You know what they say about people who become statisticians? They lacked the personality to become accountants.

Whatever their personalities may be, those who spend their lives sorting through reams of numbers often lose sight of what those numbers mean and represent. The Skeptical Environmentalist is a big and infuriating book, written by a statistician and self-described former environmentalist who confesses to having no training in science. The book purports to disclose the true numbers describing a vast terrain, from ecosystems and biodiversity to human health and climate change. The author, Bjorn Lomborg, notes that given the enormous amount of information available on the global environment today, an infinite number of stories can be told, proffering both good news and bad. Arguing that the bad news has received more than its fair share of attention, Lomborg chooses to focus on the “good” stories, and on some bona fide mistakes that have been made by environmentalists.

There is much in this book with which many reasonable people would agree. What could possibly be wrong with an environmental treatise that offers a vision of a world where children will live longer and better, have cleaner water and food, more economic and social resources, and enjoy a safer planet? As the author notes, many aspects of life around the world are, in fact, better than ever. And yes, some environmental organizations and experts have erred in the past in their use of numbers.

A statistically dead duck.

But “better than ever” does not mean good enough, and Lomborg is hardly immune from mistakes either. When it comes to public health, his lack of understanding of science has led him to produce many fundamentally flawed analyses. It is true that people are, on average, living longer and better than ever — especially people who are white and wealthy. But considering only global or national averages conceals far too many tragedies. Good statisticians know to beware of averages, recognizing that they do not map perfectly onto reality. Consider the story of the two hunters who wait around for hours until a duck flies overhead. One hunter fires a shot into the air a foot in front of the duck. The other fires and hits the air one foot behind the duck. On average the duck is dead — but the hunters go home hungry.

In other words, understanding the causes of health and disease that can be controlled through public policy requires more than just a surface treatment of numbers; it requires studying patterns and undertaking meaningful analyses. While modern medicine treats individuals for specific diseases in localized organs, public health scholars understand that the patterns of these diseases reveal characteristics of the groups to which we belong and the ways in which we live.

To Health in a Hand Basket

Although he doesn’t intend to do so, Lomborg documents (but fails to acknowledge) a number of instances in which good environmental policies have lead to successes in public health. For instance, he shows that there has been a dramatic drop in measured levels of DDT and related pesticides in human blood and fat. The recent declines in breast cancer incidence and mortality that he correctly reports could, in part, reflect this decreased exposure to pesticides and other agents known to stimulate hormonal activity.

Public health problems keep cropping up.

Photo: ArtToday.

In general, Lomborg focuses on denying or minimizing environmental threats to public health. For example, notwithstanding the aforementioned declines in breast cancer rates, the disease remains a serious public health problem. Moreover, it is still largely unexplained, with fewer than one in 10 cases occurring in a woman born with a genetic defect. Doctors and scientists have traditionally invoked individual risk factors, such as reproductive history and nutrition, to explain breast cancer incidence, but that practice ignores a growing body of research on the risks from exposures to chlorinated organic solvents, plastics, fuels, and other harmful agents.

The jury is still out on such toxics, largely because of an appalling failure to collect useful data. Lomborg fixates on recent findings from several studies showing that women who already have breast cancer do not have higher levels of pesticides in their bodies when diagnosed with advanced disease. In fact, pesticide levels in people have dropped because of the success of the environmental movement. It is not possible to estimate pesticide levels from 10 to 20 years ago, when tumors that are discovered today may have begun to grow. Cancer takes decades to develop — and some types of cancer, including breast cancer, can stem from prenatal exposures about which we have no records whatsoever. So are we really confident that finding no difference in chemical residues in women who are ill and those who are healthy means that these chemicals are safe?

Moreover, the body chemistry of those with cancer changes in ways that are not well understood, and certainly not by someone with Lomborg’s lack of training. Consider DDT. The parent compound DDT is highly estrogenic; that is, it stimulates the female hormone and raises estrogen levels. There is no question that the greater the cumulative exposure to hormones such as estrogen in a woman’s lifetime, the higher her risk of developing breast cancer. Hence, exposure to DDT is a risk-factor for cancer. But DDT’s long-lived metabolite, DDE, which is what can be measured in the human body years after exposure to DDT, is actually anti-estrogenic and androgenic. However, in another form, DDE acts primarily as an antiandrogen. Total PCBs, a group of toxic chemicals that include materials which are both estrogenic and anti-estrogenic, are similarly complex. Many estrogenic PCBs are not persistent and would not be detectable in plasma years after exposure. So we don’t know if some women with breast cancer have been exposed to such toxins at a critical point in their lives, causing the disease to develop — but we do know that these same compounds can affect the health of turtles, fish, rodents, and polar bears.

Not Very Trendy

Lomborg’s analysis of cancer trends is as convenient, and as lacking, as his analysis of possible carcinogens. He shows that in the developed world, total death rates from cancer have dropped as men have stopped smoking. He does not show that the incidence of new cases of cancer not known to be linked to smoking has increased, so that young men of Generation X are four times more likely to get cancer than were their grandfathers. Lomborg ignores one of the most widely accepted and unexplained health trends in modern society — the growth of testicular cancer in young men in industrial countries. Ethylene glycol ethers and a variety of modern solvents and plastics have been shown to shrink the gonads of rodents, increase deformities of the male genitalia, lower sperm count and quality, and result in smaller testes in exposed workers.

In looking at the decline in sperm counts, Lomborg makes a remarkable point. First he tries to argue that sperm count has not really dropped as much as some people say; then he acknowledges that it has in fact declined, but adds that, “Of course, this is not a problem if it is simply due to the fact that we have more sex.”

Fair enough. The notion that increased sexual activity on a broad scale could be occurring and could cause sperm count to d
rop is pretty straightforward. However, Lomborg fails to address the possibility that the decline in sperm counts is due to more than one factor. What if exposure to the same environmental hormone exposures that have been shown to affect fish, turtles, polar bears, whelks, snails, and deer has permanently damaged the human gene pool? What if by the time we can be sure it is three generations too late? Are sick and injured people the only valid evidence on which to base public policy?

These questions might seem like precisely the kind of vague alarmism that Lomborg decries. But the point is that although answers to questions like these are unknowable right now, we do know this: When it comes to matters involving our own health and that of our planet, it is better to be approximately correct than precisely wrong.

In his efforts to be precise, Lomborg is wrong in some important ways. He generally argues that we lack sufficient proof that the environment is harming humans. He takes this absence of irrefutable evidence to mean that such harm does not and cannot occur. In other words, Lomborg is willing to assume the risk that this unprecedented global experiment in which we are engaged will not produce irrevocable damage. But let’s be clear here: What’s at risk are our lives and the sustainability of our only planet. That is not a risk many of us take willingly.