Book review: Human Frontiers, by Tony McMichael (CUP, 2001)

The book reviewed here was - with the ideas of Art De Vany - jointly the primary inspiration for this site.  To understand fitness and health in an evolutionary and environment context, this book is a superb introduction.

Tony McMichael, presently Director of the ANU's National Centre for Epidemiology and Population Health, has produced a book that is a model of organization and its theme is stated at the beginning: humankind’s long evolutionary and historical experience shows how the natural and social environments affect patterns of disease and survival.  Appreciating this ecological perspective on human population health – at a time when critical stresses are appearing – is a prerequisite to achieving a sustainable future.

McMichael draws on all the life sciences and his compact style leaves readers without a life sciences background somewhat breathless and wishing there was a glossary to guide them through the underlying science.  Nevertheless, the book remains comprehensible to the interested lay person and should be read by every environmental policy-maker. 

The book introduces the three elements of natural selection: variation, competition and differential reproductive success, pointing out that a species does not have capabilities surplus to their current circumstances.


On that foundation McMichael traces human evolution beginning with the climatic cooling 5–2.5 mya which brought plant food species under pressure.  These external influences coincided with a point where our ancestors had the opportunity to evolve rapidly.  The change favoured a more complex human brain that could plan and dig, not merely gather visible and obvious foods.  Survival was more likely for those with a good memory and with the greatest capacity for sharing.  Charting human evolution from vegetarian, forest-dwelling Ardipithecine, through the Australopithecine to the omnivorous Homo genus, McMichael describes how humankind’s “wild Pleistocene genome” adapted to these changes: a restless species evolving at a breakneck pace.  As the climate cooled, forests withdrew and there were more grazing animals which happened to be propitious food sources for our ancestors.  As the Australopithecines lacked tools for catching meat live, they were originally scavengers.  Later, as meat, especially bone marrow, enabled a bigger brain, they became more intelligent and more adaptable to climatic fluctuations and also able to make hunting tools and cooperate in hunting.

This larger brain came at a higher metabolic cost.  But the increased intelligence made it feasible to adopt the previously too-risky strategy of sacrificing the energy-expensive colon (used to digest vegetation) for a larger brain (to hunt energy-rich meat).

Physical and mental attributes enabled non-specialized predation; each preyed-upon species was expendable.  Humans were opportunistic and versatile and readily switched to other food species.

The mismatch between our Pleistocene-attuned biology and our current way of life has been amplified over the last century as urban sedentariness, dietary excesses and various socialized addictive behaviours (alcohol and tobacco) have become prominent features of modern human ecology.

McMichael shows how behavioural adaptations had social as well as physiological impacts on our species.  Thus the controlled use of fire not only affected diet, it provided warmth and nocturnal security and so prolonged group interaction which, in turn, would have facilitated the emergence of language.

The detail intensifies as McMichael charts Homo sapiens through the Neolithic, from hunter-gatherer to agriculturalist, over the most recent 0.2% of our evolution as a distinct species.  The more specialized and settled farming communities were dependent upon a few staples, reducing their range of nutrients and increasing their exposure to famines.  Settled living, in close proximity to livestock, also enabled microbes to cross easily to humans.

The industrial revolution brought new environmental risks and occupational hazards and about a century ago the modern affluent lifestyle exchanged infectious diseases for chronic non-communicable diseases, especially those of late adulthood: dietary imbalances, physical inactivity, addictions, diabetes, heart disease – diseases which do not exert natural selection pressure.

One of the book’s clear messages, stated more clearly and comprehensively than I have seen before: healthy people need healthy food.  But the food should be of Pleistocene quality, produced in a Pleistocene biosphere.  We know this can no longer be.  The questions are: how distant are we from our ecological inheritance?  Does it matter?  If it matters, what can be done about it?

McMichael uses the book to argue for a refocusing of the discipline of epidemiology to take it beyond a base in traditional germ theory (an individual-oriented cause-and-effect approach, asking why this person has pathology X?) to an ecological approach (asking why a given population has a particular rate of pathology X).

In reading through this part of the book, I found no attempt to define good health, other than negatively (as the absence of poor health).  McMichael is not as direct as he could be about the prior conditions for good health: societies with a sustainable ecological footprint; stable, rational, reliable social institutions; good topsoil, water, biodiversity; materially provident governance; societal equity and ecological sustainability.  Within those societies, the individuals should be fit, with good nutrition, musculature and bones; active and well-coordinated; well-educated, enquiring and critical; well-adjusted; cooperative - contributing to the creativity and well-being of the society of which they are a part.  McMichael's “health” indices are about outcomes of morbidity and mortality and inputs – nutrition, female literacy that may, at population level, lead to improved health.  But what leads to the best health?

If we do not address this, are not our Health Departments going to remain Injury and Illness Departments?  Will not physical health be linked - too narrowly – to sport, specialist service providers and expensive technologies?  Will not diet be emphasized at the expense of ecological health and physical activity patterns, two more important factors?

McMichael draws on "post-normal science" for his critique of epidemiology and also for his wider criticism of our traditional ways of looking at the planet's ecology.  Post-normal science enables us (a) to go beyond actual, current conditions to describe plausible future conditions; (b) to accommodate complexity, multiple layers of system-based uncertainties, a high level of decision stakes and a diversity of interested party perspectives.  Further, (c) post-normal science is unsettling for traditional scientists as well as for non-scientists who are accustomed to rely on reductionist explanations and simple causality.

He develops this approach to show how post-normal science enables "ecological thinking".  Ecological thinking is subversive in two ways: (a) it criticizes the consumption-driven, high throughput, environmentally damaging economy; and secondly (b) it transcends traditional, reductionist disciplines.  To an ecologist the world is one of contingent probabilities within mutually adapted, self-ordering systems; ecological ideas lack the crispness of definition, simplicity of process and precision of measurement that characterize much physical and chemical science (and popular discourse).  Understanding the world requires comprehension of non-linearities and uncertainties, complexity, self-organizing properties of systems and emergent properties. 

McMichael's reach extends to globalization and politics.  He shows how free trade can reduce labour and environmental controls and lead to the spread of disease.  Although he refers to land pressures, he ignores power relations that underlie systems of land tenure: willing workers are excluded from productive land, not to preserve it for ecological reasons, but to enable rack-renting of tenants and to create and maintain a class for subsistence-wage exploitation in industries supplying the affluent West.

He shows how the rich/poor gap both within and between countries is directly correlated with poor population health.  However, he does not consider whether poverty necessarily leads to poor health.  Tribal, fourth world people have the least money but, where traditional lifestyles survive, do not experience such poor health as third world people.

Although McMichael describes the huge ecological footprint of the food industry in Western economies – compared with, for example, China - he does not consider the immense institutional clout of that industry which militates against a wide change toward eating fresh, Pleistocene foods.  If we made that change, 90% of our supermarket aisles would be empty!

McMichael does, however, provide a stimulating and informative discussion of genetic modification of food which lays out where GM is equivalent to and different from natural processes; also the benefits and hazards of GM.  Using the precautionary principle, he comes down against GM - for the present.

As a member of the International Panel on Climate Change, McMichael is strong on the whether climate change is a reality and how climate change increases disease risk.  His conclusion is that “It will be reasonable from here on to regard each extreme weather event as containing at least some human-induced component”.  He illustrates the inertia in Earth's climate saying that if we halt the build-up of greenhouse gases by 2070, the seas will continue to warm and expand for another thousand years, rising 1.5m.  He adds that “As a culture medium, the world today is more conducive to the spread and circulation [of disease] than in the past”.

At this point I became impatient with the author's call for more research and modelling – is more needed?  We know we have to act; we know we have to change.  Will yet more research convince more people?  We can fine-tune our responses but McMichael is really telling us we need simple, significant measures now, not fine tuning over the decades to come.  Surely there is a danger that further research excuses procrastination while more bizarre and desperate “patches” are proposed and evaluated (e.g., the proposal earlier this year to dump iron into the Indian Ocean to absorb CO2).

The later parts of the book are interwoven with insights from evolutionary psychology: “The task of achieving sustainability does not easily fit into our usual frame of social and political decision-making.”  The changes required to achieve sustainability are immense.  However, we have a brain that can contemplate the future and plan to influence it.  Are these human intellectual powers a match for our “short-termist” heritage, manifest in selfish competitiveness?  One of McMichael’s big questions concerns the way the tension between two evolutionarily-determined human mental attributes is played out: given our long standing expertise at dealing with urgent crises, flight-or-fight, which has brought us to our present environmental predicament, can we use our more recently acquired abilities for long-term planning, sophisticated scientific reasoning and information technology to rescue us from the short-termism of flight-or-fight?

McMichael illustrates this problem most clearly with his model which shows how (a) unsophisticated low-income economies produce environmental pressures (smoke, garbage, sewage) which are amenable to solutions of the flight-or-fight kind; (b) later industrialization produces pressures that are less apparent but more sinister (air pollution, heavy metals, poor water quality); (c) late industrial and population pressures (biodiversity loss, global warming, fresh water depletion, CO2) impact on the entire biosphere and our flight-or-fight short-sightedness, which leads to treatments which manifest the “tragedy of the commons”, militate against effective global solutions.  More recent pressures are difficult both to understand and to comprehend, more expensive to treat and the time required for remediation extends beyond the timeframes humans have needed to consider in the past.

Perhaps falling victim to his own evolutionary psychology, McMichael is somewhat anthropocentric.  His account of biodiversity, for example, explains how biodiversity is required for human health - excellent so far as it goes.  But, given the book's ecological and evolutionary underpinnings, this begins to jar as the book progresses.  His best possible future appears to be one of a planet in which the domination by humankind can continue with sustainable good health and well-being for the species Homo sapiens.  His past is one of human kind living and evolving with an “eternal frontier”; his future is one where forests, wildernesses, the oceans, Antarctica, the atmosphere – all will need precision management so human populations can be sustained healthily.  For McMichael biodiversity is desired to sustain Homo sapiens’ domination of the planet.

Throughout, McMichael uses the useful concept of the ecological footprint.  But is this too benign a term?  Perhaps “monopolized destruction zone” or “planetary damage area” would be better.

What are the author's conclusions?  He does his best to end with optimistic words.  But his optimism requires that we resolve the many problems he has outlined.  This implies the coordination of people and governments, altruism, priority to decision making with very long-term time horizons, subjugation of short-termism and irrationality (which lead to conflict and huge opportunity costs of human and natural resources). 

And his practical solutions?  Education is an answer: from increased female literacy in third world societies through to an understanding of science, especially the natural causes of natural events including evolution and ecology.  This would mean confronting creationism among Christians, Muslims and indigenous peoples alike.  Perhaps a Biocentre, not "more research", to convince more people in our open democracy.

McMichael seems to shy away from confronting his predicted massive environmental catastrophe which is so complex and so far outside our historical experience that we are unlikely to act soon enough to avert it.  He struggles with the political reality that the criteria of efficiency, fairness and environmental sustainability each have to be met for any solution to be politically achievable before a disaster can be avoided.  He treads gingerly so as not to offend rather than address patterns of future planetary governance for sustainability.

While the science points to ecological crisis, politicians look to the next election and economists assume there is no future worth considering beyond a generation.  This leaves only the ecologists and spinners of speculative fiction with a time horizon stretching thousands of years into the future.

Having thus criticized the book, I should add that the author himself gave me the tools to make these criticisms in ways I would not have been able to manage before reading it.  Although the book lapses into anthropocentrism, other books are totally anthropocentric and it is rarely remarked upon. 

So, I'll end with five positives about the book.

Although the book was put together quickly, its logical sequencing, easy flow and cumulative explanations are remarkable.

McMichael makes his points with well-chosen illustrations.  One this reader found most striking was the difference in timescale between nature and the political decision-makers: we learn that Finland is slowly rising above sea level: it is actually bouncing back after being compressed by the polar icecap during the last ice age.  Another example: humans consume 40% of terrestrial photosynthetic product by way of plant foods, clearing land and forest, degrading land and building over land.  For a quick taste of his compact and entertaining style, read his account of Lyme disease on page 117.

His graphs, also, are brilliantly selected and very telling – powerful examples of a picture being worth a thousand words.  Each repays careful study.

 Each chapter ends with a 2-3 page summary and conclusion.  How did the author find time to be so well organized with such a short gestation time for the book?  Many of the references in the annotated bibliography of 36 pages are from 2000, even 2001.  

With its effective presentation of the pros and cons of topical, controversial issues, this is a resource book for activists.  I indulged myself by giving copies to my close relatives last Christmas!

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