A ‘Nearly Zero’ Climate Sensitivity Paper Finds A 16-Fold CO2 Increase Cools Earth Below Pre-Industrial Temperatures

In yet another new paper (Drotos et al., 2020), scientists determine the climate sensitivity to CO2 is “practically zero” the more the concentration rises. A ~4450 ppm CO2 concentration has cooler climates than observed in the pre-industrial (278 ppm) era. Why? A self-amplifying cloud feedback mechanism cools the Earth by magnitudes “as large as 10 K” upon warming saturation.

Earlier this year, scientists published a paper using mesocosms (controlled outdoor experiments) to demonstrate CO2 concentrations of 3200, 7500, and 16,900 ppm are associated with colder temperatures than in outdoor environments with 480 ppm CO2 concentrations.

Now, in another new paper (Drotos et al., 2020), several more scientists are asserting the Earth system has an internal, self-amplifying negative cloud feedback mechanism so powerful that

“at CO2 concentrations beyond four times the preindustrial value, the climate sensitivity decreases to nearly zero as a result of episodic global cooling events as large as 10 K”.

The cooling events spawned by the high CO2 concentrations lead to temperature “drops below the coldest values of the control [278 ppm pre-industrial CO2]” such that the climate sensitivity to CO2 doublings is “practically zero” over time.

“In particular, the climatological mean value of the global mean surface temperature practically stops responding to an increase in the CO2 concentration. This practically zero climate sensitivity suggests that the effect of a feedback on the global mean surface temperature may turn out to be as strong as the radiative effect of CO2.”

In other words, scientists have found yet another way the claimed “runaway greenhouse” response of the climate system to elevated CO2 turns out to be a false alarm.

Image Source: Drotos et al., 2020

22 responses to “A ‘Nearly Zero’ Climate Sensitivity Paper Finds A 16-Fold CO2 Increase Cools Earth Below Pre-Industrial Temperatures”

  1. A ‘Nearly Zero’ Climate Sensitivity Paper Finds A 16-Fold CO2 Increase Cools Earth Below Pre-Industrial Temperatures — NoTricksZone - Climate- Science.press

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  2. Stephen Richards

    I saw a thought experiment published on a sceptic site a few years ago and it made sense.

    If you have a tube of co². The tube is non absorbent to infra-red light so only the gas reacts. You place an infra-red source at one end and an infrared detector at the other.

    What will the thermometer read. Will it show a higher energy than the emitter, a lower energy than the emitter or will the detected energy be the same as the emitter.

  3. RickWill

    We are often reminded that water vapour is the most powerful “greenhouse gas”. We are also advised that the presence of CO2 in the atmosphere provides a positive feedback loop by increasing the amount of water vapour.

    So this begs the question why is CO2 needed to provide the positive feedback when water vapour is the most powerful. Water vapour alone would provide the positive feedback.

    Anyhow simple evaluation of the satellite data demonstrates that water vapour and global heat loss are positively correlated; meaning the feedback is negative:

    Climate might be changing but it is not due to “greenhouse gasses” – the whole story is a fairy tale for gullible adults.

    1. Stephen Richards

      It’s the other way round, Rick. They believe that water vapour enhances the co² effect. They do this because they know that even the most serious numpty would not believe that 0.04% of anything could affect the whole.

      1. David Appell

        Stephen: In the ozone layer of Earth’s atmosphere, its concentration is about 5 ppm. But without it we’d all be dead.

  4. rusty

    This paper seems to accept and use as a starting point that increasing co2 causes temps to significantly rise in the first place. But still, they make a point.

  5. RoHa

    But we are still doomed, aren’t we?

  6. Ari Okkonen

    This result explains why I did’n find any effect of recent CO2 increase in North-Atlantic sea surface temperature. https://www.researchgate.net/publication/339274895_Increasing_Carbon_Dioxide_Concentration_in_Atmosphere_Has_Negligible_Effect_on_North_Atlantic_Sea_Surface_Temperature

    1. Jeremy Poynton

      Plummeting it seems, from a paper featured here a few days back.

      Oddly not reported by the BBC…


      “From 2008 to 2016 a widespread cooling ranging from 0.6°C to more than 2.0°C has chilled effectively the entire oceanic region from E. Canada to N. Iceland to S. Europe. The cooling persists year-round and extends from the surface down to depths of 800 m.”

    2. David Appell

      Ari, using a long-term trend is only justified if the causative factors don’t change much over the time period. In this case, 1856-present, the causative factors certainly *have* changed — in particular, CO2’s forcing was hardly present since about 1950 and really not since about 1975.

      Still, the total warming of your trend is about +0.7 C. Where did that come from?

      Using HadSST3’s global SST data, their total warming since 1850 is +0.76 C. But over the last 30 years, when CO2 forcing has been strong and getting stronger, warming has been +0.42 C. The 10-yr change in their 10-yr moving average is +0.13 C.

      HadSST3 source (monthly):

  7. Lloyd Martin Hendaye

    We say again, from July 13, 2019 (Sat): Regardless of myriad other factors, Finnish researchers focusing on planetary “cloud cover” as a proxy for total solar irradiance (TSI) have confirmed Australian Robert Holmes’ December 2017 equation deriving all planets’ global atmospheric surface temperature (GAST) T = PM/Rp (Atmospheric Pressure P x Mean Molar Mass M / Density R x Gas Constant p), his peer-reviewed Mean Molar Mass version of the Ideal Gas Law.

    On this basis, given that human activity can account for no more than a .01°C rise in global temperatures per century, no human (industrial) activity targeted by radical climate-change alarmists –airline flights, combustion engines, “fossil fuel” (sic) emissions of any nature whatsoever– has any measurable impact on Earth’s temperature.

  8. Steve C

    I recall reading somewhere a few years ago that atmospheric CO2 levels increased slightly just before the ends of previous interglacials. This result would seem to support that as being a valid observation, and if it is so then maybe we sceptics should suddenly realise the urgency of reducing CO2 levels …

  9. drumphish

    The coronavirus causes a shutdown of China’s manufacturing base, the power plant carbon emissions are reduced due to the almost complete halt of economic activity, there has to be some kind of effect on the weather.

    After the three weeks of nobody really working at the factories in and around Wuhan, the last ten days of February were indeed warmer than normal winter temps for the middle of the NA continent where I am.

    Probably just a coincidence, not caused, however, it is worth noting.

  10. A ‘Nearly Zero’ Climate Sensitivity Paper Finds A 16-Fold CO2 Increase Cools Earth Below Pre-Industrial Temperatures – Truth is difficult but essential…
  11. Jeremy Poynton

    Warming before cooling. And yes, the only thing climatewise we know for sure is at some point in the future, Manhattan will be covered in 2 miles of ice again. And we fret about a bit more warmth.

    1. David Appell

      How can you be sure of that? The Pleistocene ice ages are a very short period in Earth’s history. It’s not known why they started (AFAIK), so how can it be known if they will continue after the Anthropocene?

  12. David Appell

    RickWill wrote:
    So this begs the question why is CO2 needed to provide the positive feedback when water vapour is the most powerful. Water vapour alone would provide the positive feedback.

    Because water vapor is condensable — put more into the atmosphere and it quickly precipitates out. The amount of water vapor in the atmosphere can’t change unless the temperature first changes (see the Clausius-Claperyon equation). It’s CO2 (or some other primary forcing causing warming or cooling) that provides that initial temperature change. Only then is water vapor a feedback (and a strong one); its amount changes by about 7% for every one degree of warming or cooling.

  13. rw

    It’s worth noting that this paper is another modeling exercise. So, who knows?

    1. David Appell

      Every conclusion in science comes from a model. Without exception.

      “Without models, there are no data.”
      – Paul N. Edwards, “A Vast Machine”

      1. Dennisa

        In praise of re-writing history to suit the paradigm.

        1. David Appell

          You completely missed the point of that remark. Whoosh.

  14. CO2 Now Shown To Cause COOLING Rather Than Warming of Climate - Randy Salars News And Comment

    […] notrickszone.com/2020/03/05/a-ne…peratures/ […]

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