From: edstrom@hsc.ucalgary.ca (John Edstrom)
Newsgroups: sci.environment
Subject: Re: population load question
Date: 7 Sep 92 18:26:15 GMT
Organization: Neuroscience Division, U of Calgary School of Medicine, Calgary, Alberta, Canada

In article tobis@meteor.wisc.edu (Michael Tobis) writes:
>In article 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.
>
>It's an ill-defined question as it stands. Do you expect energy supplies
>to be limited or unlimited? Do you expect wild environments to be protected
>or destroyed? Do you expect people to be affluent, barely comfortable, or
>desperate? Do you believe that raw materials will be supplied from space
>or not? (I think the last point is moot, as in a steady state earth will
>not have much to offer extraterrestrially based people in trade unless
>the natural environment is preserved. However, others may argue.)
>

Yes, it is an ill-defined question.  But where do you start on a topic
like this?  As I said subsequently I am not looking for a singl,
simple answer like X billion.  Rather a range of populations given
reasonable goals of comfort where "comfort" covers issues of both
physical and mental well-being, the chance to live a creative and
rewarding life.  Acceptable levels of comfort will vary form culture
to culture so even then it will be difficult to agree on a baseline
level of affluence ot work with.  Obviously history and current events
show that people can survive circumstances none of us here would call
comfortable or desire to share for very long and I wouldn't consider
these sustainable levels.

For my purposes I would narrow the question down to how many can be
supported with technology now in place or currently conceivable
without seriously further affecting the wild or unused environments
that exist today?

>So let me rephrase the question: assume that the world lives well, with
>an affluence comparable to, say, Connecticut. Assume no major technological
>brieakthroughs or changes in life style, except that energy remains
>available at current prices. Assume that there is no net loss of wilderness
>area, and less than 10% loss of remaining species. WHAT IS THE LIMITING
>PROCESS on sustained (steady state) human population?
>

OK

>Any takers? What limits human population with land use, and
>technology fixed at current levels, and affluence at the high end of
>existing societies' conditions?
>
>I think it is land use. I do not know much about agriculture, and I
>understand there is some controversy about the sustainability of modern
>practices. However, given the vast areas around here dedicated to the prolific
>production of low-value animal feed, one suspects that the existing
>agricultural land could sustain at least ten times the existing population.
>

I tend to agree but can't really support this conclusion.  I do know
that around here farming is becoming more difficult as yields decrease
and prices don't rise more farms go out of business each year.  Nobody
is starving (here) but society is not willing to pay the price of
production here.  Either the food must be produced elsewhere to
support other farmers at a lower standard of living, population will
have to stay about where it is or people will have to pay more for
food and sacrifice some part of their own standard of living.
Additionaly, our food, clothing and shelter production methods are
adequate for us for now but are supported by industries of dubious
sustainability.

Perhaps alternative food sources can be developed but I don't see that
happening.  In developing countries agricultural production is usualy
increased at the expense of forrests or other wild lands since their
economy can't afford our technology or else their land and climate
isn't ammenable to that sort of development.  This strategy of
expansion will work for a while but can't go on forever since the
available space for expansion is limited.

There is ample food for people today but people do starve or are under
nourished.  The reasons are political and economical rather than
physical; many poor countries are net importers of food who owe huge
debts.  Somewhere human nature has to be taken into account.  To
what extent are developed countries with ample resources willing to
support other nations and cultures which cannot support themselves or
produce anything developed nations desire enough to trade food for?


Clearly the world can support 5 or 6 billion people but I have serious
doubts about how or for how long that can be done.

>Then the question of where to put them arises. If they all live a Connecticut
>lifestyle, their endless suburbs will take up a lot of room. Since we
>specified no loss of wildlands, a tradeoff occurs.
>

I don't see the physical storage of people a major problem.  But
Connecticut-style is probably too high a target to hope for and
expectations will have to be lower.

>mt


John Edsrom | edstrom @ elmer.hsc.ucalgary.ca
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