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From: tan@ihlpg.UUCP (Bill Tanenbaum)
Newsgroups: net.politics,net.sci
Subject: Re: Nuclear power: Petr Beckmann
Message-ID: <2226@ihlpg.UUCP>
Date: Fri, 18-Jul-86 10:26:46 EDT
Article-I.D.: ihlpg.2226
Posted: Fri Jul 18 10:26:46 1986
Date-Received: Sun, 20-Jul-86 04:11:37 EDT
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Organization: AT&T Bell Laboratories
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Xref: watmath net.politics:17481 net.sci:1299

>  [Richard Carnes, (I think quoting from Paul and Anne Ehrlich)]
>  Beckmann's chapter on coal contains a variety of confused assertions,
>  one of which is that "in the United States, for example, the
>  fertility rate has dropped below the `Zero Population Growth' level,
>  but its population is still expanding." ...
-----
Please, Richard, tell me why this assertion is "confused".  If the
fertility rate did drop below the ZPG rate (the rate that, if sustained,
would eventually lead to a stable population), the total population
would still continue to rise for years thereafter because of the initial
age distribution of the population.  This is even without taking into
account immigration into the U. S., which is significant.
	Beckmann's assertion about the fertility rate may be true
or false, but it is clear and consistent.  It looks like the
confusion is elsewhere.  (I think that, in fact, the U. S. fertility
rate did drop below the ZPG level sometime in the 1970's, but I am not
sure.)
-- 
Bill Tanenbaum - AT&T Bell Labs - Naperville IL  ihnp4!ihlpg!tan