The Skeptical Environmentalist: Measuring the Real State of the World

  • Bjørn Lomborg
Cambridge University Press: 2001, 515 pp. £47.50, £17.95

The subtitle gives the book away. It rehashes books such as Ronald Bailey's The True State of the Planet (Free Press, 1995). As Bjørn Lomborg tells us, the book's origin was a class he taught in 1997. The original Danish version appeared a mere year later —remarkably fast, given the delays of academic publishing. It shows, too. This survey of global environmental problems — food, forests, energy, water, pollution, biodiversity, global warming — reads like a compilation of term papers from one of those classes from hell where one has to fail all the students. It is a mass of poorly digested material, deeply flawed in its selection of examples and analysis.

Lomborg admires the late Julian Simon, author of The Ultimate Resource (Princeton University Press, 1996). Beside Simon, Voltaire's optimistic Dr Pangloss is gloomy and Albert Einstein a theoretical novice. Simon impressed the US political right by his assertion that we have “the technology to feed an ever-growing population for the next 7 billion years”. Ecologists were challenged by this remarkable rejection of basic ecological laws. At present growth rates, the human mass would exceed that of the biosphere within the millennium. Physicists should be in awe, too. Well before the allotted time, human mass would be expanding faster than the Universe.

Thus influenced, Lomborg begins with “the litany” — the list of things wrong with the planet, and why, when we see things his way, “things are getting better”. The litany quotes news magazines and a book by two science-fiction writers, but not scientists directly. No external references support the ensuing paragraphs justifying that 'things are getting better'. Quoting the primary literature troubled Simon, too.

Like bad term papers, Lomborg's text relies heavily on secondary sources. Out of around 2,000 references, about 5% come from news sources and 30% from web downloads — readily accessible, therefore, but frequently not peer reviewed. A mere 1% are original papers in Nature, half as many again come from contributors to Simon's books. This bias towards non- peer-reviewed material over internationally reputable journals is sometimes incredible — for example, the claim that the evidence for pollution at New York's Love Canal was “jaded”. At other times it seems fictional. “Scientific luminaries such as Harvard biologist E. O. Wilson and Stanford biologist Paul Ehrlich are the enthusiastic supporters of an ambitious plan ... to move the entire population of the US. ... people would live in small enclosed city islands.” The reference is directly attributable neither to Wilson nor to Ehrlich. “Is it true?” we asked them. Ehrlich: “I know of no such plan. If there were one, I wouldn't support it.” Wilson concurred.

Lomborg's great optimism about humanity's future shows up in the way he presents statistics. In the hell-hole that is so much of sub-Saharan Africa, “starving people” constituted “38 percent in 1970 ... [but only] “33 percent ... in 1996. [The percentage is] expected to fall even further to 30 percent in 2010.” The absolute numbers of starving are curiously missing from these paragraphs. Roughly, the region's population doubled between 1970 and 1996. To keep the numbers of starving constant, the percentage would have had to have dropped by more than half. The absolute numbers of malnourished in the region — as well as those whom fate will spare through their death from the myriad consequences of poverty (including AIDS) — are surely inconsistent with the first-listed “global trend” in a chapter entitled “Things are getting better”.

Often, Lomborg misses the critical literature in exactly the same ways as did Simon. For example, consider the chapter on biodiversity. It starts out with the by-now standard denigration of consensus estimates on extinction rates and omits relevant papers in even obvious places — including the paper demonstrating that Simon's estimates are three to four orders of magnitude below everyone else's.

The text employs the strategy of those who, for example, argue that gay men aren't dying of AIDS, that Jews weren't singled out by the Nazis for extermination, and so on. “Name those who have died!” demands a hypothetical critic, who then scorns the discrepancy between those few we know by name and the unnamed millions we infer. Exactly repeating Simon, Lomborg juxtaposes the small number of named dead species against the huge number of species for which we have no knowledge at all. After pages of confused argument, his extinction estimate of “0.7 percent over the next 50 years” is strikingly discordant with the 10– 40% of well-known species that teeter on the brink of extinction just from human actions to date. About 2% of well-known species are already so desperately rare that we don't know whether they do survive. Lomborg finds comfort when some are rediscovered. Like terminally ailing humans, their lingering survival does not allay fears about the unfolding epidemic.

On future trends based on forest losses, his flawed examples are unoriginal. “In the US, the eastern forests were reduced ... to fragments totalling just 1–2% of the original area ... this resulted in the extinction of only one forest bird”. The correct percentage is close to 50%, and the number of extinctions four, plus two seriously wounded. Those extinctions constitute 15% of the bird species found only within the region (the only ones at risk of global extinction). They strikingly confirm the predictions made from the species-area models that Lomborg disparages.

An industry has arisen debunking this book chapter by chapter. At present, it includes a website (; a series of essays planned for Scientific American; a guide for journalists documenting Lomborg's more egregious errors being assembled by the Union of Concerned Scientists; and various published pamphlets. We have provided only a sampler.

But Nature instructs its reviewers to do more than merely describe a book's contents; we must examine its wider implications. The only such implication we see causes us to ask why Cambridge University Press would decide to publish a hastily prepared book on complex scientific issues which disagrees with the broad scientific consensus, using arguments too often supported by news sources rather than by peer-reviewed publications. Certainly, controversy is part of science, but extraordinary claims require the extraordinary scrutiny that comes from competent peer review — something that appears to be missing in this case.

More on environmental risk analysis The Precautionary Principle: A Critical Appraisal of Environmental Risk Assessment by Indur M. Goklany Cato Institute, $17.95