Arvid Pasto
August 2024
A major climate parameter called “climate sensitivity” has been the subject of scientific inquiry for literally hundreds of years. This parameter, basically, is the amount of global temperature increase caused by a doubling of atmospheric CO2. If the parameter’s value is 2, then the world’s temperature will increase by 2°C when the CO2 level in the atmosphere reaches twice what it is now. It is therefore, by implication, a constant number. Scientific estimates have ranged very widely, from much less than 1 to well over 6 (see later). Exact knowledge of its value is “priceless” to climate modelers and alarmists, much like the Golden Fleece was to its owner(s) in Greek mythology.
Inasmuch as global warming is considered to arise from the presence of greenhouse gases in our atmosphere, a great deal of attention has been paid to assessing the effects of these gases (principally CO2, methane, and nitrous oxide, along with a myriad of gases typically occurring at very low concentrations).
Blaming global temperature change on any single factor, such as CO2, is folly. Beer’s Law1 describes the well-known phenomenon of “saturation”, wherein as CO2 increases, atmospheric temperature will rapidly increase starting at a CO2 level of 0, but as it increases, the temperature increase is NOT linear. Instead, it decreases, ultimately appearing to level off. (Figure 1) Thus, you can see that, using only one factor, climate sensitivity is NOT a constant. However, at high levels of CO2, the climate sensitivity can be considered to be “nearly” constant. There is a perfectly good reason for that behavior, as can readily be shown1. The major result of this expression is that, after some given amount of CO2 has been added to the atmosphere, any additional amounts will cause smaller temperature increases. At some level, these increases will be insignificant.
Figure 1. The effect of CO2 Concentration on Atmospheric Warming
(From page 8 of The Skeptics Handbook, Joanne Nova 2009)
The same non-linear relationship is true for any gaseous species in the atmosphere. And of course, our atmosphere is composed of anything but a single gas. Each will exhibit its own self-flattening concentration-temperature curve, depending on its properties.
Theoretically, knowing the atmosphere’s exact composition, and the requisite spectroscopic properties for each gas, it should be simple to calculate the resultant absorption curve. Earth’s global temperature is thought to be governed by a balance between the incoming solar radiation plus the earth’s own internally-generated heat, and the outgoing heat (radiation).
Gaseous molecules will absorb heat from both the incoming and outgoing radiation. The incoming heat is absorbed primarily via electronic transitions, while the outgoing heat is absorbed via vibrations and/or rotations of the molecules. These interactions can be easily measured via spectroscopy, with each species showing a distinct spectrum of absorption versus radiation wavelength (or frequency). See Figure 2.
Figure 2. Absorption of energy by several gases as a function of incident radiation wavelength, and their affect on incoming solar and outgoing earth radiation. (From a presentation by Dr. William Happer, of Princeton University, at Marshall University)
One can then calculate how much heat will be generated in the atmosphere via these processes, since the specific heat of each component is known. The calculation basically asks: how much heat is generated, and then how much temperature change does that heat cause.
Such calculations have been done for many years, with results such as shown below. These calculations allow for a more precise estimation of the “greenhouse gas effect” of a certain gas, since one can simply double the concentration of the species of interest in the calculation and see what happens. (Figure 3)
Figure 3. This figure shows that increasing the CO2 level from 0 ppm (green line), to 400 ppm (around today’s value, black line) has a significant effect, raising earth’s temperature from what it would be with no CO2 (ca. 16°F) to today’s level (ca. 60°F). You can plainly see that doubling the CO2 to 800 has almost no effect (red line). [Ron Clutz.com 2021]
The two principal “evils” of climate change, CO2 (carbon dioxide) and CH4 (methane) are easily shown to be unlikely to cause any significant global warming, through calculations like those discussed above. Both are known to be continuously increasing (Figures 3 and 4), and have been painted as the major cause(s) of global warming for decades.
Figure 3. CO2 concentration in earth’s atmosphere through 20232.
https://www.yahoo.com/news/methane-emissions-speed-tracking-improves-143117916.html
Obviously, then, something is missing from these global warming calculations. Many factors, other than atmospheric gaseous heating, can be easily inferred. These include assumptions about how much incoming solar radiation is reflected or absorbed by clouds or the oceans, how much incoming light is scattered by clouds or “dust” in the atmosphere, how much incident light is reflected by clouds, or ice and snow patches on the earth, and numerous others. The latest climate models have defined all of these terms in great detail (Figure 5).
https://wattsupwiththat.com/2024/07/30/the-return-on-your-investment/
Additional hard-to-account-for factors include extraneous heat sources (underwater volcanoes, underground coal- or- methane fires), soot deposited on glaciers (heat absorbing), the recent huge world-wide wildfires (which produce heat, soot, and CO2), and others.
Finally, there are the so-called “feedbacks”: these include interactions between two gases such as CO2 and water vapor, and others. These can be positive, wherein the presence of one gas, e.g.- CO2, is thought to cause an increase in the presence of another, e.g.-water vapor, from enhanced evaporation from the oceans. They can also be neutral or negative. (Figure 6) The heat inputs, called “forcing factors” are added to the “feedbacks” in climate models.
Figure 6. Climate feedback considered in global climate models. [From IPCC AR4 report.]
The water vapor feedback is especially troublesome: it is NOT known to be “positive”, much less as positive as climate scientists claim to know.
Because there are so many forcing factors, and so many complicated feedbacks, climate sensitivity is impossible to calculate a priori. Assumptions must always be made. Yet scientists have tried in vain for decades to do just that. (Figures 7, 8, 9)
Figure 7. Scientific estimates of climate sensitivity. In 2013, Nobel Prize-winning physicist Nur Shaviv said, about this graph, “More seriously, let me put this in perspective with the most boring graph I have ever plotted in my life. Below is the likely range of climate sensitivity as a function of time. As you can see, with the exception of AR4 with its slightly smaller range mentioned above, the likely range of climate sensitivity did not change since the Charney report in 1979. In other words, after perhaps billions of dollars invested in climate research over more than three decades, our ability to answer the most important question in climate has not improved a single bit!”
https://wattsupwiththat.com/2020/01/12/paper-praising-models-predictions-proves-they-greatly-exaggerate/2019
Figure 9. Historical estimates of climate sensitivity.
It turns out that climate sensitivity is actually a physically useless term, except to help show what influence certain forcing factors or feedbacks may have on global warming. Global atmospheric temperature can now be measured directly 24 hours per day via satellite and/or weather balloons, and ocean temperature via diving buoys, and “earth” temperature via thermometers located on every continent. (The latter two have their own problems, especially the surface measurements, but these will not be discussed here).
Global climate models currently utilized on supercomputers worldwide do not actually use “climate sensitivity” as an input, but their output can be used by generalists to suggest its value from the computer’s input and output.
Given the results of actual global temperature versus the results of computer climate models (black line on Figure 10), one can see that earth’s temperature is NOT increasing at anything like the rate that would be predicted by a “climate sensitivity” of over 2.
The global CO2 level in 1976 was2 332 ppm, and the starting temperature change is taken as 0.00. In 2016, CO2 was 404, and the rise in temperature was 0.3°. At an average rate of 2 ppm/year increase, it would take 166 years to double from 1976. {I use 2 ppm/yr, even though from 1976 to 2016 it was 1.8 ppm/yr, but it has been increasing to over 2 ppm/yr lately}. Now, 40 years represents 0.24 of that time difference (40/166). Thus the “climate sensitivity” starting in 1976 would be 0.3°C/0.24, or 1.25. If the climate sensitivity (C.S.) had been 2, the expected temperature rise would have been 0.48°, and if C.S. was 3, then the rise would have been 0.72°C, and etc. The average of the climate models shown on the graph gives between 4 to 5 for the climate sensitivity (and increasing).
Figure 10. Comparison of computer climate model forecasts and actually observed global temperature. [From Dr. John Christy, Univ. Alabama-Huntsville]
If the rate of rise rate in CO2 dramatically increases over the next few decades, then the climate sensitivity will also increase, and so will the predicted global temperature. Actually, the CO2 emission rate is expected to slow, which will extend the CO2 doubling time, and decrease the climate sensitivity.
However, since actual temperature and CO2 data result in a current climate sensitivity of ca. 1.25, there is plainly something wrong with the current “fad” for climate sensitivities of 3 or more.
AND…the real problem with the term “climate sensitivity” is that it implies that CO2 is the driver of climate change, which it is not.
REFERENCES
- M. N. Berberan-Santos, “Beer’s Law Revisited”, Jour. Chem. Ed. 67, Sept. 1990
- https://www.statista.com/statistics/1091926/atmospheric-concentration-of-co2-historic/q
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Figure 3:
what the atmosphere emits into space, which is an energy transer (the downward IR flux from the space at 4 K is negligeable) should be compared to what it absorbs from the surface (the net upward flux = upward minus downward fluxes), not to the upward flux only, since the latter is a mere flux, not an energy transer.Figure 5 shows that the atmosphere absorbs 339 – 321 = 18 w/m² from the surface, it is this value that must be compared to the 147 W/m² emitted into space by the atmosphere (according to figure 5).Green curve (CO2 concentration = 0 ppm) : thus, no biomass, and then, which albedo ? Whitout albedo data the 304 W/m² value has no physical basis.Red curve : which temperature can induce an increase of the CO2 concentration so that it can double ? WHich albedo ? Whitout those data, the 277 W/m² value has no physical basis.Black curve seems to be a tautology : it only demonstrates that the correct calculus done with correct parameters and the same data used to spectrometers calibration gives the correct result with respect to spectrometers measurements … but nothing proves that these ad hoc parameters apply to a different atmospheric state (T, CO2+WP+O3 mix, cloudiness, biomass increase, albedo, laps rate, …). And taking into account all these unknowns one can’t conclude anything from the calculated difference of 3 W/m² between the red and black curves. It could be -12, +5 or whatever other guessed value.The conclusion is that the null hypothesis prevails.Figure 5 :
It shows that the troposphere absorbs 18 W/m² from the surface and emits upward 271 – 147 = 124 W/m² (I guess that the 50 W/m² are emitted by clouds …). Thus active gases in the IR spectrum cool the troposphere.It shows that the tropopause is not impacted by IR fluxes : so much for the tropopause hot-spot which has indeed never been ovserved.It shows that the low stratosphere absorbs 271 + 13 (O3 ?) – 147 = 137 W/m² and emits into space 147 W/m². Thus, active gases in the IR spectrum cool also the low stratosphere.And these gases globally cool the atmosphere which absorbs 18 W/m² from the surface and emits 147 W/m² into space.So be it in the troposphere or the low stratosphere or globally, according to figure 5, atmospheric IR active gases DO NOT trap energy, they transfer it into space.And the CO2 in the mix ? 60 years of modern data and ice cores show no correlation from [CO2] to T at any timescale : thus the null hypothesis applies here too.FIgure 6 :
clouds feedback : observations show that there is a negative correlation between cloudiness and global temperature, thus the positive feddback has no observational basis.WV feedback : since WV emits more into space than it absorbs from the surface (see figure 5, considering that the fluxes are mostly due to WV), moreover, a positive feedback has never been observed, thus the claim of a positive feedback has no observational basis.Conclusion : there is (at the very least) something wrong in the GHG world.
Newton was lured from his extraordinarily brilliant science career by the Philosopher’s Stone. Every generation seems to have the fault built in, being fantastical rather than practical. Newton wrote of standing on the shoulders of giants we choose dwarves.
Using the Happer formula (doubling CO2 leads to a reduction of outgoing radiation of approx 1% which requires a heating of the globe of the fourth root of 1% which is approximately 0.7 degC), CO2 concentrations have increased by about 22% from 1976 to 2016 so perhaps causing 0.15 degC in global warming. The actual warming is double which could be caused by positive feedback or some other warming mechanism.
Climate alarmists would gave us believe that the graph at the top is back to front.
How is it that denizens of WUWT accept this drivel written by a “guest blogger”, when neither he nor they know anything about the extensive body of research on climate sensitivity or even what a “logarithmic relationship” means?
A physical theory of climate does not exist.
“Climate sensitivity” therefore has no explicit physical meaning, other than the ad hoc association with CO₂.
You’ve just confirmed my post.
You just confirmed you are an ignorant twit, that is for sure.
Present the physical theory of the climate that defines climate sensitivity, Warren.
Or confirm that you don’t know what you’re talking about.
You should read more, Mr Frank. The physical theory of climate is to be found in the body of scientific research, and it’s affirmed and summarized in every University textbook, in reports published by the national science academies, and in the IPCC Assessments.
You don’t seem to appreciate Mr Frank, that this is not about you, or me. It’s about what is found in this enormous body of scientific research. The fact that you can’t understnd or accept those findings is your problem, not mine, and certainly not of concern to the world of science.
Perhaps you should read more of the research so you can quote from it. Your assertions without support are without merit.
So, you can’t point to a physical theory of climate. That’s no surprise, Warren, because I know the literature that you don’t.
The whole of AGW alarm and global warming assertionism rests purely on the radiation physics of CO₂. Period.
The extrapolation to climate warming is by ad hoc fiat, not by deduction from a valid physical theory.
You’ve been misled by practitioners of an artful pseudo-science. Critical Global Warming Theory — yet another subjective academic ersatz discipline, but this one decorated with mathematics.
And climate modelers? They’re not scientists at all. They’ve got no idea how to critically evaluate the physical integrity of their own data or models.
Do you find the IPCC Assessments tough sledding, Mr Frank? Have you even tried to understand them?
You might try Dr Pierrehumbert’s classic,
“Planetary Climates”It’s also a bit challenging, but we ll worth it.
if you want a basic explanation, go to https://climate.nasa.gov.
Finally, I’d be interested to know if you’ve read any of these peer reviewed sources? Or do you depend on “intuition” for your posts?
You are clueless!
How to win friends and influence enemies is entirely beyond you.
Carnegie, Dale. How to Win Friends and Influence People
My objective is to test your knowledge of science. So far, it’s a fail
My job is to tell you that you provide no evidence, ever, for your assertions. That generally means none exists or that you have not done any research. Google Scholar could be your friend to obtain convincing evidence. Otherwise you are a blowhard standing on nothing.
LOL, you never did show the evidence YOU claim it exists to answer his requests for them.
Epic Fail!
Hmm…so you don’t know where to look either? Lack of a scientific education seems to be a common problem on this forum.
What is it that they do not know?
Check out the scientific literature on the topic. Unless Mr Frank has recently published his first paper in a scientific journal, you won’t find anything in the body of published science that supports Mr Frank’s nonsense.
Poor beetroot doesn’t know what anything means.
It continues to wax gibberish.
Losing argument. Appeal to Anonymous Authority. The least you could do is post one study that shows a physical relationship that causes ECS. Otherwise, you are blowing in the wind with an argument that cannot be refuted. That is what trolls do.
Huh? ‘Physical relationship’? The science of the climate is all about physical relationships in our physical world.
Did you miss the part about providing at least one study?
Your answer leads one to believe that you haven’t really studied the literature to have an appropriate one available.
He doesn’t know, he is being a typical warmist/alarmists pushing bogus narratives.
I don’t understand graph 5 showing back radiation of 321 at what I assume is the earth’s surface. Radiation nets, right? As far as I can tell, much of what is presented assumes there is a conservation of Photons. That is, all radiation that is absorbed is assumed to be reradiated. Near the surface almost none of the radiation absorbed by CO2 gets reradiated. The absorbed radiative energy is transformed into vibrational or kinetic energy, which is transferred through collisions.
A portion of the visible and IR light absorbed by the surface causes the land to heat up. The amount of the heat retained depends on the heat capacity of the material in the land. In summer for example, concrete roads and buildings can absorb lots of heat during the day and release it at night.
Water has a high heat capacity. The subtropical oceans absorb lots of heat starting in spring. When enough heat has been accumulated, hurricanes can form. So far for this season there has been 3 major hurricanes and numerous tropical storms. September is the month with the most hurricanes.
Just one nit.
Thermal radiation is not infrared radiation.
Just ask Eunice Foote.
Thermal radiation covers a wide range of the EM spectrum with its peak frequency and distribution governed by the absolute temperature(s) of the radiating object or substance. For temperatures in the range of 200-350 K, representative of Earth’s surfaces, thermal radiation peaks in the long wavelength infrared part of the spectrum . . . that is, 99.9 % of the radiated photons will have energies less than 0.5 eV.
Heck, even the cosmic background radiation, at an effective temperature of only 2.7 K has some radiation extending into the infrared region (where infrared detectors on orbiting satellites are used to map its spatial variations), even though its peak frequency is in the microwave region of the EM spectrum (ref: https://sentinelmission.org/cosmology-glossary/cosmic-infrared-background/ ).
For reference, the cosmic background radiation peaks at an EM wavelength of about 2 mm, corresponding to a microwave frequency of about 150 GHz. In “radio-speak” that is in the middle of the Extremely High Frequency (EHF) radio spectrum, often used for radar.
Nevertheless, “The Far-Infrared Absolute Spectrophotometer (FIRAS) instrument on the COBE satellite measured the cmBR spectrum between 60 and 630 GHz very precisely.”
— source: S.T. Staggs, N.C. Jarosik, S.S. Meyer, and D.T. Wilkinson, An Absolute Measurement Of The Cosmic Microwave Background Radiation Temperature At 10.7 GHz, The Astrophysical Journal, 473: L1–L4, 10 December 1996.
Bottom line: thermal radiation does commonly have a component of infrared radiation.
Thermal radiation and infrared radiation are both EM radiation. Thermal and IR are the same thing.
Infrared is a descriptor based on color. Thermal is a descriptor based what is felt at normal earth temperatures.
Physical characteristics are determined by wavelength and temperature regardless of what the EM wave is called.
I know Wikipedia uses the term thermal radiation, but that is terribly misleading. Heck microwaves frequencies can heat water. Are those thermal radiation also? They are far below infrared frequency.
“Color” is defined as a particular frequency range that a biological eye and nervous system reacts to, be it human, animal or insect (i.e., colors are restricted to the “visible” part of the total spectrum of light energy). Human eyeballs do not sense infrared radiation.
But if you think otherwise, please state for all the color that YOU assign to infrared radiation.
BTW, most observed white dwarf stars have surface temperatures, between 8,000 K and 40,000 K. At 40,000 K, the peak in blackbody thermal radiation is at 0.072 microns, far into the ultraviolet rage of the EM spectrum and far away from the infrared portion of that spectrum.
Therefore, it is simply wrong to claim that “thermal and IR (radiations) are the same thing” . . . they might be, but then again they often are not.
I guess you have a different definition of color than Max Planck.
Max Planck. The Theory of Heat Radiation by Max Planck (English Edition) – Unraveling the Mysteries of Heat Radiation: Max Planck’s Groundbreaking Theory in English (p. 3). Prabhat Prakashan. Kindle Edition.
You should really read his thesis on heat radiation. It would explain a lot to you about energy and “heat”. A search shows at least 60 uses of color. There are at least 73 mentions of the word monochromatic.
If we limit ourselves to the absorption of the infrared radiation from the earth (primarily in the range from 600 to 800 cm^-1) by increasing CO2 concentrations, assuming a blackbody Planck distribution of emission intensity, the global average sensitivity for doubling from 420 to 840 ppm CO2 comes out to about 0.48 C/doubling.
This value comes from an analysis of the vertical profile of IR absorption as a function of altitude for various values of initial ground temperature and relative humidity, and assuming that the profile of pressure and temperature with altitude follows the adiabatic lapse rate.
Water vapor also absorbs IR radiation in the main CO2 absorption band (which peaks at 667 cm^-1). Although the molar absorption coefficients for water vapor are lower than for CO2 in that band, the fact that water vapor concentrations are much higher than CO2 concentrations means that water vapor absorbs a substantial fraction of the available IR radiation in that band, leaving less available to be absorbed by CO2. For this reason, the surface warming due to CO2 is much lower in warm or humid climates than in cold or dry climates.
This analysis also found that, for a constant absolute humidity but an increase in CO2 concentration, the absorbed IR radiation in a volume of air would increase up to a relatively low altitude (< 10 meters above the ground) and decrease slightly above that altitude, meaning that warming would be limited to a layer within a few meters above the ground, and increasing CO2 concentrations would cause a slight cooling in the atmosphere at higher altitudes.
The maximum difference in absorbed radiation between a low CO2 concentration and a higher CO2 concentration was inserted into the Stefan-Boltzmann law to calculate the required increase in surface temperature to maintain equilibrium.
Based on a distribution of surface temperature and humidity as a function of season and latitude proposed by Arrhenius in 1896, the calculated sensitivity would come out to about 0.3 C/doubling in the tropics. At higher latitudes, the sensitivity was higher, in the 0.4 to 0.6 C/doubling in summer, and 0.7 to 1.0 C/doubling in winter. The 0.48 C figure for the global average is a weighted average over the globe, weighted by the relative area of the earth at each latitude.
This model does not account for any feedbacks, or changes in solar radiation. However, it is reasonable to assume that any water-vapor feedback would be negative. In order to maintain a constant relative humidity in a warming atmosphere, liquid water must be evaporated into the air by contact with a body of water, such as an ocean or large lake. The heat required to evaporate this water must be supplied by the air, which results in a negative feedback.
This analysis shows that the absorption of infrared radiation by CO2 has a relatively weak influence on the surface temperature, and the warming observed since 1976 is mostly due to natural forces beyond human control.
Your Response conclusively demonstrates you don’t even know where to look.
Why don’t you start with the IPCC 6th Assessment.
appeal to authors nonsense from this clown and his sock. Over and over. It’s pathetic.
the fact that you are ignorant of the body of science on the same topic you bang on about is deplorable. The fact that you don’t accept the body of science is a characteristic of primitive peoples.
Medicine
Climate
Tropical Hot Spot – nope
GB Reef dying – nope
More extreme weather – nope
Modern science fails all the time don’t ya know. Science requires questioning and answers from the folks who say they know. You can’t even show the research that substantiates your assertions. Fail all the way around.
Yet you fail to articulate it while your insults show that you are frustrated in trying to bamboozle people with your baloney.
Your replies in the thread are primitive.
How come the older reports IPCC 1-5 assessments over a 30-year period is never good enough that they have to produce another version, I thought the science was already settled years ago……..
Could it be a racket is why they produce a new report to keep the climate scam going?
So you never heard of the concept of scientific research to improve the state of scientific knowledge? You continue to impress us with how little you know.
Thankyou.
The phenomenon of saturation is not referred to nearly often enough, by skeptics.
It demolishes catastrophist claims of runaway warming.
Yes, some catastrophists claim there is a positive feedback loop. Yet there is evidence that the Medieval Warm Period was warmer than today yet climate was stable. (Vikings farmed southwest Greenland during the MWP.)