Climate Change: The Unsettled Science – Part 2

Iain Davis

In Part 1 we questioned the fundamental principles said to underpin “the Climate Science™.” Specifically we considered the scientific validity of the claimed “consensus” and explored some of the many scientific doubts expressed about Anthropogenic Global Warming (AGW) theory and the so-called “greenhouse effect.”

We noted the contradictory layman’s explanation of AGW theory offered by some climate scientists. This apparent lack of basic knowledge should not simply be dismissed. “The” climate science is being exploited by a global public-private partnership as claimed justification to transform the world. The least we can expect is that the selected climate scientists understand their own theory.

With the 2023 publication of a series of policy briefs called Our Common Agenda, the United Nations (UN) announced that questioning “the Climate Science™” is tantamount to hate speech. As we discussed in Part 1, the legacy media has already adopted editorial policies that rule out any possible questioning of the climate science orthodoxy. Thus the internet is an important remaining public square where people can still ask questions.

Therefore, the UN asserted, efforts must be made to censor any and all scepticism expressed online:

The impacts of online mis- and disinformation and hate speech can be seen across the world, including in the areas of health [and] climate action. [. . .] A small but vocal minority of climate science denialists continue to reject the consensus position. [. . .] Strengthening information integrity on digital platforms is an urgent priority for the international community. [. . .] [M]easures that limit the impact of mis- and disinformation and hate speech will boost efforts to achieve a sustainable future.

The UN made absolutely no mention of the fact that many of the people it calls “climate science denialists” are scientists, including climate scientists. By omission and by misrepresenting anti-scientific statements about “consensus” as scientific arguments, the UN spreads disinformation globally.

The purpose of these articles—Parts 1 to 3—is to stimulate open and honest debate about climate change and climate science. They are not offered as conclusive rebuttals of the prevailing climate science. Based upon the inspiring Ph.D dissertation of Rob Jeffrey, they merely provide a limited record of some of the reasons to question the prevailing climate science and the climate change narratives we are all asked to accept without question by the UN and others.

These articles form a series. Please read Part 1 first to fully grasp the arguments made here.

Questioning AGW Theory Experimental Proof

The AGW theory paper Halpern et al. (2010) clarified that the naming of the “greenhouse effect” was misleading because the proposed AGW related mechanism is nothing like the process that keeps the atmosphere warm in a greenhouse:

Concisely, greenhouses work by restricting the outward flow of thermal energy to the surrounding atmosphere by convection, while the atmospheric greenhouse effect works by restricting the outward flow of thermal energy to space by radiation.

Wherever possible, science generally proves theories through repeatable experiments that consistently produce results that evidence the theory. Based on the 1856 published theories of Eunice Foote, in 1859 John Tyndall conducted his famous experiment to show how CO2 absorbs and transmits radiant heat. This is often cited as experimental proof of the “greenhouse effect.” Tyndall’s experiment did not demonstrate the claimed greenhouse effect.

In order to do so, Tyndall would have needed to show a temperature gain in the emitting and absorbing objects. Something Tyndall didn’t even measure. Tyndall demonstrated that thermal energy radiates from a warm body to a colder one and the comparative electromagnetic radiation absorption properties of various gases.

Other experiments are cited as claimed proof of the greenhouse effect. In 2020, the Royal Society conducted an experiment which they said qualitatively illustrated climate change mechanisms. They placed a heating element, set to 50°C, inside balloons inflated to various fixed pressures filled either with air or pure CO2. They then switched the element off and observed how long it took to cool. The researchers noted that the cooling rate was much lower in the CO2 filled balloons.

Firstly, this was not a demonstration of the “enhanced greenhouse effect” suggested by proponents of AGW theory. Without any additional energy supplied to the system, AGW theory claims that if a constant power supply was maintained to the heating element so-called “back” radiation from the CO2 would increase its temperature. The Royal Society experiment certainly did not prove AGW theory or the alleged physical mechanism of “global warming.”

Gasses trapped in balloons at fixed or constrained pressures behave nothing like the actual freely expanding and contracting gasses in the Earth’s atmosphere. Nor is pure CO2 comparable with atmospheric CO2 levels. In the atmosphere, the CO2 would cool by expansion and adiabatic lapse. It couldn’t do that in the pressurised balloon. This experiment did not demonstrate the alleged greenhouse effect either.

Other so-called greenhouse gas theory proofs are equally inconclusive. Nature published a paper that supposedly quantified the atmospheric greenhouse effect using satellite readings to measure the infrared radiation energy trapped by atmospheric gases and clouds. Having done so, the climate scientists then claimed this provided compelling evidence of atmospheric “positive feedback,” in this case, the alleged radiative forcing of the enhanced greenhouse effect. They did not prove the “enhanced greenhouse effect,” they simply assumed its presence and observed the same gas properties that Tyndall demonstrated more than 165 years earlier.

Another scientific principle to demonstrate that a theory is sound is the lack of any other plausible explanation. This doesn’t appear to be the case with the “enhanced greenhouse effect” that is central to AGW theory.

Many physicists, astrophysicists, such as Joseph Postma, and other scientists have offered other plausible explanations. For example, Holmes 2018 suggested that surface temperature could also be maintained through nothing more than the effects of atmospheric pressure and thermal convection within the troposphere:

[. . .] it is proposed that the residual temperature difference between the effective temperature and the measured near-surface temperature, is a thermal enhancement caused by gravitationally-induced adiabatic auto-compression, powered by convection. A new null hypothesis of global warming or climate change is therefore proposed and argued for; one which does not include any anomalous or net warming from greenhouse gases in the tropospheric atmospheres of any planetary body.

Two climate scientists, Ned Nikolov and Karl Zeller, achieved some infamy for publishing papers under pseudonyms. Earmarked as “climate deniers,” they couldn’t even get their papers submitted for peer review let alone published in “respected” journals. In 2014 they decided to publish using pen-names and their papers were then peer reviewed and published. The papers were subsequently withdrawn, not for any scientific reason but because their clearly necessary use of aliases was discovered. Karl Zeller observed “disagreeing with current greenhouse effect theory does not constitute an error.”

In 2017, the climate scientists published Nikolov, Zeller (2017) which offered a model for calculating the mean global temperature for the surface of a solid planet with or without an atmosphere. They applied their model to Mars, Venus, Triton (a moon of Neptune) and Titan (a moon of Saturn) and claimed their model proved accurate.

Crucially, their model relied upon calculated surface air pressure and solar radiation to estimate mean global temperature. Their model implies that the chemical composition of an atmosphere does not control the surface temperatures of a planet. In the abstract for their 2017 paper, the scientists wrote:

[. . .] the atmospheric ‘greenhouse effect’ currently viewed as a radiative phenomenon is in fact an adiabatic (pressure-induced) thermal enhancement analogous to compression heating and independent of atmospheric composition. Consequently, the global down-welling long-wave flux presently assumed to drive Earth’s surface warming appears to be a product of the air temperature set by solar heating and atmospheric pressure. In other words, the so-called ‘greenhouse back radiation’ is globally a result of the atmospheric thermal effect rather than a cause for it.

Questioning AGW Theory Warming

A core element of AGW theory is the notion that humanity’s CO2 emissions are causing “additional” and “unprecedented” global warming. Therefore, there must be some empirical evidence that the rise in atmospheric CO2 precedes any measurable warming. There doesn’t appear to be any.

It is commonly acknowledged that there is no paper, anywhere in science, that proves the existence of the AGW mechanism using nothing but empirical data. The link between humanity’s GHG emissions and climate change is based upon a complex network of interdependent theories, computer models and projections. Indeed, making empirical measurements of such things as the average “surface air temperature” (SAT) are highly problematic.

Rob Jeffrey observed:

Almost all scientists believe that natural forces have driven long-term climate change in the past. The earth’s history shows that climate change is a process taking place for over four billion years. There would appear to be broad agreement that long-term climate change cycles are driven by the Milankovitch cycles, the history of which is well recorded.

The Milankovitch cycles describe the major orbital cycles of the Earth as both the shape of the Earth’s solar orbit and its “axial tilt” fluctuate relative to the sun. This causes the Earth to receive varying intensities of TSI (Total Solar Irradiance). Over time, this is part of the natural variation that impacts the climate.

The “official” Intergovernmental Panel on Climate Change (IPCC) climate science concedes that historical temperature proxy records, such as ice cores, show that there is a lag, possibly of up to 800 years, between the initiation of global warming and rising atmospheric C02. Caillon et al. (2003), noting that interglacial warming appears to initiate in the southern hemisphere, found:

The sequence of events [. . .] suggests that the CO2 increase lagged Antarctic deglacial warming by 800 (+ or – ) 200 years and preceded the Northern Hemisphere deglaciation. CO2 is not the forcing that initially drives the climatic system during deglaciation [warming].

Shakun et al. (2012) developed a “computer model” which the authors claimed explains what happens next from an AGW theory perspective. This has been reported by, among others, Skeptical Science:

In short, the initial warming was indeed triggered by the Milankovitch cycles, and that small amount of orbital cycle-caused warming eventually triggered the CO2 release, which caused most of the glacial-interglacial warming. So while CO2 did lag behind a small initial temperature change (which mostly occurred in the Southern Hemisphere), it led and was the primary driver behind most of the glacial-interglacial warming.

To be clear: AGW theory posits that the sun, which is only apparently capable of heating the Earth’s surface to -18°C, starts the process of glacial-interglacial global warming but then, assuming a kind of naturally occurring enhanced greenhouse effect, “additional” released GHGs—notably CO2 from the oceans—trap the heat causing “positive feedback.”

Supposedly this, in turn, exacerbates global warming. This is said to explains why historical C02 and temperature records appear to show that the increase in atmospheric CO2 does not cause global warming and simultaneously demonstrates why CO2 does cause global warming.

As Skeptical Science puts it:

Thus while the initial warming hasn’t historically been caused by CO2, CO2 has amplified the warming for thousands of subsequent years, and thus is still the principal control knob governing Earth’s temperature.

AGW theory reportedly suggests that C02 is the “principle control knob” and, while the sun is the power switch, it is not the power supply. Radiative forcing appears to produce significant amounts of additional atmospheric heat energy, if AGW theory is to be believed.

The problem with this idea is that global temperatures have seemingly been historically as high if not higher than they are today, while CO2 levels were lower during those warm periods. For example, by sampling mercury levels in peat bogs as a climate proxy, Martinez-Cortizas et al. (1999) showed that the climate in north-west Spain was, on average, 1.5°C warmer during the Medieval Warm Period (c 950 to c 1250) and possibly up to 2°C warmer during the Roman Warm Period (c 250 BCE to c 400 CE) when compared to the stated modern average (1968 – 1998) at the time of publication.

These findings correlate with numerous other studies that show these warmer, relatively low CO2 periods. For example, Desprat et al. (2003) used pollen levels from core samples taken from the Iberian peninsula that also show both the Roman and Medieval warm periods. This is evidence that seemingly contradicts both the notion of unprecedented modern global warming and AGW theory.

Ljungqvist (2010) took multiple proxies from across the northern hemisphere to reconstruct historical temperatures. Again, these show both the Roman and the Medieval warm periods. During these periods, according to AGW theory proponents like NASA, atmospheric CO2 levels did not eclipsed 280 parts per million (ppm).

Fig 4: Ljungqvist (2010) Reconstruction of Temperature Variability

This kind of empirical evidence has led many scientists, including Rob Jeffrey, to question AGW theory in its entirety:

There is strong evidence that non-atmospheric culprits, for example, the sun, are primarily responsible for global warming and any climate change.

For example, Soon et al. (2015) found:

Using thermometer-based air temperature records for the period 1850–2010, we present empirical evidence for a direct relationship between total solar irradiance (TSI) and the Equator-to-Pole (Arctic) surface temperature gradient (EPTG). [. . .] Overall, evidence suggests that a net increase in the TSI, or in the projected solar insolation gradient which reflects any net increase in solar radiation, has caused an increase in both oceanic and atmospheric heat transport to the Arctic in the warm period since the 1970s [. . .].

In 2018, atmospheric scientist Rex J Flemming Ph.D noted:

Many believe and/or support the notion that the Earth’s atmosphere is a “greenhouse” with CO2 as the primary “greenhouse” gas warming Earth. [. . .] There is now a much clearer picture of an alternative reason for why the Earth’s surface temperature has risen since 1850. There is a thermal blanket or buffer for atmospheric surface conditions that has been in existence for the past billion years [. . .]. Its exact form depends on the effective solar energy reaching the Earth’s surface. The sources of the thermal blanket and the subsequent transfer of heat upward are from three forces: the Earth’s gravitational field with its impact on convection, the condensation of water vapor (H2O), and the radiation effects of the two primary atmospheric trace gases of H2O and CO2. It will be demonstrated that the radiative roles of H2O and CO2 are relatively minor.

Jeffrey highlights the work of the astrophysicist Professor Valentina Zharkova who has been the lead author of numerous papers highlighting how variable solar activity effects the known TSI impacts of the orbital cycles. Zharkova has identified many solar cycles, some as short as 11 years in duration. She has shown how these solar activity cycles either enhance or counteract the TSI effect of the major orbital cycles:

This approach revealed a presence of not only 11-year solar cycles but also of grand solar cycles with a duration of 350–400 years. [. . .] These grand cycles are always separated by grand solar minima of Maunder minimum type, which regularly occurred in the past, forming well-known Maunder, Wolf, Oort, Homeric, and other grand minima. During these grand solar minima, there is a significant reduction of the solar magnetic field and solar irradiance, which reduce terrestrial temperatures.

Globally, the planet is in a warming interglacial phase after emerging from the Little Ice Age that ended in the mid 19th century. With regard to recent warming, if we look at the data from the US National Oceanic and Atmospheric Administration (NOAA) temperature records set across all US states since 1890, the hottest decade in the US was the 1930s.

AGW theory states that it is man-made CO2 emissions from burning fossil fuels that have strongly exacerbated global warming. The bulk of these emissions are said to have occurred in the post WWII period. Which begs the question: why were the 1930’s the hottest decade of the 20th century in the US if CO2 levels rose markedly post WWII?

Fig 5: World Economic Forum – anthropogenic CO2 emissions since 1900

The Thames periodically froze solid during the Little Ice Age. Perhaps most regularly during of the solar Maunder minimum [c.1645–c.1715]. Even relatively recent global warming began prior to the notable post WWII increase in man-made CO2 emissions. If it hadn’t Londoners would still have been holding frost fairs on the frozen Thames in the 1920s.

It seems likely that global temperature rises over the last few centuries have been as a result of the Earth absorbing more shortwave solar radiation due to lower cloud albedo. The warming of the planet in the last 20 years is apparently due to the higher ultraviolet permeability of clouds. The degree of infrared radiative forcing, allegedly caused by the so-called greenhouse effect, appears negligible.

Dübal and Vahrenholt. (2021) stated:

We found the declining outgoing [reflected] shortwave radiation to be the most important contributor for a positive TOA (top of the atmosphere) net flux of 0.8 W/m² in this time frame. [. . .] We compare clear sky with cloudy areas and find that changes in the cloud structure should be the root cause for the shortwave trend. [. . .] The drop of cloudiness around the millennium by about 1.5% has certainly fostered the positive net radiative flux. [. . .] This leads together with a reduced incoming solar of −0.17 W/m² to a small growth of imbalance of 0.15 W/m². We further present surface flux data which support the strong influence of the cloud cover on the radiative budget.

These finding were corroborated by a NASA research team who published Loeb et al. (2021) which stated that 21st century warming was “primarily due to an increase in absorbed solar radiation associated with decreased reflection by clouds and sea-ice.” This references the observed reduction in planetary albedo.

Similarly, professor Antero Ollila found that the “SW [shortwave] anomaly forcing was the major reason for this temperature increase. SW anomalies have had their greatest impacts on the global temperature during very strong (super) El Niño events in 1997-98 and 2015-16”

Consequently, Rob Jeffrey noted:

The earth’s orbit causes these cycles around the sun, the different periods of the Earth’s Eccentricity cycle, the Obliquity cycle and the Precession of Equinoxes. Until the last 200 years, any significant climate change has been naturally driven [. . .], it is believed by many experts that these shorter-term cycles are driven by solar cycles. [. . .] These are caused by fluctuations in the solar flux [incoming shortwave radiation measured in W/m2], affecting cosmic ray penetration and cloud formation in the earth’s atmosphere leading to warming and cooling periods. [. . .] The remaining question is how much humans currently contribute to short-term global warming. Earth has been in similar short-term natural warming phases eight times over the last 11,000 years.

Questioning The Impact of Human CO2 Emissions

Perhaps the arguments we have explored here and in Part 1 show little more than scientific debate. However, even if we accept how the “enhanced greenhouse effect” is supposed to work, there is still further reason to question the AGW theory.

As Rob Jeffrey stated:

Even if CO2 is scientifically proven to cause some global warming, there is significant evidence indicating that human-made CO2 is only a tiny part of the overall global CO2 generated.

The atmosphere contains approximately 78% nitrogen, 21% oxygen and about 0.9% argon. The remaining 0.1% consists of carbon dioxide, nitrous oxides, methane and ozone. In addition, water vapour (H2O) is a notable variable. Some AGW theorists claim that greenhouse gases make up 1% of the atmosphere, but argon is not a greenhouse gas, so that doesn’t appear to be true.

Adding complexity, water vapour readily condenses into a liquid and evaporates back to a gas in the atmosphere. It’s transient nature means it can account for up to 3% of total atmospheric gases.

As is often reported, atmospheric CO2 currently constitutes more then 400 ppm of the atmosphere. That equates 0.04% of total atmospheric gases.

This suggests that CO2 accounts for about 40% of GHGs, if we temporarily discount water vapour. According to the US Energy Information Administration (EIA), throughout the 1990s, of an estimated annual average of 793 billion metric tons (bmt) of atmospheric CO2, approximately 23 bmt were the result of annual human emissions.

This suggests that human CO2 emissions accounted for about 3% of all atmospheric CO2 at the end of the last century. Human CO2 emissions have continued to increase during the first two decades of the 21st century. A current average of around 35 bmt, about 4.5% of total CO2 emissions, isn’t unreasonable. Consequently human CO2 emissions appear to represent approximately 1.8% of all GHGs—H2O content is a variable that impacts this figure.

The climate scientists who write at Skeptical Science state that the human induced enhanced greenhouse effect is the “principal control knob governing Earth’s temperature.” Unfortunately, if we radically transform every aspect of our lives and somehow manage to reduce human CO2 emissions to zero (which isn’t possible unless we go extinct) at least the 98.2% of annual global emissions of GHGs would seemingly remain.

This situation is further complicated by water vapour which can contribute 80% of GHG by mass and 90% by volume. Thus supposedly increasing the total alleged GHGs in the atmosphere. NASA states that water vapour is, by a considerable margin, the dominant GHG:

Water vapor is known to be Earth’s most abundant greenhouse gas. [. . .] [Researchers] used novel data from the Atmospheric Infrared Sounder (AIRS) on NASA’s Aqua satellite to measure precisely the humidity throughout the lowest 10 miles of the atmosphere. That information was combined with global observations of shifts in temperature. [. . .] Water vapor is the big player in the atmosphere as far as climate is concerned.

The variation of atmospheric H2O gas is said to be a product of the greenhouse effect, which causes further evaporation. Water vapour supposedly accounts for between 66% – 85% of the overall “greenhouse effect.” Crucially, in AGW theory, water vapour “does not cause global warming.” Apparently, while it is by far the most influential GHG it does not constitute a “forcing” GHG. “Radiative forcing” is reserved for other GHGs, such as CO2 and, too a much lesser extent, CH4 (methane).

If we accept that up to 90% of GHG by volume is water vapour, then this reduces the human emission of CO2 to about 0.3% of total GHGs. Leaving 99.7% of GHGs to contend with if we achieve “net zero” emissions.

As AGW theory rejects the notion that climate change is caused by the sun, the extent to which clouds alter the absorption of solar radiative flux is largely dismissed. This means the alleged “radiative forcing” of greenhouse gases includes water vapour as a passive product of the “forcing” GHGs, but excludes cloud cover as a significant variable for any corresponding “climate change.”

The IPCC explains this by stating that primarily human CO2 emissions, which represent about 0.3% of GHG’s (if we include water vapour), has a “net warming” effect, while water vapour, in its entirety, doesn’t. This is supposedly because CO2 has a much longer “residence time” in the atmosphere.

As noted by the EIA, of the total 793 bmt of emitted CO2, from both natural and human sources, 781 bmt were re-absorbed by the planet—via trees, oceans, weathering, etc.—in the same period.

This emission and absorption rate between carbon “reservoirs,” such as forests, mountains and oceans, is called the carbon cycle. The carbon “sink” is the measured amount of CO2 that absorbed or emitted by the reservoir per unit of time. This is measured, for example, in kilograms of CO2 per day—kg C/day.

Harde (2016) found:

We have critically scrutinized this [carbon] cycle and present an alternative concept, for which the uptake of CO2 by natural sinks scales proportional with the CO2 concentration. In addition, we consider temperature dependent natural emission and absorption rates, by which the paleoclimatic CO2 variations and the actual CO2 growth rate can well be explained. The anthropogenic contribution to the actual CO2 concentration is found to be 4.3%, its fraction to the CO2 increase over the Industrial Era is 15% and the average residence time is 4 years.

Noting this, Rob Jeffrey added:

The residence time of CO2 in the atmosphere is critical, as the longer, it remains in circulation, the longer any purported artificial imbalance will exist. The IPCC position (unproven) is that CO2 atmospheric residence time is 100+ years. Further evidence indicates that the CO2 atmospheric residence time is more like ten years (or less) — an extraordinarily significant difference with major ramifications.

This observation is entirely contrary to the claims of the IPCC and other promoters of AGW theory. Certainly with regard to the IPCC, as we shall discuss in Part 3, the fact that such findings are seemingly ignored may be due to political bias.

Questioning the AGW Computer Models

The reason the climate scientists insist that AGW is settled science, apart from the fact their funding is largely dependent upon them saying so, is that all the AGW theory based “climate models” are offered as if they are evidence supporting the theory. Models are dependent upon theory.

Even if subsequent measurements are congruent with the model, unless other explanations have been discounted, the model still doesn’t “prove” the theory. As Jeffrey, Clauser, Postma, Soon, Flemming, Lindzen, Giaever, Dyson, Curry, Spencer, Coombs and many other sceptical scientists and other sceptics have tried to highlight, not only is it illogical to claim a model “demonstrates” a theory, the AGW theory computer models frequently appear to be either biased or just plain wrong in any event.

Given that stratospheric cooling has been observed, according to Dr Hossenfelder and other climate scientists, concordance with Manabe and Wetherall’s 1967 model—see Part 1—“proves” AGW theory and supposedly dispels the notion that a change in solar radiation has anything to do with recent global warming. It is instead caused by an “enhanced greenhouse effect” they say.

As mentioned in Part 1, Santer et al, (2023) claims to have detected the supposedly undeniable AGW theory “fingerprint.”

When looking at the signals in the mid to upper stratosphere Santer et al. (2023) noted that the 1991 Mount Pinatubo eruption caused stratospheric warming but that after the initial warming period the volcanic eruption “augments the gradual anthropogenically induced stratospheric cooling.” It should be noted that this is the observed augmentation of an unproven theoretical effect.

Satellite data from the University of Alabama shows the volcanic stratospheric warming and subsequent cooling effects following both the El Chichon (1982) and Mt Pinatubo (1991) eruptions. After each eruption stratospheric temperatures settled lower than they were prior to each eruption. Rather than a monotonic linear temperature decline, the data indicated that volcanic activity led to a marked downward step in stratospheric temperatures. In 2009 the US National Center for Atmospheric Research wrote “the stratospheric changes are not monotonic [not consistently linear in a single downward trajectory], but more step-like in nature.”

Fig 6: Non monotonic “step down” in stratospheric temperatures following volcanic eruptions

In January 2022 the the underwater Hunga Tonga-Hunga Ha-apai volcano erupted. Sellito et al. (2022) stated:

We find that the Hunga Tonga-Hunga Ha-apai eruption produced the largest global perturbation of stratospheric aerosols since the Pinatubo eruption in 1991 and the largest perturbation of stratospheric water vapour observed in the satellite era. [. . .] The likely stratospheric ozone depletion due to aerosol and water vapour injections might produce a large additional cooling of the stratosphere.

Ozone (O3) has a heating effect in the stratosphere, as noted by NASA in 2004:

Ozone generates heat in the stratosphere, both by absorbing the sun’s ultraviolet radiation and by absorbing upwelling infrared radiation from the lower atmosphere (troposphere). Consequently, decreased ozone in the stratosphere results in lower temperatures. Observations show that over recent decades, the mid to upper stratosphere (from 30 to 50 km above the Earth’s surface) has cooled by 1° to 6° C (2° to 11° F).

The stratospheric cooling potentially caused by the Hunga-Tonga eruption was clearly observed by Schoeberl et al. (2023). This and earlier findings, following the El Chichon and Mt Pinatubo events, suggests that stratospheric cooling is more than just “augmented” by volcanic activity. It cannot be ruled out that volcanic eruptions are, in fact, a significant driver of ozone depletion and, therefore, stratospheric cooling.

The other aspect of the claimed AGW theory “fingerprint” is that stratospheric cooling occurs concurrently with tropospheric warming, all allegedly caused by the “enhanced greenhouse effect.” But lower planetary albedo results in more shortwave “ultraviolet” radiation warming the earth. Data from NASA’s CERES EBAF readings suggest that the the Earths albedo, particularly in the northern hemisphere which has far greater “blackbody” land mass, has reduced significantly over the last 20 years.

In addition, Ozone depletion, cooling the stratosphere, also increases the amount of ultraviolet (UV) radiation that reaches Earth’s surface. This, combined with reduced albedo, suggests the Earth is absorbing more solar shortwave “ultraviolet” radiation, warming the planet. Volcanic ozone depletion has evidently contributed to the process.

Santer et al. (2023) stated that from 1986 to 2022, human-produced greenhouse gases caused warming of the Earth’s surface. Data from CERES EBAF and evidence from Schoeberl et al. (2023) among others, suggests warming caused by increased solar radiative flux. The surface could be warmed by the sun and the stratosphere could cool as a result of natural variability.

Seen from this perspective, there is no conclusive AGW theory “fingerprint,” as claimed by some “climate scientists.” Manabe and Wetherall’s 1967 model simply offers another possible explanation.

We might also question both the degree and the pattern of tropospheric warming alleged in the AGW climate models. For example, Mitchel et al. (2020) found evidence of consistent bias in the AGW climate models that tended to exaggerate both tropospheric warming and stratospheric cooling:

[. . .] we find considerable warming biases in the CMIP6 [Coupled Model Intercomparison Project] modeled trends, and we show that these biases are linked to biases in surface temperature. We also uncover previously undocumented biases in the lower-middle stratosphere: the CMIP6 models appear unable to capture the time evolution of stratospheric cooling, which is non-monotonic.

Jain et al. (2023) have suggested the reason AGW models are frequently at odds with the empirical data is because of poorly understood “internal variability”:

The scientific literature presents many examples where a mismatch between model and observed climate features has been reported, such as trends in regional rainfall amount and temperature, multidecadal changes in atmospheric circulation and climatology, the frequency or magnitude of extreme events [. . .] or external forcing effects. There can be many reasons why models disagree with observations. However, [. . . ] a lack of agreement between the modeled and observed climate can still arise simply due to chaotic internal variability

Ayer et al. (2021) defined internal variability as “the natural variability of the climate due to its chaotic and nonlinear nature.” The IPCC concedes that the climate is a chaotic system that defies accurate prediction:

The climate system is a coupled non-linear chaotic system, and therefore the long-term prediction of future climate states is not possible. Rather the focus must be upon the prediction of the probability distribution of the system’s future possible states by the generation of ensembles of model solutions.

The fact that “long-term prediction of future climate states” are, according to the IPCC, impossible, rather undermines all the current “climate alarm” about what the climate will be like in a hundred or two hundred years. Perhaps “the generation of ensembles of model solutions” can predict “the probability distribution” of likely future climate states, but nearly all of the models referenced by the IPCC are constructed solely from a AGW theory. They could all be fundamentally flawed.

“Equilibrium climate sensitivity” (ECS), in accordance with AGW theory, is defined in Sherwood et al. (2020) as “the steady-state global temperature increase for a doubling of CO2.” The Sherwood paper offered an AGW theory based ECS model. It was extremely influential in the IPCC’s 6th Assessment Scientific Report (AR6), published in 2021.

Hitherto, the IPCC ARs claimed that doubling in C02 would cause somewhere between 1.5°C and 4.5°C of “global warming.” This changed in AR6, largely thanks to the Sherwood model, to a claim that the ECS would allegedly lead to 2.5°C of warming or maybe up to 4.5°C, or perhaps 5°C.

When independent researcher and mathematician Nic Lewis checked the methodology of the Sherwood paper, cited more than twenty times by the IPCC, he claimed to have found significant errors, inconsistencies and other mathematical shortcomings. Using the same dataset but different analysis techniques, Lewis found that ECS leading to “between 1.5 °C and 2 °C” warming. Considerably lower than the Sherwood influenced IPCC claims.

Dr Roy Spencer is a former Principal Research Scientist at the University of Alabama in Huntsville and Senior Scientist for Climate Studies at NASA’s Marshall Space Flight Center. He is currently team leader for the Advanced Microwave Scanning Radiometer on NASA’s Aqua satellite. Dr Spencer contends that climate sensitivity, suggesting that man-made CO2 emissions are causing an “enhanced greenhouse effect,” overlooks internal variability to such an extent that the “enhancement” is virtually undetectable.

Consequently he is called a climate denier by the legacy media. Nonetheless, Dr Spencer states:

Global warming” refers to the global-average temperature increase that has been observed over the last one hundred years or more. But to many politicians and the public, the term carries the implication that mankind is responsible for that warming. [. . .] Figuring out how much past warming is due to mankind, and how much more we can expect in the future, depends upon something called “climate sensitivity” [ECS]. [. . .] You would think that we’d know the Earth’s ‘climate sensitivity’ by now, but it has been surprisingly difficult to determine.

Wikipedia tells us:

In technical terms, climate sensitivity is the average change in global mean surface temperature [GMST or just GST] in response to a radiative forcing

The GST is currently calculated by averaging the temperatures anomalies of the oceans (sea surface temperature – SST) and the surface temperature anomalies of continents (surface air temperature – SAT). These are absolutely essential inputs into the AGW theory “climate sensitivity” based models.

NASA’s Goddard Institute for Space Studies (GISS) provides the IPCC with “estimates” for the SAT which is the air temperature within about 2m above the Earths surface. The so-called “GISTEMP analysis” provides one of the four key dataset inputs into the IPCC’s favoured AGW theory models. When considering what the SAT is and how to measure it, until 2018, GISS stated that it:

[. . .] doubt[s] that there is a general agreement how to answer this question. [. . .] To measure SAT we have to agree on what it is and, as far as [GISS] know, no such standard has been suggested or generally adopted.

In terms of working out the SAT component of the GST, GISS added:

Again, there is no universally accepted correct answer. Should we note the temperature every 6 hours and report the mean, should we do it every 2 hours, hourly, have a machine record it every second, or simply take the average of the highest and lowest temperature of the day? On some days the various methods may lead to drastically different results.

GISS has more recently updated its thoughts on this issue. It now states:

SAT varies quite substantially and so this number is not necessarily reflective of a broader area average. SAT maps can only be created using a model of some sort. [. . .] In the global average, this variation is around 0.5°C

and

[. . .] different approaches can give systematically different answers depending on the specifics of the weather that day. [. . .] [D]ifferent models will produce slightly different estimates of the SAT. [. . .] Statistical approaches (such as used by Jones et al. (1999)) have a similar uncertainty.

To be clear: there is no universally accepted, systematic methodology even to calculate the current average SAT of the Earth. Yet nearly all AGW theory based models rely upon calculated SAT for the input “climate sensitivity.”

Santer et al. (2021) (not 2023) showed that between 1988 to 2019 the observed sea surface temperature [SST], tropospheric temperature, and total tropospheric water vapour showed less tropical warming than predicted by the AGW theory climate models. The conclusion was not that the AGW theory computer models could possibly be awry but that the “large uncertainties in observations” needed to be accounted for.

The legacy media exploited the paper to amplify climate alarm by reporting that satellite readings had underestimated global warming for 40 years. While this is not what the paper said, it could certainly be inferred from it and that is the story that was told.

Upon examining the Santer et al. (2021) paper, Dr Roy Spencer noted:

I conclude that there is nothing new in the paper that would cast doubt on the modest nature of tropospheric warming trends from satellites — unless one believes climate models as proof, in which case we don’t need observations anyway. [. . .] [T]he Santer et al. study [is] largely consistent with the view that global warming is proceeding at a significantly lower rate that is predicted by the latest climate models, and that much of the disagreement between models and observations can be traced to improper assumptions in those [AGW theory] models.

Recently more than 1,800 signatory scientists, academic researchers and other AGW theory sceptics, including Nobel Laureate scientists, issued a joint statement:

To believe the outcome of a climate model is to believe what the model makers have put in. This is precisely the problem of today’s climate discussion to which climate models are central. Climate science has degenerated into a discussion based on beliefs, not on sound self-critical science. Should not we free ourselves from the naive belief in immature climate models?

We are supposed to believe that the science is settled and to question “the Climate Science™” constitutes some sort of heresy. The UN and its IPCC are among the “intergovernmental” bodies that not only demand that we unreservedly agree with whatever they tell us but, if we don’t, accuse us of engaging in a form of hate speech.

As we shall discuss in Part 3, the IPCC and other proponents of AGW theory have gargantuan conflicts of financial interest. Public and private institutions and organisations that push AGW theory have a clear political agenda that has little to do with addressing any environmental concerns. Nor does there appear to be any evident basis for “climate alarm.”

In Part 3 we explore the evidence that suggests the narratives we are given about the alleged “climate emergency” are nothing more than propaganda.

I extend my gratitude to my editor, who has provided invaluable contributions to my articles since October 2021 (but who, for personal reasons, prefers to remain anonymous).

You can read more of Iain’s work at his blog IainDavis.com (Formerly InThisTogether) or on UK Column or follow him on Twitter or subscribe to his SubStack. His new book Pseudopandemic, is now available, in both in kindle and paperback, from Amazon and other sellers. Or you can claim a free copy by subscribing to his newsletter.

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