3 Atmospheric Scientists: Greenhouse Effect
Based On ‘Physically Irrelevant Assumptions’
Dr. Gerhard Kramm Dr. Nicole Mölders
Yet another new scientific paper has been published that questions the current understanding of the Earth’s globally averaged surface temperature and its relation to the theoretical greenhouse effect.
Perhaps the most fundamental equation in climate science is the “thought experiment” that envisions what the temperature of the Earth would be if it had no atmosphere (or greenhouse gases).
Simplistically, the globally averaged surface temperature is assumed to be 288 K. In the “thought experiment”, an imaginary Earth that has no atmosphere (or greenhouse gases to absorb and re-emit the surface heat) would have a temperature of 255 K. The difference between the real and imagined Earth with no atmosphere is 33 K, meaning that the Earth would be much colder (and uninhabitable) without the presence of greenhouse gases. Of that 33 K, it is assumed that CO2 concentrations in range of 200 – 280 ppm (the pre-industrial ranges for the last 800,000 years) contribute 7.2 K (~20%), while water vapor concentrations (ranging between about 1,000 to 40,000 ppm for the globe) contribute 20.6 K to the 33 K greenhouse effect.
“The size of the greenhouse effect is often estimated as being the difference between the actual global surface temperature and the temperature the planet would be without any atmospheric absorption, but with exactly the same planetary albedo, around 33°C. This is more of a “thought experiment” than an observable state, but it is a useful baseline.”
Atmospheric scientists Dr. Gerhard Kramm, Dr. Ralph Dlugi, and Dr. Nicole Mölders have just published a paper in the journal Natural Science that exposes the physical and observational shortcomings of the widely-accepted 288 K – 255 K = 33 K greenhouse effect equation. They conclude that this “though experiment” is “based on physically irrelevant assumptions and its results considerably disagree with observations“.
The scientists offer a new approach to gauging the Earth’s surface temperature(s), and their results are significantly at variance with the 288 K – 255 K = 33 K “thought experiment”. For their calculations, they use observational measurements for the moon — which actually does not have an atmosphere — as their “testbed”. Using moon data would appear to yield more reliable results than an imaginary-world Earth with no atmosphere.
The following is a very abbreviated summary of these scientists’ conclusions about calculating Earth’s mean temperatures.
Kramm et al., 2017
The planetary radiation balance plays a prominent role in quantifying the effect of the terrestrial atmosphere (spuriously called the atmospheric greenhouse effect). Based on this planetary radiation balance, the effective radiation temperature of the Earth in the absence of its atmosphere of Te ≅ 255 K is estimated. This temperature value is subtracted from the globally averaged near-surface temperature of about ⟨Tns⟩ ≅ 288 K resulting in ⟨Tns⟩ − Te ≅ 33 K. This temperature difference commonly serves to quantify the atmospheric effect. The temperature difference is said to be bridged by optically active gaseous gases, namely H2O (20.6 K); CO2 (7.2 K); N2O (1.4 K);CH4 (0.8 K); O3 (2.4 K); NH3+freons+NO2+CCl4+O2+N2NH3+freons+NO2+CCl4+O2+N2 (0.8 K) (e.g. Kondratyev and Moskalenko, 1984).
Since the “thought experiment” of an Earth in the absence of its atmosphere does not allow any rigorous assessment of such results, we considered the Moon as a testbed for the Earth in the absence of its atmosphere. […] Based on our findings, we may conclude that the effective radiation temperature yields flawed results when used for quantifying the so-called atmospheric greenhouse effect. The results of our prediction of the slab (or skin) temperature of the Moon exhibit that drastically different temperature distributions are possible even if the global energy budget is identical. These different temperature distributions yield different globally averaged slab temperatures. […] These [“drastically different temperature distributions” using the same global energy budget parameters, described in detail in the paper] values demonstrate that the power law of Stefan and Boltzmann provides inappropriate results when applied to globally averaged skin temperatures.
It is well known from physics that the mean temperature of a system is the mean of the size-weighted temperatures of its sub-systems. Temperature is an intensive quantity. It is not conserved. On the contrary, energy is an extensive quantity. Energies are additive and governed by a conservation law. Thus, one has to conclude that concept of the effective radiation temperature oversimplifies the physical processes as it ignores the impact of local temperatures on the fluxes in the planetary radiative balance.
Instead of focusing on the technicalities of these authors’ Earth-temperature calculations using moon data, it’s important to call attention to the 5-point critique of the 288 K – 255 K = 33 K greenhouse effect equation outlined in the introduction to the Kramm et al. (2017) paper. The very first criticism listed is, by itself, worth expounding upon in detail. Here it is:
(1) “Only a planetary radiation budget of the Earth in the absence of an atmosphere is considered, i.e., any heat storage in the oceans (if at all existing in such a case) and land masses is neglected.”
This is crucial. Not only is the heating contribution of the water vapor-and-CO2 greenhouse effect viewed as a “thought experiment” because it uses an imaginary world without an atmosphere as its premise, the 288 K – 255 K = 33 K greenhouse effect equation only considers a radiation budget analysis that pertains to atmospheric heating, not ocean heating. This is theoretical negligence, as it is tantamount to claiming that we should measure the temperature of a person’s spit to accurately determine his overall body temperature.
According to the IPCC (citing Levitus et al., 2012), 93% of the Earth’s heat energy resides in the oceans. The atmosphere hosts just 1% of the Earth’s heat energy “trapped” by greenhouse gases. To be physically meaningful, then, the Earth’s energy budget and “mean global temperature” should be calculated by featuring measurements for the thousands-of-meters-deep oceans, and not the atmosphere vs. no-atmosphere conceptualization
Furthermore, it is essential to consider that the heat flux for the Earth’s climate system nearly always goes from ocean to atmosphere, and not the other way around. The atmosphere does not warm the oceans; the oceans warm the atmosphere.
Ellsaesser, 1984 : “…the atmosphere cannot warm until the oceans do“
Murray et al., 2000 : “…net surface heat flux is almost always from ocean to atmosphere“
Minnett et al., 2011 : “…the heat flux is nearly always from the ocean to the atmosphere“
And because the direction of the heat flux is from ocean to atmosphere, for greenhouse gases like water vapor and CO2 to warm the atmosphere by 33 K, they necessarily must heat the oceans by that equivalent first. In other words, for the Earth’s theoretical greenhouse effect to “work”, downwelling longwave infrared radiation (LWIR) from water vapor and CO2 must be fundamental players in heating the Earth’s oceans to depths of thousands of meters.
An unheralded problem with this conceptualization arises: We have no physical measurements from a real-world scientific experiment that identify how much, if at all, parts per million (0.000001) increases (or decreases) in atmospheric CO2 concentrations heat (or cool) water bodies.
Even the anthropogenic global warming (AGW) advocacy blogs RealClimate.org and SkepticalScience.com acknowledge that we have no real-world evidence identifying the extent to which heat changes occur in water bodies when CO2 concentrations are varied in volumes of +/-0.000001 above them. We have to use proxy evidence from clouds instead.
RealClimate.org : “Clearly it is not possible to alter the concentration of greenhouse gases in a controlled experiment at sea to study the response of the skin-layer. Instead we use the natural variations in clouds to modulate the incident infrared radiation at the sea surface.”
SkepticalScience.com : “Obviously, it’s not possible to manipulate the concentration of CO2 in the air to carry out real world experiments, but natural changes in cloud cover provide an opportunity to test the principle [that CO2 heats water].”
And the problem with using clouds as a proxy for CO2 is that even very small (1%) cloud cover variations can quite easily overwhelm and supersede the greenhouse effect associated with changes in CO2 concentrations due to the magnitude and dominance of cloud LWIR forcing.
Ramanathan et al. (1989) : “The greenhouse effect of clouds may be larger than that resulting from a hundredfold increase in the CO2 concentration of the atmosphere.”
RealClimate.org : “Of course the range of net infrared forcing caused by changing cloud conditions (~100 W/m2) is much greater than that caused by increasing levels of greenhouse gases (e.g. doubling pre-industrial CO2 levels will increase the net forcing by ~4 W/m2)”
Using clouds as a proxy for CO2 in assessing how CO2 concentration changes affect water temperatures is therefore not comparing apples to apples in calculating their radiative significance, and thus any experimental results using clouds can not be generalized or assumed to simulate the heating effects of CO2 when varied over water bodies.
So we are left with an equation (288 K – 255 K = 33 K) that (a) is based upon a “thought experiment” using an imaginary world without an atmosphere; (b) claims to measure Earth’s temperatures, but doesn’t consider the temperatures of the Earth’s oceans as its primary parameter; and (c) assumes ppm changes in CO2 concentrations heat or cool water bodies to a measurable degree when raised or lowered even though no physical measurements from a real-world scientific experiment exists to support such a claim.
And this is just point (1) in the Kramm et al. (2017) critique of the 288 K – 255 K = 33 K greenhouse effect equation. Four other criticisms of the “inadequate” equation are also listed below.
As these three atmospheric scientists conclude, the 288 K – 255 K = 33 K equation underlying the theoretical greenhouse effect “lacks adequate physical meaning as do any contributions from optically active gaseous components calculated thereby“.
Kramm et al. (2017) critical analysis of the 288 K – 255 K = 33 K greenhouse effect “thought experiment” (here referred to as Equation 1.4):
Kramm et al., 2017
(1) Only a planetary radiation budget of the Earth in the absence of an atmosphere is considered, i.e., any heat storage in the oceans (if at all existing in such a case) and land masses is neglected.
(2) The assumption of a uniform surface temperature for the entire globe is rather inadequate. As shown by Kramm and Dlugi (2010), this assumption is required by the application of the power law of Stefan (1879) and Boltzmann (1884) because this power law is determined by (a) integrating Planck (1901) blackbody radiation law, for instance, over all wavelengths ranging from zero to infinity, and (b) integrating the isotropic emission of radiant energy by a small spot of the surface into the adjacent half space (e.g., Liou, 2002, Kramm and Molders, 2009). These physical and mathematical reasons do not justify applying the Stefan-Boltzmann power law to a statistical quantity like ⟨Tns⟩ [globally averaged near surface temperature]. Even in the real situation of an Earth with atmosphere, (near-)surface temperatures vary notably from the equator to the poles owing to the varying solar insolation at the top of the atmosphere and from daytime to nighttime. Consequently, the assumption of a uniform surface temperature is inadequate. Our Moon, for instance, nearly satisfies the requirements of a planet without atmosphere. It has a non-uniform surface temperature distribution with strong variation from lunar day to lunar night, and from its equator to its poles (e.g., Cremers et al., 1971, Vasavada et al., 2012). Furthermore, ignoring heat storage would yield a Moon surface temperature during lunar night of 0 K (or 2.7 K, the temperature of the space).
(3) The choice of the planetary albedo of αE=0.30 is rather inadequate. This value is based on satellite observations. Hence, it contains not only the albedo of the Earth’s surface, but also the back scattering of solar radiation by molecules (Rayleigh scattering), cloud and aerosol particles (Lorenz-Mie scattering). Budyko (1977) already stated that in the absence of an atmosphere the planetary albedo cannot be equal to the actual value of αE = 0.33 (at that time [1977], but today αE=0.30). He assumed that prior to the origin of the atmosphere, the Earth’s albedo was lower and probably differed very little from the Moon’s albedo, which is equal to αM=0.07 (at that time [1977], but today αM=0.12). A planetary surface albedo of the Earth of about αE=0.07 is also suggested by the results of Trenberth et al., 2009. Thus, assuming a planetary albedo of αE=0.07 and a planetary emissivity of εM=1εM=1 (black body) in Equation (1.4) yields Te ≅ 273.6 K. For αE=0.12 and εM=1εM=1 , one obtains: Te ≅ 270 K. Haltiner and Martin (1957) explained the so-called atmospheric greenhouse effect by the difference between the Moon’s surface temperature at radiative equilibrium and the globally averaged near-surface temperature of the Earth. They argued that the mean surface temperature of the Moon must satisfy the condition of radiative equilibrium so that Te ≅ 266 K.
(4) Comparing Te [Earth’s temperature without an atmosphere] with ⟨Tns⟩ [Earth’s globally averaged near surface temperature] is rather inappropriate because the meaning of these temperatures is quite different. The former is based on an energy-flux budget at the surface even though it is physically inconsistent because of the non-uniform temperature distribution on the globe. Whereas the latter is related to globally averaging near-surface temperature observations made at meteorological stations (supported by satellite observations).
(5) The Moon’s mean disk temperature of about 213 K retrieved at 2.77 cm wavelength by Monstein (2001) is much lower than Te ≅ 270 K which can be derived with the Moon’s planetary albedo of αM = 0.12. Even though the Moon’s mean disk temperature observed in 1948 by Piddington and Minnett (1949) is about 26 K higher than that of Monstein (2001), it is still 31 K lower than Te ≅ 270 K . Despite the Moon is nearly a perfect example of a planet without atmosphere, some authors argued that Equations (1.3) and (1.4) are only valid for fast-rotating planets so that the Moon must be excluded. Other authors, however, applied these equations for Venus that rotates a factor of four slower than the Moon. Pierrehumber (2011), for instance, used Equation (1.4) to calculate the temperature of the planetary radiative equilibrium for Venus. With αV=0.75α and εV = 1εV = 1 , he obtained Te ≅ 231 K. Choosing αV = 0.12α for the Venus in the absence of its atmosphere (which is similar to that of the Moon) yields Te≅317 K and for αV = 0.90 as listed in NASA’s Venus Fact Sheet Te ≅ 184 K.
(Equation 1.4) is based on physically irrelevant assumptions and its results considerably disagree with observations. Consequently, the difference of ΔTae ≅ 33 K [the alleged planetary temperature difference with the greenhouse effect] lacks adequate physical meaning as do any contributions from optically active gaseous components calculated thereby.
via NoTricksZone
September 25, 2017 at 08:50AM
Iowa Climate Science Education 