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Chapter 23:





Lomborg claims that biologists are seriously overstating the number of species that go extinct, and he implies that they do this in order to make society give them larger grants. He stubbornly sticks to the estimate that only 0.7 % of all species will go extinct within the next 50 years, although this estimate is extremely weakly founded and in all probablity much too low. The hitch is that in the tropics where most species live, it is extremely difficult and expensive to prove a species extinct, even if it is. The average price of proving a tropical tree species extinct could probably be about 30,000 Euro (Fog, 2002), and if that money were available, it would be wiser to use it for the active prevention of extinctions, rather than for passive recordings. That would give us more species for the money. But Lomborg rejects this with a circular argument: Unless you prove that many species go extinct, you should not have any money, and because you have no money, you will not be able to prove that many species go extinct. Another awkward argument used by Lomborg is that because so much effort has been invested in saving species from extinction, few have gone extinct, and when few go extinct, there is no need to save them from extinction. A crucial issue is when the doomed species actually disappear. In the beginning, some of the alleged "professional pessimists" claimed that by the year so and so, x species will have gone extinct, when the proper thing to say would have been that x species are doomed to extinction within an unknown time phrame. We are now waiting to see if such predictions come true, but nobody knows how long to wait. Unless the "dead bodies" soon begin to accumulate, "professional optimists" like Lomborg will not accept the predictions, even if they are likely to come true later on.

Three general references that correct many of Lomborg´s claims:

K. Fog (2002): How many species go extinct ? Pp. 123-157 in "Sceptical questions and sustainable answers", to be downloaded here.

S. L. Pimm (2002): The dodo went extinct (and other ecological myths). Ann. Missouri Bot. Gard. 89: 190-198. The paper may be downloade here.

A. Balmford, R. E. Green & M. Jenkins (2003): Measuring the changing state of nature. Trends in Ecology and Evolution 18(7): 326-330.

Some recent information on the status of various animal groups can be found at the following web sites: Mammals and birds in N and S America: www.natureserve.org/infonatura. Amphibians worldwide: www. globalamphibians.org.


P. 249 left: (REMARK)

"We lose something in the region of 40,000 species every year." Remark: This statement was published by Norman Myers in 1979. It was based on extrapolation of the past exponentially increasing trend. Today, the general opinion is that this estimate is too high, but as explained in Fog (2002) (referred to above), it is actually within the range of possible values predcited by realistic species-area curves, although very much in the upper end.


What Lomborg writes here, is based on his icon, the American economist Julian Simon, who has attacked Myers. Myers has actually defended his views in public and countered the criticism, explaining the rationale of his statements. There exists a book which brings the discussion between the two parties, viz. N. Myers & J. Simon (1994): Scarcity or abundance? A debate on the environment. New York. If Lomborg´s aim were to check if Simon is right in his dispute with Myers, which he alleges, then he would bring the statements of both the accuser and the defendant. But the pleading of one of the parties (Myers) is completely left out. So, the "judge" (Lomborg) listens to only one of the parties. This is not acceptable. Myers arguments of defence should have been cited.

P. 249 left and note 2006: (COMMENT)

"The message was relayed to the world at large in the official US environment report Global 2000." The author of that chapter in the report Global 2000 happened to be Thomas Lovejoy, who reviewed Lombors´s biodiversity chapter in Scientific American in January 2002. In the ensuing debate on the S.A. web site, Lomborg writes: ". . it is astounding that Lovejoy does not feel any need to confront the fact that he himself in the Global 2000 report from 1980 estimated about 15-20 % of all species would have died in 2000." Comment: The point here is that in 1980, the use of species-area-curves to estimate how many species will survive reductions in habitat area was only in the making. There was not yet any understanding of how long time it takes before a species doomed to disappear from a reduced habitat area, actually dies out there. The first attempt to address this question was the establishment of coordinated investigations of forest fragments north of Manaus in Brazil. The results have been widely referred to since then. The organizer of this project was precisely Thomas Lovejoy, and so it is not warranted to claim that Lovejoy has not felt any need to confront the question of whether and when species predicted to disappear acutally do disappear. The proper thing to say in 1980 would have been that because of habitat reductions now, this number of species are sure to go extinct some day in the future. Only much later have scientists begun to make estimates of when these extinctions will occur. A present estimate for some of those species that ultimately will go extinct, is a half-life of about 50 years, i.e. half will be gone after 50 years, half of the remaining after 100 years, and so on (Pimm 2002, referred to above).

P. 249 left: FLAW

"Al Gore repeats the figure of 40,000 species . ." Flaw: This is not fully correct. On pp. 27-28 in his book (the page cited by Lomborg), Al Gore refers to the action to rescue three whales that had become trapped under polar ice. He writes: "Along with millions of others, I had been delighted to see them go free, but . . it occurred to me that if we are causing 100 extinctions each day - and many scientists believe we are - approximately 2,000 living species had disappeared from the earth during the whales´ ordeal." His text continues with the mentioning of the heroic rescuing of a small girl, Jessica, with the comment that "during the three days of Jessica´s ordeal, more than 100,000 boys and girls her age or younger died of preventable causes - mostly starvation and diarrhea . . ". Thus, in this section of his text Al Gore presents views that are actually close to Lomborg´s views - that we should keep a proper sense of proportion and look at the global figures rather than focusing on single cases with large appeal to the media. And Al Gore makes due reservations; he writes "if we are causing . . ". On another page, page 24, Al Gore does present a graph that includes the figure of 40,000 species per year, but the legend below has that this is the "estimated loss", and the figure of 40,000 is nowhere mentioned in the text. Instead, Al Gore writes that the rate of species loss is 1,000 times the background rate, which actually agrees with Lomborg´s estimate. So, instead of mentioning that Al Gore in several ways share Lomborg´s views, Al Gore is given the role as a doomsday sayer.

P. 249 left: ERROR

". . the famous Harvard biologist E. O. Wilson points out that we are losing between 27,000 and 100,000 species a year." Error: What Wilson actually has written, is that this proportion of the species are extinguished or doomed each year. The addition "or doomed" is crucial, because it implies that the "death sentence" may actually not be "executed" until much later. That Wilson´s estimate includes species that will only go extinct much later, is also stated very explicitly in the notes in Reid (1992), which Lomborg likewise has used as one of his main sources.

P. 249 left: ERROR

"Paul Ehrlich even estimated in 1981 that we lose some 250,000 species every year . . . ". Error: Lomborg has taken this information from Stork (1997) - cf. below - but he has overlooked an important reservation. Stork says in a note: "The estimated rates include species "committed" to extinction.". This reservation is crucial, because it implies that the "death sentence" may actually not be "executed" until much later. Furthermore, it seems that the figure of 250,000 is mentioned nowhere in Ehrlich´s book. It is probably a figure which others have calculated on the basis of Ehrlich´s text.


"With half of the Earth´s species gone by the year 2000 and all gone by 2010-25." Error: Lomborg refers (indirectly) to pp. 159-162 in the book "Extinction" from 1981. Here, the carefully explained estimates deal only with species in moist tropical forests, and for an extreme case it was said: "there could be a catastrophic loss of species and populations within fifteen to twenty years, and the majority of rainforest species would have disappeared within thirty to fifty years". Thus, it is not true that Ehrlich and Ehrlich spoke about all species of the Earth, it is not true that they predicted that so many species would go extinct - they just mentioned this as a possible scenario - and they did not talk about "all gone", but about "the majority". Such a misleading quotation must at least be due to gross negligence.

P. 249 left, note 2010: ERROR OF REFERENCES

To check if Ehrlich really said that all species in the world would be extinct by no later than 2025, we consult note 2010 which refers not to Ehrlich directly, but to Stork 1997. When we look up Stork 1997 in the bibliography, we are referred to Wilson et al. 1997, and when we look up Wilson et al. 1997, it is not there. So, we are unable to check if Ehrlich really made this unbelievable claim. Actually, the reference "Stork 1997" is in Reaka-Kudla, Wilson & Wilson 1997. And the reference that we sought in the first place, is P. Ehrlich & A. Ehrlich (1981): Extinction. The causes of the disappearance of species. 305 pp. Random House, N. Y.

P. 249 left, note 2011: FLAW

Nearly hidden at the end of note 2011, Lomborg has this remark: "This chapter is to a large degree based on Simon and Wildawsky 1995." Comment: It is peculiar that the two authorities upon which Lomborg bases his text on biodiversity, are business economists ! Flaw: Lomborg´s declared aim is to check if Simon is right (p. xix). When that is the aim, he cannot allow himself to use Simon as a source to check if Simon is right !

P. 249 left: (COMMENT)

" . . the more realistic figure of 0.7 percent over the next 50 years . . " Comment: This figure is not more realistic, see p. 255 right.

P. 250, table 6: FLAWS

In this table, Lomborg lists the total number of documented extinctions from the year 1600 to the present day. Flaws: Several reservations made in the original sources have been omitted. The data for reptiles and amphibians respect the 50 year rule, according to which the extinction is only regarded as documented if the species has not been observed for 50 years; thus these figures concern the situation up to about 1950, not up to 2000. The data on fish are mainly restricted to North America and lake Victoria in Africa, and thus do not represent the global situation. The data on molluscs go back only to the mid 1800s, not to 1600 as indicated. The data on crustaceans and insects are practically all from North America and Hawaii, and thus do not represent the global situation. Even for North America, the data are not complete; they include mainly conspicious species, especially butterflies, whereas for instance the two species of lice that went extinct when the passenger pigeon disappeared, are not included (May et al. 1995). The data on vascular plants respect the 50 year rule, and thus do not include the approximately 371 species declared extinct or presumably extinct during the period 1947-1997. It may be added that even where Lomborg cites the figures correctly, they do not necessarily represent the true situation. Thus, according to the figures cited by him, only 5 species of amphibians have gone extinct up to now. But the most recent data (see www.globalamphibians.org) tell that 34 species are now declared extinct, and a further 113 species are probably extinct. These figures include extinctions after 1950. So, Lomborg´s figure (5) is 30 times lower than the probable actual figure (147).

P. 251 top left: FLAW

" - although most of this medicine is now produced synthetically". Flaw: Rebutting Lomborg´s text (www.grist.org/advice/books/2001/12/12/specious/), Norman Myers writes: "In several instances, scientists have tried for decades to synthesize plant-drived alkaloids and other biocompounds in the laboratory, investing huge amounts of money in the effort, to little or no avail." Indeed, although simple compounds like salicin may be relatively easily synthesised by chemists, many effective natural compounds - probably the main part - have so complicated molecules that synthesis is not practical. Vincristine, an alkaloid extracted from the Madagascar Periwinkle, Cathranthus roseus, is still an indispensable part of most curative regimens used in cancer chemotherapy nowadays. Because the amounts of vincristine that can be obtained from one kg of leaves is very small, alternative production methods have been studied intensively, but chemical synthesis has turned out not to be practical. The much heralded taxol, used against ovarian cancer, is a tremendously complex molecule; although a small amount of taxol is being synthesised, the majority of the drug is still being derived form the bark of a yew tree growing in the pacific northwest of North America. When new disesases appear, still new species of plants may turn out to be useful. Calanolide A is derived from a latex from a tree (Calyphyllum lanigerum) in the state of Sarawak in Malaysia. It was found active against the HIV-1 virus. However, this tree now seems to have disappeared from the area where it once grew. Although this compound may now be synthesised chemically, it would never have been found if the plant had not existed, or if it had not been investigated before it was eradicated. Many more examples may be found in a report from a conference on "Nature´s pharmacy", see next paragraph.

P. 251 left: FLAW

"But so long as we do not even have any practical means of analyzing even a fraction of those plants already known to us . . . " Flaw: Up to now, already 3,000 species of plants are known to be useful against cancer, that is, large numbers of useful plants have already been found. Furthermore, chemical means of scanning large numbers of plants do exist. Thus, by electron spin resonance (ESR), it is very simple to search for quinones in plant extracts, and actually large numbers of plant species from many parts of the world are being scanned by this method - it has been done at Aarhus University, a few hundred meters away from Lomborg´s former working place. In a conference on "Nature´s pharmacy", it is stated that large scale screening of crude extracts made from plants has so far been more successful than rational drug design using computers.

P. 251 left: (COMMENT)

". . . the value of losing the last beetle of a million species of beetles". Comment: Here, Lomborg refers to two discussion papers by D. R. Simpson and others. These papers discuss the pharmaceutical value of preserving even the last out of a total of 5 or 10 million species. However, those organims that are believed to be of pharmaceutical interest, are first of all the plants, and in addition some others, e.g. some groups of marine animals. It is not commonly proposed that the millions of insect species have any appreciable pharmaceutical value. The paper of Simpson and Sedjo concludes that with a total of 5 million species, the marginal value of preserving the last of these when all others have already been preserved, is an absurdly small amount. However, preserving all of 250,000 species - corresponding approximately to preserving all plant species - gives a very different result: the value of the last species is 2,600 $. But we cannot let the plants survive and eradicate the insects - the eradication of a nature area will eradicate plants as well as insects. So if we preserve all plant species, we preserve all nature. The paper by Simpson and Craft uses a different analysis, in which various pharmaceutical products are allowed to vicariate for each other. By this method, the value of the last species becomes much larger. If this method had been used for the world´s plant species alone, the result might have been more favourable. Simpson and Craft also try to calculate the pharmaceutical value per area unit in one of the world´s biodiversity hotspots. However, doing this, they disregard the possibility of mapping the occurrence of plant species and creating reserves to preserve the maximum number of species. Biologists do not argue that all untouched nature should remain untouched. They argue that sufficient nature should remain that nearly all species survive, which involves a clever mapping of what nature areas can be eradicated and what areas should be preserved.

P. 251: FLAW

Lomborg discusses the genetic argument for preserving plants and concludes that it will suffice to have extensive gene banks of crop varieties. Flaw: First, not all organisms are suitable for preservation in gene banks; this refers not least to animals (genetic diverstiy is as important to animal husbandry as to crop growing). Second: Wild relatives of cultivated plants may contain relevant genes. Lomborg himself presents a history about a wild strain of wheat from Turkey. But up to now, we have not prudently protected such relatives, as Lomborg presupposes that we will do. Among the globally extinct plant species are one species of maize, one species of coffee, and five species of tulips. Third: We have entered into an age of genetic engineering, when it will in principle be possible to transfer valuable genes from only distantly related species to cultivated species. Therefore, the argument that distantly related species are not worth protecting, does not hold anymore. Fourth: If many valuable genes are present only in a few genetic banks, then catastrophes (fires, earth quakes etc.) might wipe out large amounts of genetic diversity in one stroke.

P. 251 right: ERROR

"Table 6 shows that about 25 species have become extinct every decade since 1600". Error: This calculation is not correct; Lomborg has forgotten the necessary reservations to the data in table 6, as explained above. He divides 1,000 species by 400 years, but as mentioned above, the data for plants go only up to 1947 and omit 371 species that have gone extinct since then. The data on molluscs go back only 150 years, not 400 years, etc. Furthermore, the number of species going extinct per decade has clearly followed an exponential rise, as is evident from Reid 1992, which he comments upon on p. 252 and cites in note 2032. Therefore, to calculate an average rate per decade is meaningless.

P. 252 top left: (COMMENT)

". . one must have looked for the species for several years wherever it may exist." Comment: "Several years" does not sound impressive to the reader, whereas "50 years" might do so. If we have to wait for 50 years after the last sighting until we can declare a species officially extinct, then it is obvious that there will in fact be many species that are not officially extinct, but are so in reality. The lay reader will miss that point. However, at the time that TSE was written, the 50 year rule did no longer apply to groups of very well studied organisms (e.g. large mammals), and Lomborg´s reference, which is from 1990, is thus outdated.

P. 252 left: FLAW

"Lovejoy constructed a model to back up Myers´controversial figure of 40,000. Lovejoy´s model is in reality attractively simple . . " Flaw: This is an extremely flawed and biased presentation of the species-area-curves, which were not invented by Lovejoy (as also stated by Lomborg in the next section), were not invented to back up Myers´ figure, and are still the most widely applicable tool available to predict the number of extinctions.

P. 252 top right: (REMARK)

"This is Myers´ argument in its entirity. . " Remark: It is true that Myers presents his figure of 40,000 species per year without any precise argumentation. The figure is presented as some sort of guess, with phrases like "Let us suppose that . . ", "far from unlikely" or "a reasonable working figure" (Myers p. 31). There is no `circular argument´ in making such a guess. What Myers tries to say is that if so many species go extinct up to the year 2000, then there will be far more extinctions at the end of the period than at its start.

P. 252 right and figure 131: FLAW

". . and 400 times the maximum guess as seen in figure 131." Flaw: Lomborg confuses Myers´ estimate for the present situation with Myers´ estimate for the near future. Myers (p. 5) assumes that already "now" (in 1979), there may disappear at least one species per day (i.e. 365 per year). This should be compared with the guess from 1974 of 100 species per year "now". Thus, Myers´ guess concerning the present rate is `only´ 3,65 times the previous guess. The rate of extinction could theoretically have increased by a factor of 3,65 from 1974 to 1979. That guess which is 400 times the maximum guess from 1974, is a guess concerning not the present rate, but the rate in the near future. Thus, it is not correct when Lomborg in his figure 131 places the figure of 40,000 species at the year 1980. It should be placed closer to the year 2000, indicating that contrary to the other figures, which indicate extinctions that have already happened, Myers´ high figure is a predcition for the future. In essence, Myers postulates that the rate of extinction may increase by more than a factor of 100 from 1979 to 2000, based on the (false) assumption that the world´s rain forests would have been nearly wiped out by 2000.

P. 253 right: FLAW

". . what would be lost would primarily be insects, bacteria and viruses". Flaw: Out of all known species, insects make out at least 75 %, yes, but bacteria and viruses make out less than 1 %. Even though the proportion of bacterial species that is unknown to us is larger than in insects, it is not true that those lost would primarily include bacteria and viruses. By the way, bacteria have a much wider range of different enzymes than any other organisms, and some of these enzymes might turn out to become important for us e.g. in the biotechnological industry. Therefore, preservation of bacteria could be important.

P. 253 right: FLAW

"Wilson formulated a rule of thumb: if the area is reduced by 90 percent, then the number of species will be halved."  Flaw: The so-called rule does not state that the number of species will go down at once. What R. MacArthur and E. O. Wilson formulated in 1967, was that when we compare two habitat areas, one of which is only 10 % of the other, then the smaller area will hold only half as many species as the larger. They did not predict what would happen if an area is suddenly reduced. All biologists, not only Wilson, assume that in case of a sudden reduction, the species number will ultimately fall to a lower stable level, but no theory predicts how and how fast this will happen. It is quite clear from the papers that Lomborg has read, e.g. Heywood & Stuart (1992) and  May, Lawton  & Stork (1995), that area reductions do not lead to extincitions immediately. The latter reference has a chapter on "Estimated future extinction rates from species-area relations", from which it is clear that species-area relations tell the number of species that are `committed to extinction´, but the time time taken for these extinctions to occur is not specified. Likewise, Heywood & Stuart (p. 255 top right) give the number of birds that will be committed to extinction by 2015, not the number that will actually have gone extinct by 2015. So the "model" does not predict exactly that which Lomborg claims that it predicts, and Lomborg should know that.

P. 254 top left: ERROR

"In the US, the eastern forests were reduced over two centuries to fragments totaling just 1 - 2 percent of their original area". Error: If we use the term "eastern forests" without further specification, then the truth is that their area declined to a minimum of about 48 % around 1872. What shrank to 1-2 %, was old growth forest.

P. 254 top left and note 2046: FLAW

". . but nonetheless this resulted in the extinction of only . . . " Flaw: The stated purpose of Lomborg´s text is to see if reality corresponds to the model, i.e. if the species-area curve for islands is valid also for continents. Now, according to note 2046, some of the species that went extinct probably went extinct from other causes. This reservation is not relevant, however. The theory predicts that the reduced habitat area will only allow the coexistence of so and so many species. If one is removed by man, e.g. through hunting, then this leaves more space for the remaining species, and thus we expect that one species less will disappear from mere habitat reduction. There will be a "substitution of death causes", and the number of species disappearing in the end will not be affected.

P. 254 top left and note 2046: ERROR

" . . of only one forest bird." Error: Actually, four species of forest birds went extinct, not one (or three as stated in note 2046). Lomborg makes this error because he relies mostly on Simon and Wildawsky 1995 (see end of note 2011). To check this, he must consult also those that have criticized Simon, and Simon´s eastern forest bird example was criticized already in 1995 by Pimm & Askins (Proc. natl. acad. sci. USA 92: 9343-9347) and by Pimm et al. (Science 269 (1995): 347-350). That the latter paper has something to say about biodiversity loss in USA was pointed out to Lomborg as early as January 1998. This paper was also referred to in articles in New York Times, Discover Magazine and elsewhere. So Lomborg should be aware of the criticism. When he neglects it, this is at best due to gross negligence.

P. 254 top left and note 2046: FLAW

" . . 1-2 percent of their original area, . . this resulted in the extinction of only one forest bird. Flaw: The question here is whether the reduction in habitat area and the number of species that disappeared correspond to theory. But there is some confounding here. Either we speak of those species that have gone completely extinct in the whole world. In that case, their number should be compared with the habitat reduction within the whole range of distribution, i. e. not just eastern USA, but also e.g. Canada. Or we are concerned only with eastern USA, but in that case the parameter is what species have disappeared from USA, not from the world. Pimm & Askins (referred to above) have chosen the solution to look at birds that were endemic to the forests of eastern USA (i.e. occurred only there). There were 28 of these. With a 50 % forest reduction, one would expect 17 % of these to have gone extinct, i. e. 4.76 species. Actually, four have gone extinct, and two more are in acute danger. This makes an excellent agreement between theory and reality.


Concerning bird extinctions in USA, it is easiest for Lomborg to make his point when he considers only forest birds. But when he enters the next example, on Puerto Rico, it is easiest for him to make his point when he can count as many species as possible, and now he counts not only forest birds, but also those of open country. So he is incosistent - he uses whatever principle fits him right now. - Concerning the extent of deforestation, Lomborg uses in both examples the felling of primary forest (= old growth forest), whereby the percentage of habitat loss becomes very high. To stress his point here, it is an advantage to him that this percentage is high. But in the forest chapter, on p. 113, it is an advantage to his point that the the percentage is low. So there, he dismisses Myers´ high figure, which concerns primary forest, and claims that the correct figures are those for all forest, including plantations, which is a lower figure. Thus, it seems that again and again, Lomborg picks just those figures which are most advantageous to him.

P. 254 left: FLAW

" . . in Puerto Rico . . the primary forest had been reduced by 99 percent over a period of 400 years." Flaw: This is not the relevant figure for the purpose of the paragraph. The relevant figure will be for total forest, not primary forest, and total forest cover was reduced to about 10 - 15 %, not 1 %, and only for a few decades (A. R. Brash (1987): Biological conservation 39: 97-111). Lomborg does mention this fact in the following paragraph; so the flaw is not that he omits the fact; the flaw is that he postpones it until after the point when he states that there is a serious problem with Wilson´s rule of thumb, when in fact he could not claim this, had the proper forest figure been used from the beginning.

P. 254 left: ERROR

"`Only´ seven out of 60 species of birds had become extinct . . This indicates a serious problem with Wilson´s rule of thumb." Error: Firstly, one of the survivors, a parrot species, declined to a mere 13 individuals and survived only through extreme conservation efforts. Thus, without this intervention, 8 species would have gone extinct. More importantly, however, out of the 60 original species on Puerto Rico, about 20 were endemic to that island. Thus, out of those species that might possibly go completely extinct due to changes on Puerto Rico, 8/20 = c. 40 % actually did or would have done so. If for the species-area curve we apply a habitat reduction to 12.5 % , then the curve predicts that 42 % of the species should go extinct, so model and reality are actually in excellent agreement. Thus, it is directly wrong when Lomborg writes that this indicates a serious problem with the model. As to the number of new species that have colonized the island, this is not relevant, because these are mainly open land species, and some of them are very widespread (e.g. house sparrow).


After having reviewed some cases where the species-area curves allegedly do not fit the actual data, any fair treatment would then include examples where the model does fit reality, i.e. where species actually do disappear over time from small fragments of tropical forest. Examples could be found e.g. in Turner & Corlett (1996): Trends in ecology and evolution 11: 330-333. Other relevant papers to cite could be Dirzo & Miranda (1990): Conservation biology 4: 444-447; Redford (1992): BioScience 42: 412-422; or Philips (1997): Biodiversity and conservation 6: 291-311.When Lomborg does not at all mention that there are cases where the model fits realitity, he gives his text an unacceptable bias.

P. 254 left bottom: FLAW

"Myers says that `we have no way of knowing the actual extinction rate . . ´ " Flaw: This quotation is from 1979, before species-area curves were applied to tropical deforestation. It may suggest to the reader the false impression that the biologists are not able to calculate ("know") the extinction rate, i.e. that biologists themselves do not trust species-area curves.

P. 254 left bottom: ERROR

"Colinvaux admits . . that the rate is `incalculable´. " Error: What Colinvaux actually wrote, was: "As human beings lay waste to massive tracts of vegetation, an incalculable and unprecedented number of species are rapidly becoming extinct." So, what Colinvaux said, is that we cannot calculate the number of species that disappear (inter alia because we know neither the total number of species per area unit, nor how much the species composition shifts when we move to neighbour areas). But Lomborg transforms this into the postulate that the extinction rate cannot be calculated, and that is not what Colinvaux said. Furthermore, by bringing the quote in this context, and by using the word "admits", the reader will get the false impression that the model - the species-area curves - is actually of no use, and that the biologists "admit" this. This error has been pointed out to Lomborg repeatedly right since January 1998, but he has refused to correct it. Thus, it is a case of deliberate manipulation with the reader.


" . . the biologists have a clear opinion of where the debate between figures and models should end. " Flaw: What Lomborg writes here, is that the biologists are not honest and do not follow the principle of objectivity in their work. This is a completely unwarranted insult, and Lomborg has brought no evidence that this is so, except for his manipulated quotations in TSE.


"There are many grants at stake." Flaw. Lomborg implies that the biologists are driven by greed for money, and thus tries to discredit a whole group of people. His insinuation is neither documented, nor warranted, nor justified. Most people in the world, including Lomborg himself, want as much money as possible to be invested in just that particular field of work where they are employed. If biologists are like that, then it demonstrates that they are normal people. Add to this that many of those working to save endangered species are doing a great and selfless task, sometimes under difficult conditions and at a miserable pay, many times lower than the pay Lomborg gets for slating them.

P. 255 left: FLAW

"One of the few examples of extinction appears in a paper by Gentry. .. something like 90 species of plants found nowhere else." Flaw: The source of this story is Heywood & Stuart (1992), which Lomborg has read. Here we get a slightly different impression. The case was that the foothills were being totally cleared of forest. Gentry assumed that at least 38 and perhaps nearly 90 plant species of the forest were endemics, which would be totally exterminated when the all the trees were cut. Lomborg omits the crucial information that "only" 38 species were definitely considered as endemics.

P. 255 left: FLAW

"In two brief return visits six years later, Gentry refound at least 17 of the previously assumed lost species." Flaw: From Lomborg´s text, the phrase "return visits" implies to the reader that Gentry returned to the same place and saw that the trees remained there after all. This was not the case, however. The true story is that Gentry examined other mountain forests in the neighbourhood, and did after all find some of the species there. So the problem consisted in knowing how wide/narrow was their geographical range. It will hardly ever be possible to know how many of the species were truly restricted to just one locality, because that would require a meticulous investigation of every single mountain ridge in the entire Andes chain. But it seems that Gentry´s first estimate that between 38 and 90 species were endemic held true, when actually, up to now, 73 of the species have not been found anywhere else, and thus are presumably extinct. Lomborg has read the source and knows all this. When he gives a different impression, his text is deliberately misleading.

P. 255 left: (COMMENT)

" . . when members of the Brazilian Society of Zoology analyzed all 171 known Atlantic forest animals, the group `could not find a single known animal species which could properly be declared as extinct´ . .". Comment: The reader may not properly understand what is referred to here. The text does not refer to organized investigations in the forests, but to some kind of office work - the first attempt to make a red list of threatened animals for this region. And the situation at that time was that there were insufficient data because of lack of investigations, and for that reason no species could be declared definitely extinct, although a few species could be declared probably extinct.

P. 255 left and note 2066: FLAW

"the group `could not find a single known animal species which could properly be declared as extinct´ . . . no species considered extinct." Flaw: As the text stands, the reader gets the impression that no animal species has gone extinct in the area. But that is not so. Careful reading reveals that what Lomborg writes, is that this group of zoologists did not consider any species extinct. Only those few readers who consult note 2066 will discover that actually, one bird species endemic to these forests is extinct in the wild. It is misleading to conceal this information in the notes. It may be added that according to www.natureserve.org/infonatura, two more bird species endemic to this region are possibly extinct by now (Calyptura cristata, Nemosia rourei), and according to www.globalamphibians.org, one frog species endemic to this region has been extinct for many years, and 4 other frog species are possibly extinct.

P. 255 left and note 2068: FLAW

"Similarly no species of plants was reported to have become extinct." Flaw: The ordinary reader will believe from this that no species of plants in this area have gone extinct. Only by very careful reading will he detect the meaning of the phrase "was reported". Lomborg only says that this group of biologists did not report any extinctions. Other biologists have done so, however. This is revealed only in note 2068, which reads: "Fog reports that since then, 10 plant species have been declared extinct". The reference (Fog 1999) is in Danish, and so most readers have no chance to check this information. Actually, what Fog did, was to point out that the official IUCN red list for the world lists 10 plant species endemic for this region, which have been exterminated. This information was new to Lomborg when it was pointed out to him by Fog in 1999. But he did not change a word in his original text because of this - that would have disturbed Lomborg´s point. He concealed it in a note which very few would read. This is deliberately misleading.

P. 255 bottom left: FLAW

"Several scientists have investigated asserted extinction rates of 15 percent for birds up until 2015". Flaw: This is not correct. The scientists have stated that 15 percent of the bird species will be `committed to extinction´ by 2015. See comments to p. 253 right on Wilsons "rule of thumb", or read the article by May, Lawton & Stork (1995) cited by Lomborg.

P. 255 top right: FLAW

" . . after thorough research on 1,000 birds that have been claimed to become extinct . . " Flaw: Lomborg makes the reader believe that biologists have predicted extinctions even when these are not likely. But this is misleading. The biologists have predicted that some species will go extinct if nothing is done to prevent it, and it now turns out that something has been done to prevent it, wherefore they will most likely not go extinct. What was scrutinized, was the world red list of birds that are classified as "endangered", i.e. under acute threat, or just "threatened". The definition of the category "endangered" is that the species is in such a precarious situation that it is in danger of extinction in the near future (within a few decades) if those negative factors that affect it at present, continue to do so. When a species receives this classification, it is a warning signal that something should be done, otherwise . . . . What the text says, then, is that conservation efforts have indeed been made in most cases, whereby the action of the negative factors has been neutralized. The text quoted by Lomborg continues: "although many will remain in a precarious situation." This part has been left out by him.


"Despite the fact that the IUCN predicts higher extinction rates it is concluded that `actual extinctions remain low´ ". Error: This turns the meaning of the original text into the opposite. The original text says: ". . . it is clear that the number of bird species that are being added to the list of critically endangered species, is increasing rapidly. Although actual extinction has remained at a low level, the number of species requiring very great efforts to be saved is becoming very large." And the text continues saying that unless more is done in the near future to save these bird species, it is likely that we will see a "considerable increase in the actual extinction rate". So Lomborg tries to give the impression that things will not turn out as bad as the pessimistic experts say, whereas the original text is that things will turn out worse than it seems now, unless more is done to prevent it. The point is that up to now, the number of threatened species has been low enough that we could afford to keep nearly all away form the brink of extinction. But as more and more species come into this situation, there will be a time when we can no longer afford to save them all, and then the actual extinction rate will boom.

P. 255 right: (COMMENT)

"Yet no known species of its old, largely endemic fauna can be regarded as extinct." Comment: As stated for p. 255 left, this claim is no longer absolutely true.

P. 255 right: FLAW

"If this model is used, it is actually possible to estimate the number of extinct birds . . . ". Flaw: What Stork and Mawdsley did, was to note that in Britain, the risk for a bird species to be on the red list is 7 times the risk for an insect species, and in accordance with this, the risk for a bird species to go extinct is 7 times the risk for an insect species to go extinct. Not very strange - it just demonstrates that red lists do indeed indicate the relative degree of threat to different groups. Under the assumption that the ratio of 7 holds also outside Britain - and there is no verification of this - then from the worldwide data on the proportion of birds that have died out since 1600, we may assume that the proportion of insects that have died out since 1600, is 7 times less. Lomborg says: " . . it is possible to show . . ", when actually this is little more than a shot in the dark. Next, we know that extinction rates are increasing, and we guess that the rates for the period 2000 - 2300 will be on average 33 times higher than the rates for the period 1600-2000. This is just an extrapolation that is founded no better than Myers´ estimate of 40,000 species a year. With these figures, 4.4 % of all insect species will go extinct within the next 300 years, which is on average 0.7 % every 50 years. Evidently, this figure is based on assumptions that are so uncertain that we should rather talk about a guess than about a calculation. Stork (1997) makes the following proper reservation: "Whether the assumptions . . match reality and whether it is possible to use models from the British fauna and flora to make global predictions is impossible to say . . ". Lomborg, on the other hand, has stubbornly stuck to the figure of 0.7 %/ 50 years right since 1998, without proper reservations. But his belief in this figure, rather than e.g. 0.5 % or 0.9 %, is completely unwarranted.

P. 255 right, note 2073: ERROR OF REFERENCE

Considering the meagre founding of Lomborg´s estimate of the extinction rate, it is very unfortunate that the reference in note 2073 (Stork 1997) cannot be traced. In the bibliography, the reader trying to find Stork is referred to Wilson et al. 1997, which is not listed there. The correct reference is Reaka-Kudla, Wilson & Wilson 1997, but how should the reader could guess that ?

P. 255 bottom right: FLAW

"An extinction rate of 0.7 percent over the next 50 years . . ". Flaw: Considering the steady increase in extinction rates, Lomborg is not justified in assuming that the extinction rate will be constant. It is not credible that the rate during the next 50 years should be the same as the calculated average over the next 300 years.

P. 255 bottom right and note 2076: ERROR

"It is a rate about 1,500 times higher than the natural background extinction." Error:  Lomborg cannot use insects because his figure of 0.7 %/50 years for insects is not measured, but inferred from indirect, very dubious calculations. Furthermore, according to Lomborg´s source (May et al. 1995), the estimated species lifetime of 11 mio. years is based nearly exclusively on marine invertebrates, whereas the species lifetime for insects is possibly considerably longer than that.

P. 255 bottom right: (COMMENT)

"However, it is a much smaller figure . . ". Comment: The discrepancy between the two types of estimates can be explained. Lomborg should know this, because it is explained in May et al. (1995), which he has read. Here it is explained (p. 16 in May et al.) that the discrepancy largely disappears if we recognize that the lower estimate refers to recorded extinctions, whereas the higher estimate refers to species that, on current trends of habitat destruction, are `committed to extinction´.

P. 255 right: (COMMENT)

Comment: It is relevant to calculate the present rate of extinction relative to the background rate. Lomborg should definitely have done that by using data for groups where there exist data on both former rates and present rates. Such calculations may be carried out for mammals, fish, molluscs and plants. This has been done in Fog (2002 - ref. at top of this web page), and the result is that the rate of documented extinctions during the latter half of the 20th century is 20 to 80 times the assumed background rate. The lowest figure is for molluscs. However, when it comes to fish, molluscs and plants, the actual number of extinctions is certainly larger than the number of documented extinctions. One may calculate the assumed rate at which insects are committed to go extinct due to tropical deforestation, and likely results are that 0.1 to 0.4 % of all insect species are doomed per year (Fog, 2002). This agrees closely with Reid (1992) who estimates 0.1 to 0.5 % per year. If we assume that the average lifetime of an insect species is 1 mio. years (we do not know if that is true), then we find that the present rate is about 1,000 to 5,000 times the background rate. Accidentally, this happens to agree with Lomborg´s estimate of 1,500 times the background rate, but this agreement arises because Lomborg, relative to the above data, has used a 10 times lower present extinction rate, and also a 10 times lower background rate.


In the 1980s and early 1990s, many estimates of future extinction rates were made, and lists of these estimates are brought in a number of papers, such as those by Reid (1992) and Stork (1997) that Lomborg refers to extensively, and also Pimm et al. (1995): Science 269: 347-350, which Lomborg ought to have read. Most estimates are estimates of species committed to extinction, based on the species-area curves, and these mostly fall into the interval between 0.1 % and 1 % of all species per year. Another approach is a detailed analysis of threatened hotspots, i.e. regions with many endemic species. A third approach is that of Smith (1993), who extrapolated current recorded extinction rates and used the dynamics of species moving into red list categories of progressively more severe threats. At least 14 different estimates exist. Lomborg uses one of them - 0.7 %/50 years, equivalent to 0.014 % per year - which is 4 times lower than the lower range limit of the lowest of the remaining estimates. As to how future rates are predicted, this low estimate is based on Smith, loc. cit. Lomborg does not with one word mention the existence of other estimates than his own, except those that are so high that he can use them as examples of ridiculous exaggerations. For instance, concerning the paper by Reid (1992), Lomborg relies very much on the flawed estimate of tropical forest loss which is presented in this paper, although Reid is just an amateur on this subject. But when it comes to Reid´s estimate of extinction rates - on which he is much more an expert - Lomborg completely neglects his estimate. Thus, on this matter, Lomborg´s bias is so large that it is quite unacceptable.

P. 256 top left and note 2078: FLAW

" : : the developing world gets rich enough to afford to help the environment, reforest and set aside parks . . " Flaw: As explained for p. 117 left in chapter 10, there is no significant trend that developing countries will reduce deforestation when they get richer. Therefore, this argumentation is not valid. As to the references in note 2078, a check of Sagoff 1995 did not bring any corroboratation of Lomborg´s claim, only some quotes where N. Myers says that those that clear the forests, are mainly poor people. One might as well have cited Myers directly, but of course, that would disrupt Lomborg´s picture of Myers as a man that cannot be trusted.

P. 256 left, notes 2079 and 2080: ERROR OF REFERENCE

The two notes referred to, point to the reference "UNDP 1995". Error: UNDP 1995 is in the bibliography, but it does not seem to have anything to do with the subject. One has to find out that the correct reference is UNEP 1995.

P. 256 left: (REMARK)

"the rate at which species are likely to become extinct in the near future is very uncertain,". Remark: Yes, what is said in this quote is very true, and therefore Lomborg should not be so cocksure about his own estimate and criticize all others.

P. 256 left: ERROR

"This translates into an extinction rate of 0.1 - 1 percent per 50 years. Error: No, it does not, because the background rate applied by Lomborg is flawed. He cannot use a species lifetime of 11 mio. years, when the average for marine invertebrates is about 4 mio. years, and the estimated lifetime for other animals is 1 mio. years.


"As late as 1999 Myers actually reaffirmed his estimate of about 40,000 species . . " Error: In the article from 1999, Myers did neither mention the figure of 40,000 species/year, nor any other figure that is equivalent to it. Comment: It should be remarked that strictly speaking, Myers did not say that "we are into the opening stages of a human-caused biotic holocaust." These words appear only in the headline and in the headnote, which was probably written by the magazine editor or by a journalist. In Myers´own text, there is no such phrasing. It is - unfortunately - commonplace that journalists exaggerate and dramatize scientists´s formulations. This should be criticized, but the criticism should be directed at the journalists, not at the scientists.

P. 256 top right: FLAW

". . biologists don´t need to know how many species there are . . . " Flaw: Lomborg criticizes this phrasing, but he is not right in his criticism. What Ehrlich says is that we do not need to know the numbers in order to see that too many disappear. It is enough to know the rates, which could be done e.g. by continuing to verify the validity of the species-area model. Actually, Lomborg agrees in principle. He writes on p. 250 right: "Because of the considerable variations in the estimated number of species, it is therefore best to discuss extinction in terms of percentage loss per decade." So Lomborg greatly overreacts when he with no justification accuses Ehrlich of abandoning the principle of scientific objectivity. It may be added that the text in Ehrlich´s book continues with: "To think otherwise is equivalent to believing no one can tell whether a beach is eroding away unless every grain of sand, seashell, piece of driftwood, and strand of seaweed has been counted, measured, and classified and a record kept of ones that have disappeared."

P. 256 right: FLAW

"We biologists should not bear the burden of proof . . " Flaw: Diamond has a point which Lomborg overlooks. The situation is that some economists want to "develop" the nature areas, and do not accept objections to this unless their opponents can provide solid proofs that the species feared to be extinct are actually extinct. As stated in the heading of this web page, to provide such proofs is very costly, and as the investment in providing the proof does not repay in money, the money for this must necessarily come from outside, i.e. from the productive sector of the economy. If economists refuse to spend money for such a purpose, they thereby say that they do not want to know what the real situation is, because it is most convenient for them not to know. If economists say that it is not necessary to provide the evidence, then this is just as reprehensible as if biologists say that it is not necessary to provide the evidence.

P. 256 bottom right: (COMMENT)

" . . because the biologists already know that things are going askew." Comment: Yes, as should be clear from the present criticism of Lomborg, biologists do indeed know sufficiently well that things are going askew - they do not just feel it or belief it, as Lomborg claims, they know it with sufficient scientific evidence at hand.

P. 256 bottom right: (COMMENT)

"In reality, of course, they are asking society for a blank check to prevent something which is claimed to be a catastrophe . . ". Comment: This is not a blank check. The official red lists point out exactly those thousands of species that have a large likelihood of going extinct within few decades if nothing is done for them. If the check were paid, and used to conserve these species, society would know exactly what they got for the money. But of course, if the conservationists were succesful - if they managed to save these species - Lomborg would claim that society had got nothing, because the species survived, so the threats were not real. As we see, Lomborg´s argument is actually a circular argument.

P. 256 bottom right: FLAW

"indicating a problem in the region of 0.7 percent over the next 50 years." Flaw: As stated above, the range of estimates made by experts is in the region of 0.1 % to 1 % per year. Lomborg has no right to neglect this, as long as his own preferred lower estimate is not supported by data and based on unverifiable guesses as to the future trend relative to present rates of extinction.

P. 257 left: ERROR

". . an ambitious plan, the Wildlands Project, to move the entire population of the US . . ". Error: Although it is true that the named persons support the Wildlands Project, it is not true that the project aims at anything like moving the entire US population to concentrate them in small, enclosed city islands. Lomborg refers to an article in Science by Mann and Plummer; two persons who are linked with a broad anti-environmental movement (Wise Use) in the Western USA, and both are employed by a right wing think tank, the "Discovery Institute", based in Seattle. It seems that Lomborg has contacted this group in order to get something to criticize his opponents with. Instead of referring to a secondary source (the Mann and Plummer article), he should have referred directly to description of the Wildalnds Project in a book by Michael Soulé and John Terborgh. Lomborg has failed to give the attacked persons a chance to defend themselves against the accusations, as he has not asked them if the allegations were true, nor has he contacted the organizers of the Wildlands Project themselves to check if the postulates were true. Clearly, Lomborg has violated not only his own rule that incredible postulates should be checked, he has also violated his own principle that he will just present the facts, so that the democratic process is assured the soundest basis for decisions. He can impossibly have written this text without specific intentions, and it is therefore fair to say that this text is deliberately misleading.

P. 257 right: FLAW

"It is a figure which with monotonous regularity has been repeated everywhere until in the end we all believe it." Flaw: Here, evidently, Lomborg has been so seized by his feelings of indignation that he forgets not to exaggerate. It is not true that the figure of 40,000 species has been repeated with monotonous regularity everywhere. Actually, for many years, scientists have agreed that this estimate is in the high end and not very likely, and it is certainly false to say that in the end we all have come to believe it; the situation is just the opposite. If, for example, we take Myers himself, he has written many texts on the subject during the last two decades, but nowhere does he repeat the figure. For instance, in the sources that have been used the most by Lomborg (Stork and Reid), we read that Myers made another, much better substantitated estimate in 1988, an estimate saying that 0.7 % of all plant species would be committed to extinction per year. Thus, Lomborg knows that his postulate about "regularity" and "everywhere" is far from the truth.