmetical madness.

    When programming in C++, the name of a variable distinguishes whether the variable is an integer or a rounded up number.

    I see such nonsense these modern days. Such as trying to compare temperature data from before the mercury thermometer, (must have been air thermometers, notorious for inaccuracies, and few indeed of them, exceedingly few locations) with modern thermometers. “The chilliest on record was 1683/84, when the average was -1.17C and the River Thames froze over for two months. ” That would be plus or minus how many degrees?

    Now history says that the River Thames did freeze over, but muddled thinking that -1.17C is somehow an accurate temperature for “Briton” is absurd, just as attempting/pretending to determine the average temperature of a small town with an area of a couple of square miles today is absurd.

    Just more grist for those who would spread panic.

    The Earth rotates on its axis, which causes the winds to blow. Actually, the rotation of the atmosphere is slower than the rotation of the surface, and disturbed greatly by the roughness (greatly varying coefficients of friction between the surface and the atmosphere) Perhaps some knowledge of fluid dynamics would come in handy. Laminar flow of a fluid is quite predictable. Turbulent flow is completely unpredictable. Air is a compressible fluid, with viscosity.

  91. “Your digression into D-O events seems to be off-topic as they occurred during a glacial period and were most likely caused by energy oscillations within the ocean-climate (cycles in deep water circulation patterns and ice-shelf building) rather than responses to external forcing (orbital or otherwise).”

    I would disagree, the same signals are present during the interglacial, (though severly attenuated as the system has a saturated upper rail), but clearly present and operative as the RWP, MWP and others. This image has the divisions set at 1168 to show the random DO events during both the glacial and interglacial periods.

    Zoomed in for the Interglacial (RWP, CWP, etc):

  92. Bill Illis says:
    December 30, 2010 at 4:43 pm
    Vince Causey says:
    December 30, 2010 at 1:25 pm
    Bill Illis,

    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 war enough to melt the winter snow and no additional glaciers will build up.

    What you are saying essentially is that the current (Pleistocene) glacial epoch is over. That is pretty big news, if correct.

  93. Sal Minella says: {December 31, 2010 at 1:49 pm}

    I hope you realize I was referring to your screen name in jest. :)

  94. Great post; went over my head a bit but i caught the gist of it. The climate scienctist still do not know! Thats what i think. Climate changes always has always will. IMO this world is full of IDIOTS and most of them are not USEFULL. Stop the world i want to get off!

  95. Tom in Florida says:
    December 31, 2010 at 4:35 pm
    Sal Minella says: {December 31, 2010 at 1:49 pm}

    I hope you realize I was referring to your screen name in jest. :)

    The effect would be clearer if the screen name were “Sal Monella”. Or maybe Bob Tulism, or even Campilo Bakta.

  96. tregembo says: (December 31, 2010 at 1:26 pm)

    “Your digression into D-O events seems to be off-topic as they occurred during a glacial period and were most likely caused by energy oscillations within the ocean-climate (cycles in deep water circulation patterns and ice-shelf building) rather than responses to external forcing (orbital or otherwise).”

    I would disagree, the same signals are present during the interglacial, (though severly attenuated as the system has a saturated upper rail), but clearly present and operative as the RWP, MWP and others.

    Granted, but still, how would this relate to McClenney’s opinion that the current interglacial is at an end? (At least, I think that’s what his point was; I have to admit the whole post was a bit too meandering for my short attention span.) Holocene D-O events are also mostly likely intrinsic cycles in our ocean-climate system (see Sections IV and VI in this 2001 synthesis by Maslin). So it’s still a digression, IMO.

    The same mechanisms may be involved in the triggering of glaciation, but only if nudged by additional external forcing, right?

    Anyway, McClenney’s conclusion that gasifying a trillion tons of carbon was a good thing is only justified if the resultant positive forcing is exactly equal in magnitude and timing to the negative orbital forcing he must suspect is occurring (and ignoring other effects such as ocean acidification). This exercise comes nowhere close to demonstrating that… or even attempting to demonstrate that.

    All of the studies that I’ve read, including the ones McClenney quotes above (at least the ones I could track down; ever heard of hypertext?), either ignore anthropogenic effects or emphatically agree that anthropogenic warming will be large enough to overwhelm any possible orbital effects.

  97. Ed Butt says:
    December 30, 2010 at 10:52 am

    “….and other possibly very relevant factors such as deforestation which only began about 5000 years ago….”

    There was a chapter about this in Lomborgs book. His curves showed that the amount of forest has been more or less stable since we stopped building wooden armadas for Nelson and other admirals. In other words; deforestation in a global sense is really a myth.

    That doesnt mean that there isnt some local problems here and there.

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