Bjørn Lomborg’s comments to the 11-page critique in
January 2002 Scientific American (SA), (in black)
Substantially finished December 31, 2001; latest update January 4, 2002, 12:06:44

• MISLEADING MATH about the EARTH. by the editor of Scientific American, John Rennie
• GLOBAL WARMING: NEGLECTING THE COMPLEXITIES by Stephen Schneider
• ENERGY: ASKING THE WRONG QUESTION. by John P. Holdren
• POPULATION: IGNORING ITS IMPACT. by John Bongaarts
• BIODIVERSITY: DISMISSING SCIENTIFIC PROCESS. by Thomas Lovejoy
• MORE TO EXPLORE. further references to read.

Scientific American, p61-71, January 2002, (in red).
The text comes from the final draft and has been transferred from pdf into Word, meaning that occasionally italics or words may have been dropped. Most of the layout has been retained in headings, subheadings and usage of capital lettering. The first page (p61) is an editorial by editor-in-chief, John Rennie, the other ten pages flow in three columns into each other, with a sentence on each page in very large font for interest. These sentences will be pointed out below, but may come from an editorial decision. On the web, Scientific American describes the collection of essays thus:

(SA) Misleading Math about the Earth
ESSAYS BY STEPHEN SCHNEIDER, JOHN P. HOLDREN, JOHN BONGAARTS AND THOMAS LOVEJOY
The book The Skeptical Environmentalist uses statistics to dismiss warnings about peril for the planet. But the science suggests that it's the author who is out of touch with the facts.

Science defends itself against The Skeptical Environmentalist

(BL) This statement is potentially the most surprising of all – that the following critique should be science defending itself against my book. In a sense this encapsulates the bias of the following critiques. My book clearly makes a claim to science and to be factually based. I openly state the facts and my sources, and thus anybody is free to point out where these are faulty or incorrect and of course, such errors will then be posted on my web site. Thus, there is no need to defend science from my book – any possible defeat of science was never the issue. The discussion is whether the statements in my book are correct or not. The need to make it sound like a battle of science against my book seems entirely to misplace and bias the focus. Rather, the standpoint that might need to defend itself from my book would be the alarmist environmentalism, and that is perhaps the headline that would make more sense: Alarmist environmentalism defends itself against the Skeptical Environmentalist.

(SA) MISLEADING MATH about the EARTH

CRITICAL thinking and hard data are the cornerstones of all good science. Because environmental sciences are so keenly important to both our biological and economic survival—causes that are often seen to be in conflict—they deserve full scrutiny. With that in mind, the book The Skeptical Environmentalist (Cambridge University Press), by Bjørn Lomborg’s reply to Scientific American January 2002 critique, 16-Feb-02 16:47 2/32
Lomborg, a statistician and political scientist at the University of Aarhus in Denmark, should be a welcome audit. And yet it isn’t. As its subtitle—Measuring the Real State of the World— indicates, Lomborg’s intention was to reanalyze environmental data so that the public might make policy decisions based on the truest understanding of what science has determined. His conclusion, which he writes surprised even him, was that contrary to the gloomy predictions of degradation he calls “the litany,” everything is getting better. Not that all is rosy, but the future for the environment is less dire than is supposed. Instead Lomborg accuses a pessimistic and dishonest cabal of environmental groups, institutions and the media of distorting scientists’ actual findings. (A copy of the book’s first chapter can be found at www.lomborg.org) The problem with Lomborg’s conclusion is that the scientists themselves disavow it.
Many spoke to us at SCIENTIFIC AMERICAN about their frustration at what they described as Lomborg’s misrepresentation of their fields. His seemingly dispassionate outsider’s view, they told us, is often marred by an incomplete use of the data or a misunderstanding of the underlying science. Even where his statistical analyses are valid, his interpretations are frequently off the mark—literally not seeing the state of the forests for the number of the trees, for example. And it is hard not to be struck by Lomborg’s presumption that he has seen into the heart of the science more faithfully than have investigators who have devoted their lives to it; it is equally curious that he finds the same contrarian good news lurking in every diverse area of environmental science.

(BL) Making it sound like all scientists disavow it is simply untrue. Many scientists, both in private and publicly (e.g. statements on the book) have praised the book. Below, you will see that none of the claims of “misrepresentation”, “incomplete use of data” and “misunderstanding of the underlying science” are substantiated. The only specific claim presented here by the editor is that I am “literally not seeing the state of the forests for the number of the trees.” This can only refer to the one paragraph on forests by Lovejoy (the only treatment of the matter in the following text) – and here the analysis is quite clear. I try to show that environmental movements will tell us we are at risk of loosing “the last remaining forests on earth” and that our time is “the eleventh hour for the world’s forests” (WWF, quoted in SE:110). Yet, the longest data series actually tells us of very little change in the world forested area in the post-war period (SE:111). Moreover, the longest future scenarios from the UN climate panel (IPCC) show that in all likelihood the Earth will have even greater forest cover in 2100 than it has had since 1950 (IPCC 2000b, SE:283). Here, exactly looking coolly at the longest data series gives us much better information than just going with the environmental myths and hype. Thus, in the editor’s only concrete claim, he seems to be wide off the mark.
Pointing out that it seems questionable that I should know better than the people who’ve devoted their lives to particular areas, though clearly circumstantial, nevertheless looks like a powerful point. Yet, any person who has devoted his or her life to a single issue will naturally come to consider this area one of the most crucial issues, and any problem inside the area will likely be seen as necessary to solve.
And this is exactly my point – we should take the science of these people seriously, but we should not uncritically adopt their evaluation of the problems. There are a multitude of problems in any area of society – there are always things we would like to improve – but we only have a limited amount of resources. Thus, as a society we need to ask, whether the problems are getting bigger or smaller (are we going in the right direction), what can we do (much or marginal) and would this be the best use of our resources (other areas where we could do even more good). Such an appraisal does not come automatically from any single issue area. This is why we need to look, not only at the science of each area, but also to ask: ‘so, all in all, how important a problem is your issue in the big scheme of things.’ This is what I have attempted to do with The Skeptical Environmentalist.

(SA) We asked four leading experts to critique Lomborg’s treatments of their areas—global warming, energy, population and biodiversity—so readers could understand why the book provokes so much disagreement. Lomborg’s assessment that conditions on earth are generally improving for human welfare may hold some truth. The errors described here, however, show that in its purpose of describing the real state of the world, the book is a failure.
John Rennie, EDITOR IN CHIEF

(BL) Notice that these four experts have certainly not been chosen randomly – two of the four reviewers are actually directly criticized in my book. Lovejoy predicted back in 1980, that 15-20 percent of all species on earth would have died by the year 2000 (1980:331, SE:252), a prediction which clearly did
not hold true and this is pointed out in the book. Holdren back in 1980 also clearly thought that many resources were running out. Along with Ehrlich and Holdren, he bet on this belief with Julian Simon:

“Frustrated with the incessant claims that the Earth would run out of oil, food and raw materials, the economist Julian Simon in 1980 challenged the established beliefs with a bet. He offered to bet $10,000 that any given raw material – to be picked by his opponents – would have dropped in price at least one year later. The environmentalists Ehrlich, Harte and Holdren, all of
Stanford University, accepted the challenge, stating that “the lure of easy money can be irresistible.” The environmentalists staked their bets on chromium, copper, nickel, tin and tungsten, and they picked a time frame of ten years. The bet was to be determined ten years later, assessing whether the real (inflation-adjusted) prices had gone up or down. In September 1990 not only had the total basket of raw materials but also each individual raw material dropped in price. Chromium had dropped 5 percent, tin a whopping 74 percent. The doomsayers had lost.
Truth is they could not have won. Ehrlich and Co. would have lost no matter whether they had staked their money on petroleum, foodstuffs, sugar, coffee, cotton, wool, minerals or phosphates. They had all become cheaper.” (SE:137).

(BL) These paragraphs do not really discuss my book but establish several important rhetorical points that need to be mentioned. First is the John Rennie’s incantation of “investigators who have devoted their lives” to the science: Schneider is the venerable scientist whereas I’m a nobody.
Second, he quotes my introduction where I state I’m not an expert as regards environmental problems. True, but the quote in full actually places this point in context:

“I have let experts review the chapters of this book, but I am not myself an expert as regards environmental problems. My aim has rather been to give a description of the approaches to the problems, as the experts themselves have presented them in relevant books and journals, and to examine the different subject-areas from such a perspective as allows us to evaluate their importance in the overall social prioritization. The key idea is that we ought not to let the environmental organizations, business lobbyists or the media be alone in presenting truths and priorities. Rather, we should strive for a careful democratic check on the environmental debate, by knowing the real state of the world – having knowledge of the most important facts and connections in the essential areas of our world. It is my hope that this book will contribute to such an understanding.” (pxx)

(SA) The climate chapter makes four basic arguments:
Climate science is very uncertain, but nonetheless the real state of the science is that the sensitivity of the climate to carbon dioxide will turn out to be at the low end of the IPCC uncertainty range—which is for a warming of 1.5 to 4.5 degrees C if carbon dioxide were to double and be held fixed over time.
Emissions scenarios, according to the IPCC, fall into six “equally sound” alternative paths. These paths span a doubling in carbon dioxide concentrations in 2100 up to more than tripling and well beyond tripling in the 22nd century. Lomborg, however, dismisses all but the lowest of the scenarios: “Temperatures will increase much less than the maximum estimates from IPCC—it is likely that the temperature will be at or below the B1 estimate [the lowest emissions scenario] (less than 2° C in 2100) and the temperature will certainly not increase even further into the twenty-second century.”
Cost-benefit calculations show that although the benefits of avoiding climate change could be substantial ($5 trillion is the single figure Lomborg cites), this is not worth the cost to the economy of trying to constrain fossil fuel emissions (a $3trillion to $33trillion range he pulls from the economics literature). Asymmetrically, no range is given for the climate damages.
The Kyoto Protocol, which caps industrialized countries’ output of greenhouse gases, is too expensive. It would reduce warming in 2100 by only a few tenths of a degree—“putting off the temperature increase just six years.” This number, though, is based on a straw-man policy that nobody has seriously proposed: Lomborg extrapolates the Kyoto Protocol, which is applicable only up to 2012, as the world’s sole climate policy for another nine decades.

(BL) Schneider deserves credit for making clear the main thrust of his criticism in these four points, though he clearly cannot bear just to state them without pejorative statements like “asymmetrically, no range…” and “straw-man policy”, both of which are incorrect and will be dealt with below.

(SA) Before providing specifics of why I believe each of assertions is fatally flawed, I should say something about Lomborg’s methods. First, most of his nearly 3,000 citations are to secondary literature and media articles. Moreover, even when cited, the peer-reviewed articles come elliptically from those studies that support his rosy view that only the low end of the uncertainty ranges will be plausible. IPCC authors, in contrast, were subjected to three rounds of review by hundreds of outside experts. They didn’t have the luxury of reporting primarily from the part of the community that agrees with their individual views.

(BL) There is an important distinction between secondary sources and media articles. When discussing the entire state of the world, it would be incredibly inefficient not to use the vast collection of data and theory offered by secondary sources – this is exactly the reason for secondary literature and in general why it is possible to have specialization in science. However, almost all of these secondary sources are exactly the ones used by almost all discussants of the state of the world – the reports of the UN, (FAO, UNDP, UNEP, WHO etc.), IMF, the World Bank, OECD, WRI, Worldwatch Institute, EU, US government agencies etc. In the climate chapter, which Schneider discusses, references to the IPCC reports constitute about one-third of all 646 endnotes. Yet, the IPCC reports are clearly secondary sources. Surely, most people – including myself – would consider these reports the best available summary of our understanding of the climate science, which exactly was my argument for primarily using them as references:

“In the following I shall – unless otherwise stated – use the figures and computer models from the official reports of the UN climate panel, the IPCC. The IPCC’s reports are the Lomborg’s reply to Scientific American January 2002 critique, 16-Feb-02 16:47 6/32 foundation for most public policy on climate change and the basis for most of the arguments put forth by the environmental organizations.” (SE:259).

“In the reporting from the major media, such as CNN, CBS, The Times, and Time, it was found that all used the high estimate of 5.8°C warming, and yet none mentioned the low estimate of 1.4°C.”

(SA) Second, it is ironic that in a popular book by a statistician one can’t find a clear discussion of the distinction among different types of probabilities, such as frequentist and Bayesian (that is, “objective” and “subjective”). He uses the word “plausible” often, but, curiously for a statistician, he never attaches any probability to what is “plausible.” The Third Assessment Report of the IPCC, on the other hand, explicitly confronted the need to quantify all confidence terms. Working Group I, for example, gave the term “likely” a 66 to 90 percent chance of occurring. Although the IPCC gives a wide range for most of its projections, Lomborg generally dismisses these ranges, focusing on the least serious outcomes. Not so much as one probability is offered for the chance of a dangerous outcome, yet he makes a firm assertion that climate “will certainly” not go beyond 2 degrees C warming in the 22nd century—a conclusion at variance with the IPCC, other national climate assessments and most recent studies in the field of climate science.

(BL) It is correct that IPCC has quantified its ‘plausible’, but IPCC themselves quite rightly made it clear what the limits were on the accuracy of their different types of probability: “the following words have been used where appropriate to indicate judgmental estimates of confidence: virtually certain (greater than 99% chance that a result is true); very likely (90-99% chance); likely (66-90% chance); medium likelihood (33-66% chance); unlikely (10-33% chance); very unlikely (1-10% chance); exceptionally unlikely (less than 1% chance),” (IPCC 2001d:2, italics added). Unless we are talking about events with very well-established probability distributions (which is the case for almost none of the important global warming issues) it really is just a judgment call whether something has a 89% or 91% chance of occurring – thus, had I made a similar endnote, defining the words of confidence, it might have appeared slightly more objective but not really made any addition to the facts at hand.
The second claim is much more serious: that I generally dismiss the IPCC ranges and focus on the least serious outcomes. Neglecting such ranges generally or without reason would, of course, be seriously misleading, which is why I don’t do it in the book and which may explain why my critic offers no examples. Take two of the most important characteristics of global warming, sea level increases and temperature impacts on agriculture. For sea level increase I clearly write out the ranges from the main scenarios (SE:264) and for agriculture impact I clearly state the IPCC ranges (SE:288).
Next, it is claimed that I do not offer any probability of a dangerous outcome. This is plainly incorrect. In a whole section entitled “Fear of catastrophe” (SE: 315-7) I discuss the two major worries of dangerous outcomes, the sliding of the West Antarctic Ice Sheet (WAIS) and the shut-down of the thermohaline circulation (THC) that drives the Gulf Stream. Here I quote the 2001 IPCC report that a WAIS breakup is considered “very unlikely during the 21st century” (SE:315). Likewise, with respect to the THC, I write out that the 2001 “IPCC conclude that ‘the current projections using climate models do not exhibit a complete shut down of the thermohaline circulation by 2100’ but point out that it could completely, and possibly irreversibly, shut down ‘if the change in radiative forcing is large enough and applied long enough’” (SE:316). In the endnote it is discussed how likely it is that the radiative forcing will be large enough and applied long enough for this shut-down to happen. Thus, for both the major dangerous outcomes I discuss the probability in detail, contrary to Schneider’s claim. The final quote of “will certainly” only works because it has been taken out of context:

“This more realistic model holds several key points. First, it shows that global warming is not an ever worsening problem. In fact, under any reasonable scenario of technological change and without policy intervention, carbon emissions will not reach the levels of A1FI and they will decline towards the end of the century, as we move towards ever cheaper renewable energy sources. Second, temperatures will increase much less than the maximum estimates from IPCC – it is likely that the temperature will be at or below the B1 estimate (less than 2°C in 2100) and the temperature will certainly not increase even further into the twenty-second century. Third, …” (SE:286, italics added).

(SA) Now let us look in more detail at the four major arguments he makes in this chapter.
Climate science. A typical example of Lomborg’s method is his paraphrase of a secondary source in reporting a 1989 Hadley Center paper in the journal Nature in which the researchers make modifications to their climate model: “The programmers then improved the cloud parameterizations in two places, and the model reacted by reducing its temperature estimate from 5.2° C to 1.9° C.” Had this been first-rate scholarship, Lomborg would have consulted the original article, in which the concluding sentence of the first paragraph presents the authors’ caveat: “Note that although the revised cloud scheme is more detailed it is not necessarily more accurate than the less sophisticated scheme.” In a similar vein, he cites Richard S. Lindzen’s controversial stabilizing feedback, or “iris effect,” as evidence that the IPCC climate sensitivity range should be reduced by a factor of almost three. He fails either to understand this mechanism or to tell us that it is based on only a few years of data in a small part of one ocean. Extrapolating this small sample of data to the entire globe is like extrapolating the strong destabilizing feedback over midcontinental landmasses as snow melts during the spring—such an inappropriate projection would likely increase estimates of climate sensitivity by a factor of several.

(BL) I am glad to have pointed out the typical way I refer to secondary sources – namely quote them accurately. The quote comes from Science magazine in 1997:

“A few years ago, a leading climate model – developed at the British Meteorological Office's Hadley Center for Climate Prediction and Research, in Bracknell – predicted that an Earth with twice the preindustrial level of carbon dioxide would warm by a devastating 5.2 Degrees Celsius. Then Hadley Center modelers, led by John Mitchell, made two improvements to the model's clouds--how fast precipitation fell out of different cloud types and how sunlight and radiant heat interacted with clouds. The model's response to a carbon dioxide doubling dropped from 5.2 Celsius to a more modest 1.9 Celsius.” (Kerr 1997a:1040).

“The importance of the representation of cloud in a general circulation model is investigated by utilizing four different parameterization schemes for layer cloud in a low-resolution version of the general circulation model at the Hadley Centre for Climate Prediction and Research at the United Kingdom Meteorological Office. The performance of each version of the model in terms of cloud and radiation is assessed in relation to satellite data from the Earth Radiation Budget Experiment (ERBE). Schemes that include a prognostic cloud water variable show some improvement on those with relative humidity-dependent cloud, but all still Lomborg’s reply to Scientific American January 2002 critique, 16-Feb-02 16:47 8/32 show marked differences from the ERBE data. The sensitivity of each of the versions of the model to a doubling of atmospheric C02 is investigated. Midlevel and lower-level clouds decrease when cloud is dependent on relative humidity, and this constitutes a strong positive feedback. When interactive cloud water is included, however, this effect is almost entirely compensated for by a negative feedback from the change of phase of cloud water from ice to water. Additional negative feedbacks are found when interactive radiative properties of cloud are included and these lead to an overall negative cloud feedback. The global warming produced with the four models then ranges from 5.4° with a relative humidity scheme to 1.9°C with interactive cloud water and radiative properties. Improving the treatment of ice cloud based on observations increases the model's sensitivity slightly to 2.1°C. Using an energy balance model, it is estimated that the climate sensitivity using the relative humidity scheme along with the negative feedback from cloud radiative properties would be 2.8°C. Thus, 2.8°– 2.1°C appears to be a better estimate of the range of equilibrium response to a doubling of C02.” (Senior & Mitchell 1993, http://ams.allenpress.com/amsonline/?request=getabstract&issn=1520-0442&volume=006&issue=03&page=0393, italics added).

“One small point of personal interest to me illustrates the rather bizarre nature of these attacks. Schneider claims that Lomborg cites a paper by me and colleagues (Lindzen, Chou and Hou, Does the Earth Have an Adaptive Infrared Iris?, Bulletin of the American Meteorological Society, 82, 2001) on what we refer to as the ‘iris effect’ in order to reduce the IPCC claimed sensitivities by a factor of 3. What Lomborg does, is devote a quarter of a page to our paper in order to point out that it ‘might pose a challenge’ to the IPCC range. Schneider goes on to chide Lomborg for failing to present an allegedly fatal flaw in our argument: that it is simply the extrapolation of data from “a few years of data from a small part of one ocean.”

(SA) As a final example, he quotes a controversial hypothesis from Danish cloud physicists that solar magnetic events modulate cosmic rays and produce “a clear connection between global low-level cloud cover and incoming cosmic radiation.” The Danish researchers use this hypothesis to support an alternative to carbon dioxide for explaining recent climate change. Lomborg fails to discuss— and I haven’t seen it treated by the authors of that speculative theory either— what such purported changes to this cloud cover have done to the radiative balance of the earth. Increasing clouds, it has been well known since papers by Syukuro Manabe and Richard T. Wetherald in 1967 and myself in 1972, can warm or cool the atmosphere depending on the height of the cloud tops, the reflectivity of the underlying surface, the season and the latitude. The reason the IPCC discounts this theory is that its advocates have not demonstrated any radiative forcing sufficient to match that of much more parsimonious theories, such as anthropogenic forcing.

Schneider calls this theory “an alternative to carbon dioxide for explaining recent climate change.” However, neither the Danish cloud physicists nor I say that they are an alternative, but a supplementary explanation: “the sun as another important factor in the explication of increasing global temperatures” (SE:276, italics added). Moreover, I do point out both its still unsolved scientific problems but also its force and an attempt to show the relative importance of the two:

“A number of unanswered questions and unsolved scientific problems still remain in these theoretical relationships. But the point is that the sunspot theory has created a possible correlation in that a shorter sunspot cycle duration, such as the one we are experiencing now, means more intense solar activity, less cosmic radiation, fewer low-level clouds, and therefore higher temperatures. This theory also has the tremendous advantage, compared to the greenhouse theory, that it can explain the temperature changes from 1860 to 1950, which the rest of the climate scientists with a shrug of the shoulders have accredited to 'natural variation'.”

(SA) Emissions scenarios. Lomborg asserts that over the next several decades new, improved solar machines and other renewable technologies will crowd fossil fuels off the market. This will be done so efficiently that the IPCC scenarios vastly overestimate the chance for major increases in carbon dioxide. How I wish this would turn out to be true! But wishes aren’t analysis. One study is cited; ignored is the huge body of economics work he later accepts to estimate a range of costs if we were to implement emissions controls. In fact, most of these economists strongly believe high emissions are quite likely: they usually project carbon dioxide doubling to tripling (or more) as “optimal” economic policy. I have attacked this literature for failing to point out that climate policies that raise the price of conventional fuels spur investments in alternative energy systems. But such incentives need policies first—and Lomborg opposes those very policies. No credible analyst can just assert that a fossil fuel intensive scenario is not plausible—and, typically, he gives no probability that it might occur.

(BL) This is perhaps the most curious and weak argument of Schneider. He does nothing to confront my critique of the new IPCC scenarios, which in the words of one of the modeling teams are “an attempt at ‘computer-aided storytelling.’” Here, IPCC has abandoned any attempt to predict the future and instead only talk about different possible futures. However, if the stories generating the worst outcomes are consistently unlikely, then clearly there is a great risk that we might end up spending vast amount of resources to combat threats that only occur in very unlikely storytelling. I point out how the price of renewables such as solar power have been dropping by more than 50% per decade over the past 30 years. Then I present a peer-reviewed model (Chakravorty et al. 1997), which shows that if this trend continues it will mean the beginning of renewables as a substantial source of energy by 2025 and the end of fossil fuels by 2065. Even if a much lower price decrease of 30% per decade is assumed for the future, it means phasing in renewables by 2035 and the end of fossil fuels by 2105 (SE:284ff). Schneider merely counters this by pointing to the many models of the cost and benefits of global warming (the integrated models), which do not show this decline in carbon emissions. This is correct but entirely irrelevant – these models deal with different issues of costs and benefits (primarily with the timing of costs from early phasing out of carbon emissions), and the Chakravorty paper was exactly written to counter this problem.
Thus, my critic does not really have a counter-argument – he only seems to dismiss the analysis as wishful thinking and stating that “no credible analyst” can say this. These are arguments of authority, not science. If Schneider is aware of any other study that has looked at the relative costs of renewables and fossil fuels over time, taking into account the remarkable increase in efficiency of the renewables over the past decades, but which shows that renewables will not take over – we should be given these references and more details.

(SA) Cost-benefit calculations. Lomborg’s most egregious distortions and poorest analyses are his citations of cost-benefit calculations. First, he chides the governments that modified the penultimate draft of the report from IPCC’s Working Group II. These modifications downgraded the significance of economic studies that aggregate climate change damages. Lomborg says: “A political decision stopped IPCC from looking at the total cost-benefit of global warming.” (As an aside, I should mention that it is strange he chose to cite the penultimate and pre-approval draft report in this case but didn’t mention the very first item in the approved summary—that recent temperature trends have caused a discernible effect on plants and animals. Even more puzzling is his failure to discuss ecological impacts in general, focusing instead on health and agriculture, sectors he thinks won’t be much harmed by climate change of the minuscule amount he predicts.)

(BL) Here, two different arguments are being confused. Yes, I chide governments for editing the WGII technical summary, which stated the controversial but fairly well established point: Moderate global warming will have grave, negative net impact on the developing world but zero or maybe even a positive net impact for the developed world. In the more technical language of the WGII summary, this was:

“Published estimates indicate that increases in global mean temperature would produce net economic losses in many developing countries for all magnitudes of warming studied, and that the losses would be greater in magnitude the higher the level of warming. In many developed countries, net economic gains are projected for global mean temperature increases up to roughly 2°C. Mixed or neutral net effects are projected in developed countries for temperature increases in the approximate range of 2 to 3°C, and net losses for larger temperature increases.
The projected distribution of economic impacts is such that it would increase the disparity in well being between developed countries and developing countries, with the disparity growing with higher temperatures. The more damaging impacts estimated for developing countries reflects, in part, their lesser adaptive capacity.” (IPCC 2001b:Summary for Policymakers, original government draft, 2.6., SE:301)

(SA) The government representatives downgraded aggregate cost-benefit studies for a reason: these studies fail to consider so many categories of damages held to be important by political leaders as to render them just a guideline on market sector transactions, not the “total cost-benefit” analysis Lomborg wants. A total analysis would have to include the value of species lost, crucial ecosystem services degraded, inequity created by the poor being hurt more than the rich (which Lomborg does acknowledge), quality of life reduced (for example, a rise in sea level driving small-island inhabitants from traditional homelands), and likely changes to climatic extremes and variability. Then again, Lomborg cites only one value for climate damages—$ 5 trillion—even though the same economics papers he refers to for costs of climate policy generally acknowledge that climate damages can vary from benefits up to catastrophic losses.

(BL) Here it is claimed without any reference that the government representatives should have stopped cost-benefit analysis because it did not include all categories, but honestly, it seems highly unlikely that it would have been stopped for such a reason – it would have been a much more obvious choice to make the cost-benefit analysis more inclusive. Moreover, it is scientifically unreasonable to argue that since we don’t have all the data, we shouldn’t even try to get them but just – stop! Then what do we do?
Finally, it is claimed that the $5 trillion (total, discounted cost) is unreasonable, since one economist (Nordhaus) has shown that the cost could be much less and with a catastrophe it could be more. I merely write out the mean estimated cost of Nordhaus’ latest model. The cost is also comparable to the one estimated by IPCC in its 1996 report (which due to the end of cost-benefit analysis is not replicated in 2001), finding an annual cost of about 1.5-2% of global GDP. This is not unreasonable, when the global warming costs are compared to the same mean estimates of mitigation (see discussion below).

(SA) It is precisely because the responsible scientific community cannot rule out such catastrophic outcomes at a high level of confidence that climate mitigation polices are seriously proposed. And to give one number—rather than a broad range—for avoided climate damages defies explanation, especially when he does give a range for climate policy costs. This range, however, is based on the economics literature but ignores the findings of engineers. Engineers dispute the economists’ typical estimates because the economists fail to take into account preexisting market imperfections such as energy-inefficient machines, houses and processes. These engineering studies, including a famous one by five U.S. Department of Energy laboratories— hardly environmental radicals—suggest that climate policies that provide incentives to replace inefficient equipment with more efficient state-of-the- art products could actually reduce some emissions at below-zero costs.

(BL) Of course the higher the probability of catastrophic outcomes the more urgent climate mitigation policies appear. However, it is surprising that my critic can now tell us unequivocally that the reason the responsible scientific community cannot rule out catastrophic outcomes that we should cut back carbon emissions. On his interpretation this means that almost the entire three IPCC 2001 reports are worthless in the discussion on what to do about global warming, because almost all of the models and results discussed are based on non-catastrophic outcomes. Indeed, the only two major catastrophes discussed (WAIS slipping and THC shutting down), the current models are exactly showing very small risks of these happening (as discussed above). Moreover, almost all of the public discussion has focused on what will happen with rising sea levels, higher mean temperatures, possibly more malaria etc. – all of which are dependent on the non-catastrophic models of the IPCC. (Notice also, that these are the issues brought forth by Schneider himself above: “value of species lost, crucial ecosystem services degraded, inequity created by the poor being hurt more than the rich (which Lomborg does acknowledge), quality of life reduced (for example, a rise in sea level driving small-island inhabitants from traditional homelands), and likely changes to climatic extremes and variability.”) I do agree with Schneider that we need to focus more of our attention to possible catastrophic outcomes (“we ought to spend more effort looking into the likelihood of such [catastrophic] occurrences than on improving our mean prognosis, since it is the extreme occurrences that are truly costly” SE:316). However, this has clearly not been the mainstay of the global warming argument and to suddenly claim so seems both incorrect and disingenuous.
Then Schneider goes on to say, as he did in the summary above, that I give one figure for the cost of global warming ($5T) but a range for “climate policy costs” ($3-33T), and that this “asymmetry” is unreasonable. (In Grist, Schneider puts it less diplomatically: “this putative statistician quotes a range of costs when convenient but not a range of benefits when inconvenient”) The problem is that Schneider is clearly comparing two different kinds of numbers and two different kinds of ranges. The $5T is indeed the central cost estimate of global warming from Nordhaus and Boyer (and it is broadly consistent with the IPCC estimate as discussed above). This is simply the cost of global warming when comparing a Business-as-usual (BAU) world with the hypothetical BAU world, where there was no man-made global warming. In essence, this is the price we’ll have to pay if we don’t do anything.
The other figures ($3-33T) come from the extra costs of choosing different emission cut policies. For instance, the Nordhaus/Boyer estimate for a global stabilization policy (a kind of global Kyoto) would be about $8.5T (SE:310). However, had we done nothing the cost would still have been $5T, so the extra cost of choosing global stabilization is about $3.5T. If we instead choose a policy to limit the temperature increase to 1.5°C, the Nordhaus/Boyer estimate is a cost of $37.5T or an extra cost of $32.5T. These strategies are some of the limit points in the range of $3-33T, which I mention and which Schneider quotes (SE:318).
Now, clearly you cannot compare the $5T with the range $3-33T, because the $5T includes the cost of global warming, the range denotes the extra cost. Thus, Schneider is plainly wrong in comparing the two (or claiming that the one should be the cost, and the other the benefits, as he does in Grist).
This also shows why the complaint of range vs. single number is entirely misplaced. The $5T is the cost of global warming under BAU. You can only ‘do nothing’ in exactly one way. Therefore there is just one number. The $3-33T is a range of net costs under a wide variety of policy choices. Now, we can make lots of different policies, ranging from very light to very invasive – the light policies incurring only a smaller net cost ($3T) and the invasive ones incurring very high net costs (e.g. $33T).
So there is no sinister, ‘putative statistician’ presenting ranges only when it fits him – the single number is a single cost – the range is net costs of a range of policy choices. Both comparing these, and complaining about their asymmetry is simply incorrect.
Then it is claimed that I base the cost estimates on the economics literature, “but ignores the findings of engineers.” This is incomprehensible and again incorrect. I spend almost two pages discussing these alternative engineer (or bottom-up) cost estimates (see SE:312-3). The problem with most of these engineer estimates is that they only count direct costs and benefits but neglect the (typically much bigger) indirect costs and benefits on economic production. A clear example of this is given in the book, where UNEP (the UN Environmental Programme) evaluates the CO2 reduction potential in Denmark: “The main question is: How much of this [CO2 reduction] potential can be realised without substantial increases in costs associated with finding and implementing these options, and without serious welfare losses? None of these costs are included in the following calculations, which are based on the concept of direct costs” (UNEP 1994:II, 21, SE:426). Thus, I conclude – along with most economists – that these engineer estimates are likely to be huge overestimates of the actual opportunities, because they systematically neglect the costs down the line. Schneider may disagree and have new data to convince us, but he should present such data instead of incorrectly claiming that I have not dealt with the issue.
Finally, Schneider writes that researchers have found that it is possible to provide incentives, which in some cases will cut carbon emissions with net benefits. He also writes this as if it was astounding and somehow in opposition to my arguments. However, the statement that some emissions may actually be cut at below-zero costs is entirely standard, and also replicated in my book. The argument is not whether there are below-zero cost ways to cut emissions (the so-called ‘no regret’ options) but how much:

“Most economists are therefore extremely skeptical towards assertions of such improvements in efficiency which can be implemented at no cost or even produce a profit, among other things because these calculations, as we have seen above, often omit important items of expenditure. For this reason, economists also argue that if it really is possible to implement profitable restructuring then it would be reasonable to expect that the possibility would already have been exploited."
One typical economist’s expression is that “there is no such thing as a free lunch” – that costs are bound to occur somewhere along the line. Nordhaus expresses the problem of the possible, profitable carbon dioxide emissions reductions thus: “In the colloquialism of economics, this analysis suggests not only that there are free lunches, but that in some restaurants you can get paid to eat!”
A new study also seems to suggest that these “no regret” possibilities are much more limited than normally assumed; it turns out that they can probably only reduce consumption by a couple of percent and could possibly be pushed to providing 5 percent. Equally, a study of monthly electricity bills showed that the engineers’ estimates of huge savings from attic insulation fell far short of real payoffs, which were closer to what economists would have expected.” (SE:313).

(SA) The Kyoto Protocol. Lomborg’s creation of a 100-year regime for a decade-long protocol is a distortion of the climate policy process. Every IPCC report has noted that carbon dioxide emissions need to be cut by more than 50 percent below most baseline projections to avoid large increases in concentration in the late 21st and 22nd centuries.
Most analysts know “Kyoto extended” can’t make such large cuts and that both developed and developing nations will have to fashion cooperative and cost-effective solutions over time. This will take a great deal of learning-by-doing: international cooperation is not a common experience. Kyoto is a starting point. And yet Lomborg, with his creation of a straw-man 100-year projection, would squash even this first step.

(BL) The book clearly shows that Kyoto-in-itself will have very little effect on global warming, and it is good to see that Schneider concurs. However, he then claims that Kyoto-in-itself is a straw-man, because we should be doing much more. Now, this entails both an analytic and a democratic problem.
To take the democratic first: almost all democratic discussion is about choosing or not choosing Kyoto. Since this is the deal offered, would it not be reasonable to discuss what is the actual outcome of the deal that we are talking about? Likewise, if Schneider contends that the real issue is not Kyoto but something much more restrictive, would it not be democratically more honest to say that the decision is not Kyoto but something much more stringent? Moreover, it is somewhat of a rhetorical misnomer to talk about “Lomborg’s creation of a 100-year regime for a decade-long protocol is a distortion of the climate policy process.” This extension I refer to actually comes from an article written by one of the lead-authors of the 1996 IPCC report, Wigley. He does in fact extend the Kyoto protocol to ascertain what its effect might be. In doing this, is professor Wigley really creating a distortion of the climate policy process?
The other, analytic problem is that Schneider only talks about my analysis of Kyoto and actually neglects that I deal with a range of much more stringent policies (which was why we got the $3-33T range, mentioned above). This seems odd, to say the least. Of course, if Schneider wants to advocate a policy of much-more-than-Kyoto, that is fine, but the cost-benefit analyses are very clear on the issue. Kyoto is almost irrespective of how it is implemented a bad deal, and going even further is a much worse deal.
This is the absolutely central issue of the book, which Schneider ignores: That all cost-benefit analyses show that high carbon reductions are not justified (SE:318): “A central conclusion from a meeting of all economic modelers was: ‘Current assessments determine that the ‘optimal’ policy calls for a relatively modest level of control of CO2.’” The last sentence, which claims that I want to “squash” the Kyoto protocol, is language from policy, not science. I try to point out the costs and benefits of our different policy choices, and yes, I point out that for the benefit of Kyoto will be to postpone global warming in 2100 by six years, whereas the cost of Kyoto each year will be as great as the one-off cost of giving clean drinking water and sanitation to every single human being, forever.

(SA) So what then is “the real state of the world”? Clearly, it isn’t knowable in traditional statistical terms, even though subjective estimates can be responsibly offered. The ranges presented by the IPCC in its peer-reviewed reports give the best snapshot of the real state of climate change: we could be lucky and see a mild effect or unlucky and get the catastrophic outcomes. The IPCC frames the issue as a risk-management decision about hedging. It is not the everything-will-turn-out-fine affair that Lomborg would have us believe.

(BL) It ought not to be necessary to point out, but IPCC offers us insight into the science of global warming, but they (exactly because of the political decision to stop pursuing cost-benefit analysis) do not give us the answer to whether our limited resources are better spent on averting more global warming or on e.g. supplying clean drinking water and sanitation to the world.
Saying that my book is an everything-will-turn-out-fine statement is a rhetorical and entirely misleading treatment of my book. I point out that we should deal with environmental problems, work to decrease air pollution even further, invest in renewable energy research and development etc., as well as tackle the many other, important global problems such as poverty and starvation. The point I make, however, is that we should continuously be aware of the necessary prioritization – that we should strive to make the decisions, which actually do good and not just the ones that sound good. This requires straight and honest analysis that is willing to challenge any however well established myth.

(SA) For such an interdisciplinary topic, the publisher would have been wise to ask natural scientists as well as social scientists to review the manuscript, which was published by the social science side of the house. It’s not surprising that the reviewers failed to spot Lomborg’s unbalanced presentation of the natural science, given the complexity of the many intertwining fields. But that the natural scientists weren’t asked is a serious omission for a respectable publisher such as Cambridge University Press.

(BL) The claim of “unbalanced presentation of the natural science” clearly cannot be upheld, given my critic’s lack of ability to provide such examples. This also suggests that his stated regret that Cambridge University Press has chosen to publish my book really amounts to a desire to see critical arguments suppressed.

(SA) Unfortunately, angry reviews such as this one will be the result. Worse still, many laypeople and policymakers won’t see the reviews and could well be tricked into thinking thousands of citations and hundreds of pages constitute balanced scholarship. A better rule of thumb is to see who talks in ranges and subjective probabilities and to beware of the myth busters and “truth tellers.”

(BL) This, of course, is a surprising ending. The entire Scientific American piece is sold as a truth-telling story. My own understanding of science is that we should exactly try to bust myths and be truth tellers. Questioning truth saying and myth busting seems to undercut the entire endeavor that Scientific American is trying to achieve, but perhaps and unfortunately it is a very accurate description of the state of the critique.

(SA) Stephen Schneider, professor in the department of biological sciences and senior fellow at the Institute for International Studies at Stanford University, is editor of Climatic Change and the Encyclopedia of Climate and Weather and lead author of several IPCC chapters and the IPCC guidance paper on uncertainties.

(BL) It is good to see that Holdren is actually saying it is correct, we’re not running out of energy, and that I am right. Somewhat contradictorily is the pejorative “scant” 19 pages – if I’m right and the issue is easily settled, presumably there is no need to use many more?
However, Holdren then goes on to say that environmentalists are worrying about running out of environment (the statement singled out in SA) and running out of the ability to manage political, economic and military dangers. This is exactly the kind of exposition which I try to counter in my book – without any references Holdren manages to describe everything as going ever worse and even include into the environmental agenda concepts that are far removed from its core, such as nuclear proliferation, terrorism and economic recession from oil price hikes. Let us just point out one issue area, air pollution (estimated by the US EPA to be the by far most important area, SE:163). Here we are plainly not running out of environment or running out of the air’s capacity to absorb without intolerable consequences for human well-being – all criteria pollutants in the US have diminished in concentration over the past few decades, as I demonstrate EPA references for in the book (SE:ch.15).
Here, Holdren simply chooses a sound-good quote (running out of environment), presumably in the quest to defend science, but without references and plainly incorrect, even as demonstrated in my book.

(SA) That “the energy problem” is not primarily a matter of depletion of resources in any global sense but rather of environmental impacts and sociopolitical risks—and, potentially, of rising monetary costs for energy when its environmental and sociopolitical hazards are adequately internalized and insured against—has in fact been the mainstream environmentalist position for decades. It was, for example, the position I elucidated in the 1971 Sierra Club “Battlebook” Energy (coauthored with Philip Herrera, then the environment editor for Time). It was also the position elaborated on by the Energy Policy Project of the Ford Foundation in the pioneering 1974 report A Time to Choose; by Amory Lovins in his influential 1976 Foreign Affairs article “Energy Strategy: The Road Not Taken”; by Paul R. and Anne H. Ehrlich and me in our 1977 college textbook Ecoscience; and so on. So whom is Lomborg so resoundingly refuting with his treatise on the abundance of world energy resources? It would seem that his targets are pundits (such as the correspondents for E magazine and CNN cited at the opening of this chapter) and professional analysts (although only a few of these are cited, and those very selectively) who have argued not that the world is running out of energy altogether but only that it might be running out of cheap oil. Lomborg’s dismissive rhetoric notwithstanding, this is not a silly question, nor one with an easy answer.

(BL) Holdren acknowledges that my targets are pundits and analysts, who have been arguing that we would be running out of cheap oil. Are these not reasonable people to challenge? He also tries to point out that many even in the 70s did not worry about running out of oil, but it is curious how he neglects the most important and influential environmental influence from the 70s, the Limits to Growth argument that clearly predicted oil to run out before 1992 (Meadows et al. 1972:58). Likewise, Ehrlich worried in 1987 that the oil crisis would return in the 1990s (Ehrlich and Ehrlich 1987:222). Finally, he tries to say that the pundits and analysts say something else than do I, because they just worry about running out of cheap oil. But of course, this is the same thing, as is also pointed out in the book: “Even if we were to run out of oil, this would not mean that oil was unavailable, only that it would be very, very expensive. If we want to examine whether oil is getting more and more scarce we have to look at whether oil is getting more and more expensive” (SE:122).

(SA) Oil is the most versatile and currently the most valuable of the conventional fossil fuels that have long provided the bulk of civilization’s energy, and it remains today the largest contributor to world energy supply (accounting for nearly the whole of energy used for transport, besides other roles). But the recoverable conventional resources of oil are believed (on substantial evidence) to be far smaller than those of coal and probably also smaller than those of natural gas; the bulk of these resources appears to lie in the politically volatile Middle East; much of the rest lies offshore and in other difficult or environmentally fragile locations; and it is likely that the most abundant potential replacements for conventional oil will be more expensive than oil has been. For all these reasons, concerns about declining availability and rising prices have long been more salient for oil than for the other fossil fuels. There is, accordingly, a serious technical literature (produced mainly by geologists and economists) exploring the questions of when world oil production will peak of oil might be in 2010, 2030 or 2050, with considerable disagreement among informed professionals on the answers.

(BL) This paragraph does not really criticize, but contains the statement “it is likely that the most abundant potential replacements for conventional oil will be more expensive than oil has been.” This statement is supplied without references and on faith, but I actually give reference to the US Energy Information Agency (EIA 1997c:37) that today it is “possible to produce about 550 billion barrels of oil from tar sands and shale oil at a price below $30, i.e. that it is possible to increase the present global oil reserves by 50 percent. And it is estimated that within 25 years we can commercially exploit twice as much in oil reserves as the world’s present oil reserves” (SE:128). Thus, Holdren’s statement seems wrong.

(SA) Lomborg gets right the basic point that the dominance of oil in the world energy market will end not because no oil is left in the ground but because other energy sources have become more attractive relative to oil. But he seems not to recognize that the transition from oil to other sources will not necessarily be smooth or occur at prices as low as those enjoyed by oil consumers today. Indeed, while ridiculing the position that the world’s heavy oil dependence may again prove problematic in our lifetimes, he shows no sign of understanding (or no interest in communicating) why there is real debate among serious people about this.

(BL) Holdren then agrees with me again, but accuses me of neglecting that the transition may not necessarily be smooth or cheap. It is of course true that this could happen (nobody can predict anything 100%) but the basic argument in the book is exactly that the crisis, Holdren sees may happen is indeed very unlikely – we have had this kind of fear of running out many times, and each time it has proven incorrect, and moreover, we have good reason to believe that the many different energy sources can give us sufficient energy also for future use at competitive prices.

(SA) Lomborg does not so much as offer his readers a clear explanation of the distinction— crucial to understanding arguments about depletion—between “proved reserves” (referring to material that has already been found and is exploitable at a profit at today’s prices, using today’s technologies) and “remaining ultimately recoverable resources” (which incorporate estimates of additional material exploitable with today’s technology at today’s prices but still to be found, as well as material both al will be exploitable with future technologies at potentially higher future prices). And, while noting that most of the world’s oil reserves lie in the Middle East (and failing to note, having not even introduced the concept, that a still larger share of remaining ultimately recoverable resources is thought to lie there), he placidly informs us that it is “imperative for our future energy supply that this region remains reasonably peaceful,” as if that observation did not undermine any basis for complacency. (At this juncture, one of his 2,930 footnotes helpfully adds that this peace imperative for the Middle East was “one of the background reasons for the Gulf War”!)

(BL) Holdren spends half this paragraph complaining that I do not explain all distinctions, while above arguing that I make an obvious point (so that I presumably should not spend vast amounts of space explaining everything). Even on a kind reading, this critique seems excessively compulsive.
Accepting that I do point out that most of the world’s oil reserves lie in the Middle East, Holdren nevertheless criticizes me for not spending enough paper on digressing into other areas like International Relations (the relative peacefulness of the Middle East and its consequences for Lomborg’s reply to Scientific American January 2002 critique, 16-Feb-02 16:47 17/32 commodity trade). Again, it is unclear what standard this critique sets up, wanting the energy discussion to take much more space or much less?
The final parenthetical comment entirely leaves out that I actually refer to a congressional research paper for this statement.

(SA) Lomborg’s treatment of energy resources other than oil is not much better. He is correct in his basic proposition that resources of coal, oil shale, nuclear fuels and renewable energy are immense (which few environmentalists—and no well-informed ones—dispute). But his handling of the technical, economic and environmental factors that will govern the circumstances and quantities in which these resources might actually be used is superficial, muddled and often plain wrong. His mistakes include apparent misreadings or misunderstandings of statistical data—in other words, just the kinds of errors he claims are pervasive in the writings of environmentalists— as well as other elementary blunders of quantitative manipulation and presentation that no self-respecting statistician ought to commit.

(BL) This is the paragraph in which Holdren gets tough. Here he says that the rest is not much better than the treatment of oil (where Holdren agreed with much and found no concrete errors). Here he also says Lomborg “is correct in his basic proposition,” but then that I make loads of misreadings or misunderstandings as well as elementary blunders. These are harsh words Holdren should be able to back up below.

(SA) He tells us correctly, for example, that the world has huge resources of coal, but in observing that “it is presumed that there is sufficient coal for well beyond the next 1,500 years” he says nothing about the rate of coal use for which this conclusion might obtain.
Concerning the environmental questions that increased reliance on coal would raise, he writes the following: “Typically, coal pollutes quite a lot, but in developed economies switches to low-sulfur coal, scrubbers and other air-pollution control devices have today removed the vast part of sulfur dioxide and nitrogen dioxide emissions.” To the contrary, data readily available on the Web in the Environmental Protection Agency report National Air Pollutant Emission Trends 1900–1998 reveal that U.S. emissions of nitrogen oxides from coal-burning electric power plants were 6.1 million short tons in 1980 and 5.4 million short tons in 1998. Emissions of sulfur dioxide from U.S. coal-burning power plants were 16.1 million short tons in 1980 and 12.4 million short tons 1998. These are moderate reductions, welcome but hardly the “vast part” of the emissions.

(BL) The first main example of how I misread or misunderstand environmental data (“just the kinds of errors [Lomborg] claims are pervasive in the writings of environmentalists”) clearly suggests a casual reading of what I have written. Holdren claims that I’m correct in saying that the world has huge coal resources, but when stating that the world has 1,500 years of coal, that I should say nothing about the rate of coal use for which this conclusion might obtain. This is curious, because I use the same metric throughout: that the years-of-consumption are measured from the year discussed (SE:127):

“As with oil and gas, coal reserves have increased with time. Since 1975 the total coal reserves have grown by 38 percent. In 1975 we had sufficient coal to cover the next 218 years at 1975 levels, but despite a 31 percent increase in consumption since then, we had in 1999 coal reserves sufficient for the next 230 years. The main reason why years-of-consumption have not been increasing is due to reduced prices. The total coal resources are estimated to be much larger – it is presumed that there is sufficient coal for well beyond the next 1,500 years.”

“Typically, coal pollutes quite a lot, but in developed economies switches to low-sulfur coal, scrubbers and other air-pollution control devices have today removed the vast part of sulfur dioxide and nitrogen dioxide emissions. Coal, however, is still a cause of considerable pollution globally, and it is estimated that many more than 10,000 people die each year because of coal, partly from pollution and partly because coal extraction even today is quite dangerous.”

(SA) Concerning nuclear energy, Lomborg tells us that it “constitutes 6 percent of global energy production and 20 percent in the countries that have nuclear power.” The first figure is right, the second seriously wrong. Nuclear energy provides a bit less than 10 percent of the primary energy supply in the countries that use this energy source. (It appears that Lomborg has confused contributions to the electricity sector with contributions to primary energy supply.) After a muddled discussion of the relation between uranium-resource estimates and breeding (which omits altogether the potentially decisive issue of the usability of uranium from seawater), he then barely notes in passing that breeder reactors “produce large amounts of plutonium that can be used for nuclear weapons production, thus adding to the security concerns.” He should have added that this problem is so significant that it may preclude use of the breeding approach altogether, unless we develop technologies that make breeding much less susceptible to diversion of the plutonium while not making this approach even more uneconomic than it is today.

(BL) Holdren is correct here that the 20 percent is an error – I should have written 20 percent of the electricity generation from nuclear power (this will naturally be put up on the error page of my web site). Naturally, one would like such errors not to occur, but to claim that it is a “serious error,” when the figure is given as general information and not used in any arguments seems out of proportion.
The other critique, that Lomborg “barely notes in passing” the added security concerns seems again out of proportion – the entire nuclear fission discussion takes up three paragraphs of 272 words, where the security concern is mentioned twice. This is hardly “barely notes in passing.” For reference, here are the three paragraphs (SE:129):

“Ordinary nuclear power exploits the energy of fission by cleaving the molecules of uranium-235 and reaping the heat energy. The energy of one gram of uranium-235 is equivalent to almost three tons of coal. Nuclear power is also a very clean energy source which, during normal operation, almost does not pollute. It produces no carbon dioxide and radioactive emissions are actually lower than the radioactivity caused by coal-fueled power plants.
At the same time nuclear power also produces waste materials that remain radioactive for many years to come (some beyond 100,000 years). This has given rise to great political debates on waste deposit placement and the reasonableness of leaving future generations such an inheritance. Additionally, waste from civilian nuclear reactors can be used to produce plutonium for nuclear weapons. Consequently, the use of nuclear power in many countries also poses a potential security problem.
For the moment there is enough uranium-235 for about 100 years. However, a special type of reactor – the so-called fast-breeder reactor – can use the much more common uranium-238 which constitutes over 99 percent of all uranium. The idea is that while uranium-238 cannot be used directly in energy production it can be placed in the same reactor core with uranium- 235. The uranium-235 produces energy as in ordinary reactors, while the radiation transforms uranium-238 to plutonium-239 which can then be used as new fuel for the reactor. It sounds a bit like magic, but fast-breeder reactors can actually produce more fuel than they consume.
Thus it is estimated that with these reactors there will be sufficient uranium for up to 14,000 years. Unfortunately these reactors are more technologically vulnerable and they produce large amounts of plutonium that can be used for nuclear weapons production, thus adding to the security concerns.”

(SA) Lomborg has some generally sensible things to say about the large contributions that are possible from increased energy end-use efficiency and from renewable energy—on these topics he seems, to his credit, to be more a contributor to the “environmental litany” than a critic of it. But on these subjects as on the others, his treatment is superficial, uneven and marred by numerous errors and infelicities. For example, he persistently presents numbers to two- and three-figure precision for quantities that cannot be known to such accuracy: “43 percent of American energy use is wasted”; “the costs of carbon dioxide” emissions are “0.64 cents per kWh”; plant photosynthesis is “1,260 EJ” annually. He makes claims, based on single citations and without elaboration, that are far from representative of the literature:
“We know today that it is possible to produce safe cars getting more than 50-100 km per liter (120–240 mpg).” (How big would these cars be, and powered how?) He bungles terminology: “Energy can be stored in hydrogen by catalyzing water.” (He must mean “by electrolyzing water” or “by catalytic thermochemical decomposition of water.”) And he propagates a variety of conceptual confusions, such as the idea that grid-connected wind power requires “a sizeable excess capacity” in the windmills because these alone “need to be able to meet peak demand.”

(BL) Again, Holdren says I am right about many things, but still the treatment is criticized thoroughly. Most incredibly, I am criticized for being too precise. Of course, there are a lot of numbers that we do not know well, but the general idea in statistics is that if these numbers have been generated by a process described by evenly distributed errors, the more precise number is still the best predictor of the real number – or to put it more clearly: If studies have shown that 43 percent of all American energy use is wasted, then the real number may very well be 38-48 percent, but had I rounded this figure down to 40 or up to 45, it would have been worth less – and Holdren could then have criticized me for conveying muddled results. Moreover, the 43 percent is actually described right off one of the bestselling college environment books by professor Miller – is Holdren also claiming that he is wrong?
Holdren claims that I make claims that are far from representative of the literature, gives us one example, but does not give us other references that show this statement to be incorrect or even an indication of why this statement would be far from representing the literature.
I am accused of bungling terminology – it is true that ‘catalyzing’ was translated from the Danish version, and should have been electrolyzing. But again, how important is this?
The conceptual confusion seems to stem from Holdren not reading the two paragraphs. If the windmills were connected to a coal-fired power grid, then clearly they would not need to be able to meet peak demand, but this clearly would not be a long-term renewable strategy. Rather, I discuss the interaction of dams and windmills (SE:134):

“If the power grid is hooked to dams, these can be used for storage. Essentially, we use wind power when the wind blows, and store water power by letting water accumulate behind the dams. When there’s no wind, water power can produce the necessary electricity. However, this implies that both wind power and water power require a sizeable excess capacity, since both need to be able to meet peak demand. The solution also depends on relatively easy access to large amounts of hydroelectric power.”

(SA) Of course, much of what is most problematic in the global energy picture is covered by Lomborg not in his energy chapter but in those that deal with air pollution, acid rain, water pollution and global warming. The last is devastatingly critiqued by Stephen Schneider on page 62. There is no space to deal with the other energy-related chapters; suffice it to say that I found their level of superficiality, selectivity and misunderstanding roughly consistent with that of the energy chapter reviewed here. This is a shame. Lomborg is giving skepticism— and statisticians—a bad name.

(BL) Given that Holdren could find little but a badly translated word and a necessary specification for nuclear energy production in this chapter, I find comfort that he finds the other chapters of equal value. However, I do find the tone of the entire critique surprisingly rough, indicating that Holdren found it necessary to substitute good analysis with plain negative words.

(SA) John P. Holdren is the Teresa and John Heinz Professor of Environmental Policy at the John F. Kennedy School of Government, as well as professor of environmental science and public policy in the department of earth and planetary sciences, at Harvard University. From 1973 to 1996 he co-led the interdisciplinary graduate program in energy and resources at the University of California, Berkeley. He is a member of the National Academy of Sciences and the National Academy of Engineering.

(BL) First, Bongaarts writes that things are going better and that the environmentalists’ predictions of widespread famines were wrong. Okay. So, not much of ‘Science defending itself against Lomborg’ here. But then he sets the high standard of saying that I am wrong in saying that the number of people is not the problem. We will see below that Bongaarts does not even try to lift the burden of proving this statement and rather abandon it at the end. But, of course, its inclusion here makes the piece appear stronger.
Curiously, Bongaarts also neglects to write why I say the number of people is not the problem and instead identify poverty (SE:48):

“We often hear about overpopulation of the Earth. We most often see overpopulation illustrated by large glossy color pictures of tightly packed masses or overcrowded underground stations.
The famous population biologist Paul Ehrlich in his best-seller on the population explosion wrote: “Psychologically, the population explosion first sunk in on a stinking hot night in Delhi. The streets were alive with people. People eating, people washing themselves, people sleeping, people working, arguing and screaming. People reaching their hands in through taxi windows to beg. People shitting, people pissing. People hanging off buses. People driving animals through the streets. People, people, people.”

(SA) His selective use of statistics gives the reader the impression that the population problem is largely behind us. The global population growth rate has indeed declined slowly, but absolute growth remains close to the very high levels observed in recent decades, because the population base keeps expanding. World population today stands at six billion, three billion more than in 1960. According to U.N. projections, another three billion will likely be added by 2050, and population size will eventually reach about 10 billion.

(BL) Here, Bongaarts accuses me of fudging the statistics. However, the ensuing documentation seems to point its accusing finger the other way. Bongaarts says that the global population growth rate has indeed declined slowly, but the absolute growth remains close to the top. First, he makes it sound like I don’t say that, but I do, as can be seen here in the relevant paragraph from the book (SE:47):

“As demonstrated in Figure 13 [graph of the rate and absolute number of growth], the growth of the global population peaked in the early 1960s at just over 2 percent a year. It has since fallen to 1.26 percent and is expected to fall further, to 0.46 percent, by 2050. Even so, the absolute growth of the population did not peak until 1990, when almost 87 million people were added to world population. Today growth is around 76 million per year and will have fallen to approximately 43 million by 2050.”

“The UN continuously calculates how many of us live on Earth now and will in the future. These figures have been adjusted downward by 1.5 billion for 1994, 1996 and 1998 and upwards again by half a billion for 2000, because of changes in the speed with which the fertility falls in different countries. The latest long-term forecast from 2000 can be seen in Figure 11. It shows that there will be almost 8 billion people on Earth by 2025 and about 9.3 billion by 2050. It is estimated that the world’s population will stabilize just short of 11 billion in the year 2200.” (SE:47).

(SA) Any discussion of global trends is misleading without taking account of the enormous contrasts among world regions. Today’s poorest nations in Africa, Asia and Latin America have rapidly growing and young populations, whereas in the technologically advanced and richer nations in Europe, North America and Japan, growth is near zero (or, in some cases, even negative), and populations are aging quickly. As a consequence, nearly all future global growth will be concentrated in the developing countries, where four fifths of the world’s population lives. The projected rise in population in the developing world between 2000 and 2025 (from 4.87 to 6.72 billion) is actually just as large as the recordbreaking increase in the past quarter of a century. The historically unprecedented population expansion in the poorest parts of the world continues largely unabated.

(BL) Again, Bongaarts seem to accuse me of not taking into account the enormous differences among world regions, though one of the most consistent factors in the book is the presentation of data for both developed and developing countries. Yet, I did not present a chart for population growth in the developing world, so I will bring it here (Figure 1). Here, again we see almost the same pattern as in Figure 13 from the book (SE:47), and indeed we also see how questionable Bongaarts analysis is: He claims that the historically unprecedented population expansion continues largely unabated, yet, the growth of 74 million in 2001 is the lowest since 1984, and the rate has dropped from the maximal 2.6% to 1.5% today. The claim that the growth from 1975- 2000 is almost the same as the growth 2000-2025 is technically true, but very misleading – the growth in the early quarter century period came from ever increasing numbers of people being added, whereas every year from 2000 onwards will see ever fewer numbers being added.
 
 

Figure 1: Absolute and relative population growth prediction.

(SA) Past population growth has led to high population densities in many countries. Lomborg dismisses concerns about this issue based on a simplistic and misleading calculation of density as the ratio of people to all land. Clearly, a more useful and accurate indicator of density would be based on the land that remains after excluding areas unsuited for human habitation or agriculture, such as deserts and inaccessible mountains. For example, according to his simple calculation, the population density of Egypt equals a manageable 68 persons per square kilometer, but if the unirrigated Egyptian deserts are excluded, density is an extraordinary 2,000 per square kilometer. It is therefore not surprising that Egypt needs to import a large proportion of its food supply. Measured properly, population densities have reached extremely high levels, particularly in large countries in Asia and the Middle East.

(BL) It is curious that Bongaarts, trying to show how wrong I am, is forced to use a hypothetical argument (of Egypt) and does not even find it necessary to point out that I never make this argument. The real challenge is in the text shown above, where I point out some of the most densely populated areas of the world are in Europe. Is Bongaarts obvious point at all relevant to my examples of e.g. the Netherlands being far more densely populated than India? We are never told.

(SA) Why does this matter? The effect of population trends on human welfare has been debated for centuries. When the modern expansion of human numbers began in the late 18th century, Thomas Robert Malthus argued that population growth would be limited by food shortages. Lomborg and other technological optimists correctly note that world population has expanded much more rapidly than Malthus envisioned, growing from one billion to six billion over the past two centuries. And diets have improved. Moreover, the technological optimists are probably correct in claiming that overall world food production can be increased substantially over the next few decades. Average current crop yields are still below the levels achieved in the most productive countries, and some countries still have unused potential arable land (although much of this is forested).

(BL) Again, Bongaarts almost tell us that I am correct, though he does underplay the argument in two rather conspicuous ways. He says diets have improved. That is true, though an understatement.
Actually, the global availability of calories has increased from 2257 calories in 1961 to 2792 in 1998, an increase of 24%, and for the developing world an even greater increase of 38% from 1932 to 2663 calories (FAO 2001a).
Moreover, he says that food production is probably capable of being increased substantially because of yield increases and “some countries still have unused potential arable land (although much of this is forested).” This, again, is a serious understatement for arable land and an overstatement for forests. In the latest FAO report on Agriculture towards 2030 (FAO 2000d), FAO explicitly discusses the use of land in agricultural production and the extra availability of agricultural land.
FAO estimates that at present about 1.5 Gha or 11% of the globe’s land surface is used for agriculture, and an additional 2.9 Gha has crop production potential (FAO 2000d:98). Of this area about 45% is forested (FAO 2000d:103). So there is ample room for bringing in new agricultural land and none of it needs be forested. Actually, the FAO estimate for the developing countries (developed will probably not increase their area at all) a much lower increase in land use till 2030 of about 0.12 Gha, an increase of 12%. This means that the agricultural land usage will go from 32% of the potential land use to 36% in 2030. Globally, this probably means an increase in agricultural land use from 11% to 12% of the land surface.

(SA) Agricultural expansion, however, will be costly, especially if global food production has to rise twofold or even threefold to accommodate the demand for better diets from several billion more people. The land now used for agriculture is generally of better quality than unused, potentially cultivable land. Similarly, existing irrigation systems have been built on the most favorable sites. And water is increasingly in short supply in many countries as the competition for that resource among households, industry and agriculture intensifies. Consequently, each new increase in food production is becoming more expensive to obtain. This is especially true if one considers environmental costs not reflected in the price of agricultural products.

(BL) This is one of the stunningly simplistic analyses from the environmental Litany: Since we have already used the best land sites with the easiest irrigation etc., an expansion of the agricultural production will lead to higher prices. However, this clearly neglects the historical trend towards ever more efficient production and better crops which has given us steadily declining prices. However, Bongaarts simply does not supply any evidence that his scenario of increasing prices should become true – yet, both IFPRI, USDA and the World Bank predicts ever lower prices (IFPRI 1997, 1999; ERS 1997:4; USDA 2000b; Mitchell et al. 1997), which is a continuation of the almost constant decrease in food prices since 1800 (data on wheat prices from 1316-2000 in SE:62).

(SA) Lomborg’s view that the production of more food is a non-issue rests heavily on the fact that world food prices are low and have declined over time. But this evidence is flawed. Massive governmental subsidies to farmers, particularly in the developed countries, keep food prices artificially low. Although technological developments have reduced prices, without these massive subsidies, world food prices would certainly be higher.

(BL) The last hypothetical sentence is true – without subsidies, prices would be higher, but the argument lies with the trend of the price, which is downwards, and has been so since early 1800s. It is still curious that Scientific American lets their critic ‘defend science’ by referring to such fickle speculation instead of giving real references. Again, this could possibly be due to the fact that all major food analysis institutions still predict decreasing food prices (as above, IFPRI 1997, 1999; ERS 1997:4; USDA 2000b; Mitchell et al. 1997).

(SA) The environmental cost of what Paul R. and Anne H. Ehrlich describe as “turning the earth into a giant human feedlot” could be severe. A large expansion of agriculture to provide growing populations with improved diets is likely to lead to further deforestation, loss of species, soil erosion, and pollution from pesticides and fertilizer runoff as farming intensifies and new land is brought into production. Reducing this environmental impact is possible but costly and would obviously be easier if population growth were slower. Lomborg does not deny this environmental impact but asks unhelpfully, “What alternative do we have, with more than 6 billion people on Earth?”

(BL) Surprisingly and without any statistical backing, Bongaarts invokes the doomsday metaphor of “turning the earth into a giant human feedlot.” However, as we saw above, we are currently using about 11% of the global land surface area for agriculture, and in 2030, where we will be feeding more than 8 billion much better (3100 calories per person) we will be using 12% – hardly “turning the earth into a giant human feedlot.” Moreover, had Bongaarts accessed the available statistics, he could have seen that the increase in agricultural land use was actually bigger over the last 25 years than the coming 30 years (increasing land use by 0.173 Gha, compared to the expected increase of 0.12 Gha, FAO 2000d:105).
Again, Bongaarts actually acknowledges that I do discuss the environmental impact, and yet only says I ask the unhelpful question of what are the alternatives? Yet, this is misleading on at least three counts. First, I do give an insight as to how to control population in the long run – this is a question of poverty reduction and development (SE:46). This is why it was also problematic that Bongaarts cut off the quote at the top of his article where I also point out poverty (SE:48).
Second, I do actually show some of the bad consequences of listening to parts of the environmental movement in their advice as to abating some of the problems with food production. An often heard call is to move to organic farming, because it would mean less fertilizer runoff. Yet, this would have other, much more drastic consequences (SE:197):

“Today, it is estimated that 40 percent of all crop nitrogen comes from synthetic fertilizer, and about one-third of human protein consumption depends on synthetic fertilizer. Moreover, fertilizer allows us to produce more food on less farmland. This is one of the reasons why the global population could double from 1960 to 2000 and get better fed, although farmland area only increased 12 percent.
This should be compared with the quadrupling of farmland from 1700 to 1960 which of course came from the conversion of large tracts of forests and grasslands. Essentially, the extraordinary increase in fertilizer availability from 1960 onwards has made it possible to avoid a dramatic increase in human pressure on other natural habitats. Had fertilizer use remained at the 1960 level, we would need at least 50 percent more farmland than the present-day use – the equivalent of converting almost a quarter of the global forests. Over the coming decades to 2070, were we to forsake fertilizer, the need for farmland to feed 10 billion people better would place ever higher demands on the globe – one study puts the farmland requirement at an impossible 210 percent of the land surface area. Thus, synthetic fertilizer has been and especially will be crucially important in feeding the world while leaving sufficient space for other species. However, the doubling of globally available nitrogen has also caused problems.”
[The text goes on to talk about the problems of fertilizer runoff problems.]

(SA) Lomborg correctly notes that poverty is the main cause of hunger and malnutrition, but he neglects the contribution of population growth to poverty. This effect operates through two distinct mechanisms. First, rapid population growth leads to a young population, one in which as much as half is below the age of entry into the labor force. These young people have to be fed, housed, clothed and educated, but they are not productive, thus constraining the economy. Second, rapid population growth creates a huge demand for new jobs. A large number of applicants for a limited number of jobs exerts downward pressure on wages, contributing to poverty and inequality. Unemployment is widespread, and often workers in poor countries earn wages near the subsistence level. Both of these adverse economic effects are reversible by reducing birth rates. With lower birth rates, schools become less crowded, the ratio of dependents to workers declines as does the growth in the number of job seekers. These beneficial demographic effects contributed to the economic “miracles” of several East Asian countries. Of course, such dramatic results are by no means assured and can be realized only in countries with otherwise sound economic policies.

(BL) Here, Bongaarts makes what seems like a reasonable argument – though unfortunately without any references. But notice his argument is entirely conditional: “Both of these adverse economic effects are reversible by reducing birth rates.” Yes, and that was the main problem, right? Yet, his only indication of how these birth rates could be reduced is that this can happen “in countries with otherwise sound economic policies.” Thus, Bongaarts solution is a subset of my point that in order to combat population growth, we need to address and reduce poverty. (It is a subset, because sound economic policies that only benefit the rich will probably still leave the mass of poor people with a high reproduction.)

(SA) Lomborg approvingly notes the huge ongoing migration from villages to cities in the developing world. This has been considered a welcome development, because urban dwellers generally have higher standards of living than villagers. Because the flow of migrants is now so large, however, it tends to overwhelm the absorptive capacity of cities, and many migrants end up living in appalling conditions in slums. The traditional urban advantage is eroding in the poorest countries, and the health conditions in slums are often as adverse as in rural areas. This points to another burden of rapid population growth: the inability of governments to cope with large additions of new people. In many developing countries, investments in education, health services and infrastructure are not keeping up with population growth.

(BL) Here, Bongaarts again makes an unsubstantiated claim that “the traditional urban advantage is eroding in the poorest countries.” Where does this come from? However, the following sentence is logically flawed because it compares health conditions among the worst areas of the city (slums) with the average rural areas, a typical and incorrect comparison as I have already pointed out in my book (SE:362):

“Of course, shanty-town newcomers may not compare favorably with the average rural population, but presumably many left the countryside because they were worse off than the average, see e.g. Siwar and Kasim 1997:1,532 for a partly unsuccessful test.”

(SA) It is true that life has improved for many people in recent decades, but Lomborg does not acknowledge that this favorable trend has been brought about in part by intensive efforts by governments and the international community. Investments in developing and distributing “green revolution” technology have reduced hunger, public health campaigns have cut death rates, and family-planning programs have lowered birth rates. Despite this progress, some 800 million people are still malnourished, and 1.2 billion live in abject poverty. This very serious situation calls for more effective remedial action. Lomborg asks the developed nations to fulfill their U.N. pledge to donate 0.7 percent of their GNPs to assist the developing world, but few countries have met this goal, and the richest nation on earth, the U.S., is one of the stingiest, giving just 0.1 percent of its GNP. The trend in overseas development assistance from the developed to the developing world is down, not up. Unfortunately, the unrelenting we-are-doing-fine tone that pervades Lomborg’s book encourages complacency rather than urgency.

(BL) This is another give-away like Schneider saying that one should be wary of truth-tellers and mythbusters. Basically, Bongaarts is telling us that I am correct in my description of life, but that I should also have said who exactly carried out the concrete improvements. This borders to silly – of course, the improvement has physically been carried out “in part by intensive efforts by governments and the international community,” and presumably in part by intensive efforts by individuals and communities.
Who else could have done so? This is seemingly a request to make an almost tautological addition to the text: “These documented examples of progress were in part due to actions from government and the international community” and that this statement is missing constitute a failure of the analysis.
Yet, the issue, as Scientific American puts it up, is whether my data is correct – whether the state of the world has indeed improved or whether the doomsayers have been right in claiming declines everywhere. And their third critic simply comes out and says: ‘Yes, Lomborg is right, but he fails to add a tautological statement.’

(SA) Population is not the main cause of the world’s social, economic and environmental problems, but it contributes substantially to many of them. If population had grown less rapidly in the past, we would be better off now. And if future growth can be slowed, future generations will be better off.

(BL) This last statement takes out much of the strength of the entire piece. It basically leaves the argument to a plain conditional: if we could have cut population growth things would be better, but of course, we could only have cut population growth if things would have been better – which is what is happening now, and which is why population growth is constantly decreasing.

(SA) John Bongaarts is vice president of the Policy Research Division of the Population Council in New York City. From 1998 to 2000 he chaired the Panel on Population Projections of the National Academy of Sciences, National Research Council. He is a member of the Royal Dutch Academy of Sciences.

(BL) Lovejoy opens his critique with saying that it was “disconcerting” that I begin the biodiversity chapter with questioning whether biodiversity is important before discussing its size. I understand why this would be disconcerting to an environmental advocate or policy participant, but why would it be disconcerting to a scientist that we question the basis for our concern?
Notice, how Lovejoy does not actually contend the finding of my discussion – only that simply by asking the question, it should be obvious to any good man or woman that I am wrong.

(SA) When he finally gets to extinction, he totally confounds the process by which a species is judged to be extinct with the estimates and projections of extinction rates. Highly conservative rules hold that to be declared officially extinct, not only does a species have to be known to science, it has to be observed going to extinction (as in the case of the passenger pigeon, the last individual of which perished in the Cincinnati Zoo in 1914). Or, in the absence of direct observation, it must not have been seen in nature for 50 years.

(BL) The text claims that I totally confound the process of judging a species to be extinct and the projections of extinction rates. This seems like an odd statement, given that I make exactly the same point as Lovejoy in at least two places:

“Note that because of the severe regulations for documenting extinctions these figures certainly underestimate their true number.” (SE:250, note to table).

“… when we look at the last 400 years, there are other things to consider as far as extinction is concerned. For one thing, in order to document extinction, one must have looked for the species for several years wherever it may exist. A task of this magnitude requires a lot of resources, which reduces the number of documented cases of extinction to a minimum. For another thing, there is much greater focus on mammals and birds than on the other groups.”

(SA) Projections of extinction rates, on the other hand, are generally based on the longestablished relation between species number and area (which dates to 1921, not to the 1960s, as Lomborg maintains, and which demonstrates the rate at which species number increases with increase in area). Researchers then project what the reduction in a natural habitat will mean in terms of species loss. The disappearance of a species is not necessarily instantaneous, and thus some species that survive the initial reduction of the habitat are essentially “living dead”—they are not able to survive over the long term. The loss of species from habitat remnants is a widely documented phenomenon—in contrast to Lomborg’s inclusion of an out-of-date assertion that no credible attempt has been made to pin down the underlying scientific assumptions.
As a consequence, a seemingly major contradiction that Lomborg then offers is no contradiction at all: the reduction of the Brazilian Atlantic Forest formation to something on the order of 10 percent of its original extent and the lack of large numbers of recorded extinctions. First, this is a region with very few field biologists to record either species or their extinction. Second, there is abundant evidence that if the Atlantic forest remains as reduced and fragmented as it is, it will lose a sizable fraction of the species that at the moment are able to hang on.

(BL) Yes, the Brazilian Atlantic rainforest has been cut down by about 90% – this would mean that the species-area formula would expect a loss of about half of all species. Yet, when the Brazilian Society of Zoology analyzed a group of almost 300 animals and could not find a single species which had died out. Likewise, when they examined their list of plants, they could find no extinctions either (see the quotes of their report in SE:255). Of course, as Lovejoy points out, there are fewer biologists than perhaps in Europe or the US to register these losses, but expecting 150 dead species and finding none?!
This is why the IUCN (World Conservation Union, the organization which manages all species threats and extinctions) found this evidence quite disturbing as to the species-area relationship.
The statement that the species are essentially ‘living dead’ – just barely hanging on, but will eventually die out, this seems almost farcical– what Lovejoy neglects to mention, is that the clearing of the Brazilian Atlantic rainforest happened in the 1800s, so we have had more than 100 years to see the ‘barely hanging on species’ die out, and they haven’t. This is the second reason why the field experiment is so powerful. And this really deserves a better discussion than Scientific American gives it.
If the exam