I was curious. So, I carefully reviewed it.
The paper is a nice collection of many of the arguments circulating among those skeptical of the atmospheric Greenhouse Effect. I appreciate the work Terigi Ciccone has done gathering, integrating, and presenting information to support greater understanding of concerns about climate science.
Unfortunately, the whitepaper:
- reflects multiple misunderstandings about thermodynamics and thermal radiation;
- offers data that is frequently wrong, misinterpreted, or questionable;
- frequently relies on appeals to the logical fallacy of Argument from Incredulity, and seems committed to the provably false belief that “small” things can’t have significant impacts;
- refutes straw-man misinterpretations of mainstream climate science;
- presents hypothesis, theories, and claims that do not stand up to scrutiny, in light of significant contrary evidence and/or flawed logic;
- assumes without evidence that others have not taken into account things that TC is concerned about.
If all the seriously flawed arguments and information were taken out, regrettably, I don’t think there would be much content of interest left over. I wish I could say otherwise.
I’ve addressed each section of the whitepaper on a point-by-point basis (in a downloadable PDF document), offering analysis and relevant references. You are welcome to consider my information and his, and come to your own conclusions.
My conclusion is that, no, I don’t think Terigi Ciccone (who I’ll refer to as TC for short) has made a compelling case that CO₂ and the Greenhouse Effect can’t cause global warming.
I’ve done my best to give serious consideration to everything TC offered, and I’ve prepared an extravagantly thorough and (I hope) respectful response.
Overview of Main Points
- Stefan-Boltzmann Constant. TC reports on an assertion that the generally-accepted value of the Stefan-Boltzmann constant which sets the scale of thermal radiation is around 40 times too large.
However, the SB constant has been applied and verified on a continual ongoing basis for over a century, by countless engineers and scientists. It’s one of the fundamental constants of nature and is at the heart of modern physics, thermal engineering, and many industrial processes. It is considered so fundamental to physics that it is now built into the SI system of units, and one couldn’t change the value of the SB constant without changing the temperature scale itself.
It’s hard to imagine that for over a century nobody would have noticed if the SB constant was off by a factor of 40. Observations of Earth’s thermal emission spectrum from space are not consistent with the idea of a smaller value for the SB constant.
- No verifiable numbers. TC asserts that there are no verifiable numbers for any thermal radiation fluxes other than Earth’s emissions to space.
However, upward and downward radiative fluxes near the surface are routinely measured. While those measurements might not have comprehensive global scope, they routinely verify general consistency with the estimated global averages, and routinely demonstrate that upward and downward thermal fluxes are on average larger than the flux of absorbed sunlight.
- Geothermal heat. TC seems to be under the impression that in 2011 NOAA reported that a “fission reactor” in the Earth’s Core generates around 163 W/m² of heat flow to Earth’s surface which climate models are failing to take into account.
Unfortunately, that impression reflects a misreading of a summary of the study. The numbers in that study actually mean that radioactive decay contributes a heat flux of 0.04 W/m², which is about half of the overall geothermal heat flux of 0.09 W/m².
- Gravitational heating. TC suggests gravity might be a source of significant heating, citing Josef Loschmidt and Nikolov & Zeller.
Loschmidt’s work is incompatible with Tolman’s later findings that General Relativity implies gravity does produce a gravitational lapse rate, but that gravitational lapse rate amounts to about 30 trillionths of a degree per kilometer of change in altitude. Even if Loschmidt’s theory was correct, it would only account for lapse rate, not absolute temperature. Nikolov & Zeller’s work has numerous serious flaws which I’ve detailed elsewhere.
- Other heat sources. TC suggests that human activities or decay of biomass might be significant sources of planetary heating.
However, total human energy use averages around 0.04 W/m². Biomass creation via photosynthesis absorbs solar energy, and biomass decay and animal/plant metabolism release heat. The rates of energy absorption and release by these mechanisms are balanced to a very high degree. As a result, on average and on a global basis, these mechanisms are not significant factors in energy balance.
- Size of CO₂ contribution to Greenhouse Effect. TC reports that water vapor is responsible for 95% of the GHE and CO₂ is responsible for about 3.6%.
However, the scientific studies I’ve found credit water vapor with around 50% of the total GHE, and CO₂ with around 19% of the total GHE. Aside from those theoretical calculations, the substantial contribution to the total GHE from CO₂ is directly verifiable by examining high-altitude balloon measurements of the spectrum of Earth’s thermal emissions to space; the area of the large dip near the middle of the emission spectrum indicates the size of the contribution by CO₂.
- Size of human contribution to the Greenhouse Effect. TC reports that human-made CO₂ is responsible for less than 0.2% of the total Greenhouse Effect.
However, other sources estimate human CO₂ emissions as seven times larger, being responsible for 1.4% of the total GHE, with other GHGs emitted by humans raising the total to 1.7%.
- CO₂ too dilute to heat/cool air. TC says that at a CO₂ concentration of around 0.04%, air has only one CO₂ molecule out of every 2500 air molecules, and argues that it’s implausible that those rare CO₂ molecules could effectively distribute heat or produce cooling for all those other molecules.
Yet, dye in water at a concentration 67,000 times more diluted (1 dye molecule for every 170 million water molecules) is capable of absorbing 99.99% of light within just 1 meter.
And in the case of CO₂, each air molecule collides with 2500 other molecules about every 0.4 microseconds. So, heat in air can be distributed to and from CO₂ very quickly and efficiently (i.e., within 0.4 microseconds).
I also calculate that the levels of thermal radiation emitted and absorbed by CO₂ in the atmosphere require each CO₂ molecule to absorb or emit a photon only around once every 10 seconds. (Although each individual LW photon doesn’t carry much energy, there are an unimaginably large number of CO₂ molecules in each cubic meter of air, even at a concentration of 0.04%.) These numbers indicate that what is required of CO₂ molecules to support radiative heating and cooling of air is remarkably undemanding.
- Trapping radiant heat. TC argues that radiant heat can’t be trapped by the atmosphere because CO₂ and other GHG molecules radiate away photons in femtoseconds, so GHG molecules radiate any energy they receive immediately, and there is no heat retention.
The idea that GHGs radiate photons away within femtoseconds is made-up and untrue; it’s impossible for that to be true for any quantum transition emitting radiation at a wavelength of around 15 microns (where CO₂ emits). In reality, once a CO₂ molecule has sufficient vibrational energy, it takes the molecule about 1 second on average to emit a photon. TC’s claim is off by a factor of around a quadrillion.
However, even if it was true, the argument is an indication of having no idea what is meant by phrases like “GHGs trap radiant heat.” Such phrases have nothing at all to do with keeping energy locked up in a particular bit of air and unable to leave.
“Trapping” radiant heat really means that the efficiency of radiant heat transfer away from the surface is reduced, so that for a given surface temperature, the radiant heat flow is lower, or for a given radiant heat flow, the surface temperature needs to be larger. It’s the same sense in which insulation with a higher R-value does a better job of “trapping” heat inside a house. In the case of Earth’s atmosphere, all you need to do to establish that radiant heat is being “trapped” is to notice that the radiative flux of thermal radiation emitted by the surface (398 W/m²) is measurably larger than the radiative flux of thermal radiation reaching space (240 W/m²).
- Emission by nitrogen and oxygen. TC suggests that air can’t hold on to radiant heat because as the (relatively rare) CO₂ molecules are absorbing infrared photons, other (more numerous) air molecules are radiating that energy away.
However, the ability to absorb and emit are always equal (according to Einstein at the quantum level, and according to Kirchoff’s radiation law on the macroscopic level). So, if nitrogen and oxygen could emit thermal radiation, then they would be able to absorb it just as well. But, they can’t do either. Molecular vibrations can interact with the electromagnetic field only if the molecule has an electric dipole moment (i.e., an asymmetry in the molecule’s electric charge). Nitrogen and oxygen molecules don’t have an electric dipole moment, and are considered unable to absorb or radiate thermal radiation, for all practical purposes. Technically, they can do so, but at a rate over 100,000 times slower than that of “greenhouse” gas molecules; consequently, even though atmospheric nitrogen and oxygen molecules greatly outnumber CO₂ molecules, their net absorption and emission rates are much smaller than those of CO₂.
- CO₂ not claimed to warm air. Many of TC’s arguments seem aimed at justifying a conclusion that CO₂ doesn’t have a warming effect on air, and that any radiant heat absorbed is quickly radiated away.
However, mainstream climate science agrees that CO₂ doesn’t have a warming effect on air. It’s believed that the main effect CO₂ has on air is to support efficient cooling of air at higher altitudes. CO₂ only causes warming indirectly. CO₂ blocks thermal radiation emitted by the surface from getting directly to space, reducing radiative heat transfer away from the surface and making cooling less efficient—that’s what is meant by “CO₂ traps radiant heat.” Because cooling is less efficient, heat from the Sun accumulates and the surface gets warmer―which indirectly leads to the atmosphere getting warmer.
- Greenhouse. TC suggests that Earth’s atmosphere is the opposite of an actual greenhouse, because a greenhouse has physical barriers that block most forms of heat transport to the outside, while in the atmosphere acts more like a chimney, sucking warm surface air higher and higher.
However, the term Greenhouse Effect is a metaphor. A greenhouse and the atmosphere don’t need to be literally the same in every respect. The similarity is that a greenhouse reduces the efficiency of upward heat transfer (to the atmosphere, primarily by blocking convection), and GHGs reduces the efficiency of upward heat transfer (to space, primarily by reducing the efficiency of radiative heat transfer from the surface to space). In both cases, the efficiency of heat transfer is reduced. That’s the basis of the metaphor. It’s understood that the types of heat transfer affected are different in the two cases.
- Over twice the power of the Sun. TC objects to the idea of the Earth’s surface emitting thermal radiation with a flux of 398 W/m², which is over twice the 163 W/m² of sunlight absorbed by the surface; he wants an accounting for the “missing” heat.
However, the mistaken impression of a problem with energy conservation arises from a lack of understanding about the difference between radiation energy flows and radiation heat flows. The features that stimulate concern about “missing heat” among some people when looking at an energy-flow version of Earth’s Energy Budget are absent in an equivalent heat-flow version of the diagram. Also, many people are unaware that, while energy can never appear “out of nowhere,” power (the rate of flow of energy) sometimes can appear seemingly “out of nowhere” without violating energy conservation.This doesn’t imply unlimited free energy or perpetual motion, since the “extra” power exists only inside a recirculating energy loop and can’t be sustainably extracted. This phenomenon of power inside a recirculation loop exceeding the power entering (and exiting) the loop is not unique to Earth’s climate, but can happen inside any resonator, including musical instruments, lasers, and the klystrons that power microwave ovens—and in the radiant heat transfer happening all around us.
- Back radiation. TC objects to the claim that 340 W/m² of thermal radiation, “back radiation,” flows from the atmosphere to the surface, given that this is comparable to the total solar irradiance of 340 W/m², and larger than the 163 W/m² of insolation absorbed by the surface and the 240 W/m² emitted to space.
These concerns reflect a lack of understanding of radiant heat transfer as it occurs in every moment. A human body at a normal temperature emits around 511 W/m² (or in TC’s framework, 1.5 times the flux of the Sun). But in a warm room, the room is returning 460 W/m² of “back radiation” back to the human body so the net radiant heat loss of a human body is around (51 W/m²)×(2 m²) ≈ 102 W.
This phenomenon of “back radiation” is not unique to Earth’s atmosphere or to GHGs, but occurs in every instance of radiation heat transfer. The formula for the rate of radiation heat transfer between two objects includes two terms: a “forward radiation” term for the thermal emissions of the first object (as radiated in accordance with the Stefan-Boltzmann Law) absorbed by the second object, and a “back radiation” term for the thermal emissions of the second object (as radiated in accordance with the SB law) and absorbed by the first object. Thermal radiation always flows in both directions, and radiation heat transfer is calculated as the difference between those two energy flows. Because a warmer object emits more thermal radiation (in accordance with the SB Law), the energy flow from warm to cool is always greater than the energy flow from cool to warm, which ensures that the net energy (i.e., heat) flow will always be from warm to cool. The magnitude of the forward and back radiation flows is not constrained to be less than the size of any external energy flows, but is determined by the temperatures of the objects. Only the difference between the flows in the two directions is constrained in steady state to be no larger than the externally supplied flow of heat.
The longwave radiative fluxes in Earth’s Energy Budget reflect normal radiant heat transfer from a surface at an average temperature of 288K/15℃/61℉ to an atmosphere that has an effective radiative temperature of 279K/6℃/42℉ as viewed from below.
- Second Law of Thermodynamics. TC says that colder air above cannot ever warm the earth’s warmer surface with thermal radiation, and suggests that the GHE involves heat being amplified in a way that is the equivalent of a perpetual motion machine, and which would violate the Second Law of Thermodynamics (2nd LoT).
However, only straw-man misinterpretations of how the GHE works violate the 2nd LoT. It can be readily seen that the mainstream understanding of the energy flows between Earth’s surface and atmosphere don’t violate the 2nd LoT by examining the individual heat flow diagrams for the surface and atmosphere. Belief that the GHE involves a violation of the 2nd LoT seems to typically stem from a misinterpretation that the “warming” process of the GHE is a direct process rather than an indirect process. I’ve tried to address these misunderstandings in a variety of essays, including this one and this one (though, I’m not sure I’ve yet found a way of explaining it that reliably gets past whatever communication mismatch may be present).
- Heinz Hug. TC offers arguments based on the work of Heinz Hug, who argued that doubling CO₂ concentrations would only increase the width of the 15-micron absorption band by 0.17% which would be too small to allow for any possibility of doubling CO₂ having an effect on global temperatures.
However, Hug’s analysis omitted two critical effects. Hug analyzed absorption but not emission, and so did not account for changes in effective emission height, which is a primary mechanism by which CO₂ concentration changes affect global temperature. Also, his analysis of saturation issues falsely assumed thermal radiation travels vertically, when it travels at a wide variety of angles, greatly altering the implications of varying saturation depths. Hugs’s analysis omitted so much of importance that it can’t be taken seriously as constraining the actual effect of doubling CO₂.
- Experimental evidence. TC calls for experimental proof of CO₂ causing warming and of radiative forcing theory.
A study by Feldman (2015) offers direct empirical confirmation that CO₂ is responsible for increases in downwelling longwave radiation, a key tenet of the radiative forcing model. Heinz Hug and others have directly confirmed the radiative properties of CO₂. Spencer (2016) offered a table-top demonstration of a key feature of the Greenhouse Effect. However, misunderstandings of the GHE among skeptics create a mismatch, in which they often have difficulty recognizing the relevance of supportive experiments, and expect experiments to be able to confirm straw-man versions of what the GHE model asserts, rather than what it really asserts.
- Historical record. TC cites ice core data indicating that historically CO₂ levels lagged temperature as proving that temperature drives CO₂ levels rather than vice versa.
However, early ice core studies had methodological errors which, once corrected, eliminated the lag so that Antarctic temperatures and CO₂ levels actually moved synchronously. Additionally, when global temperature data was examined, it turned out that global temperatures lagged CO₂ levels.
- Sunspots and cosmic rays. TC asserts that solar activity affects cosmic rays which affect Earth’s albedo, presumably through cosmic rays stimulating cloud formation.
However, data showed that what initially appeared to be a correlation between cosmic rays and clouds disappeared in the mid-1990s.
- Clouds. TC suggests that the current climate models do not consider the effect of clouds.
However, the 2021 IPCC AR6 report talks about clouds on 50 pages, describes extensive cloud modeling work, and offers modeled cloud feedback estimates for 7 different categories of clouds. Their modeling assesses cloud feedback as being the second-largest feedback effect, after water vapor feedback.
* * *
More details on these and many other issues are provided in the detailed point-by-point response.
Although I, regrettably, took issue with most of the points in TC’s whitepaper, I appreciate his good intentions, and I enjoyed thinking about the issues he raised.
I can’t imagine it’s likely to be fun to receive so much disagreement. Yet, I hope that what I’ve offered might in some way support TC and others in refining their work.
If you’ve found this analysis helpful, I’d appreciate it if you let me know what you found to be of value.
If you’d like to offer your disagreement about anything I’ve written, I hope you’ll do so politely, and in the spirit of a sincere mutual inquiry into what’s true. I’ve tried to be respectful, and I hope you will be too.