Physics Prof. Concludes CO2 Climate Effect Is ‘Fairly Negligible’ – Adds Just 0.5°C For A Doubling To 760 ppm

A new CO2 climate sensitivity study suggests that, beyond the 300 ppm threshold, “any further increase of (anthropogenic) CO2 cannot lead to an appreciably stronger absorption of radiation, and consequently cannot affect the earth’s climate.”

Dr. Schildknecht is a Bielefeld University physics professor affiliated with the Max Planck Institute in Munich.

His equilibrium climate sensitivity estimate (0.5 or 0.6°C for a doubling of CO2 from 380 to 760 ppm) is identical to many other recent estimates (Stallinga et al., 2020, Ollila, 2019, Smirnov, 2017, Smirnov, 2020, Harde, 2016, Bates, 2016, Kissin, 2015, Abbot and Marohasy, 2017, Gervais, 2016).

Schildknecht, 2020

“Based on new radiative transfer numerical evaluations, we reconsider an argument presented by Schack in 1972 that says that saturation of the absorption of infrared radiation by carbon dioxide in the atmosphere sets in as soon as the relative concentration of carbon dioxide exceeds a lower limit of approximately 300 ppm. We provide a concise brief and explicit representation of the greenhouse effect of the earth’s atmosphere. We find an equilibrium climate sensitivity (temperature increase ∆T due to doubling of atmospheric CO2 concentration) of ∆T ≃ 0.5°C. We elaborate on the consistency of these results on ∆T with results observationally obtained by satellite-based measurements of short-time radiation-flux versus surface-temperature changes.”

“The absorption reaches values close to 100% for a realistic CO2 content of 0.03%, it is concluded that any further increase of (anthropogenic) CO2 cannot lead to an appreciably stronger absorption of radiation, and consequently cannot affect the earth’s climate.”

[T]he effect of an anthropogenic CO2 increase on the climate on earth is fairly negligible.”

Image Source: Schildknecht, 2020

17 responses to “Physics Prof. Concludes CO2 Climate Effect Is ‘Fairly Negligible’ – Adds Just 0.5°C For A Doubling To 760 ppm”

  1. Shoki Kaneda

    Well, that’s the end of his career. The greatest sin is to speak the truth.


    […] Fonte: No Tricks Zone […]

  3. Richard Greene

    Well, that makes the 225th estimate
    of TCS or ECS climate sensitivity
    in my record book.

    not one scientist had the right,
    and obvious, answer:

    Modern Climate Science:
    Get your wild guess TCS study
    peer reviewed and published
    = you’re considered to be highly intelligent

    Get media attention and
    state your TCS conclusion
    with great confidence
    = you’re considered a genius

    Say “We Don’t Know”
    = you’re are considered a fool

    1. MGJ

      Very true.
      Whenever I visit the doctor for a diagnosis and the answer is “I don’t know”, it immediately gives me confidence that they MIGHT be competent.

      In contrast, so many quack psychologists, physios etc. will deliver a 100% certain diagnosis without even examining you.

  4. RoHa

    Dr. Schildknecht should be fired. Accuse him of lack of collegiality, as was done with Norman Finkelstein and Peter Ridd, or find some tweets that can be twisted into “hate speech”, as with Stephen Salaita.

    Come on, Bielefeld University, Max Planck Institute, do your duty to Pippi Långstrump and save the planet.

  5. William Astley

    The warming from a doubling of CO2 is less than 0.4C. A surface warming of 0.4C is a conservative high estimate that ignores other factors which reduce the warming.

    The Hansen and friends, ‘estimate’ of 1.5C, for a doubling of CO2, was incorrect to enable models to amplify. To create the possibility of CAGW.

    0.4C warming for a doubling of CO2 cannot be amplified by feedbacks as the climate would not be stable. A large step change, like a large volcanic eruption would/could initiate a glacial cycle.

    An example of a CO2 specific offset/negative feedback that is ignored. Is that due to electromagnetic theory and water’s high absorption for infrared radiation, the oceans reduce amount of warming by moving radiation into the CO2 infrared radiation windows.

    The CO2 infrared radiation (it is surface warming that is the issue) is absorbed in the ocean… and re-emit broadening the infrared radiation to enable it to pass through the CO2 absorption window.

    “The implication of this is that much of the radiation emitted will escape directly to space through the IR windows, so it could be viewed as a negative feedback. About 40% of the energy will escape this way.

    Alternatively, this mechanism implies that climate will be less sensitive to greenhouse gas warming than it would be to an equal solar radiation forcing. In addition, there are many moist areas over land and clouds are also moist, so this negative feedback or reduction in climate sensitivity is also operable nearly everywhere.

    Another issue is the reduction of the lapse rate.

    The surface warming for a doubling of C02 is less than 0.4C. 80% of the heat transfer below 5km is via convection. CO2 increases the specific heat capacity of air. This causes a reduction in the lapse rate.

    1. Petit_Barde

      There is also another mechanism – atmospheric – that can explain why we observe a lack of CO2 15 microns emission from satellites (except over Antarctica – see William Happer 2020 paper which shows – when confronting observations with his model – that CO2 is a cooling contributor over Antarctica, maybe because H20 is less abundant in the dry atmosphere due to very cold temperatures) :

      Photon 15 microns –> absorption by CO2 –> Transfered by collision as kinetik energy which induces an increase dT (3/2 kT = mean kinetic energy) –> which is then mostly re-emitted (via other collisions) by the 25 to 100 folds more abundant gaz active in the IR spectrum, H2O, in any of its absorption – emission spectrum, escaping thus the absorption/emission wavelength region of the CO2.

      1. Petit_Barde

        Antarctica’s vertical intensities observed at the top of the atmosphere
        (see figure 15.f page 33) :

  6. John F Hultquist

    This and similar studies do not matter.
    The horse (barn), train (station), Elvis (building), Climate Cult (brains) have exited the structure.

  7. edmh

    a similar calculation

    there will be a non-problem in 150 years time

    So lets trash the Western world

  8. Ken Coffman

    Because a heated CO2 molecule will move outward, it becomes an agent of convective cooling.

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  11. mwhite

    I can see trouble ahead.

    “While not enough for an outright majority, that level of support would make the Greens the largest party in parliament and give them a mandate to form a coalition government.”

  12. Richard Greene

    I finally found the quote I wanted to include with my comment yesterday:

    The last official IPCC statement I found was a footnote in IPCC, 2013: Summary for Policymakers. In: Climate Change 2013: The Physical Science Basis. SPM page 16.

    It reads ‘No best estimate for equilibrium climate sensitivity can now be given because of a lack of agreement on values across assessed lines of evidence and studies.’

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