American Journal of Epidemiology Vol. 155, No. 1 : 101-102
Copyright © 2002 by The Johns Hopkins University School of Hygiene and Public Health
BOOK REVIEWS |
Human Frontiers, Environments and Disease: Past Patterns, Uncertain Futures
Department of Epidemiology and Community Medicine University of Ottawa Ottawa, Ontario, Canada K1H 8M5
In Human Frontiers, Environments and Disease (1
), Tony McMichael explores how changes in human biology, culture, and the environment have influenced patterns of health and disease over many millennia. His perspective is ecologic and integrative, transcending conventional disciplinary boundaries. The book is steeped in epidemiology, richly blended with ecology, evolutionary biology, paleontology, population dynamics, history, complexity theory, and much else, all of it spiced with literary and cultural insights. It is written gracefully and with clarity that is rare in monographs on medical science. Its economy of words (a sure sign of a skilled literary craftsman) requires concentrated attention, and the epidemiology is unobtrusive.
There are many important messages in this volume. One is about the way we conduct science:
During the twentieth century, we humans doubled our average life expectancy, quadrupled the size of our population, increased the global food yield sixfold, water consumption sixfold, the production of carbon dioxide twelve-fold, and the overall level of economic activity twenty-fold. In so doing, we exceeded the planet's carrying capacity by approximately 30%. That is, we are now operating in ecological deficit. These rates of change in human demography, economic activity, and environmental conditions are unprecedented.... This is why there is a need to seek an understanding, in ecological terms, of the underlying determinants of human population health... There are now serious questions about how we can reorient our social and economic priorities so that we conserve and reuse, rather than consume and despoil. And there are serious questions about the future risks to population health if life-support systems continue to weaken. The need, then, is for a more integrative approach that addresses the patterns of population health in terms of our interactions with the natural world, with other species and their complex ecosystems, and within and between human societies. This, however, raises an important tension between the classical precepts of experimental science, which reduces complex realities to manageable and specifiable parts, and the recognition that the whole is usually greater than, and often very different from, the sum of its parts. The tension is the familiar one between reductionism and holism" (1, p. 318).
All epidemiologists should read this book. Only a very wise one like Tony McMichael could have written it. In just over 400 pages, he covers the entire sweep of human history, starting with our origins in Africa. He describes our ancestors' diasporas and their proliferation into every nook and cranny of habitable land on our planet; discusses the interplay of our species with the earth's diverse ecosystems; and explains how and why the diseases that afflict us have waxed and waned over the millennia since we evolved from early primates through hunter-gatherers to pastoralists, agriculturalists, and city slickers, leaving increasingly heavy ecologic footprints on this fragile earth. Malaria, epidemic infections, cancer, diabetes, asthma, and other afflictions are explained lucidly in the context of evolutionary biology. He examines the present human and planetary condition and raises disturbing questions about the effects of our ingenious species on essential life-supporting ecosystems that we are disrupting in alarming ways. Continuing to live the profligate lifestyle to which we in the West have become accustomed is not a viable option. Despite the "pursuit-of-happiness" policies of the present US administration (gas-guzzling sports utility vehicles for all), the immovable object of limits to growth foretold by the Club of Rome more than a quarter century ago (2) will restrain the apparently irresistible force of perpetual economic expansion that is the goal of globalization.
What must we do to adapt to our changing global circumstances? We must tread more delicately on the earth; conserve more and consume less; and recycle and reuse so that we generate less waste, especially the waste products of fossil-fuel combustion and the poisonous by-products of our industries. We must abide by the precautionary principle: "When the outcome of a course of action is uncertain but potentially disastrous, then preventive action is the prudent option. Better to be safe than sorry" (1, p. 330). Epidemiologists studying health-related changes at the global level must abandon reductionist approaches; they must come to grips with the reality that "complex non-linear dynamic systems—including ecosystems, the climate, the workings of the human brain, urban transport systems, and the economy ... are not susceptible to precise mathematical description" (1, p. 332). To study global change, we must forsake comfortable traditional methods and consider plausible future scenarios, not actual current conditions—an intellectually demanding and unsettling task that requires us to work with "multiple layers of systems-based uncertainties, a high level of decision stakes, and a diversity of interested-party perspectives" (1, p. 332).
In the final chapter, McMichael suggests how the human community should approach the future: "We must ensure that the globalizing process will... bring a more coordinated international approach to managing the global commons, such as the stratosphere, the world climate, fresh water, forests, fertile land, and the stocks of biodiversity" (1, p. 343). In short, to achieve global sustainability we will require global governance. There are some problems with this agenda, of course. He considers one at the heart of the matter: "...the meaningful implementation of many policies that are conducive to ecologically sustainable living... will work best through local communities at a sub-national level. In between these two foci—global governance and community engagement—is the... nation-state. It is, say some political scientists, a nineteenth-century political device with a twentieth-century morality, ill-equipped to tackle many of the problems of the twenty-first century" (1, p. 348). McMichael is a latter-day Virchow, reminding us that public health is nothing less than politics writ large. Political realities, including American antipathy to international accords and widespread quarrelsomeness among even outwardly friendly states, present challenges almost too daunting to contemplate. But however we go about it, we must achieve a sustainability transition to go along with our demographic and epidemiologic transitions. The alternative is chaos, conflict, and the collapse of multiple ecosystems and life support systems—our world ending, as T. S. Eliot put it, not with a bang but a whimper.
The book does have shortcomings. McMichael uses the metaphor of the Four Horsemen of the Apocalypse, even adding a Fifth Horseman (industrialization). He mentions war, but says little about this primus inter pares of the Horsemen. Aggression is an innate part of human nature; without it, we probably would not have reached the evolutionary pinnacle to which we cling rather precariously. Unfortunately, perversion of humanity's aggressive instincts into total war, genocide, and indiscriminate use of weapons of mass destruction (a phrase that covers almost all modern weapons of war) caused more than 100 million deaths and several times that many permanent disabilities in the 20th century—a major public health problem by any standard, and one that could be studied by epidemiologists aspiring to prevent further carnage. Moreover, environmental stress can lead to violent armed conflict as well as be aggravated by it. Perhaps war merits more than a passing glance in a book as important as this, but it would have been hard to do justice to such a huge topic in addition to everything else that was discussed so admirably.
Epidemiologists face formidable challenges if we are to contribute usefully to human progress in the coming decades. We must put aside trivial debates about risk factors and concentrate on finding tools and techniques for assessing the impact of global environmental changes that threaten our species (and the many other species we are foolishly exterminating). We must focus on efforts, feeble thus far, to adapt to these global environmental changes and take action to mitigate the impact of the most dangerous changes.
For whom was this book written? Sometimes, as on page 336 when alluding to the task ahead for epidemiologists, Tony McMichael speaks directly to his professional colleagues. At other times, his translations into lay language address a wider constituency of thoughtful people—opinion leaders and movers and shakers in all walks of life. I hope they all will read this book, heed it, and act on what McMichael makes clear we all must do if we want to leave the world as good a place for coming generations as it has (mostly) been for us.
NOTES
ISBN 0-521-00494-2, Cambridge University Press, Cambridge, United Kingdom (Telephone: (44) 1223-312393, Fax: (44) 1223-315052, World Wide Web: http://uk.cambridge.org, E-mail: directcustserv{at}cambridge.org), 2001, 430 pp., Paperback $24.95, Hardcover $59.95
REFERENCES
- McMichael AJ. Human frontiers, environments and disease: past patterns, uncertain futures. Cambridge, United Kingdom: Cambridge University Press, 2001.
- Meadows DH, Meadows DL, Randers J, et al. The limits to growth. New York, NY: Universe Books, 1972.
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