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Human Overpopulation, Poverty and Wildlife Extinction

By Dr. Robert E. Wrigley, Curator, Assiniboine Park Zoo, Winnipeg


Incessant human population growth is viewed as the leading cause of most of humanity’s scourges, such as poverty, war and starvation. While the wildlife-conservation movement is valiantly attempting to save the world’s remaining diversity of life, this effort is overwhelmed by the demands of mounting numbers of people. The obvious solution of birth control and family planning remains largely unknown or ignored -- a heritage of our ancient customs and religious beliefs.

Under the onslaught of an ever-increasing human population, it has become clear that humanity and the world’s environments and ecosystems are under serious threat. In their landmark books, Ehrlich and Ehrlich (1970) and Wilson (1992) demonstrated with overwhelming evidence that reducing the human population, and hence lessening demands on natural ecosystems, is the over-riding factor in the struggle to conserve the natural world. The current frenzy for exploiting natural resources and the escalating environmental degradation by the world community are in stark contrast to traditional beliefs of Aboriginal Peoples about Mother Earth. The spiritual inter-relatedness of earth, water, plants, animals and people demanded that great respect be shown to each part of this unity of life. They appreciated (as few people do today) that their very survival depended on caring for the natural world.

However, in past times and present, when people are in desperate need, they have little choice but to exploit Nature to the fullest of their abilities and technologies. Witness the rapid extinction of hundreds of species of large animals in North America, Europe, Madagascar, Australia and New Zealand, shortly after early people arrived and populated these land masses. The American Great Plains region formerly supported a fauna of large animals as rich as that found today in Africa. In the last 18,000 years, rapid climatic changes, ecosystem dislocations, and particularly over-hunting by early people, have left a decimated assemblage of large animals. Over 73% of large mammals and large birds in North America were wiped out (Martin and Klein 1984) before the arrival of Europeans, and the assault process has continued ever since -- witness the almost-complete elimination of the Tall-grass Prairie Community, which formerly stretched from Manitoba to Texas.

Overpopulation and conservation

Dedicated wildlife conservationists valiantly try to manage ecosystems and wildlife populations by conducting research projects, establishing large natural preserves, signing cooperative agreements with landowners, maintaining genetically diverse captive-breeding programs, developing education programs, and many other activities. But increasingly, all these positive efforts are being overwhelmed by the demands of an ever-growing human population. As a biologist and educator, I find it disheartening how infrequently the critical topic of birth control and family planning are stressed in society. We feel justified and safe in discussing human overpopulation and the resulting habitat loss and environmental degradation, but fear to tread further to the logical conclusion. True, family planning is a taboo subject fraught with public-relations risks, and it may challenge dearly held concepts about individual rights and family, however, it is ultimately the most important message our leaders and educational institutions can champion in saving the Earth’s ecosystems, their treasury of wondrous life forms, and for our very survival.

Perceiving the problem

It is a daunting task to be heard and understood by people who do not wish to be confronted with lifestyle restrictions, or with depressing facts about human poverty and the demise of wildlife and the environment. Pre-election platforms of political leaders often include promises to eliminate or alleviate the serious problem of child poverty and related tragedies of society. While no one questions the desperate need to find solutions, debate, funding and programs all focus on treating symptoms and seldom on the over-riding cause of the dilemma -- lack of family planning.

As long ago as 1798, a young British clergyman and economist Thomas Robert Malthus pointed out, in his “Essay on the Principle of Population,” that in favorable times food production increases in an arithmetic progression (2,3,4,5) while the human population (like all life forms) increases geometrically (2,4,8,16). Unfortunately, this compounding of humanity means that the population will always outstrip food supply and social services, leaving an ever-increasing segment of people without adequate resources on which to survive or to lead a decent quality of life.

Unknown to most people, species are tuned by natural processes, over immense periods of time, for parents to produce (on average) only a sufficient number of surviving offspring to replace themselves -- meaning two. Ancestral females of our species evolved the ability to have over a dozen children in their short lives -- a necessity under high levels of mortality. Around 20,000 years ago, there was an estimated world population of three million people, which likely had a negligible effect on their surroundings. To ensure tribal survival and integrity, customs and spiritual beliefs of our ancestors became ingrained with the concepts of large families and dominion over all other life.

The population explosion

The discovery of agriculture around 9,000 years ago changed everything, generating a giant leap in human birth rate and survival. Starvation lessened as an ever-looming factor in limiting population numbers, as it had likely operated effectively over several million years of human evolution. During the period of the Egyptian Pharaohs, the world’s population passed 100 million, 250 million at the time of Christ, 500 million by 1650, and 1 billion by 1850 (Ehrlich and Ehrlich 1970). With improving technology for food production and distribution, medical care, and social programs, numbers climbed to 2.5 billion in 1950 and 6 billion in 1999. Over 78 million people are currently added each year, and the population-doubling time continues to drop dramatically. I find it appalling that the human race has more than tripled (2 to 6.7 billion) in just my life time, and may quadruple before the end of my life. Obviously this rate of growth cannot continue indefinitely without severe repercussions, which are becoming more evident everyday (e.g., acidification and pollution of the oceans, global warming).

Check the state of the world's population at: US and World Population Clocks

By the year 2050 (within our children’s lifetime), it is anticipated that the burgeoning human population will level off between 11 and 15 billion, driving over 25% of the Earth’s remaining wildlife into extinction (Wilson 1992). The World Wildlife Fund believes one-third of all plant and animal species could be gone within 20 years. We are now losing wildlife at the rate of 75-100 species per day (Wilson 1992), squandering through ignorance and greed a 3.6-billion-year heritage of life on the planet. All these unique life forms are our kin; all of us traceable back over 3.6 billion years of evolutionary history to a common ancestral stock.

Humans now consume almost half the entire world’s photosynthetic capacity (Girardet 1999). In terms of biomass, there is an estimated 250 million tonnes of humanity and over one-half billion tonnes of our livestock (Cincotta and Engelman 2000). There are simply not enough room and resources for all us and wildlife to survive. We surpassed a sustainable level, in balance with Nature, many centuries ago. A recent study of global human numbers revealed that the existing population is already three times the planet’s carrying capacity to provide a reasonable lifestyle (Pimental 1994).

The human tragedy

Countless millions of children and adults die of starvation and neglect each year, and over half the world’s population is seriously malnourished and drinks contaminated water, in spite of massive humanitarian efforts by generous countries and charitable agencies. Some organizations (including certain religious and political groups) and leaders continue to encourage large families, in an outdated effort to increase membership, and maintain institutional power and influence; but at what cost? Few people appear to realize that all this human suffering, loss of wildlife, and environmental damage are needless, preventable through education and the practice of family planning in which couples produce no more than two children. Ancient customs and religious beliefs die hard.

As we begin to fathom the molecular basis of life and to search remote solar systems throughout the infinity of space, we still cannot escape our animal instincts and ancient codes. “Be fruitful, and multiply, and replenish the earth, and subdue it: and have dominion over the fish of the sea, and over the fowl of the air, and over every living thing that moveth upon the earth.”

These profound words from Genesis were written during a time when large families and mastery of local natural resources were absolutely essential to the survival of family and tribe. Instincts and customs of procreation and exploitation of Nature, which served our ancestors so well for several million years, are now tearing apart the very fabric of our world.

To maintain the present course is madness and irresponsible. Nature’s ecosystems and environments progressively curb plague species like ours through drastically increased rates of mortality -- escalating famine, terrible wars over contested lands and beliefs, clashes over disappearing resources, devastating outbreaks of old and new diseases, massive loss of life from each major natural event of weather and earth movement, debilitating stress, and poisoning from thousands of toxic and waste products (all negative-feedback loops in the jargon of biologists).

A matter of education

When will parents, educators, politicians, and clergy gain the knowledge, courage and dedication to speak out and support family planning? When will leaders and the public recognize that overpopulation is the root of so many community problems, and stifles our most-earnest efforts to solve them. When will women be granted their right to the reproductive control of their bodies and lives? While the birth rate in Canada and a few other developed countries has finally dropped below two young per couple, there are still many parents exceeding this critical limit, and often without the resources to care for them. Even if parents can afford to raise many children, each individual in a first-world country consumes and pollutes over 18 times that of a poor person in an under-developed country, thereby compounding the negative effects of overpopulation, and postponing the obvious solution.

As Malthus pointed out so long ago in harsh economic terms, ‘the surplus’ is destined for a life of poverty and misery. Society’s caring social programs, technology, and natural resources can never keep pace with the incessant demands arising from exponential human-population growth. The survival of life-support systems and wildlife, our civilization, and social justice depend ultimately on an ethic of family planning, communicated through the teaching of life skills at home, school and church, and supported by governments, concerned groups, industry and the media. With a right to reproduction must come knowledge and responsibility.

Conserving biodiversity

Wildlife species cannot be “saved” in the long term by protecting them solely in a cocoon of captivity in zoos or small reserves. Without the existence of sustainable wild populations -- free-ranging, interacting with their environment, and evolving -- each species will end up hopelessly inbred, a mere genetic shell of its ancestral stock, and eventually doomed to extinction. Humans and all other species were created within magnificently complex ecosystems, and without these nurturing wombs they will surely pass away before their time. Maintaining natural ecosystems is absolutely dependant on a massive reduction in the current human population, which cannot occur without family planning, which in turn relies on a strong educational message backed by resources.

What can we do?

We may stagger under a feeling of hopelessness as we become conscious to what is happening to our only home -- the Earth -- and to the terrible plight of so many people and wildlife. One often hears the question; “What can I do to help?” Many of us respond by attempting to live in moderation, purchasing wisely, donating to worthy causes, recycling materials, and by supporting conservation legislation. While these actions are positive steps, by far our most-significant individual contribution is to have two or fewer children. In the long term, this is the only factor that really counts.

Editor's Comment

I'd like to thank Dr. Wrigley for giving NatureNorth the opportunity to present his thoughts on this important issue. Too many of us (pun intended) take too much for granted, and we just plain "take too much" from nature and the planet. We can all make an effort to "live lighter" on Mother Earth and make more room for the rest of the planet's inhabitants.

-- Doug Collicutt, --



Cincotta, Richard P, and Robert Engelman. 2000. Nature’s Place; human population and the future of biological diversity. Population Action International, Washington DC. 80 pp.

Ehrlich, Paul R., and Anne H. 1970. Population, resources, environment -- issues in human ecology. 383 pp. W.H. Freeman and Company.

Girardet, Herbert, 1999. Workshop: Greening urban society. World Conservation 1:10.

Martin, Paul S., and Richard G. Klein, editors. 1984. Quaternary extinctions -- a prehistoric revolution. University of Arizona Press.

Pimentel, David. 1994. Quoted in; Mobilizing to combat global warming, by D. Hayes, 2000. World Watch, March/April 2000.

Wilson, Edward O. 1992. The diversity of life. W.W. Norton and Company, New York. 424 pp.

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