October 18, 2009

Dr. Paul Ehrlich
Department of Biology
Stanford University
450 Serra Mall
Stanford, CA 94305

Dear Dr. Ehrlich:
I am posting this letter on my website nobabies.net recommending your classic book (The Population Bomb, Dr. Paul R. Ehrlich, Vail-Ballou Press, Binghamton 1970).  Like Tamerlane I read, perhaps too carelessly, a mingled feeling with my own.  Like you I should like to see the long term survival of humanity at some acceptable level of comfort.  That requires a stable population.  You suggest one to two billion as being about right.  I note from your chart that one billion was about the population in 1850, when we may not quite yet have been addicted to fossil fuels, but we were cutting trees at an unsustainable rate, so I take a billion still to be somewhat high.  The most basic prudence mandates a level that could be sustained even if, horror of horrors, our high tech civilization should be lost. 

I also like your style.  Like me you acknowledge that things can get very bad.  You are comfortable with numbers.  And you think there is hope in public spirit.  Much of what you say seems very contemporary considering the many changes since you wrote your book.  Surely some of the reason that your direst predictions have not yet come true is that your warning was heeded. 

Currently people seem to place their faith in ever increasing technology to feed us and in the demographic transition, whereby urban populations have reduced fertility, to control our numbers.  The demographic transition seems to be the only thing that really does reduce fertility on the required scale, but its cause, although known, is almost unknown. 

Let me review where babies come from.  Three things are needed.  There must be couples.  There must be suitable air, food, shelter and so forth to keep them reasonably healthy.  And they must have sex.  All of these are necessary.  None is sufficient alone.  As it turns out, even the combination of all three are not adequate for long term survival, for having enough babies.

A rather small randomly mating population will have ample fertility.  If the number in the mating pool rises very much, fertility will fall below replacement levels.  That is proven on the enclosed ten minute DVD.  There is more evidence on the web site and more to come.

In other words, if and only if a man and woman marry and are closely enough related, but not too closely, they will have enough babies for the community to survive.  (The effect accumulates over generations.)  This must be understood before any rational approach to a stable population is possible. 

In a sense we are looking at instability from opposite sides.  You see the dire consequences of too many babies.  While I thoroughly agree, I also see the dire consequences of no babies at all.  When I look at the crude fertility rate of Mexico over the past eight years, it appears that the last Mexican woman who will ever have children will be born in about 11 years.  The fall is almost a straight line.  Looking at what German statistics I have, it looks like the last German woman who will ever have babies was born about 10 years ago.  In other developed countries, immigrants are counted as members of the population, so the numbers are less clean, but the entire developed world has fertility below replacement and it has remained there for a generation or more.  I suspect Germany is a reasonably good surrogate for the developed world.

The fertility being lowest in rich countries, one is tempted to observe that those people are the most expensive to feed and they represent a disproportionate drain on resources anyway.  But for the foreseeable future, maintaining the green revolution will require even more scientific and technological advances.  Those are most likely to come from the countries we are going to lose first, leaving behind a world of maybe seven billion on a planet that can support without high tech only a couple of billion under the best of circumstances, and circumstances will not be the best.  We might conceivably transfer our science and education to the least developed countries over a couple of generations, but so far the developed world appears to be a brain drain on the less and least developed. 

I am sure people listen to you and think, “You don’t like babies,” even though they may not say it to you.  And if anybody listens to me, I am sure some are thinking, “But there are too many babies in the world anyway,” even though they do not say it to me.  So in their minds they are playing the two problems off against each other. 

I am thinking myself that we should make common cause.  You have a sensitivity to environmental and practical limitations and are eloquent and forceful in your arguments.  I know what has happened to the babies in the rich world.  Actually, I have given you enough so that you don’t really need me any longer.  I notice on page 104 that you had written a letter to the USDA and actually got a reply that attempted to address your challenges.  I just about never get that much of a response from anybody.  So my chances, despite every effort I am able to make, of getting this concept into the public consciousness are very small. 

If things were to go by the usual pattern, I would not even get an answer from you addressing the issue.  If you do, I shall be delighted to help you in any way I can in getting this terribly important matter understood adequately and getting public debate started.  Nothing could be more important that stabilizing the population.  Apathy is useless.


M. Linton Herbert MD

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