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 also is 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 also is 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 the Earth can sustain. Hyper-consumption is given
consideration, too, in our abuse of the planet's resources.
The Ehrlichs 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 they can produce per acre, even with modern agronomy. Our planet can sustain only 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 usually is 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 already has
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 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
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 obviously is 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 The Population Bomb was written - 1968.
They also point out that an aging populace 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.
Richard Grossman practices obstetrics and gynecology in Durango. Reach him at firstname.lastname@example.org.
Â© Richard Grossman MD 2009