An interview with top climate scientist Bjorn Stevens

by Nic Lewis

This week Die Zeit published an interview with Bjorn Stevens. Die Zeit is the largest German weekly newspaper (circulation well over one million), and has a highly educated readership.  

Bjorn Stevens is Director at the Max Planck Institute for Meteorology, the principal German climate science research and modeling centre. He is very well known for his work on climate sensitivity, aerosols and, particularly, clouds. Professor Stevens is an excellent scientist and a key figure in the climate science establishment. He is joint lead co-ordinator of the World Climate Research Programme’s Grand Challenge on Clouds, Circulation and Climate Sensitivity, and led the 2015 Ringberg Castle workshop that kicked off its climate sensitivity arm.

The interviewer, Max Rauner, an experienced science journalist with a PhD in physics, focused mainly on clouds, however Stevens also had interesting things to say about pronouncements by alarmist climate scientists. An English translation of the interview appears below.

Read more: An interview with top climate scientist Bjorn Stevens

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Climate research: “Too many children’s book clouds”

How much fear are scientists allowed to spread in the climate debate? Cloud researcher Bjorn Stevens accuses his colleagues of being alarmist. He finds: We still know far too little.

What do the clouds do when the climate warms up? This is what Bjorn Stevens, director at the Max Planck Institute for Meteorology in Hamburg, is researching. His research group simulates clouds in climate models. When it comes to cloud issues, the World Climate Report relies heavily on his expertise. At the moment, however, Stevens would like to rewrite the world climate report.

DIE ZEIT: Professor Stevens, the world climate report describes clouds as the greatest uncertainty factor for climate forecasts. Why is that?

Bjorn Stevens: See that cloud out there? In my field, most people think of a cloud as these compact white objects in the blue sky.

ZEIT: Just like in the children’s book.

Stevens: Yes, a pretty fluffy cloud. As if you could draw a line around the edge of the cloud. But that’s an optical illusion, as anyone who’s climbed into a cloud in the mountains knows.

ZEIT: Because it’s getting foggy?

Stevens: Exactly. Clouds are tricksters. Even if the contours are sharp, the cloud structure is more like that of puff pastry. Nevertheless, many scientists use the children’s book clouds as a guide because they are easier to simulate. This makes the climate models less accurate.

ZEIT: How much water does this cloud contain?

Stevens: A cloud the size of an old building can only hold a liter of water.

ZEIT: That would fit in a pint of beer!

Stevens: If you distributed all the condensed water in the atmosphere evenly around the globe, you would get a water film that is only two tenths of a millimeter thick.

ZEIT: Why then do clouds affect the climate so much and flood entire countries?

Stevens: Flooding occurs because clouds can be huge and air circulation during storms constantly replenishes the water. And they affect the climate because they are made up of a huge number of droplets that interact with sunlight and thermal radiation. A very large cloud has almost as many droplets as there are stars in the universe. And there are many clouds.

ZEIT: Are they warming or cooling the planet?

Stevens: Both. The energy balance of the earth has two parts: firstly, the incident sunlight and secondly, the heat given off by the earth, i.e. infrared radiation. All clouds have a cooling effect by reducing the amount of sunlight that reaches the earth’s surface. And all clouds have a warming effect by absorbing the earth’s infrared radiation so it doesn’t escape into space – the greenhouse effect. The balance sheet shows: Water-rich low clouds over the tropical ocean have the greatest cooling effect and low-water ice clouds at high altitudes have the strongest warming effect. Overall, the cooling effect is greater.

ZEIT: And how does this balance change with global warming? Scientists from the Potsdam Institute for Climate Impact Research (PIK) recently published a worst-case scenario . It also mentions that by the end of the century our planet could get so warm that all the clouds are practically evaporating and we are doomed.

Stevens: That’s nonsense. Put simply, the atmosphere wants to be cloudy because air rises. It’s hard to get rid of clouds.

ZEIT: Why do the Potsdam climate researchers claim otherwise?

Stevens: You’ll have to ask them that. I can only admire how the colleagues there comb through the specialist literature for the most alarming stories. I find it a pity that these are then presented uncritically.

ZEIT: So the scenario is wrong?

Stevens: Yes. It is based on a work by our institute taken out of context and on a second paper that has numerous shortcomings.

ZEIT: What shortcomings?

Stevens: The dramatic behavior of the climate in this simulation was based on an oversimplification of the clouds, which has nothing to do with reality. If you look closely, the most alarming stories often don’t stand up to scientific scrutiny.

ZEIT: Do you also mean tipping point forecasts such as the melting of the Antarctic ice sheet, the collapse of the Gulf Stream and the desertification of the Amazon rainforest?

Stevens: Yes, and most others. Of course, the world will change as a result of global warming, even more dramatically in some regions. But how, where and when is far from certain.

ZEIT: In the German climate discourse, the PIK usually warns of tipping points , while your institute tends to downplay the danger of tipping points. Why is that?

Stevens: Tipping points are fascinating, and there’s a good chance they exist. But they are also a matter of definition. What do you think of when you hear the word tipping point?

ZEIT: Of a self-reinforcing feedback that is irreversible.

Stevens: An accelerating change that cannot be reversed, right. Like a pencil falling down. He cannot fall back up by himself. But the tipping points highlighted by my colleague Hans Joachim Schellnhuber and others at PIK are based on their private, much weaker definition . Tipping points are reinterpreted to include less abrupt or even reversible climate changes. With this redefinition, they find tipping points everywhere. Then the alarm goes off. My institute does not play down tipping points, we just place more value on clarity.

ZEIT: Do you envy the Potsdam Institute for its media presence ?

Stevens: Who doesn’t want to be interesting? Unfortunately, people prefer stories about the end of the world. I don’t understand much about that.

ZEIT: Are you saying that global warming is not a problem?

Stevens: It’s a huge problem, partly because we know so little about its actual impact. According to the IPCC , whether and where biblical droughts and floods will occur is uncertain for almost all regions .

ZEIT: Stefan Rahmstorf from PIK compares himself to a doctor who found out that smoking is dangerous and now has to call on people to stop.

Stevens: As a scientist, I like to explain to people how things I understand work. But what qualifies me to tell them how to behave? That must result from the social discourse, which should be shaped more by good journalism than by charismatic scientists. If people don’t learn to think for themselves, we’re lost anyway.

“The contribution of the clouds is still overrated”

ZEIT: Let’s talk about the danger of clouds again. Will Clouds Accelerate Global Warming?

Stevens: The interesting number here is climate sensitivity. It quantifies how much the earth will warm up if the CO₂ concentration in the atmosphere doubles…

ZEIT: …compared to the CO₂ concentration before industrialization. That would still be in this century?

Stevens: If we continue as before, yes. In the last IPCC report , it was agreed that the global average temperature would then probably rise by 2.5 to 4.0 degrees Celsius. According to the simulations, the higher temperatures are mainly caused by a change in the clouds. We consider this effect to be overestimated today.

ZEIT: Were the models faulty?

Stevens: Yes. Too many children’s book clouds, not enough real clouds. In the world climate research program we have tackled the climate models. The models with the most extreme predictions have failed, and confidence in the less catastrophic values of climate sensitivity has increased . In my opinion, however, the contribution of the clouds is still overstated.

ZEIT: How great is it?

Stevens: Based on our latest measurements and advances in theory, I would say today: zero.

ZEIT: Zero?

Stevens: Right, at least that’s my working hypothesis. The climate sensitivity is then at the lower end of the IPCC estimate, around 2.8 degrees. We should keep looking, but so far there’s no evidence that clouds play a major role.

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The original German version of the above interview, updated October 19, 2022 at 4:50 pm, is available here.

As a matter of interest, if, in the light of Bjorn Stevens’ comments, one were to replace the cloud feedback estimate given in the recent IPCC Sixth Assessment Report (AR6) with a zero estimate, the AR6 feedback-based estimate of climate sensitivity would reduce by 27%. Applied to the AR6 3.0°C central estimate of climate sensitivity, that reduction would change it to 2.2°C, identical to the feedback-based estimate in my recent paper that estimated climate sensitivity using multiple lines of evidence.

205 responses to “An interview with top climate scientist Bjorn Stevens

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  3. Thanks Nic for posting this. As a German I can confirm that the “PIK” ( Potsdam institute for climate impact research) has a great influence in the German media. They are omnipresent, it doesen’t matter if they are outliners in the science community. It was IMO overdue that a real and honest scientist ( Bjorn is a real one indeed) contradicts the strange ideas ( “Hothouse and Endgame”-Sci-Fi but no scientific papers) and crude phantasies. In a brighter view they feed the fear of young people doing strange things like clueing on streets and painitings to save the world, as they imagine. In so far the PIK and their autors are real firebugs which feed the media with nonsense. This is partly the duty of themselfes, but also the duty of the media itself. In this sense I can only say Thank you to Bjorn to clarify this.

  4. Pingback: An interview with leading climate scientist Bjorn Stevens - News7g

  5. I find this interesting. I have some thoughts that I will post after writing offline and thinking about it, then I will post.

  6. William R Cotton

    It is refreshing to read an honest appraisal of the role clouds in the climate system

  7. ” In my opinion, however, the contribution of the clouds is still overstated.

    How great is it?

    I would say today: zero.”

    On balance: ” Water-rich low clouds over the tropical ocean have the greatest cooling effect and low-water ice clouds at high altitudes have the strongest warming effect. Overall, the cooling effect is greater.”

    Are there climate models out there that don’t take clouds into consideration at all?

    • “Overall, the cooling effect is greater.”

      Very good catch, RiH, his “zero” statement is a seeming walk back of his earlier cooling effect is greater.

      • I should have read on. Nic clarifies that Stevens’s zero statement is in regards to the cloud contribution to hypothesized positive feedback to warming. In other words Stevens believes that clouds overall give a cooling effect to global temperature but does not believe that warmer or cooler average temperatures will affect cloud’s degree of effect.

      • He is saying the net effects of clouds on global temperatures is cooling; that clouds interrupt more SW energy from the Sun than the LW energy they radiate toward the surface. That is an entirely different statement from his zero effect comment which relates to climate sensitivity. Sensitivity is the response to GHGs and any feedbacks.

        He is saying in essence that clouds are not affected one way or another by GHGs. One needs to read higher up in the exchange to understand this distinction. At least this is my interpretation of meanings expressed in the larger exchange. Sadly, details are lost in the interview format.

      • The reflectance of clouds is greater than the absorption. As the planet warms more clouds will be produced (higher water vapor pressure) and more sunlight will be reflected. Clouds thus act as a control mechanism to limit global warming and cooling.

  8. Lots to comment on here. It seems that a lot may be lost in translation and in the simplified language. eg. “Stevens: [..] In my opinion, however, the contribution of the clouds is still overstated.
    ZEIT: How great is it?
    Stevens: Based on our latest measurements and advances in theory, I would say today: zero.”

    Here, I would say that Bjorn Stevens is not talking about the total contribution of clouds, he is talking about cloud feedback. I agree totally that there is no positive cloud feedback, but I disagree with his “zero” assessment. The data indicates that cloud feedback is negative. See Figures 2-4 in my paper https://wjarr.com/sites/default/files/WJARR-2022-0478.pdf
    The alarmism is a bit worse than Bjorn Stevens thinks!

    • Yes, I believe Bjorn Stevens was referring to the contribution of clouds to total climate feedback here.

    • Mike Jonas wrote: The alarmism is a bit worse than Bjorn Stevens thinks!

      Of course the alarmism is worse than Stevens thinks, Stevens is a luke-warmer, a luke-warmer is a scaled down alarmist.

      • Wei Zhang (MN)

        “Stevens is a luke-warmer, a luke-warmer is a scaled down alarmist.” I’m a luke-warmer and I find nothing alarming at all about 0.01 deg a year of temp trend with an annual range of 60 deg.

    • Hi,

      “[..]Evaluation of the changes in clouds and CO2 over the study period indicate that this unspecified factor had as much positive impact as the increase in CO2, with respect to the amount of radiation reaching the surface (radiative forcing), and possibly a much larger positive impact. The climate models, which have zero or negative cloud impact on radiative forcing independently from CO2, need to take this into account in order to avoid over-estimating the influence of CO2.[..]”

      According to Raghuraman et al 2021, “the significant positive trend in observed EEI is driven by a −0.70 ± 0.23 Wm−2/decade trend in RSW and a 0.28 ± 0.22 Wm−2/decade trend in OLR”.

      https://www.nature.com/articles/s41467-021-24544-4

      If we read Quaas et al 2022, without Aerosols “This implies that without the cooling effect of aerosols, the world would al- ready have reached the 1.5 ◦C temperature threshold “.

      https://acp.copernicus.org/articles/22/12221/2022/

      So you are right about CO2 and/or temperature as the cause of more radiation hitting earth. But as far as science is finding, the anthropogenic aerosol decreasing trend (Quaas) is the main responsible of less clouds and more SW radiation hitting earth (Raghuraman).

      So from my perspective, the bad news is that in the abscence of anthropogenic aerosols, GHGs radiative forcing is way bigger than the thought.

  9. Top climate scientist Bjorn Stevens said: In my opinion, however, the contribution of the clouds is still overstated.

    ZEIT: How great is it?
    Stevens: Based on our latest measurements and advances in theory, I would say today: zero.

    He said that CO2 has no influence on clouds.
    Then he said:
    Stevens: Right, at least that’s my working hypothesis. The climate sensitivity is then at the lower end of the IPCC estimate, around 2.8 degrees. We should keep looking, but so far there’s no evidence that clouds play a major role.

    So, CO2 went from 300 to 400 Parts per Million in the Atmosphere, that had no influence on clouds, yet adding One Molecule of CO2 can be responsible for 2.8 degrees of warming to the climate, actually not yet because there has not been that much warming and not yet a doubling of CO2. I guess, without influencing clouds, adding more Molecule of CO2 to the Atmosphere is supposed to cause the rest of the warming. This is the coldest warm period in the most recent ten thousand years, maybe it will get as warm as the Medieval or Roman time periods, or as warm as warm periods before that, which all occurred with the CO2 Below 300 parts per million. Ice core records for ten thousand years in Greenland showed the climate temperature getting cooler as CO2 increased from 260 to 280 parts per million.

    How much fear are scientists allowed to spread in the climate debate? Cloud researcher Bjorn Stevens accuses his colleagues of being alarmist. He finds: We still know far too little.

    Bjorn Stevens: See that cloud out there? In my field, most people think of clouds as these compact white objects in the blue sky.

    ZEIT: Just like in the children’s book.

    Bjorn Stevens has clearly drunk the alarmist CO2 cool aid, but he did not get as large of a dose as others, I suspect he has not been paid as much as some of the others. But, the alarmists welcome his opinion because he supports that CO2 is significant for warming the climate system. The modern climate system has warmed, but less than any time in any warm period, before this one in ten thousand years.

    • “He said that CO2 has no influence on clouds.”
      No, I am pretty sure Bjorn Stevens was saying that clouds did not contribute to climate feedbacks, that is to say clouds in total do not amplify the warming effects of increased atmospheric CO2 concentration. I think his statement implicitly relates to climate states ranging from preindustrial to several degrees Centigrade warmer.

    • Mr. Pope, you are a nasty piece of work. What is it about Bjorn Stevens’ “The climate sensitivity is then at the lower end of the IPCC estimate, around 2.8 degrees. We should keep looking, but so far there’s no evidence that clouds play a major role.” that you find so offensive?

      • Perhaps Herman is worried by the fact that 2.8 is 27% more than the actual limit of justified disingenuousness, Dave.

        Or 30% if we we round off 2.16 differently.

    • Herman A. Pope: I think there is a misunderstanding about Feedbacks. CO2 warms the planet, about 3,7 W/m² radiative forcing is without any doubt accepted in the science-community, also by Nic Lewis and Bjorn Stevens. The open question is how this warming, not the CO2 itself, impacts clouds. The AR6 estimated: clouds amplify this warming. Bjorn estimates now ( with more time has gone and knowledge appeared) a netto zero impact, reducing the whole sensitivity. This is the core of this story. If you believe CO2 has not a warming impact it’s your believe, not the knowledge of science. .

    • Surely you’re joking , Mister Pope—

      Why else omit this interview’s truly memorable punch line ?

      https://vvattsupwiththat.blogspot.com/2022/10/die-zeit-all-science-news-thats-fit-to.html

  10. A liter of water won’t fit into a pint of beer. A liter is more than 2.0 pints.

    • True of US pints (16 fluid ounces), not British pints (20 fl. oz.). A liter amounts to ~1.7 British pints.
      Unfortunately the German original is pay-walled, so I didn’t check, but I presume he said a mug of beer — the liter-size Bierkrug. British mugs hold (and might be called) pints, leading to mistranslation.

      • My deepest congratulation for your take home message of this interview! There is also the possibility the the translator doesen’t drink too often beer, in the German original article they talk about a “Maß Bier”, in Bavaria this is 1l. Do you have more take home messeges or is this all you learned about clouds an sensitivity? This would be sad.

    • The AGU is famed for the tonnage of beer its annual meetings consume, and high pressure geophysicists universally agree that compressing a liter of water to a density of 2.2 in a one pint container runs the risk of a Maß extinction.

  11. Here are some quotes from https://climatesense-norpag.blogspot.com/

    ………….Earth’s climate is the result of resonances and beats between the phases of natural cyclic processes of varying wavelengths and amplitudes. At all scales, including the scale of the solar planetary system, sub-sets of oscillating systems develop synchronous behaviors which then produce changing patterns of periodicities in time and space in the emergent temperature data. The periodicities pertinent to current estimates of future global temperature change fall into two main categories:

    a) The orbital long wave Milankovitch eccentricity, obliquity and precession cycles. These control the glacial and interglacial periodicities and the amplitudes of the corresponding global temperature cycles.
    b) Solar activity cycles with multi-millennial, millennial, centennial and decadal time scales.

    The most prominent solar activity and temperature cycles are : Schwab-11+/-years ; Hale-22 +/-years ; 3 x the Jupiter/Saturn lap cycle 60 years +/- :; Gleissberg 88+/- ; de Vries – 210 years+/-; Millennial- 960-1020 +/-. (2)

    The Oulu Galactic Ray Count is used in this paper as the “solar activity ” proxy which integrates changes in Solar Magnetic field strength, Total Solar Insolation , Extreme Ultra Violet radiation, Interplanetary Magnetic Field strength, Solar Wind density and velocity, Coronal Mass Ejections, proton events, ozone levels and the geomagnetic Bz sign. Changes in the GCR neutron count proxy source causes concomitant modulations in cloud cover and thus albedo. (Iris effect)

    Eschenbach 2010 (3) introduced “The Thunderstorm Thermostat Hypothesis – how Clouds and Thunderstorms Control the Earth’s Temperature”.

    Eschenbach 2020(4) in https://whatsupwiththat.com/2020/01/07/drying-the-sky uses empirical data from the inter- tropical buoy system to provide a description of this system of self-organized criticality. Energy flow from the sun into and then out of the ocean- water interface in the Intertropical Convergence Zone results in a convective water vapor buoyancy effect and a large increase in OLR This begins when ocean temperatures surpass the locally critical sea surface temperature to produce Rayleigh – Bernard convective heat transfer.

    Short term deviations from the solar activity and temperature cycles are driven by ENSO events and volcanic activity.
    ……………
    5. CO2 -Temperature and Climate.
    The whole COP Net Zero meme is founded on the flawed assumptions and algorithms which produced the IPCC- UNFCCC model forecasts of coming dangerous temperature increases.
    The “consensus” IPCC models make the fundamental error of ignoring the long- term decline in solar activity and temperature following the Millennial Solar Activity Turning Point and activity peak which was reached in 1990/91 as shown in Figure 1

    The amount of CO2 in the atmosphere is .058% by weight. That is one 1,720th of the whole. It is inconceivable thermodynamically that such a tiny tail could wag so big a dog. (13)

    Stallinga 2020 (14) concludes: ” The atmosphere is close to thermodynamic equilibrium and based on that we……… find that the alleged greenhouse effect cannot explain the empirical data—orders of magnitude are missing. ……Henry’s Law—outgassing of oceans—easily can explain all observed phenomena.” CO2 levels follow temperature changes. CO2 is the dependent variable and there is no calculable consistent relationship between the two. The uncertainties and wide range of out-comes of model calculations of climate radiative forcing (RF) arise from the improbable basic assumption that anthropogenic CO2 is the major controller of global temperatures.
    Miskolczi 2014 (15) in “The greenhouse effect and the Infrared Radiative Structure of the Earth’s Atmosphere “says “The stability and natural fluctuations of the global average surface temperature of the heterogeneous system are ultimately determined by the phase changes of water.”
    Also See AleksandrZhitomirskiy2022 Absorption of heat and the greenhouse gas effect. https://independent.academia.edu/AleksandrZhitomirskiy (16) which says:
    “The molar heat capacities of the main greenhouse and non-greenhouse gases are of the same order of magnitude. Given the low concentration of greenhouse gases in the atmosphere, their contribution to temperature change is below the measurement error. It seems that the role of various gases in the absorption of heat by the atmosphere is determined not by the ability of the gas to absorb infrared radiation, but by its heat capacity and concentration. ”

    Zaichun Zhul et al 2016 (17) in Greening of the Earth and its drivers report “a persistent and widespread increase of growing season integrated Leaf Area Index (greening) over 25% to 50% of the global vegetated area from 1982 – 2009. ………. C02 fertilization effects explain 70% of the observed greening trend.”
    Policies which limit CO2 emissions or even worse sequester CO2 in a quixotic attempt to greenwash or mitigate these natural cycles would decrease agricultural food production and are antithetical to the goals of feeding the increasing population and bringing people out of poverty.

    The tropical rain forests and tropical oceans are the main source of the atmosphere’s water vapor and the rainfall essential to life and agriculture on land. Potable and agricultural water supplies are now now stretched to their limits in many areas because of the demographics of global population increase. Temperature limits and targets as set in the Paris Accords to ameliorate future temperatures are completely useless when formulating policies relative to adaptation to the actual real world problems. These require more local inputs for particular regional ecosystems delineated by coastlines, major river basins and mountain range limited intra-continental divides.

    • “It is inconceivable thermodynamically that such a tiny tail could wag so big a dog. (13)”
      Why?

      • George – See quote from https://independent.academia.edu/AleksandrZhitomirskiy
        above “The molar heat capacities of the main greenhouse and non-greenhouse gases are of the same order of magnitude. Given the low concentration of greenhouse gases in the atmosphere, their contribution to temperature change is below the measurement error. It seems that the role of various gases in the absorption of heat by the atmosphere is determined not by the ability of the gas to absorb infrared radiation, but by its heat capacity and concentration. ”

      • Geoff Sherrington

        Curious George,
        Tail wagging dog.
        Here is a scientific starting point.
        If you invoke a “doubling” of some concentration, you need to specify the start point.
        Various authors have assumed CO2 at pre-industrial 280 ppm, our present 410 ppm, some have assumed 20 ppm for no stated reason. It is vital to define where you start because the curve flattens to near horizontal after a few score of doublings, that is, saturation is working. But where does saturation start?
        I once proposed that the appropriate start is 1 molecule. Nobody took it seriously, but nobody showed it wrong. Doubling successively to 2, 4, 8, 16 … molecules has little effect on global climate because each molecule would need the ability to attain predigious energy.
        Therefore, understanding of the point at which CO2 has a chance of an effect is governed by
        1. A need for a mechanism that disallows molecular scale doublings.
        2. A reason to allow doublings based on higher numbers of molecules, like many, many orders of magnitude higher. There are about 5 x 10^40 molecules of CO2 in the air.
        3, An agreed starting point concentration of CO2 in the air at which doubling can have a measurable effect. I have never seen such an estimate.
        4. A demonstration that a nominated starting concentration does not violate physics, that is, a demonstration that the change of energy that a CO2 molecule absorbing IR radiation is within physical limits; plus the rate that absorption/emission process can be sustained over and over to produce the alleged “warming” effect in the air
        My work started with atomic spectroscopy, for little was then known about molecular. In atomic, there is a concept of quantum energies, wherein an incoming excitation has to be above a certain energy to cause an energy gain. Then, emission of that energy gives characteristic spectral peaks that allow identification of elements, like the Sun’s Fraunhofer lines. What I do not know: Are molecular tranitions quantized in a similar way? Can a molecule of CO2 or water be heated by all iuncoming IR, or does that IR have to exceed a certain energy level?
        Geoff S

      • Curious George

        Gentlemen, thank you for responding to my question. I don’t consider your responses to be answers. They invoke very complex mechanisms and don’t reach the level of “inconceivable”. I’ll consider Norman’s statement a little bombastic.

    • George and Geoff From above
      See AleksandrZhitomirskiy2022 Absorption of heat and the greenhouse gas effect. https://independent.academia.edu/AleksandrZhitomirskiy (16)
      Please use the link and scroll down to the “Absorption of heat and the greenhouse gas effect. ” .It should answer all your questions.

  12. I’m so thankful for all of you scientists who aren’t intimidated to the point that we can’t even discuss these ideas.

  13. That’s the crux of the issue.

    Clouds have a cooling effect on climate. For them to have a positive feedback means that with warming there are less clouds, so less cooling resulting in positive feedback.

    Yet with warming there is more water vapor in the atmosphere, which is another positive feeback.

    Now would anybody that accepts the IPCC view bother to explain how more water vapor is supposed to produce less clouds? Because it does not make sense to me.

    Even the zero value on feedback from Bjorn Stevens makes no sense, unless he also thinks water vapor in the atmosphere does not increase with warming, so cloud cover does not change.

    I say the emperor has no cloths.

    • That is really lame for a “so called” top climate scientist.

    • Javier – The argument is that more water vapour doesn’t form more clouds because a warmer atmosphere has a higher carrying capacity. NB. I’m not claiming that the argument is correct, only that that is what is argued. In fact, I deduce from the data that the argument is incorrect – please see my earlier comment and my paper at https://wjarr.com/sites/default/files/WJARR-2022-0478.pdf

      • “more water vapour doesn’t form more clouds because a warmer atmosphere has a higher carrying capacity.”

        Thank you, Mike. The argument doesn’t hold water. The warm tropical atmosphere above the Indo-Pacific Warm Pool, and the Inter-Tropical Convergence Zone has more clouds than anywhere else in the planet.

      • The argument doesn’t hold water.

        Prove it. I bet you can’t.

      • “Prove it.”

        How Total Precipitable Water Vapor Anomalies Relate to Cloud Vertical Structure
        The NOAA operational total precipitable water (TPW) anomaly product is available to forecasters to display percentage of normal TPW in real time for applications like heavy precipitation forecasts. In this work, the TPW anomaly is compared to multilayer cloud frequency and vertical structure. The hypothesis is tested that the TPW anomaly is reflective of changes in cloud vertical distribution, and that anomalously moist atmospheres have more and deeper clouds, while dry atmospheres have fewer and thinner clouds. Cloud vertical occurrence profiles from the CloudSat 94-GHz radar and the Cloud–Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) are composited according to TPW anomaly for summer and winter from 2007 to 2010. Three geographic regions are examined: the North Pacific (NPAC), the tropical east Pacific (Niño), and the Mississippi Valley (MSVL), which is a land-only region. Cloud likelihood increases as TPW anomaly values increase beyond 100% over MSVL and Niño. Over NPAC, shallow boundary layer cloud occurrence is not a function of TPW anomaly, while high clouds and deep clouds throughout the troposphere are more likely at higher TPW anomalies. In the Niño region, boundary layer clouds grow vertically as the TPW anomaly increases, and the anomaly range is smaller than in the midlatitudes. In summer, the MSVL region resembles Niño, but boundary layer clouds are observed less frequently than expected. The wintertime MSVL results do not show any compelling relationship, perhaps because of the difficulties in computing TPW anomaly in a very dry atmosphere.

        https://journals.ametsoc.org/view/journals/hydr/13/2/jhm-d-11-049_1.xml

        The evidence shows more water vapor means more clouds. Now you prove the opposite.

      • While a warmer atmosphere will hold more water vapor, the top of the atmosphere is still going to be very cold. Thus, there will certaiinly be more clouds, and they will be at higher altitudes. These are just the kind that reflect more sunlight so they will have a net cooling effect.

    • Hmm. It really depends on where and what type(s) of clouds are involved in changes as the climate warms.

      Stevens correctly pointed out that low equatorial clouds are overall cooling, but high latitude clouds are overall warming. It is possible that both are changing.

      My own guess relating to those times in the geological past when the poles were largely ice-free, is that there were a lot more clouds in the polar regions which suppressed heat loss there and enabled the earth’s surface to be much warmer than today.

      We should gain a better understanding of cloud changes over time as we get ever more data from satellite observations, especially of the polar regions which had very sparse surface based observations in the past.

      • Been intrigued by the: Re “–those times in the geological past when the poles were largely ice-free,–”

        There is a condition no one would contemplate, but that is variously correlated by proxy evidence. It is the abrupt change of Earth’s axial tilt.
        See this as one case that explains why the poles can be ice-free: https://www.facebook.com/melitamegalithic/photos/a.433731873468290/1957722401069222/

        One proof is this: https://www.facebook.com/melitamegalithic/photos/a.433731873468290/2093466177494843/
        It is a record measurement in year 173CE of abrupt change, leaving its evidence in sudden increase in glacier ablation and lake sedimentation.
        Also in year ~2345bce a similar abrupt change that is evident in the ablation rate (curve). That was a major one that left plenty of evidence (new). Reason for abrupt change: earth dynamic instability (in both tilt and precession). It led to the 4K2 climate change and civilisation disruption.

        None of that will be found in the clouds.

      • melitamegalithic: “It is the abrupt change of Earth’s axial tilt.” What is “abrupt” and how “abrupt” can it be when respecting the mass inertia of the earth? The (slowly) changes (Milankowic) are understood, it comes from the Jupiter. What new physics did you find?

      • frankclimate: Abrupt, as (per Plato) ‘in a day and a night’. You guessed it, comes from Jupiter, but also the new moon. What triggers it I am still somewhat in the dark, but one thing is getting clear. Earth dynamic instability, when the greatest moment of inertia (presently in the ‘Z’ axis – the present axis) becomes the Intermediate Axis.
        It can be momentary, or it may last some hours, quite/very destructive geologically, but still in detail ??elusive??. It happened in year 173CE, but also in near ~2345bce for which evidence is greater (See Dodwell manuscript, but also this link:
        https://melitamegalithic.wordpress.com/2017/02/24/first-blog-post/ this site records a tilt change, from previous ~14 to ~24).

        Re Milankovitch; in a mix of forcing signals in a system, these may be evident, but the abrupt step input signal are never visible unless caught as discontinuities in a record, or experienced. Milankovitch deals with some (and anticipated). Not the step changes.

      • melitamegalithic: “What triggers it I am still somewhat in the dark…” My 1st step to an approach to enlighten the dark would be to calculate the needed energy for the descibed “step change” in the tilt of the earth axis which must impact in such short times like 1 day. Thereafter I would estimate if this value is realistic.

      • frankclimate: No energy is needed once the ‘Z’ axis becomes the Intermediate axis. The question is what and how the earth distorts enough to set the instability in motion. There is a link to planetary alignment, which may distort earth’s geoid enough to make it unstable. As the earth rotates it can be only for a short time, but enough for abrupt change with no return to its precise original orientation.
        Year 173ce produced such an event, and planetary alignment was present. So were tsunamis in that year.
        You may like to see this: https://thatsmaths.com/2019/12/12/the-intermediate-axis-theorem/ Just don’t bet on the last sentence, it happened in the past and more than once.

    • Hi Javier,

      as far as i read modern evidence, we are experiencing less clouds because long term anthropogenic aerosol decreasing trend, so in theory, the GHG forcing should be even worse.

      “This implies that without the cooling effect of aerosols, the world would already have reached the 1.5 ∘C temperature threshold of “dangerous” climate change as set out by the Paris agreement.”

      https://acp.copernicus.org/articles/22/12221/2022/

    • Since 1995, water vapour has increased up to at least 500mb heights, low cloud cover has declined, middle and upper clouds have increased. Effects of a warm AMO.

  14. In the tropics, the hotter the day, the more there are thunderstorms or just rain that cools the afternoons.
    As polar regions heat up in warmest times and get really colder in coldest times, the tropics heat up every morning and in lots of places, have cooling rain in the afternoons. Tropics are cooled a little in coldest times and warmed a little in warmest times but are self-regulated very well by tropical storm self correction.

    So called climate scientists only study the sensitivity of an almost trace gas, they study none of any other self correcting forcing or internal self correction.

  15. I used Word to translate this comment to English.
    This tells a different story, in this, he did not write anything that supported any sensitivity of CO2 in causing Climate warming.

    Translate and read it yourself. Here is a little, taken out of any context, but read it all yourself.
    supposedly “trapping heat” and thus somehow warming the Earth’s surface. A few years later, they realized that there was no evidence to support this explanation

  16. Now do Andrew Dessler.

  17. My replies are still being censored here, I see. Says all you need to know about the “contrarian” position.

    • Oops, they’re just delayed. My bad.

      Still let’s hear from Andrew Dessler, he’s an expert in clouds and climate.

  18. Judy,

    Doug started to spam Roy’s again, from time to time using G translate.

    So caveat emptor.

    Hope you are well.

  19. ZEIT: And how does this balance change with global warming? Scientists from the Potsdam Institute for Climate Impact Research (PIK) recently published a worst-case scenario . It also mentions that by the end of the century our planet could get so warm that all the clouds are practically evaporating and we are doomed.

    Stevens: That’s nonsense.

    Professional scientist, allegedly, thinks he can dismiss a peer-reviewed paper in a prominent journal merely by saying “that’s nonsense.”

    Of course he knows better than that, so you have to wonder what his agenda is.

    Real professionals know that science is carried out in the professional literature. It’s very telling that he hasn’t done that he hasn’t done that in the scientific literature, not in media interviews, and if Stevens thought something was wrong with this paper he would have written to the journal and published a counter argument. It’s very telling that he hasn’t done that.

    • David, we can act of the assumption that Bjorn IS a professional scientist. So there is another possibility when it comes to this published worst case scenario of “Climate Endgame”: It’s less a scientific paper but more a Sci-Fi story to fear laymen people without any merrit for the science, not able to be discussed in the community. Think about this.

    • I side with Bjorn on this one. Bjorn (not to mention myself) know way more about clouds and thermodynamics than the authors of the PNAS paper. I for one can’t be bothered with swatting down all the nonsense that lands in the peer reviewed literature.

      • “…and there has been net global cooling since 1998 as seen in Roy Spencer’s monthly graphs.”

        Douglas, Just because the peak of a the 1998 super El Nino may have been a higher GMST than present does not mean GMST is going down in any statistical estimation. I think anyone looking at the Roy Spencer’s graph would agree that the lower troposphere temperature is oscillating upward since 1979, when the data started.

        Temperature station records show temperature oscillating upwards for the last 150 years, since reasonably good data started.

        The better question is: Why temps oscillated upwards for the last 400 years (since the depth of the Little Ice Age) when significant CO2 emissions did not start until ~70 years ago?

      • Ron Graf:

        The peak of the 60 year cycle could have been predicted decades earlier to be around the year 2000 from the peaks in 1880 and 1940. You might well argue that the el niño brought it on 2 years earlier and clearly from the graphs there is a further peak that supports a kind of average around 2000. But by now it is most certainly not warming as I predicted back in August 2011 would be the case until at least 2027 in an archived webpage.

        But I am more focussed on the physics than the temperature records, so feel free to ask questions after reading my website (by clicking my name) and this comment below:
        https://judithcurry.com/2022/10/22/an-interview-with-top-climate-scientist-bjorn-stevens/#comment-981428

      • Jeff Cunningham

        One thing that has always puzzled me is how the earth ever managed to escape a runaway greenhouse effect back in the Mesozoic when CO2 levels were twenty or thirty times higher. We are not far above all time low levels now. Photosynthesis was stalling for lack of it.

    • David Appell – That was a bit sneaky, not using the full quote:
      Stevens: That’s nonsense. Put simply, the atmosphere wants to be cloudy because air rises. It’s hard to get rid of clouds.

  20. Long pauses are evidence of a failure to demonstrate an association between global warming and rising atmospheric CO2 levels, increasing the lack of causal plausibility which is then papered-over by the concept of tipping points too keep fears of AGW causation alive.

  21. Refutation of False Physics

    Well I have just written to the two main Directors of PIK.

  22. Refutation of False Science

    The Intergovernmental Panel on Climate Change (IPCC) originally told the world in the 1980’s that carbon dioxide and methane act like a blanket in the atmosphere supposedly “trapping heat” and somehow thus warming the surface of the planet. Several years later they found there was no evidence supporting this explanation and, instead, they started to talk about radiation that went downwards towards the surface. This radiation was mostly from water vapour, carbon dioxide and methane. Even though it came from cold regions of the atmosphere it was assumed to be able to raise the temperature of the warmer surface. But Professor Claes Johnson proved early this century that this type of radiation cannot warm the surface. Instead it undergoes resonant (or “pseudo”) scattering without raising the temperature at all. I wrote about Professor Johnson’s research in my peer-reviewed scientific paper “Radiated Energy and the Second Law of Thermodynamics” which was acclaimed and published on several websites.

    However, there was still an unanswered question: Why is the global mean temperature of Earth’s surface warmer than direct solar radiation could make it? The reason is primarily to do with the height of the atmosphere rather than any radiation from carbon dioxide, methane or water vapor. The surface of Venus is far hotter mainly because its atmosphere is far thicker (meaning higher) than ours. The lowest region in the planet’s atmosphere is called the troposphere and there is a fairly uniform rate of cooling with increasing altitude. Back in the 1870’s a physicist Josef Loschmidt explained that this temperature gradient is actually formed by gravity acting on individual molecules: the temperature depends on the speed of these molecules (between collisions) and that speed can be affected by gravity. We can now confirm that Loschmidt was right and we see this effect in every planetary troposphere, though there are reasons why it does not occur in higher regions because the density is insufficient in the stratosphere and above. This phenomenon enables us to now understand why the surface temperature is what it is, and I wrote about this in my scientific paper “Planetary Core and Surface Temperatures” in 2013. The heat process involved now enables us to understand how the observed temperatures in planets and satellite moons are kept at observed levels with the required energy input.

    The inevitable conclusion is that the world has been seriously misled by what is incorrect physics used by climatologists. For those with a knowledge of physics, they use the Stefan-Boltzmann Law incorrectly when they add to the solar flux about double that flux supposedly coming from the atmosphere. Then they use this total in Stefan-Boltzmann calculations to “explain” the average temperature of the planet’s surface. But this law is only applicable for a single source of radiation and that source must be effectively hotter (after any attenuation due to distance) than the target. It is not correct to add flux from another source, especially from a colder source. In reality they end up having to assume molecules somehow “know” they must send more radiation downwards than upwards. Furthermore, their energy diagrams (such as that on the NASA website) show more energy supposedly escaping from the lowest level of the atmosphere into the surface than the Sun provides at the top of the atmosphere. An atmosphere cannot create energy like this! Note this quote from a physicist:

    Ten years ago I simply parroted what the IPCC told us. One day I started checking the facts and data – first I started with a sense of doubt but then I became outraged when I discovered that much of what we were hearing from the IPCC and the media was sheer nonsense and was not even supported by any scientific facts and measurements. To this day I still feel shame that as a scientist I made presentations of this climate science without first checking it.

    Klaus-Eckert Puls, German Meteorologist, Physicist

    • Klaus: Unfortunately, we have learned in the past 150 years that Josef Loschmidt was WRONG: Gravity is a force (with unit of kg-m/s2 in dimensional analysis) that can’t be converted into energy/heat (kg-m2/s2) without motion. Work = force * distance. The temperature of the soil under the foundation of massive building isn’t warmer than nearby soil the same distance below the surface because the building isn’t moving.

      In the case of gases and atmospheres, work (energy/heat) is calculated by P*dV (Force per unit area * volume change, an area times a distance moved with or against pressure). The volume of the atmosphere is not changing appreciably because the pressure at any altitude is created by the weight of the atmosphere above that altitude and supports exactly that weight. On the average, the atmosphere is not falling under the force of gravity and therefore isn’t warmed by it. (Lots of heat was released as matter FELL towards a common center of mass under the force of gravity to make the Earth and the Moon long ago. That heat was enough to melt all of the solid, which is why all of the large bodies in the solar system are spheres with a slight bulge at the equator do to their rotation. However, that heat was radiated away to space long ago. The temperature of the Earth today is the temperature at which there is a balance between incoming and outgoing radiation with no additional outgoing heat having been generated by gravity.

      This is basic physic taught in first-year college and even high school physics courses.

      Some skeptics have correctly calculated that the lapse rate in a dry atmosphere would be g/Cp, if this lapse rate were produced by gravity. A conventional derivation also affords a lapse rate a dry adiabatic lapse rate of g/Cp based the heat released by P*dV work as “parcels” of air rise or fall. We know that the latter explanation is the correct one, because molecules are not fractionated by molecular weight with the heaviest molecules near the surface. The lack of fractionation by molecular weight proves that the lapse rate is created vertical transfer of heat by bulk convection of gas molecules.

  23. UK-Weather Lass

    “If people don’t learn to think for themselves, we’re lost anyway.”

    My takeaway truism from Professor Stevens which should echo throughout academic, political and media institutions around the globe. Take away our freeedom to use our brains and our freedom to enter discussions on climate change mitigation and we end up with the empty headed and repetitious propaganda we are urged to listen to and read on a daily basis from the many who will never dare to upset their paymasters or paymistresses.

    Much damage has already been done because our leaders have not behaved as leaders but just gormless followers of orders from who knows where. The stupidity seen in SARS-CoV-2 has been alive and handsomely rewarded in climate alarmism and it has to be stopped. We all have a right to be told the absolute truth and for climate change that hasn’t been done by officialdom for decades.

    • Well said UK-Weather Lass

    • “If people don’t learn to think for themselves, we’re lost anyway.”

      If people haven’t learn to think for themselves already, they won’t learn now.

      Homo sapiens doesn’t seem appropriate. Perhaps Homo irreflective.

  24. Global warming is beneficial, not harmful. Therefore, we should be doing nothing to reduce GHG emissions.

    • Lang, P.A. Nuclear Power Learning and Deployment Rates; Disruption and Global Benefits Forgone. Energies 2017, 10, 2169. http://dx.doi.org/10.3390/en10122169.
    • Lang, P.A.; Gregory, K.B. Economic impact of energy consumption change caused by global warming. Energies 2019, 12, https://doi.org/10.3390/en12183575.
    All impact sectors except sea level rise benefits from global warming. The negative impact of sea level rise is negligible – similar to or slightly more than last century.

    The planet is currently in a severe ice house phase – i.e. with ice at the poles and in glaciers. The severe ice house phases occur about every 300 Ma and last about 60-70 Ma (Scotese et al., 2021). Slightly less severe ice house phases occur about every 150 Ma. There has been no permanent ice at the poles or in glaciers for approximately 70% of the past 540 Ma. The current severe icehouse phase will last about another 50-60 Ma. So, there should be no concern about GHG emissions or global warming – it is beneficial not harmful.

    • Scotese, C.R.; Song, H.; Mills, B.J.W.; van der Meer, D.G. Phanerozoic paleotemperatures: The earth’s changing climate during the last 540 million years. Earth-Science Reviews 2021, https://doi.org/10.1016/j.earscirev.2021.103503.
    • Scotese, C.R.; Song, H.; Mills, B.J.W.; van der Meer, D.G. Phanerozoic paleotemperatures: The earth’s changing climate during the last 540 million years – Supplementary Materials. 2021. https://drive.google.com/drive/folders/1654vkl6b_Fy-2R_VdvcUpg4IZP4r4rqP.

    We do need to transition from fossil fuels and renewable energy to nuclear power (SMRs) as quickly as possible (to reduce the cost of electricity and for human health reasons).

    • “We do need to transition from fossil fuels and renewable energy to nuclear power (SMRs) as quickly as possible”
      Transition, yes, ‘as quickly as possible’, NO. To do so would sentence billions of people to perpetual poverty and decimate our technological society.
      Unless, of course, ‘as quickly as possible’ means over the next couple of centuries at which time we will run out of fossil fuels and be required to use nuclear energy. All the renewable energy sources are much less efficient/environmentally friendly than nuclear energy. We just need to learn how to handle it safely and economically.

  25. nobodysknowledge

    This Attention Bjorn Stevens is an abuse of scientists name. False flag.

  26. Noted, thanks. I will remove from this thread posts by him that are clearly off-topic.

  27. “Oh, Lord, its hard to be humble when you’re perfect in every way.”

  28. Pingback: An Interview with Top Climate Scientist Bjorn Stevens – Watts Up With That?

  29. Pingback: The Media Balance Newsletter: 24/10/22 - Australian Climate Sceptics blog

  30. Pingback: An Interview with Top Climate Scientist Bjorn Stevens – Watts Up With That? - Lead Right News

  31. Nic, Do you think that Stevens will be called to the carpet by the climatariat for his loose talk like he was in 2015?

    Does Stevens still stand behind his 2015 slicing of aerosol forcing by a factor of 2.5 from the then CMIP5 mean assumption?

    https://climateaudit.org/2015/03/19/the-implications-for-climate-sensitivity-of-bjorn-stevens-new-aerosol-forcing-paper/#:~:text=CMIP5%20models%20with,Stevens%E2%80%99%20best%20estimate.

    • Stevens rocked the establishment in 2015 coming to the world climate conference in Ringberg with a paper that said all the models are assuming way too much cooling effect from anthropogenic aerosols (air pollution). The reason this was controversial is because without the very high cooling factor of air pollution the models would not be able to recreate a fit to the historical temperature record (last 150 years). And, in order to rework assumptions to make the models work they would need to lower CO2’s effect.

      Here is the link to Judith’s post in 2015 when Bjorn Stevens published papers unfavorable to the climate industrial complex. https://judithcurry.com/2015/04/22/bjorn-stevens-in-the-cross-fire/

      Here is Steven’s journal comment defending his paper, “Rethinking the lower bounds of aerosols,” a couple years later in 2018. https://journals.ametsoc.org/view/journals/clim/31/22/jcli-d-18-0185.1.xml

      • Others have used my findings to suggest that Earth’s surface temperatures are rather insensitive to the concentration of atmospheric CO2. I do not believe that my work supports these suggestions, or inferences.

        […]

        [E]ven a warming of only 2ºC from a doubling of CO2 poses considerable risks for society. Many scientists (myself included) believe that a warming of more than 2ºC from a doubling of the concentration of atmospheric carbon dioxide is consistent with both my new study and our best understanding.

        […]

        So contrary to some reports that have appeared in the media, anthropogenic climate change is not called into question by my study. I continue to believe that warming of Earth’s surface temperatures from rising concentrations of greenhouse gases carries risks that society must take seriously, even if we are lucky and (as my work seems to suggest) the most catastrophic warming scenarios are a bit less likely.

      • Joshua, of course “believed” Bjorn that his work not supported the suggestion that the GMST is rather insensitive to CO2-concentration. If he would have some hard facts, that a smaller then suggested ERF aerosols not demands a mandatory smaller sensitivity vs. CO2 when the historical GMST is given he would have published a paper showing this. His “believes” were not contadicted becaus one can’t contradict believes. However this approach also was the one used in Tokarska 2020, see: https://www.science.org/doi/full/10.1126/sciadv.aaz9549

      • For better or worse, only SSP1 seems to cohere with Nic’s luckwarm limit, Frank. More precisely, SSP1-2.6.

        Please advise.

      • Frank –

        > Joshua, of course “believed” Bjorn that his work not supported the suggestion that the GMST is rather insensitive to CO2-concentration. If he would have some hard facts, that a smaller then suggested ERF aerosols not demands a mandatory smaller sensitivity vs. CO2 when the historical GMST is given he would have published a paper showing this. His “believes” were not contadicted becaus one can’t contradict believes. However this approach also was the one used in Tokarska 2020, see: https://www.science.org/doi/full/10.1126/sciadv.aaz9549

        I had a bit of trouble following your comment, and who you were saying believed what, but I’ll just say that sure – when someone in these discussions states what they do or don’t “believe,” I tend to trust that’s what they do or don’t “believe.” That is, of course, different than believing what they do or don’t “believe” is necessarily correct. And I don’t particularly have “beliefs” on any of this, so much as rough evaluations of what is more or less probable.

        Do I believe that Stevens work was misconstrued and/or misrepresented by others to support theories he doesn’t think they support? I dunno. I can’t evaluate that independently on a technical basis. But yeah, I do think that if you’re going to consider him a “top climate scientist” it’s worth taking it seriously if he says that’s what happened.

        I try to take what people say at face value, and I have a healthy respect for the limitations of mind-probing to explain why people did or didn’t do things, based on second-guessing and conjecture about what would other people think would fit logically with what people said they believe.

        Seems to me that reverse-engineering the reasons why Stevens did or didn’t publish particular papers showing particular scientific phenomena, would be pretty complicated.

      • Joshua, can you provide a link to the Steven’s disclaimer that he is a climate denier? I remember his having to draft an apology to the establishment for embarrassing them. I think I read it more as a hostage letter. You and Willard seem to think he disclaimed his own paper. It makes a lot more sense that he just wanted to be sure that he wasn’t going to get smeared as a “climate heretic” or something.

      • Willard, I need your help! Nic investigated the climate sensitity, not the radiative pathways (RCP) in the future. How did you make the conclusion “only SSP1 seems to cohere with Nic’s luckwarm limit, Frank. More precisely, SSP1-2.6.” I can’t replicate this, therefore I can’t respond. I recalculated the Sensitivity, following Nic’s approach, and this gives exactly 2.0 K vs. pre industrial in 2100 with 4.5 W/m² Forcing in 2100. What is your result?

      • Frank,

        As requested, here is the procedure to replicate my result:

        Open the document; search for the string *ssp*; read the relevant paragraphs; find the results that look like the luckwarmest ballpark.

        That should be it.

        No need to calculate what can be allocated to the tribute we might owe Mr. T.

        Tell me if that works for you.

      • What you quote from Stevens, Joshie, is uncontroversial and really more a “cancellation insurance policy.” His deep fear is very understandable. The Wash Po had an editorial from their media columnist owning up to his own cowardice in the face of the NYT’s firing of its editor over the Cotton editorial. You should read it as it rather proves that there is a culture of fear that has been created to silence dissenting voices.

      • Entirely predictable that the same cast of characters will point proudly to what a ‘top climate scientist” has to say only as long as they can use what’s said to advance their agenda. If said scientist says something that directly contradicts that agenda, it should be summarily dismissed and said scientist’s integrity should be besmirched

      • Joshie’s response is as usual content free and really just claiming that I am biased while he is a perfect bias detector. Such self righteous childishness is hard to imagine in an adult, but this has been his decades long MO.

        How about the climate of fear created by the left? I cited a specific example of how many people lie about their opinions to avoid the mob.

        https://greenwald.substack.com/p/the-consortium-imposing-the-growing

      • Joshie, As is typical of your comments, you are lying about what I said. I did not smear anyone, nor accuse them of lying. I just suggested that people often shade what they say in order to avoid the cancel mob and cited Wemple as an example. Wemple did admit that he was dishonest about his views to appease the mob. I said that Stevens statements might be a cancellation insurance policy. You didn’t respond to the substance of this point. Ron agrees with me.

      • Steven’s 2015 disclaimer letter was absolutely cancellation insurance. But as Judith pointed out at the time, it might not save him if he get’s too close to the line. That line is obviously not to allowing one’s unhelpful-to-the-team results be quoted by “climate skeptics” or worse, lukewarmers.

        Therefore Steven cooperated with Scientific American when they came calling him to clarify his beliefs that climate change is real and dangerous and real dangerous (without wasting print on boring details of his new scientific findings). The disclaimer was all the climate left needed for the punching headline condemning Nic for writing an article using Steven’s aerosol numbers.

      • “But it was not the type of attention that the study author, Bjorn Stevens, a climatologist and director at the Max Planck Institute for Meteorology in Hamburg, Germany, was seeking. His work has been portrayed by conservative news outlets and blogs as undermining the theory of human-caused global warming. Red lights lit up. “New Climate Paper Gives Global Warming Alarmists ‘One Helluva Beating,'” Fox News declared.”

        ….The study in question, published in Journal of Climate, is titled rather drably, “Rethinking the lower bound on aerosol radiative forcing.”

        It delves into the impacts of aerosols, which are tiny pollutants of mineral dust, soot and organic matter emitted by sources such as power plants, factories and quarries. Not to be outdone, nature occasionally spews her own aerosols from volcanoes.”

        …Stevens’ paper was analyzed by Nic Lewis, an independent climate scientist.* In a blog post for Climate Audit, a prominent climate skeptic blog, he used Stevens’ study to suggest that as CO2 levels double in the atmosphere, global temperatures would rise by only 1.2 to 1.8 degrees Celsius. The measure is called “climate sensitivity.”

        That’s less than the assumed 2 C threshold for catastrophic climatic change in parts of the world. It’s also lower than an IPCC estimate that a doubling of CO2 will raise global temperatures by 1.5 to 4.5 C.

        Lewis’ blog post prompted conservative publications to crow that global warming is not a major threat. Stevens was inundated with email.

        “All sorts of schoolteachers were contacting me, and they were all worried that everything they’d learned was wrong,” he said.

        Soon after, he took the unusual step, for a climate scientist, of issuing a press release to correct the misconceptions. Lewis had used an extremely rudimentary, some would even say flawed, climate model to derive his estimates, Stevens said.

        …..

        ….
        ….Correction: A previous version of this story did not accurately reflect Lewis’ work. Lewis used Stevens’ study in an analysis that was used by some media outlets to throw doubt on global warming.

        https://www.scientificamerican.com/article/how-to-misinterpret-climate-change-research/

      • Of course you smeared him.

        You said he misrepresented his own science out of cowardice.

        You should he ashamed, although I know you’re not capable of that.

      • Even worse, you insult his integrity so you can advance your petty political agenda.

      • Here David –

        I continue to believe that warming of Earth’s surface temperatures from rising concentrations of greenhouse gases carries risks that society must take seriously,” he wrote, “even if we are lucky and (as my work seems to suggest) the most catastrophic warming scenarios are a bit less likely.”

        Tell us again how his statement of what he believes, in fhr fact of what he believes being misrepresented in the “skept-o-sphere” wasn’t actually because it was important for him to clarify what he actually believes, but because of his “fear.”

        Despicable – even for you. But also pathetic is that you do it in a thread where Nic appeals to Stevens authority as a “top climate scientist.”

      • > Steven’s 2015 disclaimer letter was absolutely cancellation insurance.

        No less pathetic coming from you Ron..

        How interesting that In thread under a post where Nic appeals to Stevens’ integrity and scientific authority as a “top climate scientist,” two “skeptics” chime in to discount what Stevens speaks to himself as his reasoning and opinions, and to instead insert what you’ve determined to be his real motivation that you’ve divined through mind-probing.

        I think neither of you really understand what skepticism is – otherwise you’d make more effort to examine for your own biases and “motivations” that lead you to thinking you have mind-probing abilities. You think you know better than what he said, and apparently think that it’s mere coincidence that your inserted motivations for Stevens, line up with your political preferences.

        Sad.

      • Doubling down on your lie does nothing to strengthen it Joshie. I did not smear Stevens, I merely pointed to a pervasive climate of fear created by a left wing cancel machine in part fueled by anonymous internet trolls like yourself. It is the best explanation for what happened.

        I gave you a persuasive reference for the fear that is out there in part inspired by people like yourself who smear and stalk. You of course didn’t respond to the main point perhaps because you know my point is correct.

      • Right. You said he misrepresented his own views on his own science, due to cowardice.

        But you didn’t smear him.

        Ok. I got it now.

      • Consider the following possibility.

        Stevens knows better than you what he thinks about his own science, and he was honestly conveying his beliefs..

        And in your zeal to score cheap political points, you over-evaluate your mind-probing skills.

        Just a thought.

      • Joshua wrote: “Of course you smeared him [Stevens].”

        ….Consider the following possibility.

        Stevens knows better than you what he thinks about his own science, and he was honestly conveying his beliefs…”

        Joshua, I consider anyone who stands up for beliefs that are sincerely held but politically dangerous a hero. Someone who practices defensive medicine is just ordinary.

        David brings up a great point in that you post anonymously . Does that mean that anyone who points that out is smearing you a coward? Not really, because it’s ordinary. Cowardice should be saved for extraordinary cases like the one male passenger on the Titanic that puts on a wig to get on a lifeboat.

        Stevens is far from a coward. He had the courage to go right up to the brink and flirt with self-cancellation by publishing what is likely unskewed science. In fact, one could rationalize that not going over the brink was for the greater good in that his work would be trashed with his reputation if he crossed.

      • Other examples of less than heroic and also less than cowardly actions, include inspector general Horowitz finding the FBI broke about every rule in the book in their frivolous Trump-Russia investigation but could not specify if it was improperly motivated. This saved the wrongdoers by allowing the media to focus on the later point to exonerate the authorities.

        Similarly, when attorney general Barr assigned Durham, the new investigator, to answer the questions of how and why the investigation got started, Durham only focused on the lowest level actors, the ones outside of government only acting a cut-out placeholders. He failed in their prosecutions because their defense attorneys rightly pointed out that they held little power to have created the misadventure. The officials holding power again went free. Was there cowardice? I think most understand that we can’t rely on a few heroes to do the obligations of our society. Exposing the truth is a universal moral and thus a shared responsibility. Because covering up the truth for the powerful is just ordinary.

      • Counterpoint, Ron:

        Sen. Burton K. Wheeler, Charles Lindbergh, and Kathleen Norris pledge allegiance to the American flag at an America First Committee rally in New York on May 23, 1941.

        https://www.msnbc.com/msnbc-podcast/rachel-maddow-presents-ultra/episode-5-shut-it-down-n1300315

        All these respectable folks were exonerated.

        Teh Donald’s slogan has never been his in the first place.

        Coincidence? You be the judge!

      • Ron –

        You avd David are saying, with total certainty, that Stevens is misrepresenting his own freakin’ science, out of fear. That’s a smear.

        Plus, you couldn’t posdibkg know that to be true. You’re just certain that it’s true because of your own ideological “motivations” – ’cause, actually, Ron, you don’t have mind-probing abilities.

        It’s entirely in-skeptical.

        But I don’t expect you to understand. You’ll just continue to stamp your feet and argue by assertion that you know things you can’t possibly know, and say Stevens is too much of a coward to honestly speak about his own freakin’ science.

      • Josh, I never called Stevens a coward or accused him of anything worse than being under political pressure. I give Stevens high praise for his achievement of academic stature, and I don’t think anyone is accusing Stevens of misrepresenting his science to the scientific community.

        As far as mind probing, people make judgements about apparent intention all of the time. When someone is held hostage and writes a letter supporting his captors political viewpoint it is not unreasonable to assume there is a slant. That would not be a slander to the hostage nor would it be grounds to call them names.

        Perhaps you don’t see what people commonly refer to as cancel culture as unproductive or a problem as much as someone like myself that believes that there are people that have become less interested in truth than political power. If that is the case is not a smear against you it is normal human behavior to see things that support your beliefs as good.

        I am as much in favor as hearing the scientist ringing the alarm about a problem as hearing that a previous alarm was a false one. I would not want them to feel coerced into going along despite their true belief either way.

      • Joshua, do you see any smear, misrepresentation or mind probing in this Scientific American Article? https://www.scientificamerican.com/article/how-to-misinterpret-climate-change-research/

        The title itself claims misrepresentation but instead of explaining the science of how aerosols and the implications for climate modeling the article is a political hit job on “climate skeptics” blogs and “Fox News” as misrepresenting science. But the article’s title is a false promise because it never points to any misrepresentation. Stevens can rightly claim he is not a climate denier and Fox news can rightly claim that Stevens’s work torpedos assumptions that are inherent in the IPCC climate models.

        All of the misrepresentation was by Sci Am. Do you agree? If not, how?

      • It is a known fact that alarmist climate scientists and their associated minions in the media and in other disciplines have directed hostile criticisms at climate scientists who have more moderate views. Our hostess can attest to that.

        So, we have the following facts:

        1. Alarmist climate scientists direct hostile criticisms to those with more moderate views.
        2. After the interview, Bjorn Stevens was inundated with communications questioning his statements in the interview.
        3. Only after all the attention did Dr. Stevens issue the clarification.
        4. He stood by his conclusions, but added global warming “may” be a problem no matte.

        This is circumstantial evidence, but to infer he may have done this due to fear of reprisal from hostile alarmist climate scientists isn’t unreasonable. Furthermore, given the facts above, it has more support than Josh’s claim that Ron’s reason for that conclusion is politically or ideologically motivated.

      • I’ll leave this for now. Joshie has an unbroken track record of misrepresenting his stalking target’s statements and then voluminously continuing to lie about it.

        Ron of course agrees with me.

    • Willard, it seems to me you have a knowledge gap. The value of forcing is only one estimation for calculating an expected warming. The SSP or RCP gives you a value, let’s use 4.5W/m² forcing in 2100. That doesn’t say something about temperatures. In a second step we need a value for the sensitivity, something like x K/ 3.7 W/m² for a doubling of CO2. And in Nic’s new assesment of the sensitivity he got 2.2 K for the x above. This is the ECS, what means after reaching an equilibirium after a few hundrets of years. If we want to estimate the warming in 2100 we need a value more, called TCR. In Nic’s paper it’s estimated with 1.5K / 3,7 W/m². In older figures they used other sensitivities therefore the look on trajectories for some SSP makes no sense at all.
      Best Frank

      • Frank,

        If you look at the paper, you should be able to see temperature estimates, e.g:

        The observationally constrained likely range of future warming (blue rectangles; Fig. 5, B and D) in response to an ambitious mitigation SSP1-2.6 scenario is 1.36° to 1.86°C by mid-century and 1.33° to 1.99°C by the end of the century with respect to the 1850–1900 baseline. These results are generally in line with the Paris Agreement target of limiting warming to well below 2°C above preindustrial temperatures

        So I am not sure what you mean when you say that SSP does not give you a temperature.

        It is as if you thought I was an idiot or something.

      • Frank,

        Here would be a quote that you would have obtained had you followed my methodology:

        The observationally constrained likely range of future warming (blue rectangles; Fig. 5, B and D) in response to an ambitious mitigation SSP1-2.6 scenario is 1.36° to 1.86°C by mid-century and 1.33° to 1.99°C by the end of the century with respect to the 1850–1900 baseline. These results are generally in line with the Paris Agreement target of limiting warming to well below 2°C above preindustrial temperatures […]

        The authors clearly associate a temperature range to a SSP, so I am not sure of the relevance of your observation that a SSP does not give you a temperature.

      • Willard, your comment shows that you have no understanding at all about the basics of climate research and to make the things worse you are not interested in education. I tried to figure it out for you, no success. So go on and think about how it should work to get a temperature difference (in K) from the forcing (in W/m²) if you don’t have a sensitivity (K/W/m²). This is the stuff for the elementary school you don’t understand. What a pitty.
        Cheers

      • Frank,

        You are too kind. In return, please rest assured that your condescension does not *cohere* (to borrow the concept you failed to grasp) with having failed to connect SSPs and temperature estimates. All you needed was to read the paper to which you paid lip service.

        I expected you to bite the bullet and told us that the lower bounds of justified disingenuousness were actually lower than than SSP1.1-9. You might even have intimated that inactivism was completely justified since we were already meeting our 1.5C goal. In other words, you were invited to drop the innuendos and cut the passive aggressive crap.

        Those who enjoy playing Socrates seldom think about how it ended for him.

      • Willard, in the mentioned paper (Tokarska et al.2020) they use a TCR (sensitivity) of 1.6 K/2*CO2. “The constrained CMIP6 median TCR (1.60°C)…” With this value they show in the supps. the expected warming to 2100 in fig. S5E with the RCP 4.5. I was so kind to download it for you: https://i.imgur.com/81wb2oj.png
        The constrained mean is slightly below 2K.
        If one incorporates some “Warming in the pipeline” and uses the TCR value estimated in Nic’s paper (medain 1,5K /2*CO2) one gets the central value of 2K in 2100: https://i.imgur.com/StqBVSM.png
        Where is the problem?? Nic’s estimation is NOT on all lower bounds, in contrast there is almost no difference for the most likely RCP 4.5.
        Best Frank

      • Frank,

        Sorry for the delay. I should have paid attention to your “His believes were not contadicted becaus one can’t contradict believes” which, beyond being false (e.g. beliefs can contradict one another), shows me that I should have put style aside.

        The paper you cited was cool to read, and I liked that it tried to filter models out with something like a correlation matrix. I’m no fan of emergent constraints in general, but the R between the 1981-2017 trend and the TCR is impressive, notwithstanding the drop when they remove the last three years. The covariance of spatial trend variation indicates that working on less than 40 years of observations is suboptimal. Constraining ECS appears even less easy. The concept of ECS is still unclear.

        In my opinion, the part where they constrain the SSPs is the most interesting one. Their results show that, even if we apply their constraints, very few models get us near Nic’s numbers unless we buy ambitious scenarios. They only look at 2.6 and 8.5, so I’m glad you give me 4.5. My eyeballs tell me that S20 is 50% more than L22. That’s not small!

        Nevertheless, I think that Nic’s 4.5 figure compares with the ambitious scenarios’ numbers. So as I see it, the luckwarmest limits themselves tell me that we should shoot for the ambitious scenarios. Just to be on the safe side. No need for emulators to make that decision. The more uncertainty there is, the less we can trust the luckwarmest frontier.

        Thanks for that figure!

        W

      • Hi Willard, indeed the Sherwood (20) TCR is higher than Lewis (22) BUT at least in the upper ( 83% : 4.45!!) bound far, far above the AR6 estimation. You should know that S20 gave no explicit value for the TCR, Nic recalculated it because ha got it’s code to run. This very high TCR (median 2.26 (!)) makes the approach of S22 a little bit less likely. If you compare the approach of Tokarska et al (20 you’ll see that this gives a little bit less warming well in the ballpark of AR6. re “Lukewarmers etc.” … this is not the stuff for science of which we talk about here.
        Best Frank

      • Frank,

        Your “less likely” remark seems mostly relevant if we make non-science “stuff” more explicit. Since you want to pull it under the rug, it might be better to stop here.

        Thank you for the chat.

        W

    • jim –

      > This is circumstantial evidence, but to infer he may have done this due to fear of reprisal from hostile alarmist climate scientists isn’t unreasonable.

      I don’t disagree with that statement. Speculate as you want. But to assert with certainty that Stevens lied about his beliefs is a smear. If you want to smear people, go ahead and do so. But own up to what you’re doing.

      Both Ron and David have a long history here of focus on ideological agendas, which include anti-“woke” advocacy. They’re entitled, but when they go over the line to mind-probe and say someone’s misrepresenting their views, and explain that they did so because they lack the integrity to stand behind their actual beliefs, that can only be explained by cognitive bias. That is unless David and Ron truly have mind-probing abilities – which I personally rather doubt although you’re entitled to think that’s credible.

      Look – we’re all subject to cognitive biases. Someone who’s actually a skeptic will be affected by cognitive biases like everyone else. But a real skeptic will also be open to examining their biases when they’re exposed. When someone states as fact, something that they can’t know as a fact, they are exposing. cognitive bias.

      Here, again, is what I said. It should be uncontroversial – not mutually exclusive with what you said. Instead, I was told as a matter of fact, I was incorrect..

      I try to take what people say at face value, and I have a healthy respect for the limitations of mind-probing to explain why people did or didn’t do things, based on second-guessing and conjecture about what would other people think would fit logically with what people said they believe.

      Seems to me that reverse-engineering the reasons why Stevens did or didn’t publish particular papers showing particular scientific phenomena, would be pretty complicated.

      Stevens stated his opinions, and David said, as a fact, that Stevens was “in deep fear” and that explained why he stated his opinion. HTF does David know that he was “in deep fear” as opposed to wanting to clarify his views that he felt were misconstrued?

      Ron chimed in to say it was “absolutely cancellation insurance.”

      Mind-probing.

  32. Pingback: An Interview with High Local weather Scientist Bjorn Stevens – Watts Up With That? - news page

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  37. I am shocked, shocked I tell you, that nobody seems to have mentioned Tim Palmer’s new book “The Primacy of Doubt” in this context! Here you go:

    https://GreatWhiteCon.info/2022/10/the-primacy-of-doubt/#Oct-22

    “We understand these [water vapour, albedo] feedback processes reasonably well. However, there is another feedback process associated with water that we understand rather poorly. This is the cloud feedback process.”

  38. NewClimateChangeTheory:

    You say “there has been net global cooling since 1998” based upon Dr. Roy Spencer’s graphs.

    However, the Hadcrut5 listing of average anomalous global temperatures shows that 16/23 years since 1998 have been WARMER than in 1998.(0.20 Deg. C. warmer in 2022)

    This, alone, invalidates your theory. There has been no net cooling.

    However, you are correct with respect to your other comments.

  39. Thanks, Nic, for posting the interview.

  40. Circular Claims Fall Flat Again … A Greenpeace update on how recycling has failed. Their solution is to use less plastic. They only mention incinerating the plastic twice, both times as polluting and not a desirable option.

    https://www.greenpeace.org/usa/reports/circular-claims-fall-flat-again/

    Save the Oceans … Stop recycling plastic by Mikko Paunio, for the Global Warming Policy Foundation, comes to a similar conclusion that recycling is a waste of time (pun intended) but calls for incineration as the best option.

    https://www.thegwpf.org/content/uploads/2018/06/Save-the-oceans.pdf

    All waste that can not reasonably be recycled should be incinerated for power generation.

  41. > Applied to the Applied to the AR6 3.0°C central estimate of climate sensitivity, that reduction would change it to 2.2°C, identical to the feedback-based estimate in my recent paper that estimated climate sensitivity using multiple lines of evidence. 3.0°C central estimate of climate sensitivity, that reduction would change it to 2.2°C, identical to the feedback-based estimate in my recent paper that estimated climate sensitivity using multiple lines of evidence.

    What was the cloud feedback effect quantification in your estimate? Was it greater than zero? If it was, than your estimate is not actually aligned with theirs, as you seem to imply.

    • After all, let us not forget a Stevens’ comment from back n the day:

      In my new paper I did not speculate as to the implications of my findings for estimates of Earth’s Equilibrium Climate Sensitivity, which is perhaps the simplest measure of the response of the Earth System to a change in concentration of atmospheric carbon dioxide. However others have used my findings to suggest that Earth’s surface temperatures are rather insensitive to the concentration of atmospheric CO2. I do not believe that my work supports these suggestions, or inferences. ”

      • There is nothing wrong with two scientists having differing views on what the implications of particular findings are. Bjorn Stevens did not assert that I had misinterpreted his aerosol forcing study.

      • Nic –

        > There is nothing wrong with two scientists having differing views on what the implications of particular findings are. Bjorn Stevens did not assert that I had misinterpreted his aerosol forcing study.

        Of course there’s nothing “wrong” with it. I would say it’s pretty bizarre to think otherwise.

        But I do think it’s important – when you talk about the views of those you selectively label as “top climate scientists,” to not selectively point to where their views might be aligned while neglecting to discuss where they diverge.

    • May I suggest that you read my paper and answer your question for yourself.

    • At the risk of getting nitpicked, I will Josh has indicated he believes global warming presents a small risk of a very bad outcome for humanity. I haven’t seen a detailed justification of that from Josh. Might I be so bold as to ask Josh to write up the analysis backing that claim and for Judith to post it here?

  42. Hi all,

    according to Raghuraman et al 2021, “the significant positive trend in observed EEI is driven by a −0.70 ± 0.23 Wm−2/decade trend in RSW and a 0.28 ± 0.22 Wm−2/decade trend in OLR”.

    https://www.nature.com/articles/s41467-021-24544-4

    If we read Quaas et al 2022, without Aerosols “This implies that without the cooling effect of aerosols, the world would al- ready have reached the 1.5 ◦C temperature threshold “.

    https://acp.copernicus.org/articles/22/12221/2022/

    As far as evidence shows, the anthropogenic aerosol decreasing trend (Quaas) is the main responsible of less clouds and more SW radiation hitting earth (Raghuraman).

    So from my perspective, the bad news is that, in the abscence of anthropogenic aerosols, natural earth equilibrium is having less clouds, so GHGs radiative forcing is way bigger than the thought.

    • I am told that subsequent work by another scientist finds a substantially smaller trend in EEI (Earth’s Energy Imbalance) from the more reliable Argo ocean heat content (OHC) measurements than Raghuraman finds using CERES data, which is subject to greater uncertainty and possible drift. Indeed, simple calculations using published OHC records seem to suggest a near zero trend in EEI over 2001-2019. This figure seems consistent with zero acceleration in the rise in 0-2000m OHC since 2000, as do such data as there are for greater depths.

    • Alberto Ruiz:

      You say that , in the absence of anthropogenic aerosols, natural earth equilibrium is having less clouds, so GHGs radiative forcing is way bigger than the thought.

      Nonsense!

      Fewer anthropogenic aerosols result in less dimming of the atmosphere, so that the Sun’s rays strike the Earth’s surface with greater intensity, causing increased warming.

      NOTHING to do with increased GHG forcing.

      • Burl Henry: you are right and wrong. The effect on the direct radiation follows your explanation. However, there are also Aerosol-Cloud-Interatcions (ACI) which can work in different directions.

      • Frank Climate:

        I am sorry, but I don’t know what you mean by aerosol – cloud interactions, or what effect they might have.

        As aerosol concentrations decrease,, warming increases, and there are fewer clouds (because of fewer moisture nucleation sites)

        (The only dimming aerosols that have any observable climatic effect are SO2 aerosols, of both industrial and volcanic origin)

        Temperatures during Minoan Warm Period, the Roman Warm Period, and the Medieval wear period (all global events) were higher because of very little volcanic activity (no dimming SO2 aerosols in the atmosphere most of the time).

        The burning of fossil fuels also produces S)2 aerosols, and their elimination because of Net-Zero activities will inevitably lead to higher temperatures!

      • Burl Henry: “I am sorry, but I don’t know what you mean by aerosol – cloud interactions, or what effect they might have.”
        You should have read more and post less!

      • Quote from Burl H: “Temperatures during Minoan Warm Period, the Roman Warm Period, and the Medieval wear period (all global events) were higher—-”

        Those three periods correspond to Eddy cycle peaks, and spaced about 980 years. So were the earlier Babylonian/Mycenaean ~1750bce, and the Akkad/Sumer ~2700bce. Volcanic and probably several other issues are mainly collateral.
        Eddy roots in between were the opposite and a main source of great civilisation distress. (Eg ~2345bce leading to the 4k2 event).

      • MelitqmeGalithic:

        The Minoan Warm Period extended from 3500 BC to 1100 BC, a period of 2,400 years, which doesn’t fit the 500 year interval from valley to peak of “Eddy Cycles”

        Also, the predicted cooling from year 2000 is not occurring

        The concept of “Eddy Cycles” needs to be discarded.

      • Hi Burl,

        think about anthro. aerosols like if you put yourself inside cool water while you are having fever. If you are pulled out from the water, your body temperature will rise again to its equilibrium.

      • Alberto:

        You are making the assumption that rising temperatures result in more cloud formation, since the warmer air can contain more moisture, and .the additional clouds have a cooling effect.

        However, the actual cause of our rising temperatures is a reduction in the amount of dimming SO2 aerosols in our atmosphere, due to global “Clean Air” efforts. As a result, there there are fewer SO2 aerosols present to provide moisture nucleation sites to produced clouds, and temperatures continue to rise.

        This is why temperatures were higher during the Minoan Warm Period, the Roman Warm Period, and the Medieval Warm period.

        These were world -wide events with very few volcanic eruptions, with the result that most of the time there were no dimming SO2 aerosols in the atmosphere, and temperatures were 2 to 4 Deg. C. warmer than the present.

        Such conditions also occur locally, today, whenever there is a stalled high-pressure weather system. They are characterized as having low wind velocities (except at their peripheries,where they can be quite high), cloudless skies, no precipitation, and high temperatures..

        Temperatures always begin rising about 4-5 days after being stalled, after the SO2 aerosols within the stalled area have settled out without being replaced, reaching temperatures of 115-130 Deg. F, or higher.

        The 1935 “Dust Bowl” in the United States was due to a stalled high-pressure weather system…(see Wilipedia map). .

        .

      • Burl Henry: The Mycenaean (Minoan) and Babylonian peaked at about 1750bce, after the global collapse of the ~2345bce (4k2 event). Collapse started about 1300bce, the Bronze age collapse.
        https://www.youtube.com/watch?v=bRcu-ysocX4
        See also here https://melitamegalithic.wordpress.com/2019/03/15/searching-evidence-update-2/
        See graph before last; comparing proxies. Note Minoan warm period at peak of Eddy cycle.

  43. Douglas you are entirely correct. I would appreciate it if you could read and comment on my earlier Post above
    Norman J Page Oct22.2022 5.55PM
    and the linked Blog post at
    https://climatesense-norpag.blogspot.com/

  44. BOEM is taking comments on their new Wind & Whales Strategy document. Feel free to comment including anonymously. You do not have to be a US Citizen.

    https://www.regulations.gov/document/BOEM-2022-0066-0003

    I am against the wind.

    • Here is the BOEM Abstract. Note that all this whale killing offshore wind is justified by the bogus “climate crisis”.

      “Abstract
      To support the Biden-Harris Administration’s goals of advancing offshore wind energy production while protecting biodiversity and promoting ocean co-use, the Bureau of Ocean Energy Management (BOEM) and the National Oceanic and Atmospheric Administration’s National Marine Fisheries Service (NOAA Fisheries) developed a joint Draft North Atlantic Right Whale and Offshore Wind Strategy to protect and promote the recovery of endangered North Atlantic right whales while responsibly developing offshore wind energy. The strategy identifies three main goals (Mitigation and Decision-Support Tools; Research and Monitoring; and Collaboration, Communication and Outreach) and focuses on improving the science and integrating past, present, and future efforts related to North Atlantic right whales and offshore wind development. The draft strategy identifies approaches to mitigate and monitor offshore wind development impacts on North Atlantic right whales, which will help guide industry during the permitting process. The strategy also establishes the agencies’ plans to engage stakeholders, partners and other ocean users on these issues. Following review of public comments, the strategy will be regularly evaluated and updated as new information becomes available. The strategy does not define new policy or regulatory actions; rather, it recognizes efforts to date and identifies areas where BOEM and NOAA Fisheries will work together alongside our industry partners in an effort to focus on the information and science needed to responsibly develop offshore wind energy while protecting and recovering the North Atlantic Right Whale. Offshore wind energy development plays an important role in U.S. efforts to combat the climate crisis and build a clean energy economy. The Biden-Harris Administration has set a goal of significantly increasing the nation’s offshore wind energy capacity to 30 gigawatts by 2030. BOEM is the lead federal agency responsible for managing offshore energy exploration and development in the United States, while NOAA Fisheries is responsible for the stewardship of the nation’s ocean resources and their habitat. BOEM and NOAA Fisheries are soliciting public comment on the Draft North Atlantic Right Whale and Offshore Wind Strategy (see Supporting Documents in this Docket BOEM-2022-0066). The deadline to submit comments to help evaluate and improve this strategy is December 4, 2022.”

    • Here is a short comment I posted:

      “We do not yet have the science to assess OSW impacts on Right Whales

      In the draft Strategy document under Research and Monitoring we find this reference to RWSC:
      “2.1.7 Coordinate with the RWSC and Federal and state partners to evaluate new data and emerging data gaps and to develop data access and sharing guidelines.”

      The Regional Wildlife Science Collaborative (RWSC) tells us that now is not the time to build any offshore wind in the Atlantic, because we lack the science to assess the impacts on wildlife.

      Here is how they put it: “The four RWSC sectors are engaging with scientific experts in several taxa-based Subcommittees to develop an Integrated Science Plan for Wildlife, Habitat, and Offshore Wind Energy in the U.S. Atlantic, or “Science Plan” by mid-2023. The Science Plan will articulate data collection and analysis activities needed for IDENTIFYING, ASSESSING AND AVOIDING IMPACTS to the distribution, abundance, and behavior of wildlife due to offshore wind development. The Science Plan will also provide a roadmap for the four Sectors to fund those activities.” (Emphasis added)

      This lack of impact science is especially true for severely endangered whales. For example we have no idea how much underwater operational noise a wind array of a hundred or more giant turbines will create, or how big an area that noise will contaminate.

      Their Science Plan is due mid 2023. After that comes funding and finally the desperately needed research. Clearly no valid environmental impact assessment (EIA) will be possible until this impact research has been done. Nor can any construction begin until a proper EIA is finalized.

      So we have years to go and much work to do before any decision can be make on the viability of any Atlantic of these huge offshore wind projects. The Strategy document should make this extensive research need clear.”

  45. Explain how a photon traveling from cloud to ground is affected in any way by the fact the cloud is cooler than the ground! When you look up on a cloudy day, you can see the clouds! Obviously, photons don’t care what object is at what temperature! Get a clue!

  46. Re “violation” of thermodynamics: How du you explain the blue sky when it’s coudless and the sun shines? It’s the “Rayligh scatter”: The incoming shortwave sunbeams (quants) lift an electron up in O2 and N2 molekles. They fall back in the same time, no energy loss…BUT: the so released quants escape with a randomly direction. This is the only difference from the lifting sunbeams which are directed. This works much better with shorter ( more energy h*f) wavelengths, therefore it looks blue. Very similiar effect when the molekles are GHG and the beam is infrared ( from heat escaping into space). The GHG have the same impact on infrared ass the N2, O2 molekles on sunshine: There is no “violation” of thermodynamics, it’s just quantum physics. If you don’t believe this you don’t believe on blue sky! Do you? . :

    • About 9% of the SWR that arrives at the Earth is scattered back to space by Rayleigh scattering and not by clouds or the surface. When SWR is being scattered towards you eye – with enrichment in blue – it is also being scattered to space.

      Later in the day and during twilight (after the sun falls below the horizon or is about to rise), the relative importance of scattered light becomes more important. Scattered light comes from all direction (a hemisphere), reducing or eliminating shadows.

  47. Please look at Moon – Mars mean surface temperature (Tmean) comparison.

    For Moon Tmean = 220K
    Moon’s Albedo a = 0,11
    For Mars Tmean = 210K
    Mars’ Albedo a = 0,25

    It can be shown for the same Albedo, Moon and Mars would have had the same mean surface temperature (Tmean).

    Moon is 1 AU (Astronomical Unit) away from sun.
    Mars is 1,53 AU away from sun.
    When applying the distance square inverse law, Mars receives 2,32 times less solar energy than Moon does.

    Moon and Mars have the same Tmean temperature. Mars receives and emits 2,32 times less energy to space than Moon.

    https://www.cristos-vournas.com

    • Christos: The average temperature of the Martian and Lunar surfaces is also influenced by the rotation rate (difference is the length of day and night), 1.03 Earth days vs 29.5 Earth days. Since the rate of radiative heat loss varies with T^4, cooling of the surface of the moon slows dramatically during the 14 days of lunar night. Averaging distorts phenomena that vary with T^4.

      So surface temperature on the Moon ranges from about 95 K to 390 K. Mars ranges from about 250 K to 170 K, but air above the darkest surfaces can reach 290 K. Temperature also varies with the particle size (heat capacity). With 34 times as much CO2 as Earth, Mars does have a GHE, but it is much smaller than Earth’s due to lack of water vapor and clouds (not to mention some severe dust storms). A complete analysis of the reasons differences in AVERAGE surface temperature is complicated, and the standard explanation of a GHE is over-simplified for an ignorant public, and not convincing for most readers of this blog.

      • Franktoo, Moon and Mars have the same Tmean temperature. Mars receives and emits 2,32 times less energy to space than Moon.
        2,32 times less energy, but still the same average surface temperature.

        Earth, because of the higher than Moon’s Albedo (a.earth=0,306 vs amoon=0,11) receives and emits 26% less solar energy than Moon.
        And yet, Earth’s mean surface temperature is 288K when Moon’s is 210K.
        The difference cannot be attributed to the GHE, because Earth’s atmosphere is very thin.

        https://www.cristos-vournas.com

  48. Problem is, once you couple plausible climate sensitivity with plausible emissions, the costs never exceed the benefits. There is just too much invested that not being the case.

    • Aaron: Cost-benefit analysis of spending money today to limit the damage caused by climate change 50 or 100 years in the future depends on the discount rate you apply to future costs. If you use a zero discount rate and add up a millennium of costs, the benefits of limiting CO2 emissions will certainly outweigh the costs. As best I can tell, when the IPCC’s economists calculate the “social costs” of CO2 emissions using a low discount rate appropriate for government borrowing (before recent inflation), a Pigou tax on carbon dioxide emissions would not be high enough to limit emissions enough to keep warming below the 2 degC goal set for political reasons. In that sense, your simplistic statement about costs exceeding benefits is correct.

      A more sophisticated analysis can explain why different people come up with very different answers to cost-benefits controversies. Instead of using an arbitrary discount rate, rigorous economists use the expected growth rate in GDP. Developing countries seeking catch up to the living standards in the developed world INSTINCTIVELY apply a high discount rate and negligible discounted benefit from limiting climate change. These countries were willing to pledge to limit CO2 emissions in the Paris Accords, but only if developed countries pay most of the added cost! On the other hand, some of the affluent in the developed world fear that their children will be less well off than they are, because “my generation has polluted the planet and depleted its resources”. If GDP is going to plateau or fall, we should apply a zero or negative discount rate to future costs. These people INSTINCTIVELY are willing to pay almost any cost to not add to the burdens their children and future generations will face. Thus, they want to limit warming to 1.5 or 2.0 degC, regardless of cost. Unfortunately for them, climate change is a global problem and the future course of CO2 emissions is mostly in the hands of the developing world.

      • Frank, one factor I think you should add is that intellectual assets are ever increasing, making solutions ever more economical as years progress.

      • Ron: Thanks for the reply. However, I don’t want unpredictable technological program to complicate a fundamental reason why differences over discount rate mean we can’t have global agreement – or even society-wide agreement – on cost-benefit analysis of emissions reduction. In economics, Ramsey mathematically proved that the optimal discount rate in problems like climate change depends mostly on the rate of economic growth. Intuitively, the amount most of us are willing to spend to make our children’s or grandchildren’s future lives better depends on how much richer we think they will be than we are today. Two generation (50 years) of 2% GDP growth makes your dependents 2.7X richer; 3%, 4.4X richer; and 4%, 7.1X richer.

        Technological progress is clearly important, but major progress is unpredictable. For example, the progress in airplanes and air travel was astounding until the first transcontinental jet appeared around 1960, but gains since then have been incremental. SSTs still aren’t practical. The cost of electricity from solar panels (and wind turbines) dropped tremendously, but some of that cost drop was the result of interest rates on capital intensive projects falling to extremely low levels, an era that may be gone. We may never double the efficiency today’s solar panels and the panel represents the perhaps only half of the material cost. Yes, fracking and horizontal drill recently revolutionized oil and natural gas production in the US, but our oil production fell for four decades and two oil crises while we were waiting for a breakthrough.

        Finally, the worst thing you can do with new technology is have the government mandate widespread adoption of new technology before the price is low enough. I can’t believe the Germans were installing lots of solar panels in a cloudy northern country two decades ago. They are still paying for them. The US Department of Energy bet on Solyndra and other “clean tech” companies under the guidance of Chu and KOONIN.

  49. On the media part of this: Germany is in a huge energy crunch right now brought to them by team warm.
    The discovery of rational climate science by its largest newspaper is not a coincidence. Hoping the trend continues.

  50. Please don’t deny Plancks law. A body with a lower temperature radiates on all wavelengths, with a peak below the peak of a warmer body. That’s a quantum (microscopic) law. The Second Law does not describe microscopic actions, only their statistics.

  51. Scientist

    You should dispense with the personal comments and stick to the science. You are coming across as a whack job, in need of intervention.

    I’m sure you’re impressed by your credentials and grasp of the science, but to me you are just another of many commenters who have their own ideas about what is truth.

    If you’re looking for converts, it’s not working.

    Chill

  52. Mars’ light falling on Earth’s surface from the colder planet Mars

    What happens to the light falling on Earth’s surface from the colder planet Mars or the colder Planet Jupiter?

    Doesn’t its EM energy get absorbed? Doesn’t it warm Earth’s surface?

    https://www.cristos-vournas.com

  53. Pingback: Worthwhile Climate Science Interview… - Trueorleans News

  54. Nic: I have a question about Manshausen et al (2022), “Invisible ship tracks show large cloud sensitivity to aerosol”. If this paper is correct, it could have a big impact on climate sensitivity estimated from energy balance models by reducing total forcing. I can’t tell if it conflicts with the deductions of Stevens. However the article wasn’t published with an accompanying News and Views article explaining its importance and I haven’t seen it mentioned elsewhere. Is there something I’m missing? If correct, how much would this increase your estimate of ECS.

    https://www.nature.com/articles/s41586-022-05122-0

    Abstract: “Cloud reflectivity is sensitive to atmospheric aerosol concentrations because aerosols provide the condensation nuclei on which water condenses. Increased aerosol concentrations due to human activity affect droplet number concentration, liquid water and cloud fraction, but these changes are subject to large uncertainties. Ship tracks, long lines of polluted clouds that are visible in satellite images, are one of the main tools for quantifying aerosol–cloud interactions. However, only a small fraction of the clouds polluted by shipping show ship tracks. Here we show that even when no ship tracks are visible in satellite images, aerosol emissions change cloud properties substantially. We develop a new method to quantify the effect of shipping on all clouds, showing a cloud droplet number increase and a more positive liquid water response when there are no visible tracks. We directly detect shipping-induced cloud property changes in the trade cumulus regions of the Atlantic, which are known to display almost no visible tracks. Our results indicate that previous studies of ship tracks were suffering from selection biases by focusing only on visible tracks from satellite imagery. The strong liquid water path response we find translates to a larger aerosol cooling effect on the climate, potentially masking a higher climate sensitivity than observed temperature trends would otherwise suggest.”

    From text: “Whereas LWP adjustments were previously shown to contribute a small but probably positive forcing, our results indicate the potential for a substantial negative forcing. Following Bellouin et al., and extrapolating to the rest of the globe (Methods), we estimate the forcing from LWP adjustment (and its 90% confidence intervals) to be −0.76 (−1.03, −0.49) W/m2. This is of opposite sign and larger magnitude than the estimate of 0.2 ± 0.2 W/m2 given in the latest Intergovernmental Panel on Climate Change report(section 7.3.3.2.1). This substantially larger estimate is mostly due to relatively strong responses in LWP in unstable atmospheric conditions, where the Nd response is weak, resulting in a large sensitivity.

    • Yes, I’ve read that study. However, its findings conflict with other studies that point to less negative aerosol forcing (e.g., Malavelle et al “Strong constraints on aerosol–cloud interactions from volcanic eruptions” (Nature, 2017) , and I have read that ship track studies are all unrepresentative.

  55. If I remember correctly, this post was about Bjorn Stevens and his outspoken criticism of PIK. That organisation has, for years, been seen as an extreme supporter of everything alarmist. it is therefore not surprising that Stevens is somewhat sceptical about their more outlandish claims.

    He states that the disappearance of clouds due to global warming is nonsense.

    He accuses PIK of scouring the literature for alarmist items.

    He criticises PIK’s obsession with tipping points. Depending on how you define them, you can use tipping points to maintain permanent alarmism.

    Well said, that man. He is absolutely right.

    While on the subject of alarmism, I want to add that we are approaching COP27 and can expect to see much more of it.

    Climate change is the UN vehicle for wealth redistribution. It goes like this: The western wealthy nations used fossil fuels to build wealth. Their emissions caused huge climate change issues for developing countries, so now the wealthy nations must pay compensation, The COP meeting is where the two parties meet. The poorer nations claim climate catastrophe and the richer nations are pressed for money.

    The UN scientific arm, IPCC, claims that it is worse than we thought, (backed by the UN WMO) and model projections by the WCRP (backed by UN WMO).

    This is important. Listen to the claims by the UN Director General, Antonio Guterres.. Decide whether these are reasonable concerns by a respectable world organisation, – or not.

  56. IMO this is a case for moderation.

    • I didn’t response coze I think the whole story is o/t here. I can’t find any reason to doubt that a doubling of CO2 generates 3.7 W/m² radiative forcing. This is a basic in Climate science. I wrote the reason why: A process very similiar to the Rayligh Scatter but with other molecules: GHG, mostly CO2 and H2O. So please stop boring posts about the “impossible” GHG effect, comparing the real physics with microwave ovens which frequency is 2…3 magintudes lower than IR. However, if you like this and the moderation doesen’t stop this very o/t posts: good luck, but I won’t respond anymore to lift up their meaning.
      Cheers

  57. Planet Earth has a very thin atmosphere, GHG are trace gases in Earth’s already very thin atmosphere.

    The GHE on Earth’s surface is so very much insignificant, it cannot be measured.

    https://www.cristos-vournas.com

    • Now, let’s see:

      The actual global average lunar temperature is more like 220K.
      Earth receives 28% less solar energy, because Earth’s Albedo is a=0,306 vs Moon’s Albedo, which is only a=0,11.

      It can be shown that Earth’s global average surface temperature (everything else equals) should be Tmean = 210K.

      Earth’s mean surface temperature actually is Tmean = 288K.

      288K – 210K = 78C difference.
      It is impossible for the very much insignificant the Earth’s very thin atmosphere’s GHE to warm Earth’s surface 78C up.

      https://www.cristos-vournas.com

  58. Speaking of COP27:

    COP27 — the Camel’s nose of Loss and Damage enters the talks
    By David Wojick
    https://www.cfact.org/2022/10/28/cop27-the-camels-nose-of-loss-and-damage-enters-the-talks/

    “Will the developed country teams jointly admit to causing the world’s bad weather? Unimaginable liability looms.”

    Truly wild.

  59. David, Admitting liability for natural warming caused by coming out of the LIA would be the sort of lunatic thing our leaders would do.

  60. We can learn much from history. Maurice Strong made his intentions very clear.
    https://www.telegraph.co.uk/news/earth/paris-climate-change-conference/12035401/Farewell-to-the-man-who-invented-climate-change.html
    Today, few people have heard of him. But it is all there, the intention to use climate change as a vehicle for wealth redistribution. The original remit of the IPCC to nail CO2 as the cause. The scientific attribution of causation before any research was carried out. The construction of a multi-agency UN project to deliver a socialist vision.

    This is not conspiracy theory, this is recorded history in black and white for all to peruse. It is a plan being implemented today before our eyes. A plan that was launched by Maurice Strong.

    Why does the WCRP that coordinates CMIP models not suggest that they tone down their sensitivity to CO2 and therefore get results that diverge less from observation? I wonder that every year, but the models get worse and worse. After a while, the inevitable conclusion is THEY DON’t WANT TO.

    The UN and IPCC use these models to justify the alarmism that drives COP. The fact that others, e.g. governments, believe them is a bonus.

    Some scientists automatically initiate “explanatory mode” to justify the inexplicable actions of their colleagues. In my experience, it is more realistic to look at the evidence and listen to what it is shouting at you.

    I don’t believe that climate change started as a scam. I insisted that for years when others disagreed. Now, the balance of evidence has tipped the other way and those who cling to alarmism have a position to protect.

    • fifty years ago, millions were spent on studying weather and some climate. They cranked that up to billions spent on promoting consensus “so called” “climate science” and now, more recently, trillions have been allocated and is being spent. To collect any of that great spending, following and promoting the consensus is required, to question it the great wealth is focused against you.

  61. Your abstract does not even begin to explain your argument. It just says read the 21 page paper.

    “Abstract:
    The paper explains why the physics involved in atmospheric and sub-surface heat transfer appears to have been misunderstood, and incorrectly applied, when postulating that a radiative “greenhouse effect” is responsible for warming the surfaces of planets such as Venus and our own Earth.

    A detailed discussion of the application of the Second Law of Thermodynamics endeavours to settle the much debated issue as to whether or not a thermal gradient evolves spontaneously in still air in a gravitational field. The author is aware of attempted rebuttals of this hypothesis, but cogent counter arguments are presented, together with reference to empirical evidence.

    The ramifications are substantial, in that they eliminate any need for any “greenhouse” explanation as to why the surface temperatures are as observed. No other valid reason appears plausible to explain how the required energy gets into the planetary surfaces, this being especially obvious in regard to the high temperatures measured at the surface of the crust of Venus.

    The paper includes some counter-intuitive concepts which sceptical readers may be tempted to reject out of hand. Physics sometimes has some surprises, and so you are encouraged to read and understand the argument step by step, for it is based on sound physics, and unlocks some mysteries of the Solar System, including core and mantle temperatures, not previously explained in this manner to the best of the author’s knowledge.”

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  63. The Earth’s mean surface temperature is 288K.
    There is not the above surface atmosphere’s a mean surface temperature.

    https://www.cristos-vournas.com

  64. “The balance sheet shows: Water-rich low clouds over the tropical ocean have the greatest cooling effect and low-water ice clouds at high altitudes have the strongest warming effect. Overall, the cooling effect is greater.”

    Obviously at night, low clouds cause the greatest surface warming, especially at higher latitudes.

    On climate forcing versus cloud cover, an increase in climate forcing equates to increased positive NAO/AO conditions, which drives a colder AMO and an increase in low cloud cover.
    According to the standard climate circulation models, the warm AMO from 1995 and associated decline in low cloud cover, in theory should not have happened as it relies on a net decline in total climate forcings.
    So then we have to understand why the AMO is normally warmer during a centennial solar minimum, and realise that cloud-driven tipping points are physically impossible.

  65. I did read it – and learned nothing. A waste of time.

  66. Pingback: Interview with climatologist Bjorn Stevens - Climate Discussion Nexus

  67. Why would you “replace the cloud feedback estimate given in the recent IPCC Sixth Assessment Report (AR6) with a zero estimate?”, when Stevens states, “The balance sheet shows: Water-rich low clouds over the tropical ocean have the greatest cooling effect and low-water ice clouds at high altitudes have the strongest warming effect. Overall, the cooling effect is greater.”

    While (earth & atmosphere) continue to receive the same amount of solar radiation annually, we know that the oceans collect and retain that radiation much more efficiently, gradually increasing the total energy in the (earth & atmosphere) system.

    However, we land dwellers, in agreement with Stevens research, can expect to see increasing cooling on the total land surface as the percentage of heat in the atmosphere compared to the land surface increases cloud cover. The distribution of heat over the oceans is therefore increasing compared to the land surface.

    ~ Earth’s “HVAC system” is shifting to a greater atmospheric (air) component to “CLOSE THE LOOP” compared to the ocean (water) component as the AMOC / Great Global Conveyor is slowing, according to Stevens statement.

  68. Call me crazy, but it seems to me that the following graph of the CERES data clearly shows that if the earth warms, the cloud cooling will increase.

    https://wattsupwiththat.com/wp-content/uploads/2021/09/scatterplot-cre-versus-temperature.png

    Almost everywhere that has an annual average that is warmer than ~ -10°C shows increasing cloud cooling with increasing temperature.

    Comments?

    w.

    • It is an effect of insolation, not of temperature. You just see it on temperature because of the close association between insolation and temperature, but it works only in one direction. Increasing the temperature without increasing the insolation should not a priori increase the cooling effect of CRE.

      Pukite (aka Webhubtelescope) is just an a**h*** that thinks he understands something about climate while playing with tidal effects on ENSO and AMO. As far as I remember he had to be kicked out of Climate Etc. for persistent bad behavior.

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