From: jdr@starflight.Corp.Sun.COM (Jon Roland)
Newsgroups: sci.environment,talk.environment
Subject: Re: population load question
Date: 7 Sep 1992 23:38:07 GMT
Organization: Sun Microsystems, Inc.
Distribution: world
Reply-To: jdr@starflight.Corp.Sun.COM
NNTP-Posting-Host: starflight.corp.sun.com

In article 26181@acs.ucalgary.ca, edstrom@Elmer.hsc.ucalgary.ca (John Edstrom) writes:
>Its a broad question but what are the current estimates of the
>carrying capacity of the earth for humans?  Somebody told me it around
>2 billion.

In ecology the carrying capacity of an environment for a species is
typically defined for a long time period, thousands or millions of
years. If we apply that definition to the earth and humans we encounter
a problem in that humans build an artificial life support system for
themselves which presently draws on resources from the natural
ecosystem and geosystem, but which could in principle recycle all
materials on draw on the external environment only for a fairly small
amount of energy.

So the answer to your question depends on how that artificial life
support system, which might be called the technosystem or arcosystem,
is structured and operated.

If it continues to depend on the natural ecosystem and geosystem, then
it will deplete its resource base and collapse.

To put it in somewhat simplistic terms, but terms which do not in
general lead to the wrong ultimate conclusion, the carrying capacity of
the natural ecosystem and geosystem for humanity is not made any
greater by the application of technology. Nothing we have done beats
the number the natural ecosystem could support when man was a
hunter-gatherer, which yields a carrying capacity of somewhere between
4 and 100 million, worldwide. The latter figure is based on ocean
fishing.

Technology has so far been used not to increase the carrying capacity
of the Earth, but to sustain a population greater than that carrying
capacity by exploiting resources in a way that is reducing the carrying
capacity of the Earth.

I would estimate that, as a result of the application of technology,
the carrying capacity of the Earth is now about 20 percent of what it
was 100,000 years ago, or between about 1 and 20 million persons. I
expect another reduction in carrying capacity by about a factor of 5 in
the next 100 years.

Now, it is possible to apply technology in other ways. As I have
discussed in other postings, it is possible to use it to build starship
cities that are sealed, compact, and totally self-contained in
materials, using only a little energy. If people lived in such cities,
the Earth could support a great many of them. I have shown that a world
population of more than 1 trillion persons is feasible (although not
necessarily desirable for various reasons).

But they could not draw on the natural ecosystem or geosystem for any
resources.  Not even air or water. Only a little energy. The natural
ecosystem could then return to something like its original state before
Man came along.

If, however, we continue to live in a scattered, open system, then
civilization is unsustainable for more than a few more decades, and the
New Stone Age will not be as congenial as the last one was, nor will it
support nearly as many people.

---

jdr@starflight.corp.sun.com, starflt@uunet.uu.net
Jon Roland
Starflight Corporation, 1755 E Bayshore Rd #9A,
Redwood City, CA 94063-4142, 415/361-8141

Newsgroups: sci.environment