Overshoot in a nutshell (Malthus was an optimist)

Overshoot in a nutshell (Malthus was an optimist)
David M. Delaney
>http://www.geocities.com/davidmdelaney/overshoot-in-a-nutshell.html

Thomas Robert Malthus, 1766-1834, famously
observed that human population, if unchecked,
would grow faster than its food supply.  He argued
that education in "moral restraint" might prevent
starvation from being the operative check on
population growth. It is implicit in his writings
that uncontrolled population growth, failing
"moral restraint", would stall near the natural
limits of the food supply. The population would
remain stable thereafter, with many people living
on the edge of starvation. But general
undernourishment of a stable population is not a
likely result of the current fantastic expansion
of the human population. Like many who have
commented on population growth, Malthus did not
understand overshoot. 

A species may greatly overshoot the long term
carrying capacity of its environment. (Its
population may become greatly larger than its
environment can sustain.) Overshoot becomes
possible when a species encounters a rich and
previously unexploited stock of resources that
promote its reproduction. 

The creation of stocks is due to ongoing
geological and biological activity.  A resource
stock forms when a part of the daily production of
a resource, a flow, accumulates slowly without
being exploited, perhaps over millions of years.
An enormous stock of a resource may accumulate
before it encounters a species that can exploit it
easily. After such an encounter, only predation
and disease limit reproduction of the species. 

Without significant predation or disease, and
while large amounts of the stock remain easily
available, the population of a species can grow to
a size hundreds of times that which can be
supported by the flows that created the stock. The
daily production of a resource is a mere trickle
compared to the flood available from a stored
accumulation. 

After a long period during which more of the stock
is consumed each day by the growing population
than was consumed on the preceding day, the stock
starts to exhaust. Deposits of the stock become
harder to find. Less can be obtained from the
stock each day than the day before. 

The time now remaining before complete exhaustion
of the stock may be much shorter than the time
that elapsed between encounter with the stock and
the first signs of approaching scarcity. Soon,
individuals begin to compete desperately for the
remaining stock.  To stay alive, they resort to
alternative resources of lower and lower quality.
By consuming the sources of flow, they destroy the
capacity of their environment to produce the
original flow. They also destroy the capacity of
their environment to produce flows of alternative
resources. Most of the population dies. 

Ecologists call the resulting collapse of the
population a crash, or die off. As a result of a
crash, the carrying capacity for the overshot
species, and for other species, becomes less than
if the overshot species had not stumbled onto the
stock in the first place. The population may
remain at a very low level for a shorter or longer
time--or forever. Because of the exponential
nature of population growth in the presence of
abundant resources, a single generation of the
population--the most numerous generation--
experiences abundance in its youth, starvation in
maturity, and premature death for most of its
members. "Crash" is an apt term--a population
crash can happen very quickly.. 

Malthus thought that population would approach a
sustainable limit, then hover there, with many
people living in poverty and misery. He did not
imagine overshoot and sudden collapse.  He did not
understand that technology was converting mineral
concentrations and much of the biosphere into
windfall stocks that would stimulate rapid
population growth. Now, two hundred years after
Malthus, humans have multiplied their numbers far
beyond any sustainable limit, and the end of the
windfall stocks is in sight. 

David M. Delaney, Ottawa, October 2003,
[EMAIL PROTECTED] 

Readings: 

1) David R. Klein.  The introduction, increase,
and crash of reindeer on St. Matthew Island. J.
Wildlife Management. 32: 350-367 (1968).  Text
on-line at http://dieoff.org/page80.htm. 

2) William R. Catton, Jr., Malthus: More relevant
than ever, August 1998.
http://www.npg.org/forum_series/catton_malthus.htm

3) Elwell, Frank W., 2001, Malthus' Social Theory,
Retrieved October 21, 2003,
http://www.faculty.rsu.edu/~felwell/Theorists/Malthus/Index.htm

4) Thomas Robert Malthus.  An essay on the
principle of population, a view of its past and
present effects on human happiness, Sixth
edition,1826.  London: John Murray, Albemarle
Street. (First edition 1798.) Complete text of the
sixth edition on-line at
http://www.econlib.org/library/Malthus/malPlong.html.

5) William R. Catton, Jr., Overshoot: The
ecological basis of revolutionary change,
University of Illinois Press, 1980. Available at
http://www.amazon.ca/exec/obidos/ASIN/0252009886/ 

6) David M. Delaney, Oil Depletion,  August 2002,
http://www.geocities.com/davidmdelaney/oil-depletion/oil-depletion.html