The Collapse of IPCC Credibility

Denmark is in the area of isostatic rebound from the last Ice Age, like most of northern Europe, Asia, and North America. The coastline around Hudson Bay, for example, has risen dozens of meters just in historical times. That means the seafloor under Hudson Bay has also been rising, displacing seawater to elsewhere on the planet. Global sea level increase is therefore fully explained by the isostatic rebound of such formerly glaciated continental shelves in the Northern Hemisphere, with no contribution from purported global warming needed.

 

The IPCC's models are a big part of the problem, but not the only part.
Climate Model Bias 1: What is a Model?

By Andy May
There are three types of scientific models, as shown in figure 1. In this series of seven posts on climate model bias we are only concerned with…

". . . Confirmation[27] and reporting bias[28] are very common in AR6. We also find examples of the Dunning-Kruger effect,[29] in-group bias,[30] and anchoring bias.[31]

In 2010, the InterAcademy Council of the United Nations reviewed the processes and procedures of the IPCC and found many problems.[32] In particular, they criticized the subjective way that uncertainty is handled. They also criticized the obvious confirmation bias in the IPCC reports.[33] They pointed out that the Lead Authors too often leave out dissenting views or references to papers they disagree with. The Council recommended that alternative views should be mentioned and cited in the report. Even though these criticisms were voiced in 2010, I and my colleagues, found numerous examples of these problems in AR6, published eleven years later in 2021 and 2022.[34]

Although bias pervades AR6, this series will focus mainly on bias in the AR6 volume 1 (WGI) CMIP6[35] climate models that are used to predict future climate. However, we will also look at the models used to identify and quantify climate change impacts in volume 2 (WGII), and to compute the cost/benefit analysis of their recommended mitigation (fossil fuel reduction) measures in volume 3 (WGIII). As a former petrophysical modeler, I am aware how bias can sneak into a computer model, sometimes the modeler is aware he is introducing bias into the results, sometimes he is not. Bias exists in all models, since they are all built from assumptions and ideas (the “conceptual model”), but a good modeler will do his best to minimize it.

In the next six posts I will take you through some of the evidence of bias I found in the CMIP6 models and the AR6 report. A 30,000-foot look at the history of human-caused climate change modeling is given in part 2. Evidence that the IPCC has ignored possible solar influence on climate is presented in part 3. The IPCC ignores evidence that changes in convection and atmospheric circulation patterns in the oceans and atmosphere affect climate change on multidecadal times scales and this is examined in part 4. . . . "

 

There is a long history of attempts to create models that are not discredited by observations. Those attempts are thus far mostly unsuccessful.

Climate Model Bias 2: Modeling Greenhouse Gases

By Andy May

Since the late 19th century, with the work by Svante Arrhenius, climate models have been used to estimate the amount of global warming due to human greenhouse…

 

The IPCC continue to damage themselves by presenting hockey stick reconstructions.

IPCC’s New “Hockey Stick” Temperature Graph
Posted on March 1, 2024 by haakonsk
The United Nations’ Intergovernmental Panel on Climate Change (IPCC) published their latest assessment report (AR6) in 2021. In 2023, the Clintel Foundation published a report which criticizes AR6.

Continue reading →

. . . .
Conclusion

Whether the average global temperature of the past 2000 years forms a hockey stick pattern or not might not be possible to determine from existing proxy records. And there’s disagreement in the scientific literature about how much the pre-industrial global temperature has varied since year 0.

Although the IPCC knew about the disagreement, they still chose to rely on a single temperature reconstruction for the past 2000 years (PAGES 2k 2019) in their latest assessment report. That in itself is unfortunate, since they’re supposed to make an objective assessment of the scientific literature. It’s even more unfortunate considering all the criticism PAGES 2k 2019 has received.

Did the IPCC want to present a hockey stick temperature graph? The Clintel Foundation and McIntyre believe so, and I wouldn’t be surprised, either. But it’s hard to prove.

 

The IPCC does not take the Sun into account.
Climate Model Bias 3: Solar Input

By Andy May
In part 2 we discussed the IPCC hypothesis of climate change that assumes humans and our greenhouse gas emissions and land use choices are the climate change…

Summary
The goal of this post is not to convince anyone that solar variability is responsible for all or part of modern global warming, a subject that is well covered elsewhere.[24] The point is that the IPCC reports and the CMIP models do not consider or investigate this possibility.

It is true that exactly how solar variability occurs and how it affects climate are not known, but the Sun does vary, and the variations correlate with climate changes. It is unlikely that climate changes are a direct result of the change in insolation, the solar changes are amplified by Earth’s climate system somehow.

We also do not know how much solar output has varied since 1650, the middle of the devastatingly cold Little Ice Age and the onset of the Maunder Solar Grand Minimum. There are several possible reconstructions of solar output since then. Figure 3 shows one of them constructed from an ice core beryllium-10 isotope record by Steinhilber, et al. The major climatic periods since 0AD are noted on it, and the Solar Grand Minima are identified.


Figure 3. The Steinhilber, et al. (2009) TSI reconstruction from 10berylium isotopes. The solar grand minima are identified, as well as the major climatic periods since 0AD.
The absolute values of delta-TSI (the change in total solar irradiation), in W/m2, plotted in Figure 3 are based on one of many possible modern TSI reconstructions (PMOD) and may not be accurate, but their values relative to one another are reasonable. None of the modern satellite TSI reconstructions are well supported, and the debate over which one is the best is furious and ongoing. See the discussion here for an introduction to the debate. It is best to not consider the absolute value of the Y axis in Figure 3, and consider it a TSI index, no one really knows how much TSI has changed, even over the satellite era. Further, as we’ve seen, how TSI changes relate to climate changes quantitatively is also not known. All we know is that they generally change together.

In Figure 3 we can see that colder periods, like the Little Ice Age, have some solar peaks and some warmer periods, and the Medieval Warm Period has solar lows. None of the climatic periods identified in Figure 3 were uniformly cold or warm. What we call the Little Ice Age, had some hot periods, and the Medieval Warm Period had cold periods (see the section after figure 2 here for references). Further, the correlation between solar activity and climate is not exact, nor is it uniform and synchronous over the whole planet. This is probably because of the effects of convection and atmospheric and oceanic circulation that I examine in the next post. Climate change is complicated.

The beginning and end of the climate periods identified in figure 3 are approximate, and mostly a judgement call. All the climate periods start and end at different times in different places.

However, we do know that some solar proxy reconstructions correlate well with climate proxies since 1850 (see Table 1 here),[25] and that alone is justification for additional research. Solar variability can explain anywhere from zero to almost 100% of the warming since 1850, depending upon the datasets used.[26]

This is a very brief summary of the evidence that changes in solar activity affect climate. More comprehensive discussions of possible mechanisms and the evidence for them are available.[27] Suffice it to say that this is an area of research that is too often ignored and brushed away as unimportant, especially by the IPCC. The sometimes excellent correlations in the peer-reviewed literature between solar activity and climate change alone should be enough to spur research. The fact that the IPCC has ignored these correlations is evidence of bias.

A point we will make many times in this series is that the Earth is not a uniform single thermodynamic body. Its surface is constantly changing. Treating it as a simple thermodynamic body, and one that can be characterized by a global average temperature is a huge mistake. Next, in part 4, we will discuss the potential impact of long-term changes in convection patterns.

 

The IPCC gets a failing grade in their treatment of Earth's atmospheric circulation system.
Climate Model Bias 4: Convection and atmospheric circulation

By Andy May

In part 3 we discussed the relationship between changes in solar activity and climate changes. Exactly how solar changes affect climate is not understood. It isn’t the immediate change in radiation delivered to the Earth, since that is too small to have much of an effect. So, it must be how Earth’s climate system reacts to the changes. The observed impact of solar irradiance changes over the solar cycle on the climate is much larger than the change in delivered radiation can account for.[1] A likely amplifying mechanism is Earth’s convection and atmospheric circulation system. This post examines that idea. It is yet another important idea that the IPCC and AR6 ignore and brush away as unimportant, vis-à-vis global warming. . . .

 

The IPCC routinely ignores research results that undermine the approved narrative.

Climate Model Bias 5: Storminess

By Andy May

In part 4 the impact of convection and atmospheric circulation on climate was discussed. When circulation patterns change, they change the speed and efficiency of the transport…

Zhongwei Yan and colleagues, which include Philip Jones and Anders Moberg, found that extreme weather has decreased, especially in the winter months since the 19th century, as the world has warmed.[7] They note that the relationship between warmth and weaker weather is most pronounced in Europe and China in the critical winter months. In contrast to Yan, et al., AR6 reports:

“… both thermodynamic and dynamic processes are involved in the changes of extremes in response to warming. Anthropogenic forcing (e.g., increases in greenhouse gas concentrations) directly affects thermodynamic variables, including overall increases in high temperatures and atmospheric evaporative demand, and regional changes in atmospheric moisture, which intensify heatwaves, droughts and heavy precipitation events when they occur (high confidence). Dynamic processes are often indirect responses to thermodynamic changes, are strongly affected by internal climate variability, and are also less well understood. As such, there is low confidence in how dynamic changes affect the location and magnitude of extreme events in a warming climate.”

AR6 WGI, page 1527
Thus, in spite of the evidence reported by Yan, et al. and many others (see Chapter 11 in The Frozen Climate Views of the IPCC), AR6 has concluded that anthropogenic global warming is causing and has caused increases in extreme weather. This is another example of bias. . . .

 

Jack there is a huge glaring hole in your OP!

You insinuated the IPCC possessed a modicum of credibility prior to the expose'. The IPCC was exposed as a corrupt propaganda outlet back in 2001. So much so, any attempt to regain any semblance of credibility whatsoever would exceed the 100 or more year timeframe necessary to resolve the debate with real-time measurements. Seeing as only 20 years have elapsed I'm quite certain you have been overly generous insinuating they were only recently exposed in 2023.

In 2001 shortly after Gore lost his bid for the presidency, ~50,000 emails were hacked from the UN's IPCC and made public. Touted as the top echelon of climate scientists throughout the world. Many thousands of email chains were made public clearly revealing the methods the "scientists" were using to alter the data to support their attempt to "Chicken Little" the issue of Global Warming, and worst of all indicated they knew it was a hoax and that GW was a myth and a fabrication. They had to publicly admit their wrongdoings to avoid being charged and convicted to avoid long jail sentences. What they were basically doing was making up Global Warming and whipping up hysteria so they could obtain funding from various member nations (especially the US) for their personal gain (essentially fraud to the tune of what they hoped was $2 Trillion from the US alone). Al Gore's campaign number.

One of the most damning was an email chain among the top 20 scientists the UN put in charge of the worldwide climate initiative. At the conclusion of which was a particularly telling statement paraphrased:

I think we all agree the election of Bush has closed our window of opportunity to obtain the $2T in funding from the US we were hoping for. Now that the 1998 peak in global temperatures has been reached, by the time another such opportunity presents itself prolonged decreases in temperature will have become apparent as the trough approaches. Might I suggest we shift our tactics by altering the terminology from Global Warming to something along the lines of Climate Change. I suggest we use this term for the foreseeable future to better align with the reality during the downward have of the cycle.

In other words, they knew it was a cycle and they new it had passed the peak. Which is also why they felt compelled to alter the data.

It was the first time I read the words Climate Change. Since the email release they have had ZERO credibility. To my amazement, the environmental wackos completely turned a blind eye to the fact that even their own top guys (the ones pushing the whole hoax) knew it was BS and eagerly embraced the new terminology. It's no longer GW that is the problem, it is drastic changes in the weather patterns. Now they don't care if it goes up or down. ANY CHANGE EITHER WAY and they run to the windows and scream Climate Change!!! Record snowfall - Climate Change. Drought - Climate Change. Wildfires - Climate Change. A hurricane - Climate Change. Heard 1 rube claim we were responsible when they announced increased solar flares. Amazing how so many can be so gullible. They just ignore the fact they've already been exposed and forced to resign (at least those at the very top). Is it any wonder people who gets paid to be Climatologists would find benefit in stirring up hysteria? Convince everyone the world is about to end and you are the only one with the solution. Great gig if you can get it.

 

The IPCC's climate model narratives don't include the benefits of warming and increased CO2.
Climate Model Bias 6: WGII
Andy May
The IPCC AR6 WGII report examines the impact of climate change but ignores the benefits of warming and additional CO2. . . .

. . . . WGII liberally discusses the potential negative impact of climate change,[4] and they discuss the potential benefits of their recommended adaptation and mitigation policies, but the report rarely mentions the well documented potential benefits of global warming and additional atmospheric CO2. [5] The fact that WGII only considers the problems of climate change and not the benefits, reveals their bias and invalidates their analysis. Even when mentioning a benefit, they find something negative in it. For example, they mention that elevated CO2 benefits woody plants, but that woody plants can cause an increase in atmospheric carbon.[6]

As Brian O’Neill writes, while many studies anticipate problems in the future, they also predict a future where humanity is better educated, better fed, longer lived, healthier, with less poverty, and less conflict. This is simply continuing a trend that has been underway for many decades.[7] O’Neill reports that currently there are 700-800 million people at risk of hunger globally. By 2050, even including the possible effects of 2°C of warming, that number will fall to 250 million.[8] . . . .

 

How the IPCC went wrong.

How we know the sun changes the climate. III: Theories
Posted on June 11, 2024 by curryja
By Javier Vinós

Part I in this series on the Sun and climate described how we know that the Sun has been responsible for some of the major climate changes that have occurred over the past 11,000 years. In Part II, we considered a range of changes that the Sun is causing in the climate today, including changes in the planet’s rotation and in the polar vortex that are changing the frequency of cold winters.

None of the evidence for the Sun’s effect on climate we reviewed is included in the IPCC reports. The role of the IPCC is to assess the risk of human-induced climate change, not to find the causes of climate change, which since its inception has been assumed to be due to our emissions.

Continue reading →

 

Bingo. The IPCC is a political organization, not a scientific organization. Its explicitly stated goal is not to advance the understanding of climate change, but to contrive justifications for pushing anthropogenic explanations -- i.e., the CO2 climate narrative -- regardless of the empirical evidence.

 

The IPCC has descended into mere advocacy.
IPCC U-Turn as it Prepares to Start Blaming Humans for Bad Weather
From THE DAILY SCEPTIC
by Chris Morrison

Fears are growing that the Intergovernmental Panel on Climate Change (IPCC) could water down or even ditch its current finding that almost all types of extreme weather events have little or no sign of past human involvement, or any going forward to 2100.

The finding in its recent sixth assessment report is a major thorn in the side of alarmists since ‘extreme’ weather event attribution has recently risen to become the major scare tactic used to promote the Net Zero fantasy. The IPCC finding has been ignored and a large pseudoscience ‘attribution’ industry has been created within the Green Blob to feed improbable and uncheckable ‘scientists say’ stories into the mainstream. At a recent ‘scoping’ meeting to prepare for the IPCC’s seventh assessment report, the press release claimed, in direct contradiction of previous work, that a century of burning fossil fuels has resulted in “more frequent and more intense extreme weather events that have caused increasingly dangerous impacts”.

The position on not attributing bad weather directly to anthropogenic causes has been a great credit to the IPCC. It has often faced justifiable criticism in the past that it is a biased body highly selective in the science it highlights. Recent research from Clintel discovered that no less than 42% of its climate scenarios used worst-case ‘pathways’ of highly improbable temperature rises. Its ‘Summary for Policymakers’ (SPM) is a political document and has to be agreed by politicians from all 195 subscribing countries. Curiously, the IPCC assessment statement that the high-temperature pathway was of “low likelihood” was missing from the more widely-distributed SPM.

Nevertheless, the IPCC in its original 1998 remit is mandated with acting on an “objective, open and transparent basis” when investigating human-induced climate change. It is also established that its reports should be “neutral with respect to policy”. All the evidence points to these instructions being often ignored.

The distinguished science writer Roger Pielke Jr. sees clear dangers ahead noting the comments of the new IPCC Chair Professor Jim Skea at the recent COP 29 in Azerbaijan which he said focused entirely on advocacy. “I want to focus most of my remarks on the opportunities – and indeed the benefits – of near-term action. But first a few words on urgency,” said Skea. It is not within the IPCC’s mandate to call for action or implore urgency, observes Pielke. “There are plenty of groups who play that role. There is only one IPCC,” he added.

Of course it has long been observed that the original IPCC remit to investigate human-caused climate change leads inevitably to a slanted narrative. It was never on the cards that the IPCC would find humans had a negligible effect on the climate since its existence would be called into question. Twenty-five years later and an elite global political movement funded by almost unlimited subsidies has arisen to capture the commanding heights of economic and social life. It needs the IPCC onside, and the IPCC, and thousands of grant-hungry scientists, need it to survive.

Looked at in these terms, it is obvious that there will be pressure for the removal of the IPCC’s irritating statement that humans have not been causing much of the weather to get worse. The press release provides further clues about the possible future direction of travel. “Impacts are to intensify with every fraction of additional warming, particularly for the most vulnerable communities, accounting for 3.3-3.6 billion people.” Such precision in some scary numbers – where do they pull these figures from? For his part, Roger Pielke notes that the statement reads like “boilerplate from any garden-variety climate advocacy group, and not what one would expect from a leading international scientific assessment”.

Meanwhile, the attribution forces continue to grow. Professor Richard Betts, Head of Climate Impacts at the U.K. Met Office and recently appointed as a Special Adviser to the Climate Change Committee, recently said weather can only be attributed once all factors are considered and “human influence remains the only reasonable mechanism driving that change”. Just from these comments it might be understood why the IPCC has held back on attribution. Running a number of opinions about a chaotic, non-linear atmosphere full of complex natural variations through a computer model and concluding humans might be responsible is not science, it is pseudoscience since its findings cannot be checked or falsified.

Roger Pielke is particularly unimpressed with what he calls “weather attribution alchemy”. In his view, attribution science is a form of “tactical science”. Such science serves legal and political ends, and the work is “generally promoted via press release”. The IPCC itself has noted that the usefulness and applicability of available extreme weather attribution methods remain “subject to debate”. Unless scientists find a way to turn pseudoscientific opinion into scientific fact, it can only be hoped that the IPCC’s current stand against the attribution industry survives all the debate and political pressure in its forthcoming assessment review.

Chris Morrison is the Daily Sceptic’s Environment Editor.

 

The IPCC's narrative takes another hit.
New Study: Recent ‘Unprecedented’ Cloud Cover Decline Driving Modern (And Past) Climate Change
By Kenneth Richard on 25. March 2025

“[T]he increase in absorbed solar radiation is primarily due to natural variations in cloudiness and surface albedo, which have served as the main forcing factors of the flux above the atmosphere over the last 2 decades.” – Diodato et al., 2025
It is commonly accepted that there has been a satellite-observed (CERES) cloud cover albedo decline that has led to an increase in solar radiation absorbed by the Earth’s oceans. This increasing trend in absorbed solar radiation (ASR) explains the post-2000 global-scale temperature increase (Dübal and Vahrenholt, 2021, Loeb et al., 2021, Stephens et al., 2022, Koutsoyiannis et al., 2023, Loeb et al., 2024, Nikolov and Zeller, 2024).

And now, in two new studies (Diodato et al., 2024 and Diodato et al., 2025), scientists have begun formulating reconstructions of cloud cover over the Mediterranean region that can be dated all the way back to the Medieval Warm Period, or 970 CE.

The authors suggest their reconstructions of cloud cover may be representative of more than just this region, as it is a product of large scale processes that may “transcend geographical boundaries.” In other words, what happens in the Mediterranean region may well have global implications.

Their reconstructions indicate the modern declining cloud cover trend may not only have been occurring since 2000, but, except for a brief increasing period from about 1945 to 1980 (that coincided with a global cooling trend), it has been ongoing for over 200 years. The “turning point” years were 1815-1818, following the eruption of Mount Tambora. From that point on there has been a precipitous decline in cloud cover that departs from multi-decadal variability.

The authors suggest the “dominant” factors linked to the post-1800s warming trend include solar forcing, volcanic forcing, and the Atlantic Multi-decadal Oscillation (Diodato et al., 2024).

In other words, the modern warming as well as the past climate changes may be “primarily due to natural variations in cloudiness and surface albedo, which have served as the main forcing factors” (Diodato et al., 2025).



Image Source: Diodato et al., 2025

Image Source: Diodato et al., 2024

 

The Medieval Warm Period remains the crushing rebuttal to climate alarmist claims.

The Medieval Warm Period In Germany: Inconvenient And very Real
By P Gosselin on 25. April 2025

By KlimaNachrichten


Grok AI generated image.

Hans-Joachim Dammschneider has written a book about the climate history of the southern Harz region. In the historical weather data, he discovered climatic fluctuations that, according to the Intergovernmental Panel on Climate Change (IPCC), should not exist.

Long before industrial CO2 accumulated in the atmosphere, there were already alternating warm and cold phases.

Here is the book description:

The so-called Medieval Warm Period (MWP) has been the subject of scientific debate for years. It is not so much a question of whether this warm period actually took place in Europe, but rather how it took place. Was it a local phenomenon that was limited in time and predominantly restricted to Europe, or was it a period of intense climatic change that also had a global impact?

One thing is certain: from around 950 AD, there was a rise in temperature in Germany lasting at least 300 years, which resulted in a marked warm phase favorable to agriculture and life. However, from the beginning of the 14th century at the latest, this period was replaced by a relatively rapid drop in temperature and climatic turbulence in the direction of the so-called Little Ice Age.

In the early reports, the IPCC (1990, AR1) still devoted relatively much attention to the MWP. Over the years, however, this focus diminished, and in the most recent assessment (2021, AR6) little space was given to the Medieval Warm Period. Studies often even question whether it was a global phenomenon. However, a mapping of the available scientific publications (as of 2022) initiated by S. Lüning shows that the Warm Period certainly left evidence across continents.

From the perspective of natural and cultural history, many accounts show that Germany was in a phase of intense cultural and economic growth from around 1000 AD. This period is characterized by the founding of numerous towns, the expansion of agricultural land and strong population growth. Forests were cleared, building methods influenced, and rising temperatures and the resulting positive agricultural economy contributed to prosperity.

Of course, there were no scientific methods for recording the weather, but modern climate research uses so-called “proxies” to derive the climate parameters of the time. For example, the cultivation of figs north of Cologne, successful wine production as far as Schleswig-Holstein and (overall) the PFISTER index resulting from numerous features indicate a longer phase of mild temperatures and favorable climatic conditions. Climate-numerical backward simulations basically confirm this ‘warm period’.

Historically, such periods were often periods in which life flourished – an idea that plays a rather ambivalent role in the climate debate for the 21st century.

The example of Walkenried Monastery and the southern Harz monastery landscape shows the solid consequences of the MWP: the reclamation of swampy areas, the development of the Upper Harz water management system, the promotion of mining and the intensive use of wood for construction and energy purposes are just a few examples.

However, this phase of monastic prosperity between 1130 and 1300 AD was apparently brought to an end by a rapid drop in temperature. The onset of the ‘Little Ice Age’ brought very uncomfortable weather conditions that lasted until the end of the 18th century. As early as the beginning of the 14th century, the country was hit by destructive rainfall and floods (“Schluchtenreisen” / Magdalenenflut), failed harvests followed intense droughts (Dante anomaly) and devastating plagues with millions of deaths in epidemics partly destroyed social structures. These instabilities and hardships, which were not least determined/induced by the climate, certainly had devastating effects on the livelihoods of the monasteries in the southern Harz region. They led to considerable internal crises (including the loss of converts and lay brothers) and ultimately the end of the Walkenried monastic ‘group’ (with the abandonment of large areas of the Harz ore mining industry) in the 15th century.

If this was the case, what overarching climatic processes contributed to this? It can be assumed that, in addition to temperatures, other factors such as the duration of sunshine also played an important role in the living conditions: The sun indeed seems to have been ‘the’ factor of the MWP, whereas CO2 is that of modern times … .

Recent analyses and the AMO (Atlantic Multidecadal Oscillation) index, which can be traced back to 900 AD, indicate that cyclical SST (Sea Surface Temperature) energy influences from the Atlantic could have significantly influenced cloud cover and thus sunshine duration and temperatures in Europe. These interactions were also important for the southern Harz and Walkenried. Can evaluations of current climatic processes indirectly allow conclusions to be drawn about past physical and social changes with associated phases of ascent and descent between 1000 and 1400 AD?

The present study examines these questions and attempts to draw conclusions for the interactions of the medieval climate from large-scale processes of potential ‘teleconnections’ and oceanic cycles. The book is intended, among other things, as a sequence of steps that helps to better understand the complex interrelationships of medieval climate change. It shows which ‘natural’ parameters could have contributed to the rise and fall of Walkenried Monastery.”

Hans-J. Dammschneider (2025)
Klimageschichte der Südharzer Klosterlandschaft – Kloster Walkenried
ISBN 9783759779878, 106 pages, Hamburg/Norderstedt 2025

 

IPCC models can't support IPCC policy advocacy.
New Analysis: IPCC’s Emissions-Based Climate Model Errors So Massive They Eliminate Predictive Validity
By Kenneth Richard on 28. May 2025

“All in all, and contra to the IPCC reports, there is insufficient evidential basis for the use of carbon dioxide, et cetera, emissions – taken together, the IPCC’s Anthro – as climate policy variables.” − Green and Soon, 2025
A new evidence-based study provides compelling evidence that for decades the IPCC has been engaged “advocacy research,” or the “antiscientific practice of undertaking research designed to support a given hypothesis.”

The IPCC-favored climate model parameters used to support the narrative that climate change is primarily caused by humans burning fossil fuels (referred to as the Anthro models in the study) is so fraught with errors that even a stripped-down benchmark model that merely projects future temperatures will not deviate from the historical average overwhelmingly outperforms the IPCC’s modeling.

“The IPCC’s models of anthropogenic climate change lack predictive validity. The IPCC models’ forecast errors were greater for most estimation samples – often many times greater – than those from a benchmark model that simply predicts that future years’ temperatures will be the same as the historical median.”

The IPCC’s Anthro models that hypothesize CO2 (primarily) will foment dangerous global warming over the coming decades woefully overestimated the warming from 1970-2019 by anywhere from 1.8°C to 2.5°C.

“The errors of forecasts from the anthropogenic models for the era of concern over manmade global warming, starting in 1970, were 1.8°C (AVL), 1.7°C (AVSL), 2.3°C (AVR), and 2.5°C (AVSR) warmer than the measured temperatures.”

Over the 2000 to 2019 period the Anthro models’ forecast errors were a staggering 16 times greater than the simple benchmark model’s errors.

“…forecasts for the years 2000 to 2019 from models estimated with 50 observations of historical data (1850 to 1899) have MdAEs [median absolute errors] of around 17°C or 1600 percent greater than the 1°C MdAE of forecasts from the naïve benchmark model.”

In contrast, the authors found the models that centered on Total Solar Irradiance (TSI) as a climate change factor did indeed have predictive validity, and their error ranges were much smaller.

Considering the magnitude of the error in using CO2 emissions as a basis for climate forecasts, the authors conclude the Anthro models’ unreliability “would appear to void policy relevance.”



Image Source: Green and Soon, 2025