Eocene Climatic Optima: Another Clean Kill of Carbon Dioxide-Driven Climate Change Hypothesis?

Guest geology by David Middleton

Introduction

Figure 1. Cenozoic Era geologic time scale. (ICS)

We are often told that the warmth of the Early Paleogene was driven by CO2; and that the cool-down from the Late Paleogene, into the Neogene and Quaternary Periods was driven by a draw-down of atmospheric CO2[1][2]. The notion of a CO2-driven climate has apparently become a paradigm.

This paradigm didn’t exist in the 1970’s [3].

Suggestion that changing carbon dioxide content of the atmosphere could be a major factor in climate change dates from 1861, when it was proposed by British physicist John Tyndall.

[…]

Unfortunately we cannot estimate accurately changes of past CO2 content of either atmosphere or oceans, nor is there any firm quantitative basis for estimating the the magnitude of drop in carbon dioxide content necessary to trigger glaciation.  Moreover the entire concept of an atmospheric greenhouse effect is controversial, for the rate of ocean-atmosphere equalization is uncertain.

[3] Dott, Robert H. & Roger L. Batten. Evolution of the Earth. McGraw-Hill, Inc. Second Edition 1976. p. 441.

Why geology is supposed to avoid paradigms

When I was studying geology, way back when The Ice Age Cometh in the 1970’s, we were taught to avoid getting hooked on paradigms or “ruling theories”. Geology, as a science, has very few unique solutions. This is why we were were taught to embrace Chamberlin’s Method of Multiple Working Hypotheses. I have to assume that either this is no longer the case or that homage must be paid to the current paradigm in order to get published.

Hat tip to Brian Pratt for sending me this paper…

Moderate levels of Eocene pCO2 indicated by Southern Hemisphere fossil plant stomata
Margret Steinthorsdottir, Vivi Vajda, Mike Pole, and Guy Holdgate

ABSTRACT
Reducing the uncertainty in predictions of future climate change is one of today’s greatest scientific challenges, with many significant problems unsolved, including the relationship between pCO2 and global temperature. To better constrain these forecasts, it is meaningful to study past time intervals of global warmth, such as the Eocene (56.0–33.9 Ma), serving as climatic analogues for the future. Here we reconstructed pCO2 using the stomatal densities of a large fossil Lauraceae (laurel) leaf database from ten sites across the Eocene of Australia and New Zealand. We show that mostly moderate pCO2 levels of ∼450–600 ppm prevailed throughout the Eocene, levels that are considerably lower than the pCO2 forcing currently needed to recreate Eocene temperatures in climate models. Our data record significantly lower pCO2 than inferred from marine isotopes, but concur with previously published Northern Hemisphere Eocene stomatal proxy pCO2. We argue that the now globally consistent stomatal proxy pCO2 record for the Eocene is robust and that climate sensitivity was elevated and/or that additional climate forcings operated more powerfully than previously assumed.

INTRODUCTION
The anthropogenic rise in CO2 concentrations (pCO2) is predicted to result in a global average temperature increase of up to 4 °C by the year 2100 (IPCC, 2014), with severe socioeconomic and ecosystem impacts predicted. However, the exact relationship between pCO2 and temperature—or climate sensitivity (the equilibrium response in mean global surface temperatures to a doubling of pCO2, generally reported as ∼3 °C)—is still not well understood…

[…]

The Eocene epoch was such a time interval, with average global temperatures 4–15 °C higher than at present (Zachos et al., 2001Huber and Caballero, 2011Anagnostou et al., 2016Cramwinckel et al., 2018). In the earliest Eocene (ca. 55.5 Ma), there was a transient episode of extremely elevated temperatures—the Paleocene-Eocene Thermal Maximum, or PETM (McInerney and Wing, 2011). Later, after the peak warmth of the Early Eocene Climatic Optimum (EECO, ca. 52–50 Ma), a gradual cooling began, briefly interrupted by a major warming reversal at ca. 40 Ma, called the Middle Eocene Climatic Optimum (MECO) (Zachos et al., 2001Cramwinckel et al., 2018). The Eocene climate still constitutes one of the greatest unsolved problems in paleoclimate research. Temperatures were globally much higher than today, with a significantly weaker equator-to-pole temperature gradient and a muted seasonal cycle compared to today, referred to as the “Eocene equable climate problem” (Sloan and Barron, 1990Greenwood and Wing, 1995Greenwood et al., 2003a). Climate modeling has been able to reconstruct this pattern with very high pCO2 levels (up to ∼4500 ppm: Huber and Caballero, 2011), but such extremely elevated pCO2 is not documented by proxy records. It is therefore assumed that Eocene climate sensitivity—often defined as Earth system sensitivity for longer time scales, including both “fast” and “slow” feedbacks (Lunt et al., 2010)—was elevated compared to present, and/or that other mechanisms, in addition to the dominant forcing of pCO2, were in operation (Caballero and Huber, 2013Anagnostou et al., 2016Zeebe et al., 2016Carlson and Caballero, 2016Cramwinckel et al., 2018Keery et al., 2018).

[…]

Comparison to Existing pCO2 Records and Implications

[…]

The most striking feature of the Eocene stomatal proxy record is that some of the highest pCO2 is indicated in the early middle Eocene (until ca. 46–44 Ma), well beyond the end of the EECO…

[…]

Although it is premature to make strong statements, this would imply that Earth system sensitivity was likely in the range of ∼4–8 °C during the Eocene, significantly elevated compared to the “modern” climate sensitivity of ∼3 °C (Lunt et al., 2010Royer et al., 2012Maxbauer et al., 2014Wolfe et al., 2017Keery et al., 2018Schneider et al., 2019). However, the various feedback mechanisms affecting Earth system sensitivity in an ice-free world are still poorly understood.
In summary, we find pCO2 of ∼450–600 ppm recorded by Southern Hemisphere fossil plants throughout the Eocene—significantly less than the forcing required by modeling, suggesting that climate sensitivity was elevated and/or that other climate forcings were stronger than previously assumed.

[4] Steinthorsdottir, M., Vajda, V., Pole, M., and Holdgate, G., 2019, Moderate levels of Eocene pCO2 indicated by Southern Hemisphere fossil plant stomata: Geology, v. 47, p. 914–918, https://doi.org/10.1130/G46274.1

Key points

  1. The Eocene was, on average, 4–15 °C warmer than today.
  2. Atmospheric CO2 was very likely in the 450-600 ppm range.
  3. Modern climate models would require 4,500 ppm CO2 to simulate the Eocene temperature range;
  4. And/or a climate sensitivity of 4-8 °C per doubling;
  5. And/or “that other climate forcings were stronger than previously assumed”.

They totally missed the most obvious reason why just about every effort to gin up a paleo example of CO2-driven climate change falls apart: Atmospheric CO2 is not a primary driver of climate change over geologic time. This wouldn’t mean that it isn’t a greenhouse gas or that it has no effect on temperature. It would simply mean that it was a relatively minor climate driver, like volcanic eruptions.

At some point over the past 30 years or so, the assumption that CO2 drives modern climate change has become a paradigm. And I think we have seen a rare failure in the application of the geologic principle of Uniformitarianism.

Uniformitarianism is often incorrectly cited as the reason geologists were slow to accept plate tectonics, the impact theory of the K-Pg extinction and why the hypotheses for a Younger Dryas impact and abiotic oil are generally unaccepted. However, Uniformitarianism may be why a CO2-driven climate paradigm appears to have come into wide acceptance, at least in academia.

The past history of our globe must be explained by what can be seen to be happening now. No powers are to be employed that are not natural to the globe, no action to be admitted except those of which we know the principle.

James Hutton, 1785

Geologists are taught that the processes we observe today are the same processes that formed the ancient rock formations that comprise the geologic history of the Earth. An example would be oolitic limestone. By observing where and how modern oolitic carbonate sediments are formed and deposited, we can deduce the past depositional environments of oolitic limestone formations.

“The present is the key to the past” is valid axiom… Unless the present is fundamentally misunderstood.

Here is figure 2 from Steinthorsdottir et al., 2019 (S19):

Figure 2. Eocene CO2 and temperature (older is toward the right). ” Eocene climate reconstructions. (A) Green diamonds show previously published stomatal proxy–derived pCO2 estimates for the Eocene (McElwain, 1998Kürschner et al., 2001Royer et al., 2001Greenwood et al., 2003bRetallack, 2009Smith et al., 2010Doria et al., 2011Grein et al., 2011Roth-Nebelsick et al., 2012Franks et al., 2014Maxbauer et al., 2014Liu et al., 2016Steinthorsdottir et al., 2016Wolfe et al., 2017). Pink circles are average pCO2 values calibrated in the present study. Marine pCO2 estimates based on alkenone δ13C data are shown with black squares (Zhang et al., 2013), while white squares are based on boron δ11B data (Pearson et al., 2009Anagnostou et al., 2016). All previously published data points are plotted without errors for visual clarity; see Foster et al. (2017) for error estimates. (B) δ18O-based ice-free deep-ocean temperature proxy (lower values indicate higher temperatures), with five-point running average curve fitted in black (data compilation of Cramwinckel et al., 2018). PETM—Paleocene-Eocene Thermal Maximum; EECO—Early Eocene Climatic Optimum; MECO—Middle Eocene Climatic Optimum; Pal.—Paleocene.”

Did you notice something odd? The moderate CO2 concentrations actually increase from the warmer Early Eocene into the cooler Middle to Late Eocene.

I added S19’s Eocene stomata CO2 estimates to my compilation of Cenozoic Era estimates and temperatures (note that my plot has older toward the left).

Figure 3a. Marine pCO2 (foram boron δ11B, alkenone δ13C), atmospheric CO2 from plant stomata (green and yellow diamonds with red outlines), Mauna Loa instrumental CO2 (thick red line) and Cenozoic temperature change from benthic foram δ18O (light gray line).
Figure 3b. Legend for Figure 3a.

A note regarding the δ18O temperature reconstruction: The conversion of δ18O to temperature is based on an ice-free model, more suited to the Paleocene and Eocene, than later epochs. However the relative changes in temperature would be in the same direction.

It is evident in Figure 3a that only the foram δ11B reconstruction yields exceptionally high pCO2 concentrations during the Paleogene. δ11B is a proxy for pH, which is related to pCO2, although not necessarily a good proxy for pCO2 itself. The alkenone δ13C and stomata reconstructions all indicate moderate pCO2 concentrations during the Paleogene and Neogene. Clearly, there was no significant coupling of temperature and CO2 over first 65,999,850 years of the Cenozoic Era.

Added Bonus

It is very tempting to assume that past CO2 concentrations can be used to directly calculate pre-industrial seawater pH and vice-versa. The following graph is a skeptic favorite:

Figure 4. Phanerozoic temperature (Scotese) and CO2 (Berner). Geocraft. Older is toward the left.

This graph didn’t sit well with the CO2-Driven Climate Paradigm crowd, so they [5] decided to “fix” the temperatures by adjusting them to pH values calculated from CO2. We can see that this yields a much better correlation between CO2 and temperature.

Figure 5. Phanerozoic pH-corrected temperature (Royer & Berner) and CO2 (Berner). Older it toward the left.

One slight problem…

Figure 6. Equilibrium climate sensitivity from Royer and Berner. Older is toward the right.

This fairly decent correlation yields an equilibrium climate sensitivity (ECS), inclusive of all feedback, of only 1.28 °C per doubling of atmospheric CO2 over the past ~540 million years. This would mean that the transient climate response (TCR), the one that actually affects us, is only about 0.85 °C per doubling of atmospheric CO2, very much inline with the low end of recent low sensitivities calculated from satellite-era instrumental observations.

Cited References

[1] Middleton, David H. “A Clean Kill of the Carbon Dioxide-Driven Climate Change Hypothesis?” WUWT. 25 September 2019.

[2] Middleton, David H. “Middle Miocene Volcanism, Carbon Dioxide and Climate Change”. WUWT. 3 June 2019.

[3] Dott, Robert H. & Roger L. Batten.  Evolution of the Earth.  McGraw-Hill, Inc.  Second Edition 1976.  p. 441.

[4] Steinthorsdottir, M., Vajda, V., Pole, M., and Holdgate, G., 2019, “Moderate levels of Eocene pCO2 indicated by Southern Hemisphere fossil plant stomata”: Geology, v. 47, p. 914–918, https://doi.org/10.1130/G46274.1

[5] Royer, D. L., R. A. Berner, I. P. Montanez, N. J. Tabor and D. J. Beerling. “CO2 as a primary driver of Phanerozoic climate”.  GSA Today, Vol. 14, No. 3. (2004), pp. 4-10

Other References

Berner, R.A. and Z. Kothavala, 2001. “GEOCARB III: A Revised Model of Atmospheric CO2 over Phanerozoic Time”, American Journal of Science, v.301, pp.182-204, February 2001.

Pagani, Mark, Michael Arthur & Katherine Freeman. (1999). “Miocene evolution of atmospheric carbon dioxide”. Paleoceanography. 14. 273-292. 10.1029/1999PA900006.

Pearson, P. N. and Palmer, M. R.: Atmospheric carbon dioxide concentrations over the past 60 million years, Nature, 406, 695–699,https://doi.org/10.1038/35021000, 2000.

Royer, et al., 2001. Paleobotanical Evidence for Near Present-Day Levels of Atmospheric CO2 During Part of the Tertiary. Science 22 June 2001: 2310-2313. DOI:10.112

Tripati, A.K., C.D. Roberts, and R.A. Eagle. 2009.  “Coupling of CO2 and Ice Sheet Stability Over Major Climate Transitions of the Last 20 Million Years”.  Science, Vol. 326, pp. 1394 1397, 4 December 2009.  DOI: 10.1126/science.1178296

Zachos, J. C., Pagani, M., Sloan, L. C., Thomas, E. & Billups, K. “Trends, rhythms, and aberrations in global climate 65 Ma to present”. Science 292, 686–-693 (2001).

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131 thoughts on “Eocene Climatic Optima: Another Clean Kill of Carbon Dioxide-Driven Climate Change Hypothesis?

  1. The last couple of paragraphs’ deduction of ECS of 1.28 using the Royer et al 2004 paper is truly the highlight of the article.

    • Climatology is cherrypicked 5y averages massages with voodoo stats; not 540Myr averages that match modern observations.

        • I think some of his reconstruction is inferred, particularly the K-Pg impact winter and “PAW”.

          • Oh, please, Mr. Middleton. Are you saying that you don’t care about your children, and their children, and their children’s children, and their children’s children, and their children’s children, and their children’s children, and their children’s children, and their children’s children, and their children’s children, and their children’s children, and their children’s children, and their children’s children, and their children’s children, and their children’s children, and their children’s children, and their children’s children, and their children’s children, and their children’s their children’s children, children’s children, and their children’s children, and their children’s children, and their children’s children, and their children’s children, and their children’s children, and their children’s children, and their children’s children, and their children’s children, and their children’s children, and their children’s children, and their children’s children, and their children’s children, and their children’s children, and their children’s children…and their children’s children (for the 200th time)?

            Personally, I only care about my children, but not their children, because I don’t think children should be having sex.

          • We have 11 “children”… 5 Pomeranian/Pom mixes, 2 Corgis, 2 Chihuahuas, 1 Toy Fox Terrier and 1 mythical creature… All are either spayed or neutered. We care about our “children”… We tolerate the neighbors’ children as long as they stay the Hell off of our property… 😉

          • But PAW is just to indicate that even the worst case antropogenic warming is NOT a hothouse. Not even close… So all the scaremongerers that are trying to frighten us with “runaway greenhouse” are wrong.

  2. “… This would mean that the transient climate response (TCR), the one that actually affects us, is only about 0.85 °C per doubling of atmospheric CO2 …”.
    I love it when eco-tyrants get hoisted with their own petard.

    • Just a (very) minor nit-pick: “hois” is a old verb meaning “to blow up”. Therefore the past participle is “hoist”. A “petard” is a small explosive device, usually used to blow in a door.
      Isn’t that interesting?

        • And being hoist on your own petard was when you were clearing a misfire, that blew you up. Lifted by your own flatulence, even funnier.

        • Grant! You’re taking away the best example of onomatopoeia I can find. If a fart becomes a blast, the word loses its literary value of sounding like the thing it represents.

          Being suspended in the air by something blowing up in your face must retain its special privileged position in climate science’s lexicon. Plus “puh-TARD” sounds just like a lit gunpowder fuse reaching the main charge.

        • It wasn’t really slang, it was taken from the French usage.
          Wikipedia—“Pétard comes from the Middle French péter, to break wind, from the root pet, expulsion of intestinal gas, derived from the Latin peditus, past participle of pedere, to break wind.”

      • “Hoist” does not mean “to blow up”, but “lifted” or “raised”, originally in a nautical sense. In Shakespeare’s famous verse, it’s the past participle of “to hoist”:

        hoist (v.)
        1540s, “to raise, lift, elevate,” especially with a rope or tackle, earlier hoise (c. 1500), from Middle English hysse (late 15c.), which probably is from Middle Dutch hyssen (Dutch hijsen) “to hoist,” related to Low German hissen and Old Norse hissa upp “raise,” Danish heise, Swedish hissa. A nautical word found in most European languages (French hisser, Italian issare, Spanish izar), but it is uncertain which coined it. Related: Hoisted; hoisting. In phrase hoist with one’s own petard, it is the past participle.

        For ’tis the sport, to have the engineer
        Hoist with his own petar: and it shall go hard
        But I will delve one yard below their mines,
        And blow them at the moon: O ’tis most sweet,
        When in one line two crafts directly meet.
        [“Hamlet,” Act III, Scene iv]

        Meaning “to lift and remove” was prevalent c. 1550-1750. As a noun, 1650s, “act of hoisting;” 1835, “that by which something is hoisted,” from the verb.

  3. “I have to assume that either this is on longer the case or that homage must be paid to the current paradigm in order to get published.” (my bold, on the latter)

    David,
    IMO it is clearly the latter. The climate change scam has so polluted top journal editors and gate-keeper reviewers, it is impossible to publish any observational result that runs counter to CC-catastrophe-narrative unless the authors then bow before the climate change pagan god in their Discussion/Conclusion and ask for forgiveness of their sins — that somehow in the distant future RCP8.5 climate model Thermageddon will reverse the “good” results they are reporting and all Hell will break loose to reverse what they are reporting.

    A recent example in the biology literature on observed biodeversity changes and climate change is this paper (link below), picked up by Science Mag as a noteworthy “Editor’s Choice” (a note-worthy paper in the Editors’ view published in another journal):

    Widespread Effects of Climate Change on Local Plant Diversity
    Andrew J. Suggitt, Duncan G. Lister, Chris D. Thomas
    Pages 2905-2911.e2, Current Biology (Open Access)
    https://www.sciencedirect.com/science/article/pii/S0960982219308395/pdfft?md5=5fb98907d355b10d623f972103914964&pid=1-s2.0-S0960982219308395-main.pdf

    The authors of that paper note in their discussion:
    – “In sum, our GLMM analyses suggest that local species richness has, on average, been increasing by +5% per decade in cooler regions of the world (Figure 3).”
    – “(Figure 1A), which suggests that species richness has increased by 9.1% per decade and 10.8% per decade at locations where temperature and precipitation (respectively) have changed the most and by roughly 3% per decade in locations subject to medium levels of temperature or precipitation change(Figure 2).”

    – “But nevertheless, it is entirely possible that we are witnessing an accrual of local diversity in response to modern climate change [21]. It is important not to confuse this positive effect of climate change on local-scale species richness with its heightening of global extinction risk for a substantial portion of the species on our planet [22, 23].
    =====
    The Science Magazine “Editor’s Choice” write-up on the good news of increasing biodiversity under climate change had to supply a genuflection to future Climate Change catastrophism, by calling this increasing biodiversity observed result a “temporary richness.” That’s a total bullshiest hogwash genuflection to the catastrophe narrative of the observed result did not fit the dogma CC narrative. How do they know that will not continue? Because some hogwash politically-motivated GCM garbage from GISS or LLNL says so?

    That last [bold] was mine to emphasize how today’s author’s have to genuflect to the Climate Change catastrophe paradigm, probably in order to get published and get past the journal gate-keepers even when they have good news that climate change is apparently beneficial to local biodiversity.

    Related to this is my belief that like politics, “All biodiversity is local.”
    For example: a biological niche in the Arctic-Kamchatka Peninsula does not care one bit about the biodiversity in South American Patagonia, and vice versa. They are two completely different responding biomes and native species habitats. To believe that some how “global warming” matters to a local or regional biome is stupid. The creatures and biome in each area respond to their own local conditions. They don’t get a telegram from the UN or from a hot-drought 8,000 km on the other side of the planet away telling them to simply die-off because that’s what some garbage model says they are supposed to do.

    But Climate Change catastrophism tries to unite them as one big disaster in a declining model under the Worst Case idiocy of the IPCC regimes to provide a narrative. But they do not respond that way. Each species and each niches responds to promote life, to promote more biodiversity under change. It is from change that biodiversity has always flourished, news species emerged, existing species migrated and infilled, to then diverge again.

    So back to what you noted David, ““The present is the key to the past” is valid axiom… Unless the present is fundamentally misunderstood.” The present is being observed and documented by field scientists. Sadly though, they are having to bow down to the CC dogma to get published.

    The entire Climate Change narrative is polluting every bit of science today with the need to genuflect to “CC must = bad” dogma. Sad.

    • “It is important not to confuse this positive effect of climate change on local-scale species richness with its heightening of global extinction risk for a substantial portion of the species on our planet”

      Translation:
      No one should think that just because everything is getting better when we take a close look at the facts, that this does not mean that overall, everything is far far worse, everywhere. And not just worse, but worse than we thought when we first thought it was worse, and the later thought it was worse than that, and later when we discovered it was ever worse than we thought when we first found out it was worse than we thought the second time, let alone the first time. And we are sure it is not just worse than we thought, it is worse than we know.
      In summary, not being able to point to any specific thing that is actually worse for people in any particular place, is separate from the aggregate finding by models, and confirmed by a show of hands among those with the correct opinions, that we are in a severe and unsurvivable crisis.

      • …We suspect that it could actually be even worse, so further studies are required. Send money….

    • You’re right that they won’t publish. That’s why it’s more important than ever that our elected lawmakers tell the gatekeepers to go $)&( themselves. The gatekeepers reduced their credibility to rubble. Just ignore them, repeatedly, and they shall exist in an influence vacuum. This has been happening recently which is why they’re increasingly so apoplectic.

  4. “first 65,999,850 years of the Cenozoic Era.”

    I disagree Dave. I think it was actually 65,999,853 years ago.
    That’s because the newest estimate of the KPg boundary date came out ~3 years ago.
    Such is the state of sig figs and zero uncertainty in climate change pseudoscience.

    (do I need a /sarc?)

  5. Kudos for mentioning T.C. Chamberlin’s “Method of Multiple Working Hypotheses.” The scientific method is simple: 1) observe phenomena that require explanation; 2) hypothesize an explanation and state the null hypothesis, i.e. what would we observe if the hypothesis were not true; 3) design and execute experiments, and/or make further observations to validate the hypothesis or not (null hypothesis). I emphasize the null hypothesis because every hypothesis is either true or not true. That, in itself, seems to have been lost on a large part of the scientific community, and definitely completely escapes the comprehension of the contemporary press. Step 2) – hypothesize to explain initial observations – requires that every possibility that might explain the observations be seriously considered. This, too, has escaped much of today’s scientific community. T.C. Chamberlin’s brilliant recognition of the dangers of a single hypothesis, and recommendation of multiple hypotheses being considered and weighed against each other as actual data is collected, should be an obligatory part of scientific training and strongly emphasized in scientific practice. In my first year as a geology student I was required to read Chamberlin’s article as published in Science, 1965. There is a link to that article in the footnotes, but it is broken. Here is another link to that article as a downloadable .pdf. Enjoy. http://webhome.auburn.edu/~tds0009/Articles/Chamberlain%201965.pdf

  6. I agree that a study of how thing occur today can be used to show what happened in the past. But what about the amount of CO2 back then, and the effect if any, on the temperature.

    What about the Logerithermic effect, whereby beyond a certain figure, such as 1000 ppm should mean that the ability to cause a rise in the atmospheric temperature is limited.

    What about a major change in the output of the Sun. As the sea warms up it releases vast amounts of CO2, but at the same time its the Sun which is really warming the Earth and not the CO2.

    MJE VK5ELL

    • If this is true why have we not seen a change to the specific heat of CO2 and the specific heat equation? Maybe Q -( (5.37ln (Cn/Co)) = Cp* m *dT

      Something has to change.

      • mkelly: Agree. Assuming equilibrium state, the value Cp of CO2 does not change as its concentration changes from 400 to 800 to 4000 ppmv (to four significant figures)…

    • It may be even far less than this, because I believe in the graph you are seeing CO2 being driven out of the oceans because of increasing temperature. In other words, the increase of 0.85 degrees (or 1.25) forces the atmospheric CO2 content to double. So this doesn’t really say anything about heating caused by CO2, except that it must be less than that.

      • I didn’t expect to see my Facies and Field Studies prof show up here. I used to run into him at GeoConvention in Calgary now and then, but I haven’t seen him in years. One of the smartest, lowest-BS-ratio people I’ve ever met.

      • Further to my earlier reply, it’s weirdly gratifying to learn that you two know each other. 😀

          • Man, that would be a beer-n-bull session for the ages, if it ever happens. I feel like if I were to witness it, my sarcasm detector would explode.

          • Geology…without…liquor…? These appear to be English words, but they make no sense in this form.

          • Geology humor…

            In the oil & gas industry, there are three main professions:
            1) Landman (Petroleum land management and lawyers)
            3) Engineer (reservoir, drilling, production, completion, etc.)
            3) Geologist (includes geophysicists, etc.)

          • After the last time you shared that Dilbert here at WUWT, I printed it out and have it on my cabinet at work, and gave a copy to a co-worker. 🙂

            I did the geology gig for a few years, but now I’m in software. These days, an upstream professional has to do a bit of all three, almost a ternary solid-solution diagram of liquor consumption. But around here, the landmen are almost legendary. 🙂

          • One of my co-workers has the cartoon hanging on his office door. I think this is modified from the original Dilbert cartoon, I think “geology” was “marketing” in the original.

  7. Minor nitpick – “I have to assume that either this is on longer the case or that homage must be paid to the current paradigm in order to get published.” Should be “no longer”.

  8. There appears to be a chasm between geologists and climate scientists on the issue of CO2 driven climate.
    In 2009, I attended a lecture by a geologist totally sceptical of the concept of CO2 dominating climatic change.
    I still retain a copy of his paper which canvassed the Geologic ages where CO2 was much higher than today and eras where temperatures greatly exceeded those of the present.
    Last year on a sea voyage another geologist gave a very similar lecture on climate change, dismissing CO2 as the driver.
    There are many books by geologists to like effect.

  9. I’m no scientist, but it seems to me that they decided that CO2 was the cause of any and all warming, then proceeded to figure out how much they would need.

    I don’t see any discussion of orbital changes (particularly eccentricity) in relation to the climate of the Eocene. It’s not something I have a particular expertise in, but my understanding is that there were periods of elevated eccentricity in some parts of the Eocene. There are inputs to the climate other than CO2. What was Earth’s orbit like and what was the Sun doing would be high on my list of things to figure out first.

  10. Did you notice something odd?

    Yes in figure 2 panel A, I noticed that the CO2 “proxies” are all over the page. Looks like incompatible data or the whole thing is unreliable. You can see things going up or down depending upon how hard you squint and which eye you close first. Green goes up while white comes down. Black goes through the root while others do not blink.

    I would not even bother trying to draw any conclusions from data like that.

    I think the main result from paleo data is that CO2 lags temperature rise. That make it rather difficult to suggest that CO2 is driving temperature and not the reverse.
    <blockquote
    This fairly decent correlation yields an equilibrium climate sensitivity (ECS), inclusive of all feedback, of only 1.28 °C per doubling of atmospheric CO2 over the past ~540 million years.

    Better correlation that most climate data we see.
    How did you get the 1.28 figure. doing very rough estimation from peak at 500Ma BP and trough at 330Ma BP :

    8/( log(7000/500.)/log(2) )
    = 2.10119628029755 deg / 2xCO2

    could you explain clearly what you did ? OLS on log CO2 ? which variable was the abscissa?

  11. Ah I see it’s a log fit due to Royer and Berner. Look credible at about 1.3 , only problem is that the lower data fits quite well but the spread is huge higher up.

    • Royer and Berner used Geocarb (Berner) to pH-adjust the temperature. So, naturally, it correlates with Geocarb. It also yields a minuscule climate sensitivity.

  12. So, if you believe that CO2 is a key determinant of client, it is now taking more CO2 to maintain desirable warmth.

  13. David,

    One earlier episode that forms a bit of an analogy to this current “paradigm” as you call it, was the age of the Earth controversy, with geologists and the occasional physicist (Heaviside) on one side, the side of an old Earth, and physicists (Kelvin) and the occasional mathematician (Tait) on the other (young Earth). The geologists knew from sedimentation rates that the stratigraphic record required hundreds of millions of years to accomplish; the physicists using physical processes like deep temperature measurements in mines or ocean salinities pushed the estimate all the way down to five million years.
    The ruling paradigm of the time was that physics, even if mal-interpreted, explained the physical world properly and everyone just needed to get on board. “You geologists had better figure out how this happened more quickly” might be a paraphrase.
    Once the real age of the Earth became more widely accepted, the cover story for those in the wrong paradigm camp became that Kelvin was wrong only because he didn’t know about radioactivity. But Heaviside showed that if one took uncertainty of mechanisms into account the deep temperature records were compatible with practically any age of Earth, and didn’t demonstrate much. Kelvin was wrong because he was simply wrong. However, the ruling paradigm prevailed for a time because Kelvin was a towering, influential figure.

  14. We have produced a generation of garbage scientists who must follow the CO2 drives climate paradigm to get grants and get published. That the separation of South America from Antarctica allowing the Antarctic-Circumpolar current was not the driving force? I am assuming the current used flow south from the Atlantic, around Antarctica, then north into Pacific before the separation.
    Also, presumably the warm equatorial current flow from east, from Africa through the gap between North and South America, into the Pacific until the Isthmus of Panama filled in. That caused it to redirect out the Florida Strait into the North Atlantic?

  15. The Sun is the driver of life. Life takes sunlight and CO2 and produces O2 as a waste product. Oxygen is a waste product for life. Over time life arose which ate the algae waste product O2 and generated as waste CO2.
    Plants don’t do so well in an ice age, there is simply less area to grow on. They generate less CO2 so it should lag temperature.

  16. Stomatal density as a good CO2 proxy is certainly putting the cat among the pidgeons regarding CO2 warming mythology.

    Your teachers were quite right to advise against paradigms.
    The current forced CO2 paradigm is flat out wrong and is like a cancer in geology.

    Kudos to Steinthor’s daughter and Brian Pratt (and Dave!)

  17. doing very rough estimation from peak at 500Ma BP and trough at 330Ma BP :

    8/( log(7000/500.)/log(2) )
    = 2.10119628029755 deg / 2xCO2

    could you explain clearly what you did ? OLS on log CO2 ? which variable was the abscissa?

    This comment is not meant to pick at Greg, but the calculation, which is either done or alluded to by so many people here is logically suspect. Supposing the relationship is true, then at very low concentration CO_2 becomes the super onmi-potent gas. Very tiny increases in its concentration cause very large changes in temperature.

    The problem is that somewhere along the way in GHG concentration local thermodynamic equilibrium no longer exists. Gas temperature revealed by the distribution of gas kinetic energy (speed distribution) suggests one temperature, while the curve of long wave radiation emitted from the scene suggests a different temperature. Temperature is a parameter describing a distribution, and if one isn’t careful, the concept leads to odd things–like negative absolute temperature in the energy distribution in a laser.

    The problem of breakdown of local thermodynamic equilibrium explains why Mars is cold despite an atmosphere composed of nothing but the venerable CO_2.

    • Kevin Kilty: “Supposing the (log) relationship is true, then at very low concentration CO_2 becomes the super onmi-potent gas. Very tiny increases in its concentration cause very large changes in temperature.”

      Precisely! To claim that CO2 forcing is logarithmic means that CO2 forcing per molecule goes up as CO2 density declines. I’ve asked for an explanation for those making this claim, because it gets absurd into very low concentrations of CO2.

      I even asked David Middleton what the lower bound of CO2 density is whence the logarithmic relationship ceases. He responded with: “I don’t think it ever ceases”

      I give them an out by providing the notion of a lower bound density under which CO2 does not behave logarithmically, but no one can derive what that lower bound density is, nor how it can be derived.

      Now they need to defend the notion that if we were to extract all of the CO2 from Earth’s atmosphere and then begin adding it back in one molecule at a time, then adding the second molecule represents a doubling of CO2 and would trap global heat? If we were to continue adding CO2 molecules until there was one for each square meter of Earth’s service area, their logarithmic relationship dictates this would be trapping in excess of 70F of global heat.

      Now, who is good at using sarcasm to belittle such an absurd idea?

      • The function doesn’t start from zero or even one molecule. Clearly if our atmosphere was a thin as Mars, the CO2 would trap no heat.

        Nor is it based on the number of in the atmosphere. It’s based on the molar fraction of the atmosphere.

        The function is based on parameters of Earth’s atmosphere. It’s logarithmic because CO2 only absorbs IR radiation in s specific bandwidth. As that bandwidth becomes saturated, the effect of additional CO2 exponentially declines as it occupies the side lobes.

        If the average surface temperature of the Earth was 14 K at 280 ppm, a 1.28 K ECS would do this:

         CO2 ppm  Temp (K)
                      1        4.76
                      2        6.04
                      4        7.32
                      9        8.60
                    18        9.88
                    35      11.16
                    70      12.44
                  140      13.72
                  280      15.00
                  560      16.28
               1,120      17.56
               2,240      18.84
               4,480      20.12
               8,960      21.40
              17,920      22.68
              35,840      23.96
              71,680      25.24
            143,360      26.52
            286,720      27.80
            573,440      29.08

        https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1002/2014JD022466

        • In a dry atmosphere…but then here on the real Earth, we don’t have a dry atmosphere. Which renders all this “CO2 sensitivity” nothing more than what it has always been – “hypothetical bullshit.”

          The truly amazing lack of objectivity in “adjusting the temperatures based on ph values calculated from CO2” is astounding. “Oh gee, look, when I calculate the temperature as a function of CO2 level, it really correlates!” Smells just as much as throwing out the temperature readings they didn’t like and substituting temperatures “calculated” from wind speed data when they didn’t get the answer they wanted while looking for the non-existent “hot spot” in the tropical troposphere.

          What they do is akin to an engineer, upon the discovery that a bridge under construction has a key dimension on a supporting structural member wrong, substitutes the length of his foot for a yardstick and says it’s “correct” based on the “new” measurement. How’d you like to drive over a bridge built on THAT philosophy?!

          • The point is that even when they use CO2 to make temperature correlate with CO2, they get a minuscule ECS, comparable to recent instrumental estimates.

          • Oh yes Dave I understand THAT point, but I always like to take that one step further – even that “minuscule” sensitivity is STILL fiction, based on the applicable caveat of “all other things held equal.” There is no temperature “sensitivity” to atmospheric CO2; only the opposite (an atmospheric CO2 sensitivity to temperature) is valid, based on the inverse relationship between temperature of water and the amount of CO2 that it will absorb/hold as opposed to release to the atmosphere.

          • It’s not fiction. It’s just not easily quantified because the Earth doesn’t allow all other things to be held equal.

          • Oh, but it has been quantified. The ice core reconstructions have done so nicely. CO2 FOLLOWS temperature, up and down with an 800 year (give or take) time lag. The fig leaf “explanation” that has been offered for this is that the alleged “contribution” of CO2 to the rise in temperature supposedly occurs after this time lag has elapsed and both temperature and CO2 are rising.

            However, the rate of temperature rise does not increase after *both* are rising, and more to the point, there is one place in those graphs where the supposed “contribution” of CO2 cannot hide. When the (excuse me) REAL cause of the temperature rise stops, what we SHOULD see is this: The temperature should continue to rise, at a reduced rate, as long as the CO2 continues to rise (that reduced rate being the, you know, “contribution” of CO2 to the temperature rise).

            But what we see, instead, is this: Temperature starts FALLING – while CO2 levels continue to rise for another (give or take) 800 years, and then CO2 (again) FOLLOWS temperature downward. Couple this with the fact that temperatures always start to rise when CO2 is near its low point, and always start to fall when CO2 is near its high point, and you have a sharp image of the temperature “sensitivity” to CO2. It’s not “difficult to quantify.” It is…

            Zero point zero (insert Dean Wormer here).

            As they say, “Observation TRUMPS theory.” Observations tell us that CO2 does nothing to temperature.

      • The log relationship is a reasonable approximation over some range. The paper David references appears to be doing all calculations near an optical depth of 1–and they also assume local thermodynamic equilibrium and ignore scattering to “derive” the relationship. But it does breakdown some place because you will note that at 100ppb or so in David’s chart the surface temperature would have gone to (Zero)K. You could use MODTRAN to see where the breakdown becomes significant, but MODTRAN is not set up to calculate in this manner, and it becomes a real burden to first change CO2, calculate OLR using MODTRAN, then adjust surface temperature to return the OLR value back to equilibrium using MODTRAN again. I found a difference of 33 \, W/m^2 in OLR in going from 0 to 400ppm, with no water vapor. This is just about equivalent to a change in the stefan-boltzmann emitted power at a surface (e=0.97) in going from 280K to 288K.

        At any rate my point was to explain what probably goes on in a thin atmosphere like Mars.

          • David Middleton –

            “Yep… Greenhouse gases don’t matter in an almost non-existent atmosphere.”

            I’ve broached this subject with you previously, and I was asking about the greenhouse gas property of CO2 on Mars and how it manifests itself. I claimed that it trapped no heat and you counter claimed something like: Mars is probably 5 degrees warmer than if
            its atmosphere were 100% nitrogen.

            Your response surprised me then, I’m glad you seem to have a differing viewpoint now.

            I always appreciate your contributions, and your willingness to respond to comments.

          • There are some who have discovered that they don’t really matter on an extremely dense atmosphere, either.

            If you compare the Venus temperature profile and compare temperatures to Earth at equal atmospheric density, you’ll find that Venus (95%+ CO2) and Earth (0.041% CO2) have a difference in temperature that can be explained purely by their distance from the Sun, and the effect that has on how much energy each receives from the Sun. No need for “greenhouse gas” hocus-pocus.

          • Venus’ thick atmosphere matters, if for no other reason, than that it warms the night side of the planet. That’s a major, perhaps the main, reason why Venus’ surface is hotter than Mercury’s. Venus never cools off, as Mercury does dramatically.

            Both planets rotate slowly, but Venus more so, which gives time for heat to build up. Very little sunlight makes it through Venus’ clouds to reach the ground. Its high albedo reflects away some 77% of incoming solar radiation, then over half of the rest is absorbed in the air. Less than ten percent of ToA irradiance hits the surface, of which under three percent directly and about seven percent scattered.

            The GHE works differently on Venus. The hot surface doesn’t even radiate in CO2’s absorption bands, although close to one peak. There’s very little water. The hypothesized runaway GHE early in the planet’s history involved water, not CO2.

          • Earth receives about half the irradiance of Venus. If our average surface T indeed be 15 C, then a 92 times denser atmosphere would yield a mean T of 1380 degrees C. Divide that by two for the sunshine difference and Earth would then average a toasty 690 degrees C.

            But Venus’s surface is “only” about 467 C.

            Venus is hot not just because of its dense atmosphere, but because it turns so slowly. Its clouds actually shade the sunny side, but warm the dark side, which, as noted, is why Venus is hotter than Mercury, whose night side is frigid.

  18. Good discussion. It took Geologist for ever to get away from Catastrophism to Uniformitarianism and now somewhere between those endpoints. The reconstructions of the Eocene always forget or ignore that the Eocene (in East Texas and gulf coast) was a period of sea level Transgression and Regression. Does that show up in the CO2 record?

  19. There’s still remnants of the old common-sense about warm climate periods — climate optimums, Eocene equable climate, etc. The climate industrial complex thought-police/history-revisionists need to clean up these dangerous leftovers.

  20. The multiple hypothesis approach is apparent in medicine with the differential diagnosis. Imagine a doctor figuring out the cause of an illness with a patient exhibiting a complex set of symptoms and only considering one explanation when the medical literature suggests multiple possibilities. That. unfortunately, seems to be the state of of the “scientific consensus” when it comes to the climate.

  21. Regarding “This fairly decent correlation yields an equilibrium climate sensitivity (ECS), inclusive of all feedback, of only 1.28 °C per doubling of atmospheric CO2 over the past ~540 million years. This would mean that the transient climate response (TCR), the one that actually affects us, is only about 0.85 °C per doubling of atmospheric CO2, very much inline with the low end of recent low sensitivities calculated from satellite-era instrumental observations.”:

    I would like to caution that the feedbacks aren’t constant. For example, the surface albedo feedback from change of snow and ice cover was probably quite great during the comings and goings of continental ice sheets during the Pleistocene, and nearly nonexistent during the world’s warmer times.

    • “the surface albedo feedback from change of snow and ice cover was probably quite great during the comings and goings of continental ice sheets during the Pleistocene, and nearly nonexistent during the world’s warmer times.”

      Not necessarily. The current feedback is strong in the northern hemisphere but weak in the south (Antarctica is always snow-covered). Before the mid-Miocene when glaciation was variable in Antarctica the albedo feedback was probably substantial in the southern hemisphere but weak in the northern.

      • Donald would be correct however for the warmest times, when there were no ice sheets, north or south, but at best some montane glaciers, seasonal snow and possibly sea ice.

      • One reason for the surface albedo feedback being weaker in/around the Antarctic than in/around the Arctic is that the Antarctic/near-Antarctic has little land that has variable snow/ice cover. Another thing about the Antarctic is that there is not much sea ice there at the end of summer, so Antarctic sea ice is less able to carry over an anomaly from a year to the next year or through the next few years than Arctic sea ice is.

  22. I won’t even entertain their circular reasoning to poke holes in their pseudoscience. The “ECS” to CO2 is ~0.0

    • Agreed. The all-important caveat of “all other things held equal” is always conveniently ignored, like an elephant in the room, and they always use the baseless and deliberately unstated assumption that all of the warming since [fill in the blank] is “caused by” CO2, without a shred of evidence to that effect.

  23. David
    There is something unusual about Figure 2. There is no zero on the δ18O axis, and the distance between -1 and +1 is the same as between -1 and -2.

      • David
        Yes the shapes of δ18O values in your Figure 2 and Zachos et al. are similar, but the δ18O values are different at 34, 51, and 56 MY. It looks like the absence of the zero level has affected Fig. 2.

        • My graph with Zachos has temperatures calculated from the δ18O values. Here’s a plot of Zachos δ18O values at the same scale (I think) as the image from the paper.

          They match fairly well with three big differences:

          1) Zachos PETM is very nuted.
          2) Zachos PETM is 1 Myr later.
          3) Zachos MECO is 1 Myr earlier.

          I don’t know if the labeling of the y-axis is a typo or a weird rounding effect.

  24. Has atmospheric pressure on Earth always been the same? Would it be possible to reconstruct atmospheric pressure levels for the last 500 million years? Has atmospheric pressure an effect on plant stomata?

    • I do think there have been efforts to reconstruct atmospheric pressure… I don’t know how that would affect plants. Stomata tend to respond to changes in CO2, water and sunlight (IIRC).

      At a higher atmospheric pressure, one would think that there would be more CO2 available at the same ppm concentration as at a lower pressure.

  25. The question would be what happened at the end of the Eocene? There are at least 3 fairly large impact craters around 35 Ma – Chesapeake, Popigai and a smaller one off the NJ shoreline. There is at least one LIP – Afar within 5 MA and another couple – Western and Central European and Northern and Central African (undated) around that time. There was a caldera outbreak from Nevada – Colorado around 30 Ma. The end of Eocene also included a minor extinction event.

    To me, it appears that the biosphere is well evolved to deal with LIP emplacement. Combine that with something else – anything else – large and you start killing off species.

    So like what happened? Better yet, after that 10 Ma period, why did global temps continue to crater? Rise of the Himalayas? Indonesia? Panama closing the flow between the Pacific and Atlantic? Something else?

    From here, there were significant geologic events, some of them in very short time frames and the biosphere seemed to respond fairly well. Still we are in a 30 Ma period of an impending ice age which got really bad the last 2 Ma. So like what happened? Cheers –

    • The Eocene-Oligocene boundary corresponds with the opening of deep oceanic channels between Antarctica and its fellow Gondwanan continents of South America and Oz. Formation of the Southern Ocean explains the onset of the Cenozoic Icehouse.

  26. Even though I have no training in climate models – using statistical analysis a few years back I reached a Climate Sensitivity figure of 1.3 degrees celsius – nice to see my maths was pretty close

  27. “And/or “that other climate forcings were stronger than previously assumed”.

    They totally missed the most obvious reason why just about every effort to gin up a paleo example of CO2-driven climate change falls apart: Atmospheric CO2 is not a primary driver of climate change over geologic time. ”

    Totally miss? err no.

    1. Either sensitivity was higher
    2. Or other forcings were higher ( get to work DETAILING what you think)
    3. Or the temperature Estimate of the past is sketchy ( laughing at geologists saying 4-15C)
    4. Or stomata from fossils are sketchy way to “measure” C02

    Lots of open questions.

    Psst open questions dont change anything

    • The pronounced rise in atmospheric CO2 over the whole Eocene when temperatures steadily declined on a trajectory toward glaciation, is maybe more problematic for a CO2 controlling role. Unless it’s of a negative sign.

    • ECS is an open question.

      Is it 0.8 to 1.8 degrees C, as in observations, around a central value of 1.3, or 2.6 to 4.1 degrees C, with 3.0 best guess, as in GIGO models which can’t handle clouds?

      • Based on actual observations, the world’s greatest living atmospheric physicist, MIT emeritus prof Lindzen and his colleague Choi estimate the climate sensitivity for a doubling of CO2 to be 0.7K (with the confidence interval 0.5K – 1.3K at 99% levels).

        I went with a higher range because even the 2011 revision of their 2009 paper was attacked as too low by the Team. My inexpert opinion however is that they’re in the right ballpark, if not at home plate.

        IMO it’s reasonable, on a homeostatic water world, to find net negative feedbacks to the lab ECS figure of 1.1 degree C per doubling of vital plant nutrient.

        In which case, no worries. More trace gas essential to most life is a good thing.

        • Spencer and Braswell came up with a similar number about a year later… The complaints were so viscous that the editor of the journal resigned.

  28. “They totally missed the most obvious reason why just about every effort to gin up a paleo example of CO2-driven climate change falls apart: Atmospheric CO2 is not a primary driver of climate change over geologic time. This wouldn’t mean that it isn’t a greenhouse gas or that it has no effect on temperature.”

    I would have to disagree with the last part – it DOES mean that CO2 has no effect on temperature. Because “all other things” have never been, are not now, and will never be, “held equal.” The basic, essential, necessary, required CONDITION for CO2 to have an effect on temperature. CO2 has a hypothetical effect on temperature, but CO2 does not have any ACTUAL effect on temperature. THAT is what the “observations” tell us.

    And if the hypothesis disagrees with observations, then the hypothesis is WRONG. That is what SCIENCE tells us, when the Scientific Method is properly followed.

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