Statistics

Modulation of Ice Ages – Without CO2 — Guest Post by Ralph Ellis

Ellis sent me his paper “Modulation of Ice-ages via Precession and Dust-Albedo Feedbacks” in Geoscience Frontiers, and I found it rather intriguing. To greatly simplify: CO2 is good for you, and it’s going to get real cold not too long from now. I asked him to write a summary, which is below, but use the paper for any intelligent criticisms.

Here is an interesting conundrum: climate scientists will claim that the science underpinning terrestrial climate is settled. And yet we can simultaneously discover that there is no clear explanation as to why the climatic changes during ice-ages occur. It is speculated that orbital cycles and CO2 are involved, but it has never been explained why some of these orbital cycles produce ice-ages and interglacials, while others do nothing at all. So why would a climate system be selective in its response to orbital cycles?

The four orbital cycles involved in paleoclimatology are: axial precession, apsidal precession, axial obliquity and orbital eccentricity. And these combine to change the amount of sunlight (insolation) impinging upon the Earth’s higher latitudes. This orbital-induced oscillation is known as the Milankovitch Cycle (singular), which has a periodicity of about 22 kyr, and the changes in sunlight in higher latitudes it induces can be quite large.

Fig 1 shows the Milankovitch Cycle in blue, while the higher latitude temperature response is in red. As can be seen, some of the peaks in the blue Milankovitch Cycle (i.e.: extra sunlight-insolation in high latitudes), produce no temperature response whatsoever. Which is odd, and not explainable by the CO2 feedback theory.

Fig 1. Graph of Milankovitch Cycles (blue) vs Antarctic temperatures (red). Each blue peak represents increased sunlight-insolation in the high latitude northern hemisphere. Each red peak represents an interglacial warming event, which occur roughly every 80 or 100 kyr. Note that some sunlight-insolation peaks produce no temperature response at all. Sources: Laskar 2004 orbital cycles, and Epica3 ice core temperature data.

In fact, the problems with ice age feedbacks and modulation are manifold. There is also the problem that during ice ages, high CO2 is coincident with cooling, while low CO2 is coincident with warming. Which is a highly contrarian response for the standard CO2 feedback theory. Plus all of the interglacial warming events are coincident with northern hemisphere Milankovitch Cycles, rather than the southern hemisphere equivalents.

Again this would be an unusual hemispherically asymmetric response for a global feedback like CO2. And lastly, CO2 is a very weak feedback indeed during interglacial warming, when calculated annually or decadally; while the true feedback needs to be fairly powerful, in order to melt the vast ice northern sheets in just 5,000 years.

The result of this short analysis is that CO2 cannot be the feedback system assisting the Milankovitch Cycle, and thus controlling interglacial modulation. Yet we know that there must be a feedback mechanism of some kind, to explain the missing interglacials (the intermittent temperature response to increased high latitude sunlight-insolation). So the requirements of this proposed novel feedback system are peculiar, because: it must be based in the northern hemisphere; it must warm when CO2 is low; it must be very strong; and yet it has to be intermittent – only operating once every 80 or 100 kyr. And that is a very strange feedback mechanism indeed.

So can we find such a peculiar, strong, intermittent feedback mechanism? A mechanism that has gone unnoticed within climate science for decades?

The intriguing answer, as is discussed and fully explained in my paleoclimate paper, is dust. Yes, humble dust falling on ice sheets and darkening their surface – or ‘reducing their albedo’, in scientific parlance. Fresh snow on polar ice sheets can have a very high albedo, reflecting up to 90% of inbound sunlight back into space, and this can have a huge regional cooling effect on the climate. This explains the missing interglacial problem, because this highly reflective ice can reject so much insolation that some of the Milankovitch Cycles do nothing at all, as can be seen in Fig 1.

While high albedo is a promising start in this quest, our humble dust can similarly explain all of the other peculiarities required by our hypothetical new feedback agent. Dust is indeed based in the northern hemisphere, because it has been determined that Greenland dust is from the high Gobi plateau. Dust can have a very strong warming influence upon ice sheet, increasing sunlight absorption by up to 215 W/m^2, or 50% of the total average sunlight available.

And finally, the dust found in polar ice cores is indeed intermittent, only occurring every 80 or 100 kyr, just before each interglacial warming period. See the dramatic correlation between dust and CO2 in Fig 2. Remember that CO2 is also proportional to temperature, so that dust correlates well with temperature too.

Fig 2. A graph of CO2 (blue) vs Dust (green). Note the good correlation between CO2 and dust (and therefore temperature and dust). Note that the dust-plot is inverted and logarithmic. Source: Epica3 2007 ice core data.

In which case, we may have discovered the true ice-age temperature feedback agent and mechanism – it is dusty-ice-sheet albedo rather than CO2. However, why would dust exhibit this strange intermittency, only arriving in vast dust clouds every 80 or 100 kyr? And arriving, I might remind readers, just before each interglacial warming period.

For the answer to this climate conundrum we must look well outside the suffocating constraints of standard climate science, and remind ourselves that CO2 is plant-food, and thus the most essential gas in the atmosphere. Without CO2, all life on Earth would perish.

But due to oceanic cooling during ice ages, and therefore oceanic absorption of CO2, atmospheric concentrations of CO2 are drawn down during the ice age and eventually reach as low as 180 ppm. This is dangerously low for much of the world’s plant life, especially at higher altitudes where concentrations can reach the equivalent of 150 ppm at the surface. And 150 ppm lies well inside the death-zone for most C3 plant-life.

The result of this low CO2 is that the high altitude Gobi Plateau turns into a CO2 desert. This is a new type of desert caused by a lack of CO2 rather than a lack of rain – a phenomena that goes largely unremarked in climate science. The surface dust from this vast and new shifting-sand desert is whisked eastwards by strong prevailing winds, forming the dusty Loess Plateau in China and also coating the Laurentide and Eurasian ice sheets in dust. And since these new CO2 deserts are caused by cold oceans at the depth of an ice age, these mostly northern hemisphere dust storms can only occur at the glacial maximum.

In other words, these dust storms are intermittent, occurring just before each interglacial warm period. And that relationship is causal, rather than coincidental. It is the dust that is lowering ice sheet albedo, allowing more sunlight absorption, resulting in melting ice sheets and interglacial warming. We are in just such a warm period now – the Holocene interglacial – and we are due another ice age in 500 to 1,000 years. Although the initiating orbital cycles are weak at present, due to low eccentricity, and so it is uncertain if the current orbital cooling cycle will be strong enough to generate a full-blown ice age.

Thus the delightful conclusion to this study, is that during ice-ages it is low atmospheric CO2 concentrations that cause global warming.

Fig 3. A summary graph of all the factors that play a role in glacial modulation.

  • Ice sheets (light blue and grey) grow, forcing temperature (red) to fall.
  • CO2 (yellow) reduces with temperature (red), due to oceanic absorption.
  • As CO2 reaches 180 ppm there are CO2 deserts and dust storms (purple).
  • When the next orbital cycle (blue sine wave) comes along, the dusty-ice sheets can melt and the world warms (red peaks).

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Categories: Statistics

47 replies »

  1. ”Thus the delightful conclusion to this study, is that during ice-ages it is low atmospheric CO2 concentrations that cause global warming.”

    That is indeed delightful, and intriguing, and worthy of Sherlock Holmes. The graph looks like an intricate dance — now swing your partner, dos-y-dos, dust on the ice cap, albedo go!, carbon’s up and temps are down, circle back and around and ‘round — called by the Delightful Caller and danced to the Music of the Spheres.

    That it stands the Official Narrative on its head is a point in its favor since that narrative is almost invariably inverted baloney. And it’s great to see independent minds fearlessly following clues wherever they lead. Of course, more study is needed, but, oh! — so sorry Mr. Ellis, your grant proposal was lost in a dust storm! No matter, doing renegade science is a great way to build character. Just ask Briggs.

    Best of luck to you Mr. Ellis.

  2. I am not a climate scientist but this looks extremely good to me – given the data shown or adduced, the conclusions seem inevitable. Now it may be, of course, that contradictory data exists and I do not know enough to know this, but right now I see this as the first internally consistent explanation of what we know about longer term climate cycles that makes sense.

    I had not seen this – so thanks for publishing your summary and a pointer to the paper.

  3. Have you ever heard of guy named Antonio Zamora and his book,” Solving the Mystery of the Carolina Bays?” He claims that there was at least one extraterrestrial impact about 12,900 years ago up in Michigan and onto a massive ice sheet. The ejecta managed to travel as ice boulders all up and down the East Coast of the USA and even in Texas, Oklahoma and Nebraska. Most of the flight was above the atmosphere and the ice block deposited ice and water vapor in outer space which changed the albedo of the Earth for a very long time maybe 1300 years. Weather is just too complicated and can’t be managed or understood with a single molecule causing everything.

  4. Very low CO2 causes warming & the end of a glaciation period / Ice age? – thats sweet & cool.

  5. I like every article which debunks the GHG hypothesis, so I naturally like this one.

    However, Javier Vinos has a theory which does not require dust to explain the conundrum of not every Milankovitch combination causing an interglacial.

    “For the last 800 Kyr, after the Mid-Pleistocene Transition (Figure 129), the planet has become so cold, and the ice-sheets grown so large, that to produce an interglacial outside the periods of high eccentricity requires the simultaneous concert of high obliquity, high northern summer insolation, and very large unstable ice sheets. This has had the effect of spacing interglacials from an obliquity-linked 41-Kyr cycle to its multiples 82 or 123 Kyr, whose average has been incorrectly termed the 100-Kyr cycle.”

    https://judithcurry.com/2018/08/14/nature-unbound-x-the-next-glaciation/

  6. >>Where do solar activity cycles come into play?

    They are the forcing agent – the blue line in the first graph. They can increase high latitude insolation (sunshine) by 25% in high latitudes.
    Ralph

  7. >>grant proposal lost…

    Tell me about it. The Royal Society rejected the paper due to the most absurd objections.

    Reviewer a. misread ‘insolation’ for ‘insulation’ throughout the paper, and could not make head not tail of it.

    Reviewer b. said that there was the same percentage of CO2 at altitude as at the surface, so my proposal was completely wrong. In return I asked why airliners carry emergency oxygen…

    Reviewer c. said the paper did not support CO2 greenhouse warming.

    I went to a different journal.

    Ralph

  8. >>Javier Vinos

    Whilst I like Javier’s attempts at an explanation, his theory is tenuous at best. He concentrates on obliquity rather than precession, but fails to adequately explain the missing obliquity cycles. As with precession, many obliquity maxima are either misaligned with interglacials, or produce no warming whatsoever. And that is a problem.

    So he has to introduce an ill-defined ‘instability’. What instability? What causes instability? The Earth has proceeded to a complete snowball-Earth on a few occasions, so why not now? This ‘instability’ is a wild card from the bottom of the pack, because he has run out of ideas.

    There is only one factor that immediately precedes each interglacial, and that is dust. We know that orbital cycles (whichever one you like best) require a feedback agent to explain the missing interglacials – the intermittent feedback conundrum. And that intermittent, northern hemisphere based feedback, is quite plainly dust-albedo.

    The difficult part was explaining the intermittency in dust.

    Ralph

  9. >>Low CO2 causes warming…

    This fact has been observed and known for a century, but scientists and their pet media will not mention it.

    a. because it goes against the narrative.
    b. because they cannot explain it.

    If CO2 were really a powerful and decisive feedback agent, this would not happen. It confirms that, at the very least, CO2 is a minor player at the mercy of orbital cycles. But if orbital cycles can induce ice ages and interglacials on their own, why bother mentioning CO2 at all?

    And yet we know that orbital cycles are not the complete answer, because of the missing interglacial problem – many orbital maxima produce no warming whatsoever. So we do indeed need a feedback agent, but that agent CANNOT be CO2.

    However, if it is dust, as I believe, this may also explain much of modern warming. It may well be Chinese industrial dust settling on Arctic Ice Sheets. See the images of dark ice, in the Dark Snow Project. Unfortunately, Dark Snow lost their funding, for going against the CO2 narrative, and so you will have to look on the Wayback Machine.

    Ralph

  10. .
    Regards modern warming, much of this may be due to Chinese industrial dust settling on Arctic Ice Sheets. See the images of dark ice, obtained by the Dark Snow Project. Unfortunately, Dark Snow lost all their funding, for going against the CO2 narrative.

    They tried continuing their research with a Go-Fund-Me, but failed to get enough support. With all the $ billions and $trillions washing around climate ‘science’, they could not afford to investigate modern Arctic ice albedo as a potential cause of Arctic sea ice melting. So you have to find the images on the Wayback Machine.

    Do note that Antarctic sea ice had been INCREASING for 40 years, until two large storms broke some of it up in 2017 and 2022. I wonder if there is a natural limit to Antarctic ice, caused by increasing temperature differentials, as the ice sheet creeps further north.

    Increasing Antarctic sea ice is one of the big secrets of modern climate ‘science’, that they will not tell the public. The other secrets include:

    a. US strong tornadoes increasing for 65 years (NOAA data)
    b. Tropical cyclone numbers reducing for 120 years (See Chand et al)
    c. Polar bear numbers increasing for 50 years (Prof Sue Crockford)

    etc: etc:

    Dark Snow Project – images.
    https://web.archive.org/web/20150108131218/http://darksnow.org

    Ralph

  11. Well, the percentage of oxygen is approximately the same throughout; just the partial pressure drops with elevation or altitude, so the absolute mass drops. Thus, the need for supplemental oxygen and pressurization. I.E. at 500 mb the oxygen part is about 20% of that (100 mb). At 250 mb the oxygen part is about 20% of that (50 mb). Once the ambient oxygen pressure is too near that of the deoxygenated blood; oxygen loading gets insufficient (not fast enough).

  12. Oh, carbon dioxide can’t cause warming, anyway. All it can do as an IR active agent is alter screening of incoming infrared at its absorption/emission wavelengths and outgoing infrared. Infrared is light, not heat. Absorption or emission of light does not have to alter the internal kinetic energies of the absorber or emitter. Can, it must be said, is not the same as must.

  13. Is it valid to conclude that a consequence of this argument is that the effects of dust and CO2 absorption by the oceans are not enough to push the earth out of an ice age by themselves, but are enough when combined with a peak in the Milankovitch Cycle? In other words, without the Milankovitch Cycle, the earth’s climate would be stable, as the sum of all the various feedbacks, positive and negative, would not be large enough to force the climate into an oscillation?

    The reason I ask is that in engineering, when an oscillation occurs due to an instability, the period of that oscillation is usually of fundamental importance. But if the period of oscillation is forced, by the Milankovitch Cycle in this case, the period of the oscillation doesn’t tell you anything new.

    I am impressed with your use of actual data from actual measurements. Feels like real science.

    You know, in a saner world, this climate science stuff would be of significantly less interest to me, on par with quantum computing or astrophysics, or other myriad topics of only passing interest best left to the experts. But the experts on those other topics don’t seem intent on destroying civilization to further an insane political agenda.

  14. >> just the partial pressure drops…

    Absolutely. Hence my jibe at the reviewer.

    No idea how the reviewer could have been confused about this, as in the paper itself, I say ‘partial pressure’ and also ‘surface ppm equivalent’.

    Ralph

  15. >>>when combined with the Milankovitch cycle.

    Absolutely.

    Orbital cycles are not strong enough to force an interglacial, because ice sheet reflectivity is too powerful.

    Ice sheet dust albedo cannot force (feedback) an interglacial, because there is not enough insolation.

    It required a combination of maximum orbital cycle (a Great Summer) plus dusty low albedo ice sheets, to give an interglacial. This is why the dust can sit there for 12,000 years, before an interglacial starts.

    There is also the benefit of dusty ice then being 10,000 or 15,000 years thick. Which means this is not simply a dusty top layer which can be washed away. It is a huge slice of the ice sheet being contaminated, with older dust always being exposed at the surface.

    Ralph

  16. Great article! This seems to nicely explain observations. Very refreshing in the world of climate nonsensery.

  17. Mr Ellis,

    You had me at ‘kyr’.

    And if you’re still lurking here, it would be wonderful to hear your story of How You Found The Dust. How, when, did the outline of this intricate dance begin to occur to you, take shape in your mind?

  18. I’d like to raise an objection. How do you know increased dust in the cores corresponds to increased arrival of new dust? It could be that per-year, equal amounts of dust have been arriving to the poles, but that in periods of warming snow melted and exposed previously accumulated dust. The dust accumulated during previous years would pack into a thin layer instead of in a wide layer. Finding a layer of many dust particles doesn’t therefore mean a lot of dust arrived, just that a lot of dust used to be exposed.

    So, as long as equal amounts of snow arrive each year and don’t melt, the snow collumn accumulates a “dust debt” or “dust capacity”. If something were to start the melt, then successive layers of accumulated dust will begin to show, creating a positive feedback loop. However something still needs to start the loop. As long as enough snow gets packed each time to cover up the newly arrived dust, the system will remain stable (the loop will not trigger).

    So my objection is that it’s not clear the high concentration of dust in snow after the fact proves greater presence of dust on the surface of snow at the start of the melt. I’d like to see this explored.

    And I love the term “CO2 desert”. xD

  19. The Antarctic temperature fluctuations are confirmed by many other proxies, including NH deep sea cores and ample geologic evidence. There really was an Ice Age, in fact a bunch of them, and they are coming back.

    Continental ice sheets up to 2 mile thick covering 1/3 of N America, dusty deserts blown by freezing katabatic winds coming off the sheets, the biosphere starved of the basic building block of life, multi-millennial-mega droughts, and mass extinctions are just a few of the features of the Pleistocene “normative” (or dominant) global climate over the last 1.8 million years.

    Warmer is better. Interglacials are great. We need to keep ours going. If CO2 doesn’t deliver warmth, and we can’t find another means, then a real global climate disaster is in the offing: cooling to the extreme. The alarmists’ nutty plans and authoritarian hooting, economy-crushing expenses and regulations, mud hut poverty, mass starvation, and social chaos are for the exactly WRONG cause. They have it bassackwards.

    We should embrace warmth and work on getting more of it, not less. Turn the heat up, not down. That’s what Gaia wants, and why she invented humans. We’re a brand new species, born in the Ice Age, and the only animal that makes fire. We have a planetary purpose: make it warmer — Mother Earth has the chills.

    Nota bene: if you don’t like that theology, use your own. The Earth was 2°C warmer during the Roman Warm Period. Jesus never complained about it.

  20. Furthermore – and I’m speaking now as a layman – what if ice core CO2 and dust are directly related? For example, what if the “dust” is actually organic matter, and as that organic matter sits in the ice for hundreds of thousands of years, it decays and realeases CO2? You would then see a lot of CO2 in the ice layer, but not because of high atmospheric CO2 but because of a lot of dust that decomposed.

    How do you control for that?

  21. OK, one more and then I’ll shut my yapper.

    IF we were to assume more then just the absolute surface layer of snow contributes to albedo, then things can get very interesting indeed. IF the depth of new annual snow accumulation is significantly less then the depth of the albedo-contributing layer, or IF the two depth are of similar magnitude, then the total albedo is not a stateless function of annual snowfall and dust arrival. Instead, it has a history. It can get *chaotic*. And most important – it can exibit a periodicity that is COMPLETELY detached from anything else whatsoever.

    It would be fun to do Monte Carlo modeling, where you start with no-ice Earth and then increase annual snowfall in some monotonous pattern and observe if albedo starts generating it’s own cyclicality. The start of the simulation (no snow on poles) is the singularity and I posit that some detachments from that singularity are going to generate a self-sustaining oscillation. Others, however, won’t. Oh if I had spare time to deal with this. 🙂

  22. No one really knows what the true variability of the Sun’s energy output is over anything longer than the last 200 years of direct observation. What the Sun was doing in that regard over the last 500,000 years before today is a big black hole. Climate scientists more or less treat the Sun’s output as a constant. This could be a big mistake.

  23. As for the orbital cyles, I would probably guess orbital eccentricity and axial procession dominate. Right now, Summer in the northern hemisphere occurs when the Sun is further away- that will slowly change over the next 13,000 years. There are a different grouping of land masses and oceans in the north and south of the globe. I think it quite likely that deep ice ages on a cycle began to occur when Antarctica became centered on the south pole, giving the pole a seasonally permanent ice cap.

  24. >>>found the dust.

    Just scanning the EPICA3 data. (EPICA is an ice core from Antarctica).

    They list many different parameters throughout the core, and I happened to note a large increase before each interglacial. The potential action of dust on ice was fairly obvious, but the reason for its sudden appearance was perplexing for quite a while.

    Luckily, I am also an airline captain, so I was familiar with the problems of low partial pressures at altitude.

    Ralph

  25. >>>How know it is new dust.?

    Because of the Loess Plateau in China.
    Greenland dust is from the Gobi (derived from isotopic analysis). But before it gets there, a whole load is dumped upon the Loess Plateau. So the Plateau has a complete record of the last eight ice ages, in the same manner as the ice cores.

    So we can be certain this is fresh deposition from the Gobi. The question is, why? Traditional science says the glacial maximum (LGM) is cold and dry, forming a desert, but Chinese scientists kept saying the Gobi was wetter during the LGM.

    This problem was never resolved, so it seemed obvious to me that the new desert was actually a CO2 desert.

    Ralph

  26. >>>is dust organic?

    No, it is mostly silicate, and it has been identified as coming from the Gobi Plateau. The only part of the Gobi that is currently desert is the Takalaman, which sits in the rain-shadow of the Himalaya. But during the glacial maximum, the entire region became a Co2 desert.

    Ralph

  27. >>>dust-ice has a history (in the ice).

    This is important. It means that as the ice melts or ablates, older dust can be exposed to enhance the albedo feedback. And it means if some dust is washed away, there is always old (previously buried) dust to replace it.

    Ralph

  28. >>> precession and obliquity dominate.

    Yes, and no.
    Precession is normally the most powerful and dominant, but it is regulated by eccentricity (400 kyr cycle). Precession is quite weak at present, yet the dust albedo feedback STILL managed to pull off an interglacial. Which shows how powerful the dust is, as a feedback.

    This is why the Holocene is such a long interglacial (same as 400 kyr ago), because it is dominated more by obliquity. There has been no sharp Great Winter (orbital minima) to plunge us into a new ice age. In fact we are nearly at the depth of the current Great Autumn-Winter, and we still don’t have an ice age – so the Earth may escape this glacial ice-age-winter, and stumble on.

    Ralph

  29. >>variability of the Sun.

    The total irradiance is often taken at constant, because it is at present. But we do have isotopic 14C and 10Be proxies, which can track solar magnetism back through many thousands of years. And these proxies pick out the Maunder Minimum quite well.

    And solar magnetism can effect climate – see Svenmark et al.

    Ralph

  30. Ice Age (LGM) Tropical Precipitation.

    In my paleoclimate paper I also suggest a reason for tropical ice age temperatures and humidity being so confused. It is because scientist have made a gross error based upon a gross misunderstanding.

    They calculated tropical temperatures and accompanying lapse rates (humidity) via mountain treeline altitudes. They assumed that treeline altitudes were controlled by ground temperature. But this is wrong. During ice ages, mountain treeline levels were controlled by a lack of CO2, not a lack of temperature.

    This is why the lapse rates they derived are so absurd (not even possible), indicating very low precipitation during a glacial maximum (hence the notion of LGM aridity deserts). But if you realise that a lack of CO2 is the controlling factor for mountain treelines, then temperatures and lapse rates can be returned to more reasonable levels. Thus precipitation does not need to reduce.

    In other words, the LGM Gobi was a CO2 desert, not an aridity desert. Which is in line with Chinese data about Gobi precipitation.

    See paper: Modulation of Ice Ages by Dust and Albedo.

    Ralph

  31. Ralph,

    Thank you for responding to my objections. I find your argument of Loess Plateau compelling. I’ll examine it myself in more detail, when I get the time.

  32. This seems important, so I’m still trying to wrap my mind around the details.

    So . . . dust plus a peak in the Milankovitch Cycle kicks off an interglacial. But what ends the interglacial?

    Specifically, in figure 1, a peak in the Milankovitch Cycle precedes the interglacial, as described. But the interglacial seems to want to hang on well after the Milankovitch Cycle. In fact, if I squint real hard, I can imagine I see a plateau of stability in the interglacial temperature after an initial rapid decline, including at the present time.

    So the dust does it job and quickly disappears, then some other effect takes over to stretch out the interglacial? Does one of the quantities graphed in figure 3 correspond to some measure of albedo? If not, perhaps that could help my understanding (although figure 3 already packs a lot of info punch).

    Finally, since the coin of the realm in climate science seems to be modelling, perhaps you should go with the flow, fight fire with fire, and create your own model to illustrate the effects you are bringing to light here. If there were such a model, and if it were simple enough, even I might be tempted to do some signal processing on the model output time series. Models only say what they are told to say, as we’ve been taught, but the flip side of that is that if your model isn’t saying what you thought you told it to say, it might helpfully be pointing to a non-obvious gap in the theory.

  33. >>What ends the interglacial?

    There are two types of interglacial, as determined by orbital eccentricity:
    a. Obliquity led Holocene and 400 kyr ago (due low eccentricity).
    b. Precessionary led other interglacials (due high eccentricity).

    Type b. have the very intense extra insolation of high eccentricity precession, which leads to rapid interglacial warming. But the precessionary Great Summer is only some 11,000 years long. ** So if interglacial warming took 7,000 years, you only have another 4,000 years of warmer high latitude annual summers, before being plunged back into a 11,000-year long Great Winter.
    It is the Great Winter cooling (cooler annual summers) that suddenly plunges the world back into ice age conditions. This is due orbital cycles alone, and CO2 and surface albedo are unable to stop it. Colder annual sprins and summer mean less melting of annual winter snows, and so a build-up of high albedo ice sheets. And it seems likely that the spread of these (very thin at this stage) ice sheets is very rapid, because subsequent Great Summers only 10,000 years later, are unable to break the ice age (due to ice albedo). So ice sheets must spread and build, rather than build and spread as in Disney cartoons (as favoured by Ganopolski et al).

    Type a. interglacials occur when orbital eccentricity is low, so precession is weak and warming is more dependent upon obliquity. It is a little surprising that (weak) obliquity has the power to forge an interglacial. (Obliquity is normally the junior partner.) But if this had not happened, the world would just wait another 22 kyr (with dusty ice sheets, ready and primed), until a stronger precessional cycle comes along.
    Yet obliquity does force an interglacial, as it did in the Holocene and 400 kyr ago. But because precession is weak, there is no subsequent deep Great Winter to force an ice age. In which case the interglacial follows the slow reduction in the obliquity cycle, and since obliquity has a much longer 41 kyr cycle, the interglacial can now stretch out to a full 10 or 12 kyr. Just as the Holocene is doing. In fact, precession is so weak at present, we might not even have a new ice age, for another 50 kyr

    Not sure about the notch, as the world cools into an ice age. I am wondering if this is a data artefact, or genuine. The data is gathered via ocean temperature-dependent oxygen isotopes. So either there is a data blip, for some reason, or the oceans resist cooling for a while. This is possible, I suppose, because there is a lot of stored energy in those huge oceans. Not sure about this.

    ** The precessionary Great Year is approx 22 kyr long, which we might divide into Great Summers and Winters of 11 ky each. Great Summer-Winter are explanatory terms, becayse the Great Year behaves like an annual year. When the north has a Great Summer, the south has a Great Winter.

    Note: the Milankovitch plot in Fig 3 appears displaced by 5 kyr. We are not yet at the minimum in the most recent cycle.

    Ralph

  34. >>Devise a Model.

    Would love to.
    I was looking to do this with Prof Fred Singer, before he passed away. I have not found another institution who would sponsor such a project.

    I cannot imagine it would be that difficult to do, but nobody in academia would dare touch it with a barge-pole.

    Ralph

  35. >>What ends the interglacial?

    There are two types of interglacial, as determined by orbital eccentricity:
    a. Obliquity led Holocene and 400 kyr ago (due low eccentricity).
    b. Precessionary led other interglacials (due high eccentricity).

    Type b. have the very intense extra insolation of high eccentricity precession, which leads to rapid interglacial warming. But the precessionary Great Summer is only some 11,000 years long. ** So if interglacial warming took 7,000 years, you only have another 4,000 years of warmer high latitude annual summers, before being plunged back into a 11,000-year long Great Winter.
    It is the Great Winter cooling (cooler annual summers) that suddenly plunges the world back into ice age conditions. This is due orbital cycles alone, and CO2 and surface albedo are unable to stop it. Colder annual sprins and summer mean less melting of annual winter snows, and so a build-up of high albedo ice sheets. And it seems likely that the spread of these (very thin at this stage) ice sheets is very rapid, because subsequent Great Summers only 10,000 years later, are unable to break the ice age (due to ice albedo). So ice sheets must spread and build, rather than build and spread as in Disney cartoons (as favoured by Ganopolski et al).

    Type a. interglacials occur when orbital eccentricity is low, so precession is weak and warming is more dependent upon obliquity. It is a little surprising that (weak) obliquity has the power to forge an interglacial. (Obliquity is normally the junior partner.) But if this had not happened, the world would just wait another 22 kyr (with dusty ice sheets, ready and primed), until a stronger precessional cycle comes along.
    Yet obliquity does force an interglacial, as it did in the Holocene and 400 kyr ago. But because precession is weak, there is no subsequent deep Great Winter to force an ice age. In which case the interglacial follows the slow reduction in the obliquity cycle, and since obliquity has a much longer 41 kyr cycle, the interglacial can now stretch out to a full 10 or 12 kyr. Just as the Holocene is doing. In fact, precession is so weak at present, we might not even have a new ice age, for another 50 kyr

    Not sure about the notch, as the world cools into an ice age. I am wondering if this is a data artefact, or genuine. The data is gathered via ocean temperature-dependent oxygen isotopes. So either there is a data blip, for some reason, or the oceans resist cooling for a while. This is possible, I suppose, because there is a lot of stored energy in those huge oceans. Not sure about this.

    ** The precessionary Great Year is approx 22 kyr long, which we might divide into Great Summers and Winters of 11 ky each. Great Summer-Winter are explanatory terms, becayse the Great Year behaves like an annual year. When the north has a Great Summer, the south has a Great Winter.

    Note: the Milankovitch plot in Fig 3 appears displaced by 5 kyr. We are not yet at the minimum in the most recent cycle.

    Ralph

  36. > I was looking to do this with Prof Fred Singer, before he passed away. I have not found another institution who would sponsor such a project.

    Perhaps you’ll have more luck with non-Western institutions. There’s some chatter that only the West believes in greenhouse-gas global warming and outside of the West people have other ideas about climate. So perhaps someone from Russia or India or China would be interested in working on this?

    Obviously that might make you into a pariah, but you’re already a heretic. xD

  37. >>More luck with non-Western.

    Been there, done that. If you look at my paper I had to go to Beijing to get it published, because no Western journal would look at it. That took some doing. And some translation difficulties.

    Then Western scientists said: “Published in a Chinese journal, that is not real scien…….”. “Oh, wait a minute, we are not allowed to say that anymore.”

    Ralph

  38. These articles i read twice before i comment.
    I like the subject.
    The modellers cannot admit that the world goes up and down depending on the will of the Sun and the Universe.
    Admitting that brings their theories up in the smoke.
    We’ve been through long hot and cold periods and we will again while the Sun dictates the tempo.
    The Sun is a huge boiler and we just happen to be at a perfect distance in our solar system which is being stretched in many directions with a massive impact on our planet.
    The effect of CO2 on our dear Earth is like having a hot oven in our living room to keep us warm while granpa farts from time time.

  39. We cannot get away from our brave planet savers.
    In a few years when we start cooling, they will be right there saving us again.
    John Kerry told us at the WEF that they were chosen individuals. That’s nice.

  40. Perhaps CO2 may play some role to reduce or increase the length of the warm period with current greening , some 15%, in the last 60 years, especially in higher altitudes and on dessert edges. I wonder what affect this may have on albedo and dust production keeping it lower than usual may have some effect. The west has largely cleaned particulates from the air as well. I do notice a slight uptick in dust near the end of each interglacial. Is the greening affect of CO2 keeping dust low and what affect would that have as we are entering a period of low magnetic flux with a shallower Milankovitch cycle.

  41. Ralph, I wrote this comment https://judithcurry.com/2023/11/06/hansens-latest-overheated-global-warming-claims-are-based-on-bad-science/#comment-995334
    which summarizes your paper. The one reply was;

    “The paper by Ralph Ellis, which you expand upon, is totally incorrect.
    The warming that began around 10,000 years ago was caused by an abrupt cessation of volcanic activity, and with no volcanic SO2 air pollution present in the atmosphere, the Earth rapidly warmed up.
    According to Volcanoes of the World, third edition (2010), For example, between 9,950 and 6,550 there were only 52 VEI4 and larger volcanic eruptions, fewer than one per century.
    In the 20th century, alone, there 75 such eruptions.
    This is their published data. If they are off by a factor of 10, say, this would still be equivalent to the number of eruptions during the MWP (~31 in 300 years). ”

    Can you refute his theory that the warming was due to “an abrupt cessation of volcanic activity”? This is an odd theory. Funny that volcanic activity must abruptly decline every 4 or 5th great summer!

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