Sunday, November 9, 2014

Why global warming is not explained by a change in "effective radiating level"

Having abandoned "back-radiation" from greenhouse gases as the explanation of the greenhouse effect, many claim global warming is instead due to an increase of the "effective radiating height" or "effective radiating level" [ERL] of greenhouse gases in the atmosphere. So the theory goes, an increase of CO2 levels will cause longwave infrared emissions from CO2 to be from colder heights in the atmosphere, and since colder bodies emit less radiation, more radiation will allegedly be "trapped" by colder CO2 in the fabled tropospheric "hot spot" & unable to escape to space. 

Let's examine whether this theory holds water, since there are no observations finding either the "hot spot" or an increase of the "effective radiating level" over the satellite era as predicted by the theory.

First, the theory summarized from slides from a climate science course at the University of Wisconsin:

And now multiple reasons why the theory does not hold water:

2. The location of the ERL at ~5.5km in the tropics is part of the fabled mid-upper tropospheric "hot spot" region, which climate models predict will warm the fastest from AGW. Thus, an increase in height of the ERL would be offset by alleged warming from AGW in this same region of the atmosphere, countering the assumption that the increased height of the ERL would be colder and emit less radiation. Further, radiosonde observations show no evidence of the "hot spot" predicted by the models, and very slight warming of this region of the tropical troposphere since 1958:

Open symbols show no relationship between tropopause height and troposphere temperatures

4. Climate scientists assume the greenhouse gases CO2 and water vapor behave as true blackbodies and that the blackbody laws of Stefan-Boltzmann, Kirchhoff, and Planck can be applied to their radiative characteristics in the atmosphere. Measurements and a recent paper show this assumption is false, and that CO2 and water vapor emissivities behave the opposite of blackbodies, decreasing with temperature. The greenhouse effect models also make this same false assumption that CO2 and water vapor act as true blackbodies. Gases have distinct emission lines and do not follow a Planck curve of radiative emissions as all true blackbodies do. 

5. Even if we assume CO2 does act as a blackbody and use the physical laws only applicable to blackbodies including Wien's Displacement Law, we find that at the peak emission line of CO2 at 15 microns, the equivalent blackbody temperature is -80C or 193K:

Therefore, the "blackbody" CO2 emits at a blackbody temperature of -80C or 193K, which is far colder than any portion of the troposphere, tropopause, or stratosphere as shown on the atmospheric temperature profile graph above. Changing the ERL does not change the "blackbody" emission temperature of CO2 one iota; CO2 emits at 15 microns/-80C no matter where it is located in the atmosphere. Thus, the notion that more CO2 can change the emissivity and emission temperature of CO2 is false and increases in ERL/CO2 levels cannot explain an increased greenhouse effect.

6. Even if an increased ERL could increase CO2 radiative forcing (already disproven above), it makes little difference to the troposphere since convection dominates over radiation in the troposphere and acts as a negative feedback that "short-circuits" radiative forcing from CO2.

7. Increased CO2 increases the radiative surface area of the atmosphere which increases the ability to radiatively cool, analogous to a bigger heat sink on your microprocessor. Warmists, however, don't agree on why increased CO2 allegedly cools the stratosphere but warms the troposphere.

Modeling shows CO2 is the primary cooling agent of the stratosphere, and has a slight cooling effect on the troposphere as well

Another model demonstrating that CO2 acts as a cooling agent throughout the entire troposphere and stratosphere, and as an alleged heating agent only at the tropopause near 15 km. and states, 
“NOTE: CO2 has very small radiative heating rates. Radiation emitted at one level is absorbed at nearby level having almost the same temperature. Only at the tropopause (near 15 km), where the temperature profile has a minimum, there is a small amount of heating. At higher altitudes, pressure broadening is much weaker allowing emitted radiation to escape to space with little compensating radiation downward from higher levels.” Fig 12.1 also shows H2O acts as a cooling agent throughout the troposphere, tropopause, and stratosphere. [note these model results are also found in the lecture notes of Dr. Irina N. Sokolik, Climate Science Professor in Judy Curry’s Dept. at Georgia Tech]

8. The ERL theory predicts a decrease of outgoing longwave radiation [OLR] from increased greenhouse gases, however, observations show the opposite of an increase of OLR over the past 62 years. 

9. The real 33C atmospheric greenhouse effect is instead entirely explainable on the basis of atmospheric mass/gravity/heat capacity/adiabatic lapse rate, and the "ocean greenhouse effect" explainable on the basis of the  ~0.76 - 0.89 far-IR emissivity of the oceans, which "traps" heat from solar radiation in the oceans.


  1. Wein's Law

    Physicists know very well that Wein's so-called law is an approximation that works well for short wavelengths and not so well for long wavelengths.

    If I recall correctly, the mismatch between "Wein's Approximation" and observations is what inspired Max Planck.

    So yes, since NASA have estimated the energy imbalance to be 0.5 Wm-2 out of a total incoming of 340 Wm-2, we might expect Wein;s Approximation to fail in estimating correctly the intensity of long wave radiation.

    The classical method of Goody and Yung is an elegant but blunt instrument for detecting an energy imbalance that is 0.15% of the total incoming energy.

    Absurd that anyone should think otherwise. You are attacking what is in reality a straw-man (Wein's Law that is not a "law" but an approximation).

    Unfortunately climate scientists don't seem to know enough physics to know that they have put up a straw-man.

    1. As I point out above, CO2 is not a black body and the physical laws that apply to black bodies including Wien's Law do not apply to non-black-bodies such as CO2. I am simply showing via climate scientists false assumptions that CO2 is a black body that CO2's peak emission at 15 microns corresponds to a black body temperature of -80C no matter where a CO2 molecule is located in the atmosphere and regardless of any change in "effective radiating height"

    2. It doesn't matter if it's a law or an approximation, it doesn't matter if 15µm is exactly -80ºC or approximately -80ºC, point being made is the same. Energy from 15µm radiation does not have sufficient flux to heat anything in the troposphere.

      To claim this point is a straw-man is highly misleading to say the least.

      Considering that the phase change temperature of CO2 in our atmosphere is also -80ºC I would say that -80ºC is likely, a very close approximation for the source temperature of CO2 emitting 15µm radiation.

  2. The "ERL" argument is no different from the "heating from back radiation" argument. It is only the latter one in a different, more vague, plausible/sciency-looking guise. The actual mechanism behind the surface warming ends up being exactly the same: the magical, internal self-amplifying flux loop of the rGHE:

  3. HS,

    Your point 3. is very interesting. Thanks for the link :)

    1. You're welcome, and here's a shout-out to your new post:

      The greenhouse effect that wasn’t (Part 1)

    2. I'm not sure about point 3.

      I know that there is a direct correlation between the ERL of -18ºC and the average temperature of the troposphere, as can clearly be seen, season to season, in the radiosonde data.

  4. A good absorber is also a good radiator so more CO2 effectively increases absorption band emissivity which increase the efficiency of radiation in those bands. The true heat trapping gasses are the non greenhouse gases that are very inefficient LWIR absorption band radiators. For those that believe the greenhouse gas theory, H2O is the primary greenhouse gas and it provides ample negative feedbacks to changes in other greenhouse gases so as to mitigate any effect they might have on climate. Besides being a greenhouse gas, H2O is a major coolant in the Earth's atmosphere moving heat energy from the Earth's surface to where clouds form via the heat of vaporization. More heat is moved by H2O vis the heat of vaporization then by both convection and LWIR absorption band radiation combined. In LWIR absorption bands, the clear atmosphere is of such low emissivity that the true radiation comes from much lower in the atmosphere and at significantly higher temperature. The AGW models simply ignore a lot of what actually happens in the Earth's atmosphere. How much does the lapse rate depend on CO2's LWIR absorption bands?

  5. "How much does the lapse rate depend on CO2's LWIR absorption bands?"


    Lapse rate dT/dh = -g/Cp, and gravity & Cp = heat capacity at constant pressure are independent of radiative forcing


    nielszoo says:
    November 10, 2014 at 7:02 pm



    mkelly says:
    November 10, 2014 at 9:11 pm


  7. Robinson & Catling paper on radiative-convective equilibrium: