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P C
  • P C
  • Miami, FL
  • United States

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On local ecological carrying capacities and ethics

An English clergyman named Thomas Malthus began writing essays on population in 1798 that later influenced many of the leading theorists on biology and ecology throughout the 19th century, including Charles Darwin. His most famous observation was "a population will continue to reproduce until it reaches the limits of its food supply."

Contrary to popular belief, population is NOT an exponential curve but a logistic one, where it eventually plateaus. The growth ceiling is called its carrying capacity. What is important to understand is that carrying capacity is not the sum total of a whole species but its limit in terms of local conditions. For example, a hectare of barren desert will feed fewer people than a hectare of dense farmland.

What further compounds this issue is that a local carrying capacity can change. Either nature or man can degrade it or improve it. I would conjecture that quality of life comes from the ability to keep a local population artificially lower its the carrying capacity so that there would be abundant food for all of its members.

Of course the ethical issues are as numerous as they are unpleasant to deal with, and I think it will be important to consider them. Here are a few:

1) Is it ethical to maintain a carrying capacity margin when neighbors are over-populated?
2) Is it ethical for over-populated regions to continue to grow their population when they can no longer feed themselves using local resources?
3) Is it ethical for over-populated regions to continue to send immigrants abroad (moral hazard) instead of trying to curb their population?
4) Is it ethical to move to a region that is already beyond its carrying capacity?
5) Is it ethical to engage in food trade to regions that are beyond their carrying capacity, which if trade routes collapse, which could consign a larger number of people to death?

Those are just few of the issues that can be raised. They're not going away and their importance will only increase this century.

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    Mar 11 2011: Question: how do you define "local" ? city ? state ? country ? region ?......
    Also, local is an arbitrary definition. any borders we define are most likely artificial anyway.
    • P C

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      Mar 11 2011: Political borders tend to be artificial and while they may roughly follow the contours of some ecosystems, they may cut others in half. While ecosystems can expand or contract, they tend to be constrained by geological features. For example, a river that flows quickly through steep terrain will probably produce a forest ecosystem vs one that flows more slowly in flat terrain that will probably produce grasslands or wetlands.
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        Mar 11 2011: still missing your interpretation of the term "local" in this context ;-)
        • P C

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          Mar 12 2011: I edited the TED talks list to include Eric Sanderson's talk on the Mannahatta Project. It provides a very good description of local ecosystems prior to the birth of cities.