The UN IPCC's Artful Bias

 Glaring Omissions, False Confidence and Misleading Statistics

in the Summary for Policymakers

 (The science summary -- Working Group 1 of the Third Assessment Report)

 by  David E. Wojick, Ph.D.

(Click here for author information)

Summary of Findings:

The UN IPCC WG1 Summary for Policymakers (SPM) of the Third Assessment Report is not an assessment of climate change science, even though it claims to be. Rather, it is an artfully constructed presentation of just the science that supports the fear of human induced climate change. It is as one sided as a legal brief, which it resembles.

Line by line analysis of the SPM reveals that all of the science that cuts against the theory of human interference with climate has been systematically omitted. In some cases the leading arguments against human interference are actually touched on, but without being revealed or discussed. In other cases the evidence against human interference is simply ignored. Because of these strategic omissions, the SPM voices a degree of certainty that is entirely false.

Glaring omissions are only glaring to experts, so the "policymakers" -- including the press and the public -- who read the SPM will not realize they are being told only one side of a story. But the scientists who drafted the SPM know the truth, as revealed by the sometimes artful way they conceal it. This deliberate distortion can only be explained by the fact that the UN IPCC is part of an advocacy process, organized by the United Nations Environment Program and supporting the Kyoto Protocol.

What is systematically omitted from the SPM are precisely the uncertainties and positive counter evidence that might negate the human interference theory. Instead of assessing these objections, the Summary confidently asserts just those findings that support its case. In short, this is advocacy, not assessment.

The UN IPCC WG1 Summary for Policymakers is available at:


Specific examples assessed in this report:

Specific examples of glaring omissions, false confidence and misleading statistics in the UN IPCC WG1 Summary for Policymakers include the following:

1. Likely sources of bias in the surface temperature record of the last 150 years, which are well known and considerable, are ignored. The amount of warming is claimed to be known with a false degree of confidence. We do not, in fact, know for certain that the earth has warmed at all.  (Details here)

2. The profound inconsistency between the recent warming in the surface temperature record, and the absence of warming in the satellite record, is simply shrugged off. (Details here)

3. The enormous, and growing, uncertainty as to the effect of aerosols on climate is masked in the discussion, and is deliberately suppressed in predicting the future. If included, the UN IPCC 100 year prediction would include the possibility of no warming or even cooling. (Details here)

4. The fact that the vast majority of all greenhouse gas emissions are natural is ignored. (Details here)

5. Advances in climate science that do not support the theory of human interference have been ignored. (Details here)


1. Do we know the earth is actually warming?

The problem of errors in the surface temperature record.

1. The discussion on UN IPCC WG1 SPM page 2 (the first page of text) begins with this headline:

"The global average surface temperature has increased over the 20th century by about 0.6°C."

Not "may have", or even "is likely to have', but simply "has". False certainty. Any suggestion of doubt is omitted, but there is plenty to doubt.

2. The text itself says "The global average surface temperature (the average of near surface air temperature over land, and sea surface temperature) has increased since 1861. Over the 20th century the increase has been 0.6 ±0.2°C (Figure 1a). This value is about 0.15°C larger than that estimated by the SAR for the period up to 1994, owing to the relatively high temperatures of the additional years (1995 to 2000) and improved methods of processing the data. These numbers take into account various adjustments, including urban heat island effects."

Fig.1 - SPM presentation of global temperature since 1860 (SPM fig.1a)

This is the only reference in the text to any possible problems with the temperature record. It says they have been "taken into account", with special reference to the urban heat island effect. False certainty. The discussion of these problems, how likely they are to be significant, and how they have been taken into account, has simply been omitted. In fact how well they have been taken into account is highly contentious.

3. Figure 1a at least has more detail, albeit finer print. It says this adjacent to the figure:

"The Earth’s surface temperature is shown year by year (red bars) and approximately decade by decade (black line, a filtered annual curve suppressing fluctuations below near decadal time-scales). There are uncertainties in the annual data (thin black whisker bars represent the 95% confidence range) due to data gaps, random instrumental errors and uncertainties, uncertainties in bias corrections in the ocean surface temperature data and also in adjustments for urbanization over the land. Over both the last 140 years and 100 years, the best estimate is that the global average surface temperature has increased by 0.6 ±0.2°C."

This at least mentions specific problems. But notice the placement of the parenthetical expression in the pivotal second sentence, just before the list. This seems to say quite clearly that the error bars give the 95% confidence level for the uncertainties listed. This is simply false. The error bars give at best the 95% confidence level for the pure error of sampling, which assumes the sample is random and there are no measurement errors of the sort listed in the very sentence being modified. This comes as close to outright lying as anything we have found so far.

The truth is there is no way to correct for most measurement errors, including the urban heat island effect. The magnitude of these errors, which may be quite large, is simply unknown. The supposed corrections that have been made to date are merely guesswork.

Nor does there seem to be any reference to the fact that this is a "convenience sample", not a random sample of the earth's surface, as required by sampling science. Unless it is the innocent sounding phrase "data gaps". Reference to data gaps suggests that sometimes a station did not record, or the data is bad, not that there is in actuality no data for most of the earth, most of the time. So the fact that we merely have a convenience sample is either omitted, or cleverly disguised.

Fig.2 - Basic kinds of statistical error

Statistical theory is perfectly clear that a random sample is required in order to estimate confidence levels. But the "sample" in question is just those stations that happened to measure temperatures in the last 150 years. No random sample of the earth's surface would look like this set of stations, which provide virtually no data for most of the earth's surface -- the oceans, poles or tropics -- for most of the period.  

The sample the UN IPCC is using is called in statistics a "convenience sample", that is, data is taken where it is most convenient. Convenience samples provide some information about the population being sampled, in this case the temperature everywhere on earth for 150 years. But statistical theory is adamant that you cannot legitimately infer the mean of the population, or assign any confidence level, from a convenience sample. Thus the UN IPCC statistics regarding temperature are completely misleading.  

While beyond the scope of this particular issue, it should be noted that the 1000 year temperature record shown in SPM Figure 1b (Fig. 3 below) involves the same misleading statistics. The case is much worse however, because in the 1000 year record temperature is not even being measured.

Fig.3 - 1,000 year temperature according to the SPM fig.1b, often referred to as the `Hockey Stick'

 Moreover, the number of items in the convenience sample is tiny. It is preposterous to claim to know the temperature of the entire earth from such a sample.

We simply do not know if the entire earth has warmed or not. The most we know is what has happened in certain places and times, and likely measurement error makes even this information highly uncertain.


2. The satellite temperature record contradicts the surface record

A profound dilemma for climate change science

The UN IPCC WG1 SPM page 4 begins with this Section headline:

"Temperatures have risen during the past four decades in the lowest 8 kilometers of the atmosphere." As explained below, this statement is highly misleading. The section itself consists of these three rather convoluted paragraphs shown left.:  

Key omission:

These three paragraphs mask a profound contradiction in climate change science. A contradiction that should be highlighted and discussed but is merely glossed over, namely that the satellite temperature record contradicts the surface record. 

What the section headline does not say is that virtually all of the atmospheric warming is in the balloon record of the first two decades of the four decade period -- the 1960s and 70s - when the surface record shows only a little warming. Then the surface record warms rapidly for two decades while the (then new) satellite record (Fig.4) shows virtually no warming at all, except for the 1998 El Niño.  

Fig 4 - Satellite and Surface Compared 1979-1998

Thus while the statement in the first paragraph that the trends are "similar" is statistically correct, it ignores the fact that the changes occur at completely different times. The last two paragraphs state correctly that these are significant differences that are not fully resolved, but any discussion of what it means is simply omitted.  

What is omitted is the fact that climate science cannot explain this contradiction. Greenhouse gases have to warm the atmosphere, where the heat is trapped, before warming the surface of the earth below.

If this science is correct, then one of the temperature records must be incorrect, most likely the surface record that shows the warming, because of known errors. But if there has been no warming in the last two decades then many of the claims made by the IPCC, which depend on such warming, are simply false. Likewise, prior warming shown in the surface temperature record may be false.

Even worse, if both temperature records are correct then our understanding of the greenhouse effect is incorrect. This is a profound dilemma for the science, and there is a great deal of speculation about it, some of which is alluded to in the third paragraph.  

It should be noted that there is a widespread misconception that a National Academy of Science panel resolved this issue in January 2000. In fact the panel concluded just what I have said above -- that we do not understand how this contradiction can arise, if both temperature records are correct.

To simply gloss over this profound scientific uncertainty is a major omission indeed, perhaps the greatest omission in the UN-IPCC SPM.


3. Ignoring uncertainty due to aerosols

The IPCC has suppressed the profound significance of aerosol forcing, not only in the WG1 SPM text, but in the modeling as well

Discussion of aerosols in the UN IPCC WG1 SPM begins on page 5 with this headline:  

The highlighted phrase reflects a false certainty. Whether or not human emissions will affect climate is obviously a matter of great debate. What follows, however, are some incredible omissions.

The role of aerosols is explained as follows:  

This text states quite clearly and correctly that an ability to predict future climate (if that is even possible) requires an understanding of the effect of aerosols. The last sentence says that "current estimates of the radiative forcing" of aerosols are shown in SPM figure 3 (page 8). This sentence is false. In fact not only are the estimated uncertainties in aerosol forcings not shown, they are also excluded from the projections of future climate. These are major omissions.  

Fig.5 - SPM presentation of forcings in the SPM fig.3

SPM Figure 3 (Fig.5 above) shows estimated forcings for five classes of aerosols. For four of these classes there is also a vertical error bar which the legend explains "indicates a range of estimates, guided by the spread in the published values of the forcings and physical understanding." In addition, each class is labeled with a "Level of Scientific Understanding." One class is labeled "Low" and the other four are labeled "Very Low."

No explanation of these uncertainty levels is provided. However, in the UN IPCC's 1995 Second Assessment Report an earlier version of this same figure appears as figure 2.16, on page 117. Here it is explained that the levels `low' and `very low' are "our subjective confidence that the actual forcing lies within this error bar." In fact the levels are called "levels of confidence" not `levels of understanding.'

In plain language, this means that the chances that the aerosol forcings actually lie within the error bars are very low in most cases. Conversely, it is very likely that the actual forcings lie outside these error bars. What then is the likely range for these forcings? We are not told, in fact the very issue, which was at least alluded to in the IPCC SAR, has now been entirely omitted.

The truth is that the possible range of forcings is very large, much larger than the error bars show. Therefore the range of aerosol forcings is much larger than the ranges for the greenhouse gases, which are shown to have a "high" level of understanding. If the correct error bars for aerosols were shown -- bars that display the likely range of forcings -- they would be seen to overwhelm the greenhouse gas forcings.

In short we simply do not understand aerosol forcing. In fact a recent paper in the journal Science claims that the range of possible forcings is as much as twice the very large range that is not shown in the TAR. This indicates that our understanding of aerosol forcing is diminishing as research proceeds. (See "Reshaping the Theory of Cloud Formation" by R. J. Charlson et al, Science, June 15, 2001.)

If, as the UN IPCC states quite clearly and correctly, an ability to project future climate requires an understanding of the effect of aerosols, then we simply do not have that ability. Yet the IPCC does project future climates, based on various scenarios.

How does the UN IPCC deal with our profound lack of understanding of aerosol forcings? The answer lies in an incredible footnote on page 13, specifically footnote 11. In the text before footnote 11 the IPCC says this:

Footnote 11 amends this 1.4 to 5.8°C projection as follows:

So the UN IPCC has simply ignored the very large aerosol uncertainties. No reason is given, but if these uncertainties were included, some of the scenarios would yield projections of future cooling, not warming. Perhaps the UN IPCC does not want to admit the possibility that there may be no warming at all, or actual cooling. In any case it is clear that entire issue of aerosol uncertainty has been omitted from the WG1 SPM, including changing the language of the key figure. Far worse, however, is that the effect of this uncertainty has been deliberately suppressed in the model projections of future climate. It is hard not to see this as scientific fraud.

4. Human GHG emissions are a tiny fraction of natural emissions

The discussion of GHG emissions on UN IPCC WG1 SPM page 7 contains these three parallel paragraphs:


Key omissions:

1. Parallel construction requires that there be a sentence explaining the fraction of CO2 emissions that are anthropogenic, but there is none. It would read as follows -- About one twenty fifth of current CO2 emissions are anthropogenic. The important fact that the vast majority of CO2 emissions are natural has been omitted.

2. In addition, not even mentioned is water vapor, by far the most important greenhouse gas. Natural emissions of water vapor are so enormous that human emissions do not even measure in comparison. If this were explained there would also be a sentence saying -- virtually no water vapor emissions are anthropogenic.


5. Ignoring chaos in climate -- the greatest omission?

The UN IPCC has ignored scientific advances that undercut the theory of human interference, including the profound chaos science that is presented in the Third Assessment Report itself.

Advances in climate science that do not support the theory of human interference have been ignored in the UN IPCC WG1 SPM. These include the role of clouds, solar variation, lunar influence, orbital cycles, decadal oscillations, and more. If anything, the science today provides less support for the theory of human interference than it did in 1995, when the IPCC Second Assessment Report was done.

Perhaps the most egregious omission is the emerging understanding of the chaotic nature of climate. Not only is this science very important, but it is presented in considerable detail in the TAR itself (see below). About one half of Chapter 14 of the WG1 TAR is devoted to discussing the profound significance of the fact that climate processes are chaotic and therefore unpredictable. But the SPM does not even mention the word "chaos".

Likewise the UN IPCC WG1 Technical Summary (TS), which was written by the same people as the SPM, has but a single sentence on chaos, tucked away on page 78. It says:

"The climate system is a coupled non-linear chaotic system, and therefore the long-term prediction of future exact 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."

In plain language the kind of prediction the UN IPCC is doing is not possible. The best that might be done is to provide a probability distribution for possible futures, but the IPCC does not do this. The profound fact of chaotic climate is simply ignored.

What makes this omission so egregious is that the chaotic nature of climate is discussed in the WG1 TAR itself, which the SPM and TS are supposed to be summarizing. Here are some statements from the expert review draft TAR, Chapter 14. (The order has been changed for clarity.)

Draft WG1 TAR, Chapter 14 -- some statements regarding chaos and climate:

"In sum, a strategy must recognize what is possible. In climate research and modeling, we should recognize that we are dealing with a coupled non-linear chaotic system, and therefore that the prediction of a specific future climate state is not possible. The most we can expect to achieve is the prediction of the probability distribution of the system's future possible states by the generation of ensembles of model solutions. This reduces climate change to the discernment of significant differences in the statistics of such ensembles. The generation of such model ensembles will require the dedication of greatly increased computer resources and the application of new methods of model diagnosis."

In short, it cannot now be done. Not only is prediction fundamentally impossible due to chaos, but the statistical substitute for prediction that may be possible cannot now be done. The uncertainty is complete. Chapter 14 also says this:

"The climate system is particularly challenging since it is known that components in the system are inherently chaotic and there are central components which affect the system in a non-linear manner and potentially could switch the sign of critical feedbacks. The non-linear processes include the basic dynamical response of the climate system and the interactions between the different components. These complex, non-linear dynamics are an inherent aspect of the climate system. Amongst the important non-linear processes are the role of clouds, the thermohaline circulation, and sea ice. There are other another broad non-linear components, the biogeochemical system and, in particular, the carbon system, the hydrological cycle, and the chemistry of the atmosphere."

"A strategy to advance our understanding must deal with the underlying chaotic nature of the climate system and the significant non-lineraities. The chaotic aspect of the climate system poses significant challenges to predicting changes in the occurrence of extreme events."

"An overriding challenge to modeling and to the IPCC is prediction. This challenge is particularly acute when predictive capability is sought for a system that is chaotic, that has significant non-linearities, and that is inherently stiff."

"However, as the temporal horizon grows, then the challenge shifts as chaotic elements begin to affect the evolution of the system. The predictive environment shifts from one of precision to one of statistical significance."

"There is a growing recognition in the scientific community and more broadly that: The Earth functions as a system, with properties and behavior that are characteristic of the system as a whole. These include critical thresholds, switch or control points, strong nonlinearities, teleconnections, chaotic elements, and unresolvable uncertainties. Understanding components of the Earth System is critically important, but is insufficient on its own to understand the functioning of the Earth System as a whole."

Chaos is a fundamental uncertainty in climate science, but the UN IPCC ignores it.  

Dr David Wojick  


1) Many of the SPM lead authors are leading activists for the theory of human climate interference

The press often says the UN IPCC reports are produced by hundreds, if not thousands, of scientists. This may be true in some vague sense of participation, and the actual TAR chapters do not exhibit as much glaring scientific bias as the WG1 Summary for Policymakers and Technical Summary.

On the other hand, only experts read the main reports. The UN IPCC's voice to the public, press and policy makers regarding climate science is through the WG1 SPM and the TS. These two documents have precisely the same 20 lead authors, many of whom are among the leading proponents of the theory of human climate interference.

Here are the 20 lead authors listed by the UN IPCC -- 

Co-ordinating Lead Authors: D.L. Albritton (USA), L.G. Meira Filho (Brazil).

Lead Authors: U. Cubasch (Germany), X. Dai (China), Y. Ding (China), D.J. Griggs (UK), B. Hewitson (South Africa), J.T. Houghton (UK), I. Isaksen (Norway), T. Karl (USA), M. McFarland (USA), V.P. Meleshko (Russia), J.F.B. Mitchell (UK), M. Noguer (UK), B.S. Nyenzi (Tanzania), M. Oppenheimer (USA), J.E. Penner (USA), S. Pollonais (Trinidad and Tobago), T. Stocker (Switzerland), K.E. Trenberth (USA).

Names in boldface in particular stand out as among the top rank of activist scientists for the theory of human climate interference. Most are frequently quoted in the U.S. and British press. (I am less familiar with the others, who may also be activists elsewhere.) These are:

Dan Albritton -- U.S. National Oceanic and Atmospheric Administration.  

Sir. John Houghton -- former head of the UK Meteorological Office, and arguably the foremost proponent of the theory of human climate interference. Mitchell and Noguer are also with the UK MET.

Thomas Karl -- NOAA and Co-chair of the U.S. National Assessment.

Michael Oppenheimer -- Environmental Defense Fund.

Kevin Trenberth -- U.S. National Center for Atmospheric Research

It is no wonder, therefore, that the two Summaries are so blatantly biased in favor of the theory of human climate interference. They are written by scientists who have staked their reputations on that theory.

2) Doubts Cloud Climate Change Science (from: Electricity Daily June/15/01)

Climate science uncertainties, cited by George W. Bush as a reason for rejecting the Kyoto Protocol, just got a lot worse. According to a report in today’s issue of Science, the largest single uncertainty -- the impact or "forcing" of aerosols on climate -- may be much larger than previously estimated. The study, entitled "Reshaping the Theory of Cloud Formation" is by a team led by R. J. Charlson at the University of Washington.

Charlson et al are quite blunt: "Droplet clouds are the most important factor controlling the albedo (reflectivity) and hence the temperature of our planet. Manmade aerosols have a strong influence on cloud albedo, with a global mean forcing estimated to be of the same order (but opposite in sign) as that of greenhouse gases, but the uncertainties associated with the aerosol forcing are large. Recent studies indicate that both the forcing and its magnitude may be even larger than anticipated."

The issue is how many droplets a cloud will have. Cloud optical properties are controlled by the sizes and numbers of the droplets in the cloud, which are, in turn, governed by the availability of atmospheric particles that serve as cloud condensation nuclei. It has been believed that an increase in atmospheric aerosols, such as sulfates, from fossil fuel combustion would lead to smaller cloud droplets because the same amount of cloud liquid water is distributed among more condensation nuclei. For the same liquid water content, a cloud with more numerous, but smaller, drops has a higher albedo than one with fewer, larger drops. This phenomenon, termed the "first indirect climatic effect of aerosols," could constitute a major climate forcing.

"But," the authors say, "current estimates of indirect aerosol radiative forcing or of its uncertainty do not include the combined influences of some recently identified chemical factors, each of which leads to additional negative forcing (cooling) on top of that currently estimated for water vapor."

According to the authors, estimates of the indirect climatic effect of aerosols are based on the theory of cloud droplet formation advanced by the Swedish scientist Hilding Kohler in the 1920s and 1930s. Kohler’s theory, they say, is too simple and when it is refined, the potential aerosol forcing gets much larger. Specifically, they say that "it has recently become clear that soluble gases, slightly soluble solutes, and surface tension depression by organic substances also influence the formation of cloud droplets, in a manner unforeseen by Kohler." For example, they say, "depending on how it is dispersed over the aerosol population, a minute amount of soluble gas can exert a profound effect on the number of activated droplets."

The researchers note that how climate models might incorporate these new findings "remains to be determined." They conclude that "lack of global data on these activation effects poses additional uncertainty beyond that already recognized by the Intergovernmental Panel on Climate Change, making the largest uncertainty in estimating climate forcing even larger."

3) Dr David Wojick - Background.

This study grows out of several years of research into the logic of the climate change debate. During that time I have operated an email listserv where knowledgeable people from all sides of the climate change issue have posted over 25,000 messages. From this experience I have gained a comprehensive understanding of just how complex and unsettled the science really is.

I have become increasingly distressed by statements made by supporters of the Kyoto Protocol to the effect that the science is settled, or that the uncertainties have diminished to the point where action is obviously justified. Nothing could be further from the truth. I am particularly concerned that the IPCC is being represented as a neutral body. Such claims are simply false, and it is the purpose of this study to demonstrate that they are false.

Because the IPCC scientific Summary for Policymakers is completely one sided, most of its deceptions are omissions. One cannot simply point to omissions as one can to falsehoods. So I have undertaken to catalog the omissions, and the false assertions of confidence that they enable, on a line by line basis. The present report is just a start, and more cases will be forthcoming over time. But time is of the essence, and the present small collection is sufficient to make the point. The IPCC SPM is a study in artful bias.

David Wojick

4) Biographical information.

Dr. David E. Wojick has a Ph.D. in mathematical logic and philosophy of science from the University of Pittsburgh, and a B.S. in civil engineering from Carnegie Mellon University. He has been on the faculty of Carnegie Mellon, where he helped found both the Department of Engineering and Public Policy, and the Department of Philosophy. He has also served with the Office of Naval Research and the Naval Research Laboratory. He is presently a freelance writer covering climate change issues for Electricity Daily, and a policy analyst.

A resume and client list are at

The free sign-up for Dr. Wojick's listserv is at

Non subscribers can follow the debate at

July 13, 2001

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