Two friends recently sent me two magazine articles on human population. At first they appear to be conflicting, but, amazingly, I agree with parts of both. Both comment on recent demographic changes—how the age structure of societies has altered in recent times. I’ll summarize the articles, and then put them in context.
David Goldman wrote “Demographics and Depression” for “First Things”. He is also an associate editor of this conservative Catholic magazine. Goldman describes the problems that all developed countries are facing when fewer babies are born and as people age. He blames our current economic collapse on the recent collapse of the housing market. That, in turn, he blames on the fact that people are having smaller families now.
“… it is fair” Goldman writes, “to point out that wealth depends ultimately on the natural order of human life. Failing to rear a new generation in sufficient numbers to replace the present one violates that order….”
Paul Ehrlich is one of my heroes. He has been a population activist since I was in medical school, when he wrote the classic book The Population Bomb. Paul is also an amazing scientist. A lepidopterist, he is a biologist specializing in moths and butterflies.
“Is the Population Bomb Finally Exploding?” by Paul and his wife Anne, appeared in “Free Enquiry.” The answer to the title’s question, simply, is yes—we are using more resources than Earth can sustain. Hyperconsumption is given consideration, too, in our abuse of the planet’s resources.
They list a litany of current and future tragedies caused by population and consumption. This inventory of predicaments includes shrinking grain production, decreasing supplies of fresh water, petroleum, ocean fish and tillable land, melting glaciers, increasing greenhouse gases, pollution, and rapid extinction of species.
The growth phase of human population has been happy. From an economic standpoint, business thrives and people get rich. Historically, it was an era of discovering new lands, including North America.
Along with the new frontiers, more productive crops evolved that yielded higher food value and allowed higher population density. Before discovery of the New World, Europeans relied heavily on grains such as wheat. Their population soared when they started growing potatoes and corn. One fifth of the increase of their population during the last three centuries can be attributed to potatoes alone!
But the growth phase cannot last forever. All crops have a limit to the number of calories that they can produce per acre, even with modern agronomy. Our planet can only sustain a finite number of people.
Every living system has a limit to the number of individuals it can support, called the “carrying capacity.” This term is usually applied to animals in a field, but also pertains to humans. One definition is: “the maximum number of organisms that can use a given area of habitat without degrading the habitat and without causing stresses that result in the population being reduced.” Our current human population and consumption of natural resources has already exceeded the planet’s carrying capacity by a third!
Human population growth is a bit like adult human growth. Most of us gain about a pound a year—but some put on much more fat. We all know that obesity is bad for us, and can kill us. But it is so much more fun to gain weight than to lose it! Well, our population has grown to an unhealthy level and it is time to go on a diet. We need fewer people and less consumption.
Goldman seems very homocentric. He does not consider other species, which we are killing off at terrifying rates. Nor does he consider the non-human world, which we subdue more each day—so that the future of even human life is endangered. And he does not look at the long history of humans, who had a relatively stable, sustainable population for all but the last three centuries.
The Ehrlich article is obviously more to my liking. Paul and Anne have a broader view of the world than the current housing crunch and economic disaster. In addition, they give hope for the future. They note that the human population growth rate has slowed markedly from the year that The Population Bomb was written—1968. They also point out that an aging populace can still thrive, with adjustments in our thinking.
We have enjoyed an era of growth. Unfortunately it is time to realize that this cannot go on forever and that we must act accordingly.
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