Earth’s Greenhouse Effect Has Not Been Enhanced, But Instead Its Impact Has Declined Since 1983

In the satellite era scientists have continued to observe the Earth’s total greenhouse effect (which includes effects from greenhouse gases and clouds) exerting an overall negative impact (cooling) on surface temperatures since the 1980s. This rules out both CO2 and an enhanced greenhouse effect as drivers of global warming.

Earth’s total greenhouse effect impact on climate is realized by the sum of all contributors to it: water vapor, clouds, and the “anthropogenic” greenhouse gases CO2 and CH4.

Given the modern assumption that humans are responsible for global warming due especially to our CO2 and CH4 emissions, it stands to reason that Earth’s downwelling longwave (LWdn) should be increasing and thus the Earth’s greenhouse effect should be enhanced due to the rising greenhouse gases emissions.

But, as Cess and Udelhofen (2003) reported 20 years ago, Earth’s greenhouse effect has not been enhanced in recent decades. Instead, it has been in a state of decline since the 1980s.

“[T]he negative trend in G [greenhouse effect] indicates that the atmospheric greenhouse effect is temporarily [1985-1999] decreasing despite the fact that greenhouse gasses are increasing.”

Image Source: Cess and Udelhofen, 2003

Song et al. (2016) also reported a flat (declining) greenhouse effect trend (shown in red) from 2002 to 2014 when all greenhouse effect factors (“all-sky”), including clouds and water vapor, are considered. The effects of greenhouse gases like CO2 were “offset” by the effects of clouds in producing the “zero-trend greenhouse effect” over this period.

Image Source: Song et al., 2016

A new study (Zhang and Rossow, 2023) employs another data set (FH) and also shows the total greenhouse effect (expressed as downward longwave, or LWdn) declining from 1983  to 2017 (and 2001 to 2020 in the CERES record) even though the data “account for increasing CO2 and CH4” and this “should produce an increase in LWdn”. It doesn’t, of course, as CO2 and CH4 are not influential enough to compete with the greenhouse effect of clouds.

“The LWdn [longwave net at TOA (W/m²)] shows a very large anomaly declining rapidly at the beginning of the record until the late 1990s. … The FH calculations (and previous versions) account for increasing CO2 and CH4 abundances, which should produce an increase in LWdn, all other things being equal; but as Fig 3…shows, the near surface air temperature (Ta) and skin temperatures (Ts) from ISCCP-H used in FH are generally decreasing. … [July 1983 to June 2017] overall downward trend in FH LWdn [longwave net at TOA (W/m²)]”

Image Source: Zhang and Rossow, 2023

The scientists also point out that trends in global mean albedo correspond to an “increase in surface solar radiation” since the 1980s (which can explain the warming over this period). Also, the W/m² trends in shortwave and longwave top-of-atmosphere fluxes are “dominated” by cloud cover changes or “caused almost entirely by cloud effects.”

Image Source: Zhang and Rossow, 2023

In recent years there have been several other studies documenting an observed decreasing greenhouse effect despite the increase in greenhouse gases like CO2 and CH4 (Stephens et al., 2022, Dübal Vahrenholt, 2021, Swift, 2018, Su et al., 2020). All of them note that natural cloud variations, which have a greenhouse effect impact larger than that resulting from a 100-fold increase in CO2 (Ramanathan et al., 1989), are driving the recent greenhouse effect decline, overriding the anthropogenic emissions impact.

Image Source: Stephens et al., 2022, Dübal Vahrenholt, 2021, Swift, 2018, Su et al., 2020

The clear implication of these observations is that an enhanced greenhouse effect has not been driving any warming trend since the 1980s.

Further, a decline in the greenhouse effect means the impact of human CO2 emissions on the global climate are too weak to be a driver of total greenhouse effect trends or climate change.

20 responses to “Earth’s Greenhouse Effect Has Not Been Enhanced, But Instead Its Impact Has Declined Since 1983”

  1. Scariest STORM Moments Ever Caught On Camera – Newsfeed Hasslefree Allsort

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  2. LOL@Klimate Katastrophe Kooks

    This is to be expected if one hews to the fundamental physical laws and the proper use of thermodynamics. The climastrologists most certain do not do that, they flip it on its head, misuse it to push a narrative, then twist it into new ‘forcing formulas’ to further push their narrative.

    There is a reason that high-DOF polyatomic CFC / HCFC / HFC molecules are used in AC units (to move more energy per unit of working fluid from evaporator to condenser), and there is a reason low-DOF monoatomics are used as a filler gas in dual-pane windows (to move as little energy as possible from one pane to the other).

    1) Let us assume one has an evaporator section of an AC unit. The working fluid consists of simple monoatomics and homonuclear diatomics, both of which have proportionally fewer DOF (Degrees of Freedom) and thus less ability to transit heat away from the evaporator to the condenser.

    With a constant input of energy, more of that energy would have to be removed via radiation, since less of it can be removed via conduction (ie: the working fluid gaining energy by contacting the surface of the evaporator section and gaining energy from it) / advection / convection / evaporation).

    2) Now let us assume that we add an increasing concentration of higher-DOF polyatomic molecules into this working fluid. Higher DOF means that molecular species can transit more energy than the lower-DOF monoatomics and homonuclear diatomics.

    The net result is that more energy is removed from the evaporator via conduction (ie: the working fluid gaining energy by contacting the surface of the evaporator section and gaining energy from it), thus less energy need be removed via radiation.

    3) Now let us assume that we introduce a literal refrigerant, a molecule with many DOF and thus high latent heat capacity. Much more energy is removed from the evaporator via conduction (ie: the working fluid gaining energy by contacting the surface of the evaporator section and gaining energy from it) / advection / convection / evaporation. Now even less energy need be removed via radiation.

    Case 1 above is akin to an Earthly atmosphere with only homonuclear diatomics (N2, O2) and monoatomics (Ar).

    Case 2 above is akin to the atmosphere in 1 but with an increasing CO2 concentration.

    Case 3 above is akin to the atmosphere in 2 but with H2O added. One can say that as regards water, we live, at the surface of the planet, in an analogy to the evaporator section of an AC unit.

    Think about it… monoatomics have no vibrational mode quantum states and thus cannot emit (nor absorb) IR. Homonuclear diatomics have a net-zero magnetic dipole and thus cannot emit (nor absorb) IR unless that dipole is perturbed via collision with other molecules or atoms.

    They can pick up energy via conduction by contacting the surface, just as the polyatomics can; they can convect just as the polyatomics can; but once in the upper atmosphere, they cannot as effectively radiatively emit that energy to space. And their high concentration dilutes the radiative polyatomics.

    In an atmosphere consisting of solely monoatomics and homonuclear diatomics, then, the upper atmosphere would warm… and the Kelvin-Helmholtz gravitational auto-compression which sets up the lapse rate would ensure that the surface would likewise warm.

    One can thus draw the conclusion that the higher the DOF (Degrees of Freedom) any particular molecular species has, the more it convectively (and advectively) transits energy from surface to upper atmosphere and radiatively emits it, whereas the fewer the DOF, the less it does so.

    Everything you’ve been told is upside-down and diametrically opposite to reality… water vapor and CO2 are not ‘heat trapping, global warming’ gases, they are net atmospheric radiative coolants which take a higher proportion of surface energy and convect / advect it away from the surface, then radiatively emit it in the upper atmosphere, where the net radiation vector is upwelling due to the air density / altitude / mean free path length relation.

    In fact, water acts as a literal *refrigerant* below the tropopause:

    The refrigeration cycle (Earth) [A/C system]:
    A liquid evaporates at the heat source (the surface) [in the evaporator], it is transported (convected) [via an A/C compressor], it gives up its energy to the heat sink and undergoes phase change (emits radiation in the upper atmosphere, the majority of which is upwelling owing to the mean free path length / altitude / air density relation) [in the condenser], it is transported (falls as rain or snow) [via that A/C compressor], and the cycle repeats.

    That’s kind of why, after all, the humid adiabatic lapse rate (~3.5 to ~6.5 K km-1) is lower than the dry adiabatic lapse rate (~9.81 K km-1). This alone should tell you that water is a coolant.

    You will note that the dry adiabatic lapse rate is largely due to the monoatomics (Ar) and homonuclear diatomics (N2, O2). This alone should tell you that the monoatomics and homonuclear diatomics are the actual ‘heat trapping, global warming’ gases.

    Fully ~76.2% of all surface energy is removed via convection / advection / evaporation. The more DOF the atmospheric molecules have, the more energy they can remove from the surface, leaving less needing to be radiated away. It is the monoatomics and the homonuclear diatomics which are really the ‘heat trapping, global warming’ gases… but the climastrologists can’t get a government-funded gravy train by removing N2 or O2 like they can for CO2, and the liberals can’t force you to live like you’re in the Dark Ages like they can for CO2.

    They might be able to do so for Ar, but removing all Ar from the atmosphere would only result in a cooling of less than 1K… and there’s an end-game at 0 ppm Ar concentration. With an increasing CO2 concentration and a few sleight-of-hand misuses of math, the liberals have a never-ending, always-impending climate doom to hang over society’s head to extort from society its treasure and its liberties.

    1. Richard Greene

      “water vapor and CO2 are not ‘heat trapping, global warming’ gases, they are net atmospheric radiative coolants”

      You are contradicting at least 99.9% of the scientists on our planet
      I would say 100%, but I am assuming a few scientists deny a greenhouse effect and that water vapor and CO2 are part of it. I have not actually found the 0.1% after 25 years of climate science reading, primarily reading the work of “skeptic” scientists and authors. William Happer and Richard Lindzen, for two examples, would not agree with you. But what do they know?

      You need t stop inb venting your own brand of science.

      1. LOL@Klimate Katastrophe Kooks

        My “brand” of science is taken directly from Thermal Physics, 2nd Edition by Philip M. Morse, Professor of Physics at MIT, co-founding editor of Annals of Physics, co-founder of MIT Acoustics Laboratory, first Director of Brookhaven National Laboratory, founder of MIT Computation Center.

        Read the paper in the link provided above and see how thermodynamics actually works, then you’ll understand just how the warmists have skewed science so much that even anti-CAGW people accept their warmist premises.

        Do remember that the warmist (and your) stance demonstrably violates several fundamental physical laws, whereas what I write of above hews to every single fundamental physical law.

        But then, you siding with the warmists isn’t anything new, right? LOL

        Remember this from CFACT?

        1. Richard Greene

          Do you spend your days inventing your own personal brand of science, contradicting almost every scientist in the world since the late 1800s about CO2, or does it just seem that way?

          1. LOL@Klimate Katastrophe Kooks

            Do you deny that the concepts taken from Thermal Physics, 2nd Edition by Philip M. Morse (Professor of Physics at MIT, co-founding editor of Annals of Physics, co-founder of MIT Acoustics Laboratory, first Director of Brookhaven National Laboratory, founder of MIT Computation Center) are mainstream physics done the proper way, or are you just incapable of understanding those concepts? Either way, it just seems that way.

            You were outed as a warmist-wannabe on CFACT long ago. You haven’t changed because you stubbornly insist upon remaining intentionally maleducated, Dick.



          2. LOL@Klimate Katastrophe Kooks

            Denial is not refutation. You have no refutation of what I’ve written of in the link above (, because there is no refutation of scientific reality.

            Although, I invite you to try your very, very best to refute scientific reality. LOL

            No, you revert to the standard warmist tactic of appealing to consensus. Same as you used to do on CFACT.


            While you’re at it, how about you address the fact that the warmist (and your) stance on radiative energy transfer demonstrably violates several fundamental physical laws. That alone would tell anyone with even a whit of common sense that it does not, cannot, reflect reality… but not you! No, sir, not you. LOL

  3. Richard Greene

    Nonsense, contradicted by CERES satellite data

  4. Tom Anderson

    Michel de Montaigne (1533-1592) said he preferred talking to peasants because they had not been educated to reason wrongly. Much is unchanged in the past half millennium. The foregoing commendable and sadly learned discussion of the targeted gases is ultimately misdirected and meaningless for dependence on an underlying artifact, belief or conceit for which there is no evidence, and, for those who give evidence weight, more than enough to the contrary. I suggest examining the underlying vehicle before trading in accessories

    And why analogize when there is ample direct evidence? NASA investigated, analyzed and recorded the Earth’s atmosphere for a decade and more, as it thins from the surface to the vacuum of space. Where in its record, “The U.S. Standard Atmosphere,” is there a hint of today’s cossetted, elaborate boondoggle, the “greenhouse”? It began as a grade-school teaching aid, an evasion of reality and responsibility from the start. It does not exist today except as an addictive cash cow.

    A review from times preceding today’s good-enough “science,” the “greenhouse” was definitively and decidedly repudiated and rejected. I submit at least R.W. Wood’s simple but very conclusive proof of the minimal effect of IR interactive atmospheric gases have in a microclimate. A brief review and unbiased consideration of this experiment ordinarily would clear the air (a pun worth risking) of this impressive, costly clutter. Wood’s dismissal of the idea was, if not the first, one of many sound rejections of a scientific and social “bad penny.” If scientists ever get past accounting for all the angels dancing on this pinhead, they would see neither pinhead nor angels.

  5. Al D

    Despite the detailed arguments and complicated math most people can’t comprehend, one thing stands out in my mind: the percentages of CO2 and methane in our atmosphere. CO2 amounts to 0.042% and methane amounts to 0.00017%. How can such a small amount of these trace gases have any more than a barely measurable impact on either warming or cooling? It’s not like these 2 gases are the only things on our atmosphere being warmed by the sun while everything else, which is far greater in volume, remains neutral.

  6. Neil McLachlan

    The Zhang and Rossow 2023 paper show clearly that down welling infra-red radiation has decreased since 1983 by as much as 4 watts per sq m.

    Warming by increasing CO2 and CH4 is dependent on down welling infra-red increasing. The warming of the planet during the satellite era cannot be CO2.

    Infra-red is not being absorbed by the ocean, it is going out to space.

    These are NASA GISS scientists. These are not climate deniers.

    My understanding from this paper is that the Earths Energy Imbalance is negative because of the large loss of infra-red radiation into space.

    1. LOL@Klimate Katastrophe Kooks

      That, again, is to be expected if one strictly follows the fundamental physical laws… 52% of solar insolation is infra-red.

      Thus, just as the NASA SABER project showed, CO2 absorbs and re-emits that IR solar insolation at the 14.98352 um waveband, and due to the mean free path length / altitude / air density relation, the majority of that emitted radiation is upwelling (mean free path length reduces exponentially with decreasing altitude, thus emitted radiation has a shorter downwelling mean free path length than an upwelling mean free path length, thus any downwelling radiation is ‘turned around’ to upwelling in short order, thus the net vector for that emitted radiation is upwelling). CO2 rejects that energy in the 14.98352 um waveband to space. An increasing atmospheric concentration of CO2 will reject that energy to space more effectively.

      With the near-surface mean free path length in the 14.98352 um band being a mere ~10.4 m, if “global warming due to CO2” were true, nearly all of the radiation causing that “global warming” would *have* *to* come from that ultra-thin layer of air within ~10.4 m of the surface, with ~90% of that coming from within ~1 m of the surface. Any radiation emitted at a higher altitude would be absorbed and re-emitted, and its net vector eventually turned to upwelling due to that mean free path length / altitude / air density relation. There is nearly no radiation in the 14.98352 um band from higher than ~10.4 m reaching the surface. The near-surface extinction depth is simply too short.

      One can use two methods to determine the extinction depth… one can treat 14.98352 um radiation as if it were a radio signal (convert wavelength to frequency) and calculate signal atmospheric attenuation; or one can go line-by-line through the 14.98352 um waveband (with ~1 um shoulders), then correlate that to the concentration of atmospheric molecules and their absorption cross-sections at that wavelength… both results are similar.

      No, the net result of CO2 absorbing radiation is an increase of CAPE (Convective Available Potential Energy), which increases convection… carrying with it the other coolant molecules such as water vapor. Convection is a surface-cooling phenomenon.

      The climastrologists and liberal politicians opted for the easiest lie to tell… an inversion of reality. Just flip everything on its head and vehemently lie your @ss off, doubling down on stupid when called out, which explains their never-ending, ever-escalating and increasingly idiotic hysteria.

      One needn’t invent new physics to explain the lie, and most people can’t tell the difference between reality and a flipped-causality lie.

      And now you know why it always seems that everything that comes out of a liberal’s mouth is diametrically opposite to reality… they’re not good liars (they’re not smart enough to invent plausible new physics concepts in order to bolster their lie), so they opt for the easiest-told type of lies… an inversion of reality… because most people aren’t smart enough to figure out the lie… a sad state of affairs due to the decades of dumbing-down and infantilization of society.

  7. LOL@Klimate Katastrophe Kooks

    If one wants to see just how ludicrous all this hullabaloo over radiative warming of Earth’s surface is, look below.

    Convection / advection / evaporation remove ~76.2% of all surface energy, emitting it at TOA. Radiation is a bit player in surface cooling… and the only way the warmists can give it a larger part is to misuse the S-B equation, using the form meant for idealized blackbody objects (which assumes emission to 0 K and (usually) emissivity of 1) upon the graybody planet… which isolates all objects into their own systems so they cannot interact via the ambient EM field, and thus because they calculate for emission to 0 K, that inflates radiant exitance of all objects, which the warmists must carry through their calculations and subtract on the back end to get their equations to balance… subtracting a wholly-fictive ‘cooler to warmer’ energy flow from the real (but too high because it was calculated for emission to 0 K) ‘warmer to cooler’ energy flow.

    That’s not how thermodynamics works… radiant exitance of the warmer object is predicated upon the energy density gradient between the objects. The cooler object will not emit toward the warmer object because energy does not spontaneously flow up an energy density gradient (2LoT). So yes, the photons “know” the temperature of the target object via that ambient EM field.

    This is how thermodynamics actually works:
    … that used to be taught in universities, and they made clear that the use of the idealized blackbody form of the S-B equation was merely to make the calculations easier… nowadays that knowledge is apparently lost, and the warmists believe energy can spontaneously flow up an energy density gradient in violation of Stefan’s Law and 2LoT in the Clausius Statement sense.

    IOW, the entire CAGW charade is hinged upon a misuse of the S-B equation and sleight-of-hand trickery as regards the fundamental physical laws.


    Radius: 6371000 m
    Density: 5513 kg m-3
    M: 60 gm
    Original Temperature: 288 K
    Emissivity: 0.93643 (per NASA CCCP program)
    Final Temperature: 287 K

    You’ll see that for the average temperature of Earth to decrease by 1K (288 K to 287 K) via surface radiative cooling requires 6708315387.893939 seconds (212.719 years). That’s a lot of thermal mass.

    That’s a grand total of 0.4701031 K / century… if the warmists are claiming the planet’s average temperature is changing at a rate faster than that, you know they’re lying, especially in light of the fact that surface radiation is a bit player, and that convection / advection / evaporation are surface-cooling phenomena acting to reduce any surface warming. The amount of energy necessary to move the temperature needle on that amount of mass is off the scales. Anything else is natural fluctuation, likely due to the ocean conveyor.

  8. tita

    This article is really amazing. .Thank you for sharing 546 GTU


    […] the 1980s. This rules out both CO2 and an enhanced greenhouse effect as drivers of global warming. (Read more) […]

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