By Andy May

The previous parts of this series investigated model bias in the CMIP6 models and in their interpretation in AR6 WGI. This part looks at model bias in AR6 WGII, Climate Change 2022: Impacts, Adaptation, and Vulnerability. The IPCC WGII report uses the possible future climate projections from the WGI report to project the future impact of climate change on society. It uses socio-economic models to accomplish this. As we saw in the previous parts of this series, the WGI report is biased and ignores possible natural contributions to recent observed global warming from changes in the Sun, cloud cover, and the meridional transport of energy.

The WGI/CMIP6 models, rather arbitrarily, assign all warming since 1750 to human influences, particularly CO₂ emissions. WGII accepts this controversial conclusion. It uses projected CO₂ emissions combined with the WGI/CMIP6 models to predict future temperature and projected knock-on effects to other climate components, like precipitation, to model the future impact on human civilization.

WGII states that:

“Human-induced climate change, including more frequent and intense extreme events, has caused widespread adverse impacts and related losses and damages to nature and people, beyond natural climate variability.”

AR6 WGII, page 9

This is only true if we accept their assumption about the range of natural climate variability, but as we saw in the previous parts of this series, their assumptions about natural warming, especially the impact of solar variability, are very controversial. Further, whether climate change is natural or human-caused, someone, somewhere, is nearly always going to be adversely affected by a change in climate, while others will benefit from the same change. How widespread is “widespread?”

WGII liberally discusses the potential negative impact of climate change, 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. 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.

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. 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.

Currently the world’s economy is growing between 2 and 3% per year and this is not expected to change much in the future. Looking ahead at a possible 2.5°C of warming in the next century or so, economists anticipate between a positive net climate change impact of about 2% and negative net impact of about 2.5% on global GDP. It is significant that the sign of the net economic impact due to climate change is not known. The average impact for 2.5°C of warming is a negative 1.3% for the average person. In the next 80 years global GDP would be expected to grow between 487% and 1,000%, so a negative 1.3% due to climate change is unlikely to be noticed. Richard Tol writes that the uncertainty in the estimates of the impact of climate change on total economic welfare is very large and if we take this uncertainty into account, the impact of climate change does not significantly deviate from zero until 3.5°C of warming.

Emissions and impact scenarios

The future cannot be predicted. So, the concept of “scenarios” was developed in the 1960s by Herman Kahn, a military strategist with the RAND Corporation. The idea is to develop a “business as usual” forecast that assumes no unusual events occur over the planning period. Then you vary something and compute an alternative forecast that shows the difference between the baseline, business-as-usual, forecast and your model. It is just a learning tool and like all models, used to investigate the possible impact of policy changes, regulations, or tactical decisions in wars or battles. We are not supposed to believe any of the forecasts, it is just the relative values between various assumptions that are important. Scenario analysis is widely used to do cost-benefit analysis. However, since WGII only incorporates the costs and leaves out the benefits, their cost-benefit analysis is invalid.

It is very important to remember that the projections used in WGII assume that there will be no natural warming or cooling between now and 2100. If there are natural forces acting on climate, then the greenhouse gas-based projections they rely upon will be wrong and their projected impacts on human civilization must be wrong as well. The AR6 scenarios of temperature change relative to 1850 to 1900 are shown in figure 1.

Hausfather and Peters have called the higher scenarios, SSP3-7.0 and SSP5-8.5 (as well as their AR5 equivalent RCP8.5) unlikely, but since this view is contested, AR6 WGII takes no position on which of the scenarios in figure 1 is most likely. This is unfortunate since the difference in the scenarios in 2100, only 76 years from today, is over three degrees. The combination of the uncertainty in the projected warming and in the potential impact of the warming is extremely large.

Roger Pielke Jr. and Justin Ritchie tell us that the ancestor of the SSP5-8.5 scenario in figure 1 originated in the first IPCC report in 1990. In 1990, with what was known then, it was a reasonable “business-as-usual” scenario. It predicted a large increase in coal consumption and a CO₂ concentration of 1,200 PPM in 2100. Today that emissions scenario is reached in SSP5-8.5, but with what we know today it is not “business-as-usual,” in fact it is an implausible future, that is becoming more impossible with each passing year. To be fair, the IPCC does not call SSP5-8.5 business-as-usual, that label is used by others, presumably because that is what it is called in the first report in 1990.

Marcel Crok reports in the book that he and I edited, The Frozen Climate Views of the IPCC, that the unlikely, and now implausible, SSP5-8.5 and its predecessor RCP8.5 are mentioned in AR6 41.5% of the time according to Roger Pielke Jr., much more than the more likely SSP2-4.5 or RCP4.5 scenarios (mentioned 17% of the time). The latter two scenarios more closely match recent observations. Thus, WGII often uses the biased and too hot WGI models as input to maximal and implausible emissions scenarios to do their modeled climate impact projections.

Ignoring the Good News

While using implausible scenarios and biased climate model results in assessing the impacts of climate change is unwise, ignoring the positive impacts of climate change and focusing only on the bad may well be worse. The whole idea of using scenarios is to investigate the full range of possible outcomes, not cherry-pick the model input to manufacture a desired outcome, a problem often called reporting bias. It is this part of the WGII procedure that cost them credibility.

Marcel Crok shows us that U.S. major and all landfalling hurricanes have been declining since 1900. Globally, there is no trend in cyclones and hurricanes. There is also no trend in accumulated global cyclone energy. AR6 WGI finds that since 1950 there has been an increase in the number of hot days and heatwaves, but as figure 1 in part 2 shows the world was cooling in 1950. At least in the United States, records show that peak hot days and heatwaves were in the 1930s. AR6 WGI also finds that there is “low confidence in general statements to attribute changes in flood events to anthropogenic climate change.” The idea that extreme weather is increasing globally is very controversial.

It is worth noting that AR6 WGII states that they have high confidence that some extreme weather is increasing as a result of climate change, including extreme rainfall events, more frequent and stronger cyclones/hurricanes, and that recent devastating floods were made more likely due to climate change. This appears to be directly contradicted by what is stated in AR6 WGI, but WGII cleverly sidesteps the contradiction by specifying “Some extreme weather…” and “devastating floods in western Europe…” Thus, to make their point, they cherry pick locations and events and avoid discussing global impacts that have not changed or are decreasing. In any given year, extreme weather events are increasing somewhere, that is the nature of weather. Their assertion is contradicted by the work of Zhongwei Yan, Philip Jones, and Anders Moberg already mentioned in part 5.

Finally, both WGI and WGII completely ignore evidence that global warming and additional CO₂ have many benefits. Bjorn Lomborg reports that human welfare will likely increase 450% in the 21^st century and damages due to climate change might reduce this to 434%, which will be hard for most people to detect. Lomborg also finds that non-climate-related deaths, due to earthquakes, tsunamis, volcanoes, etc. have fallen only slightly in the past 100 years, but climate-related deaths have fallen a staggering 99%. Part of this is that cold-related deaths are much more common than heat-related deaths, and as the world warms, cold-related deaths fall more than heat-related deaths increase.

Cherry picking

The authors of AR6 WGII were particularly guilty of selecting papers to discuss that supported their assumptions and ignoring papers that refuted or disagreed with them. In a classic case they discussed Grinsted, et al., which claims to be able to attribute some U.S. hurricane losses to human-caused global warming. Grinsted is the only paper, out of many that was able to attribute hurricane losses to human-caused or human-enhanced hurricane activity. However, Roger Pielke Jr. has found that the paper is flawed and has requested that it be retracted.

Even though the paper is likely flawed and is contradicted by many other studies, it is used to support the idea that some U.S. hurricane losses can be “partly attributed to anthropogenic climate change” in AR6 WGII. To be fair, they do mention one of the many studies that disagree with Grinsted. However, they also mention one other paper, Estrada et al., that they imply supports attribution to human-caused climate change, but the paper does not say that. Estrada, et al. say that their results are ambiguous, and that in 2005 2-12% of normalized losses “could be attributable to climate change.” So, they chose one year, and only considered the United States, and maybe 2-12% of the damage was due to climate change. In Estrada’s conclusions they note:

“Increases in wealth and population alone cannot account for the observed trend in hurricane losses. The remaining trend in itself does not prove the existence of a climate change signal, as it could be due to causes not considered here.”

Estrada, Botzen, and Tol, Nature Geoscience, 2015

In other words, they detect a trend in normalized hurricane damage that cannot be fully explained by increasing wealth and population and it is possible that this excess is due to climate change. Estrada, et al. explain that prominent ocean oscillations, such as the Atlantic Multidecadal Oscillation (AMO) can account for some of the excess hurricane damage observed. Also, data problems prior to 1940 could produce a spurious upward trend in damage. So, Estrada, et al.’s analysis uncovered a small excess trend in damage that might be explainable by climate change but could also be caused by other factors. Not very convincing.

AR6 WGII leaves the reader with the idea it is two against one, when actually one of the pro-attribution studies is inconclusive and they ignored a large number of studies that found no connection between hurricane damage and climate change. WGII does make the following statement, which partially absolves them:

“Climate change explains a portion of long-term increases in economic damages of hurricanes (limited evidence, low agreement).”

IPCC AR6 WGII, page 1978

They are saved by the “limited evidence, low agreement” bit, but somehow that part is always left out of the press releases and news media.

WGII Model Bias, Summary

Just as WGI ignored the potential impact of solar variability and changes in meridional transport, WGII ignored the potential benefits of warming and additional atmospheric CO₂. This invalidates the report. By ignoring the well-documented benefits of global warming and additional CO₂, they clearly cannot assess the impact of climate change or our vulnerability to climate changes. It makes their report useless for policy making or cost-benefit analysis.

It is hard to decide exactly how to characterize this problem in AR6 WGII, it could be described as reporting bias, since they ignored so many studies that report warming and CO2 benefits. It could also be described as confirmation bias given their stated assumption that warming and additional CO2 is a bad thing. But, either way, they failed to honestly report the current state of the existing literature on the subject.

Next, we look at model bias in WGIII.

Download the bibliography here.

1. (IPCC, 2022) ↑

2. (IPCC, 2021, p. 67) ↑

3. (IPCC, 2022, p. 9) ↑

4. (IPCC, 2022, pp. 44-70) ↑

5. (May, Are fossil-fuel CO2 emissions good or bad?, 2022g), (Idso, 2013), (Zhu, Piao, & Myneni, 2016), (Tol R. S., 2018) , (Tol R. , Correction and Update: The Economic Effects of Climate Change, 2014b), and (O’Neill, 2023) ↑

6. (IPCC, 2022, p. 264) ↑

7. (O’Neill, 2023) ↑

8. (O’Neill, 2023) ↑

9. (International Monetary Fund, 2022) ↑

10. (Tol R. S., 2018) ↑

11. (Tol R. S., 2018) ↑

12. (Pielke & Ritchie, 2021) ↑

13. (Hausfather & Peters, 2020) ↑

14. (IPCC, 2022, p. 136) ↑

15. (Pielke & Ritchie, 2021) ↑

16. (Pielke & Ritchie, 2021) and (Hausfather & Peters, 2020) ↑

17. (IPCC, 1990, pp. 55-56) ↑

18. (Crok & May, 2023, pp. 122-126), (Hausfather & Peters, 2020), and (Pielke Jr, Burgess, & Ritchie, 2021) ↑

19. (Crok & May, 2023, p. 142) ↑

20. (Weinkle, Maue, & Pielke Jr., 2012) and see Dr. Maue’s site https://ift.tt/Tgf9mKO ↑

21. (Crok & May, 2023, p. 147), also see Dr. Maue’s site https://ift.tt/Tgf9mKO ↑

22. (IPCC, 2021, p. 82) ↑

23. (Crok & May, 2023, p. 146) ↑

24. (IPCC, 2021, p. 1569) ↑

25. (IPCC, 2022, p. 588) ↑

26. (Lomborg, Welfare in the 21st century: Increasing development, reducing inequality, the impact of climate change, and the cost of climate policies,, 2020), (Lomborg, We’re Safer From Climate Disasters Than Ever Before, 2021), and (Pielke Jr., 2021) ↑

27. (Yan, et al., 2001) ↑

28. (Lomborg, Welfare in the 21st century: Increasing development, reducing inequality, the impact of climate change, and the cost of climate policies,, 2020) ↑

29. (Dixon, et al., 2005) ↑

30. (Grinsted, Ditlevsen, & Christensen, 2019) ↑

31. For a list see: (Crok & May, 2023, p. 153) ↑

32. (Pielke Jr., Apples, Oranges, and Normalized Hurricane Damage, 2024) ↑

33. (IPCC, 2022, p. 1978) ↑

34. (Estrada, Botzen, & Tol, 2015) ↑

35. (IPCC, 2022, p. 1978) ↑

“Psychology is no longer just about diagnosing or fixing us, it is now about socially engineering and shaping us. If you don’t control your mind, someone else will.”

Dr Patrick Fagan, behavioural psychologist, University of London

The relationship between psychology and your average climate sceptic is a strange one indeed. On the one hand psychologists are reputed to have generated a “dramatically growing body of research” that demonstrates how our inability to think critically leads to conspiracy ideation. For example, our cognitive failings are presupposed to lead us to think that the public is being unwittingly manipulated as part of some government masterplan. But, on the other hand, it is open knowledge that psychologists have been responsible for developing techniques of behavioural science that have been extensively used by governments to surreptitiously manipulate public opinion. They even have a cute name for the departments involved – they’re called nudge units. So it seems that psychologists are not averse to aiding and abetting social engineering whilst simultaneously pathologizing those amongst us who suspect them of it. Indeed, it may be that the pathologizing is all part of the surreptitious manipulation, since the discrediting of the sceptical voice is important for the nudging to go unnoticed.

Well, I’m sorry, but it has been noticed and no amount of accusatory psychobabble is going to stop me from saying so. It wasn’t my conspiracist imagination that led me to observe the IPCC openly advocating for such manipulation in AR5, WG3, Chapter 2, when it spoke of using “social cognitive theory to develop a model of climate advocacy to increase the attention given to climate change in the spirit of social amplification of risk”. And doesn’t AR5’s talk of “entry points for the design of decision aids and interventions”, “choice architecture”, and “other ways to frame climate change information and response options in ways consistent with the communication goal and characteristics of the audience” all sound a little bit nudgey to you? And what about AR5’s call to “Characterize the likelihood of extreme events and examine their impact on the design of climate change policies”?

Is it really a failure in critical thinking to note that there has been a near hysterical level of reporting of extreme weather in the wake of the IPCC’s AR5 recommendations? Are we supposed to swallow the line that attribution scientists looking at extreme weather patterns suddenly realised that it’s worse than we thought, and so we should no longer see climate change as a purely future risk? My conspiracist mind would find this narrative of a scientific advancement much easier to accept were it not that the scientific ‘revelations’ of a present day risk had been preceded by the AR5 edict to reach out to the public in order to promote that very idea. And it would be a lot easier to accept the narrative had its promotion not been proposed as a good move by behavioural scientists. Whatever the case, every episode of bad weather is now confidently offered as clear proof of the devastation already being wrought, and few in the media seem interested anymore in talking about the essentially statistical nature of climate change’s contribution, nor the uncertainties behind such statistics.

But if you thought that the IPCC’s behavioural scientists were hiding in plain sight, that is as nothing compared to the UK government’s nudge unit — the euphemistically titled Behavioural Insights Team. They even have their own website upon which one can find a number of handbooks going under titles such as ‘Target, Explore, Solution, Trial, Scale’, ‘MINDSPACE’, and ‘Four simple ways to map and unpack behaviour’. It’s as if the magic circle had a website telling you how each trick works. I’d love to indulge my conspiracist ideation but these guys are doing me out of a job. And yet, what can you do when the government itself says on its ‘Behaviour Change’ website:

“Behaviour change is one of the primary functions of government communications – helping change and save lives, helping the government to run more effectively as well as saving taxpayer’s money.”

Government improvement and saving the taxpayer’s money sound laudable enough goals until one realises that methods of behaviour change can also be used for any social engineering of a government’s choosing. These techniques do not come with a moral compass. Take, for example, the techniques that can be employed to ensure public acquiescence in the face of measures designed to remove basics such as free speech and liberty of movement. Just how effective could such measures be? Well, let’s take a look at our Covid-19 experience.

One strategy developed by behavioural scientists sometimes goes by the name Deny, Debate, Demand. It’s a three stage process designed to improve the chances of the public’s acceptance of a radical new measure. Firstly, the unthinkable proposal is ‘accidentally’ leaked before then being denied. Even though denied, it is now thinkable and, as such, can be debated. The government could even portray itself as accommodating a public interest by ‘allowing” such debate. And before you know it the government is demanding what they claim the public wants. A case in point was the introduction of vaccine passports, as proposed by the Secretary of State for Health and Social Care, Nadhim Zahawi. The existence of such a proposal was denied no fewer than 11 times by Zahawi before he finally opined, “it would be completely remiss and irresponsible” not to at least allow debate on how such passports might work in practice. Not long after that phoney debate we were all dutifully applying for such ‘passports’ in order to enter nightclubs and other events. There is no way of proving that Zahawi was dancing to the beat of behavioural scientists, but it is a fact that SAGE had its very own Scientific Pandemic Insights Group on Behaviours (SPI-B) to advise the government on how best to enable the introduction of such measures.

Also, one should keep in mind that those who seek to socially engineer are usually playing the long game. Vaccine passports have now been dropped in the UK, but the point is that the Covid-19 experience has primed the public for the next Deny, Debate, Demand sequence, this time to be applied in the furtherance of the longer-term objective: the proposed introduction of mandatory digital IDs. It’s a case of achieving a long-term goal through a deliberate strategy of two steps forward and one step back. That is what your behaviourist would advise. And I have to say, as an experiment in the effectiveness of the precepts of behavioural science in persuading us all to implement dangerous nonsense, the ground gained during the Covid-19 pandemic must have shocked even the most optimistic of behavioural scientists. Any strategy for manipulation that could get us all wearing a mask whist walking to our restaurant tables before taking it off, only to put it back on again when going to the toilet, strikes me as potent beyond measure. And this matters because, even as I type, the same behavioural scientists are busily advising the UK government on the implementation of Net Zero.

The Behavioural Insight Team’s methodology (one might say, its manifesto) for nudging us all down the Net Zero road is detailed in their handbook, ‘How to build a Net Zero society: Using behavioural insights to decarbonise home energy, transport, food, and material consumption’. I could go through it in detail but I think the only point that needs making here is that it was written by people who are self-proclaimed experts in manipulation. Therefore one must expect the document itself to be a masterly demonstration of the nudger’s art. To illustrate this point I will focus upon a single sentence used by the group to introduce the document and to set the scene:

“Tackling climate change is not only a moral and legal obligation in the UK, but is also the growth opportunity of the 21st century, and is backed by huge public support.”

How much nudging can one possibly pack into a single sentence? This is not so much a sales pitch as a religious exhortation. Dare you be the one to flout moral authority? Do you really want to be the one to deny us all of the abundance of a promised land? Dare you stand up against the rest of society? The Behavioural Insights Team is not making a statement of fact here but offering a masterpiece of their art, employing just about every coercive trick in the book.

But I’m afraid the nudging is not just evident in the quasi-religious proselytising of a government agency’s handbook. The real-life consequences of such nudging surround us all and have already deeply penetrated our society. Every time your child comes home from school and asks why you are not doing more for the environment, you are being nudged. Every time you switch on the BBC’s Countryfile, you will be nudged. When your favourite soap opera runs with a climate change storyline, you are being nudged. Every fact-check is a nudge. Car adverts that exclusively promote EVs are nudging you. Emotive terms such as ‘denier’ and ‘global heating’ are nudges. Employing comedians to translate already simplistic science into skits designed for your average ignorant human is a case of nudge-nudge-wink-wink. All references to scientific consensus and protests of ‘false balance’ are designed to nudge out debate. And when your government sets up a website claiming that all their nudging is benign, don’t forget that they are nudging you. In fact, just about every vector for the promulgation of ideology has now been infiltrated by the merchants of nudge.

But amongst all of the manipulative trickery, perhaps the most impressive has been the portrayal of the suspicious sceptic as a conspiracy theorist. Boasting on their own websites that they are experts in manipulation and coercion, whilst simultaneously branding as conspiracy theorists those who suspect the manipulation to be taking place, has to be the behavioural scientists’ finest triumph, matched perhaps only by their success in convincing the public that only a cognitively challenged conspiracy theorist could possibly suspect them of such an achievement. Nudging us all into the idea that the greatest risk to democracy is a dark army of conspiracist misinformers, each with their nudge playbooks, is perhaps the greatest risk to democracy.

These government advisers are very good at what they do. They are very, very good. Underestimate them at your peril, and certainly don’t take your government’s good will for granted. We were all placed on this Earth to want something, and rest assured that there is much more at stake here than government improvement and the taxpayer’s money.