Purpose and principles
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The problem: Lomborg himself does not admit errors

In all what Bjørn Lomborg has published, right from his first articles published in Danish in January 1998, there are flaws and errors which have been pointed out to him by a large number of scientists. But during his whole career, he has admitted extremely few errors, and has silently corrected just a few others. Of the few errors that he has acknowledged, most are very small (cf. the page with links).

Pointing out errors

When one simply reads Lomborg´s text, the errors are seldom apparent. Although you often disagree with his interpretations, you must admit that the text is well-written, logical and, in most cases, consistent. Most errors can only be found by comparing the text with other texts. The clue is: "Check the sources". The errors arise when Lomborg writes something that is not in complete accordance with what his sources say. He lies, and he believes that his lies will not be revealed because nobody bothers to check thousands of references. That is precisely why we have to do that. Try to make a random choice of a few references, and check them. Chances are fairly good that you get a "bingo". But the problem is that most readers do not have the time to do that.

So, one purpose of Lomborg-errors is to be a service to readers of Lomborg´s books. If you read something of which you think "That is hard to believe, but I cannot point out where the flaw is" or "This is a surprise to me, so I must admit that I will have to revise my ideas", then try to check if Lomborg-errors has something to say about this point. There is a good chance that it will be one of those parts of the book which are already covered by the error list. And most likely you will find out that you had become misled by Lomborg in ways which were not apparent to you.

The need for a review process

Another purpose of Lomborg-errors is to compensate for the lack of proper scientific review of "The skeptical environmentalist". Cambridge University Press claims that the book was accepted by four referees before it was published, but it also admits that all four referees have political interests besides their scientific occupation (see "The Lomborg-story" here). In any case, the alleged referees have not carried out their work properly, for the book is full of misleading errors and flaws. To avoid misinformation of the public, it is necessary that these be pointed out by some kind of international peer review. Such a process was in a way carried out when Scientific American in its January 2002 issue printed four chapters of harsh criticism of Lomborg´s book, followed by a process on the S. A. web site where Lomborg defended himself, whereafter the editor of S.A. evaluated and rejected his defense. Even so, Lomborg practically denies that any actual errors (e.g. wrong data) were pointed out, and all objections were lost on him.

A main problem with criticizing Lomborg´s text is that although some of the errors are large and obvious, many of them are not. Instead, there are many of them, and they are part of a systematic bias. When sentence after sentence is biased or flawed or not quite correct, the overall impression can become greatly distorted, even though it is difficult to say exactly where the crucial errors are. One may say that the text is permeated with bias and even with dishonesty - i.e. the bias and the dishonesty is not concentrated in a few places, it is nearly everywhere in the text. So, to correct the bias in Lomborg´s text, it is necessary to be able to document the amount of errors. At the same time, these errors, even if each in itself may appear rather small, must be so clearcut and indisputable as possible.

Because Lomborg stubbornly denies any error or flaw that one may point out, the ongoing debate in public media has led to no clarification of whether Lomborg is dishonest or not. Even with hundreds of errors and flaws pointed out, he still plays the role of the innocent brave young man who dares to contradict the clergy of environmentalists and chronic pessimists. Therefore, there remains a need for a place where documentation can be found for all the allegations against him. Lomborg-errors serves as this place. It has been established and written by webmaster Kåre Fog on his own initiative.

Review and quality check

Many of the errors listed here have been detected by the editor of the web site himself. Many others have been found by other persons and have either been described on print, mentioned on web sites, or mentioned in unpublished documents. In nearly all cases, I have made an independent evaluation of the case, e.g. I have checked references that have allegedly been wrongly cited by Lomborg. Usually I have confirmed that there was indeed an error, but in some cases I have rejected the case, either because the flaw was too small to mention, or because Lomborg´s error was not unequivocal.

I would like to stress that contributions to Lomborg-errors are still more than welcome. Consult the bottom of this page or the page "correspondence". After a proper check, the errors will be inserted at the appropriate place in the error catalogue.


The freedom of expression gives Lomborg and anybody else a right to express any opinion that they may have, however weakly founded it may appear to others. Such opinions that differ from the opinion of most scientists cannot be considered as flaws or errors.

Examples of errors proper, on the other hand, are statements in clear conflict with the demonstrable truth. Such errors may be involuntary - the author simply did not know that he was wrong, e.g. when he trusted a source which later turned out to be unreliable. Such errors should of course be corrected, even when it is not fair to blame Lomborg for them. Other errors, however, may be due to gross negligence or may even be deliberate. An example of gross negligence is when an author reads and cites references that support his view, whereas references which, according to their title or summary, do not support the view, are not read and not cited. Another kind of gross negligence is when the original source contains explicit reservations as to the range within which the data are applicable, but the data are nevertheless cited as if they were valid outside of this range. A deliberate error is e.g. when a piece of text is quoted incorrectly in such a way that the meaning is changed, or it may be that Lomborg cites erroneous evidence which Lomborg himself knew was erroneous.

Types of errors and flaws

Types of expressions that qualify to be listed in the Lomborg-errors catalogue are listed either as ERRORS, marked with red, as FLAWS, marked with pink, or as (COMMENTS), marked with pink and put in brackets.

An ERROR is a statement that clearly does not agree with the evidence available. For instance this (TSE p. 233):

"Arsenic has been used as a weed-killer and is a naturally occurring mineral. " Error: What has been used is not arsenic as such (the element), but arsenic trioxide. Neither this, nor the element arsenic, is a mineral. It has not been used as a weed-killer, but as a wood preservative.

A FLAW is a misleading statement which does not fully agree with the facts. For instance this (TSE p. 233):

"Aflatoxin is the most carcinogenic pesticide known . ." Flaw: Aflatoxin, which is produced by fungi, not by humans, is not usually designated a pesticide, and even in the special context here it seems unjustified to use the word pesticide.

A COMMENT is given when Lomborg´s text is not directly at variance with the facts, but is nevertheless misleading, or avoids to mention relevant facts, for instance like this (TSE p. 243):

"Third, the incidence of breast cancer has been increasing while concentrations of DDT, DDE and PCB in the environment have fallen." Comment: In the light of what is explained in the general comments on synthetic estrogens and breast cancer on Lomborg-errors, there is nothing strange about this. The present incidence rate of breast cancer may reflect pollution levels as long as maybe 50 years ago.

Furthermore, the catalogue also includes a few paragraphs which have the designation REMARK. These are notes which do not imply some sort of criticism of Lomborg, but just stress a point of some importance. This may be that on a particular issue, Lomborg is actually right.

Those items that are counted when making up the total number of "errors" are only the FLAWS and ERRORS. The others - that is REMARKS and COMMENTS - are put in brackets to indicate that they are not included in the counts.

Errors can be of different kinds, e.g.

ERROR OF QUOTATION: Quotations that distort the meaning of the original text

ERROR OF REFERENCE: E.g. when the reference cannot be found in the reference list.

ERROR OF BIAS: E.g. selectivity in presentation of data

ERROR OF OMISSION: This heading does not include simple omission of relevant information or references; but it includes gross negligence of information which should absolutely have been included.

WRONG STATEMENT: This term is mainly used for concluding statements at the end of a chapter in which an overall conclusion is formulated which is simply completely wrong.

ERRORS OF OTHER TYPES: Any other kind of statement in clear conflict with the demonstrable truth.

Likewise, flaws can be of the same types, e.g. FLAW OF OMISSION.


There are also many cases when the manipulation does not mislead about the state of the environment, but rather about the participants of the environmental debate. A general feature is that Lomborg tries to let his opponents stand in an unfavorable light. A main message in Lomborg´s text is that you cannot trust the environmentalists - they hide what is inconvenient to their message (therefore, Lomborg is criticizing them of just that sin which he commits himself all the time!).

The criticism of what his opponents say and do is sometimes justified. But Lomborg seems to have an agenda that all opponents should be put in an unfavorable light, which means that if there is no basis for just criticism, Lomborg invents some unjustified criticism by various types of manipulation.  Such cases of manipulation are also important and should also be pointed out. Therefore,  the error lists include these cases under the heading (GROUNDLESS DEROGATION). This heading is put in brackets to indicate that such cases are not counted as flaws that mislead about factual matters. But if Lomborg´s text clearly is contrary to what his opponents actually said, then the heading will be GROUNDLESS DEROGATION in red colour, and this will be counted as an error like other erroneous quotes.

The importance of groundless derogations is described more detailed on this page.

Accidental and deliberate errors

Some flaws and errors are obviously involuntary, like that mentioned above concerning arsenic, which just reveals that Lomborg knows too little about the subject. However, this type of errors are rather few. Most errors seem to be a part of the general bias in the text, and many are evidently deliberate. To prove that an error is deliberate is hard, because it requires that one know what Lomborg thought or knew when he wrote his text. However, in a number of cases it is possible to state beyond reasonable doubt that the error was indeed deliberate. This is the case e.g. when an unequivocal error has already long ago been pointed out to Lomborg, so that he knows that his text is erroneous, but in spite of this, he perseveres. In such cases, the intention to mislead is marked with red or pink colour in the text, like "deliberately misleading" or "intentional bias".

Accidental errors are mainly of two types: 1) Cases where Lomborg is not aware of the terminology or the facts in the field that he is dealing with. This includes cases where new evidence existed before Lomborg finished his book, but where Lomborg was evidently not aware of it. 2) Errors of reference, e.g. a reference is missing in the list. Altogether, there are not many of these kinds of error.

On the other hand, some errors are clearly deliberate. These will typically be marked "The text is deliberately misleading.".

In addition, some errors are very likely to be deliberate. These will typically be marked "The text seems to be deliberately misleading.". Certain other cases are counted in the same category, e.g. those marked with "gross negligence" or "unacceptable bias".

The majority of all flaws and errors fall into neither of these groups. There are several hundreds of these, and their bias is always to the optimistic side. The likelihood that by mere chance several hundred accidental errors all should tend to the same side, is practically nil. Thus, we can be pretty sure that in most of these cases the bias is deliberate. But as we cannot know for sure why Lomborg e.g has cited papers that support his views, but not papers that contradict his views, we cannot proof his intent to mislead.

Submission of alleged errors and flaws

If you have found an error or flaw in Lomborg´s book, you are kindly requested to submit it to the editor of this web site. This can most easily be done by sending an email. The email must state precisely what part of Lomborg´s book is concerned, e.g. "The legend to figure 24 on p. 61". The error must be defined precisely, and, if possible, phrased in a way similar to the errors that are already included in the list. If it is necessary for the judgment of the error, a copy of relevant text in other sources should be appended. If this exceeds about 2 MB, it will have to be sent by snail mail (see correspondence for details).