Johnny1a wrote:
Population growth is a _good_ thing in the long term, survival-wise,
population decrease is a sign of a declining society and even stablity
is death in the long haul. Survival _requires_ growth and expansion,
because sooner or later something unlikely in the short term but near-
certain the long will do bad things to any given habitat.


Population growth on Easter Island wasn't a good thing, nor in many
areas where it led to soil depletion via overfarming to support a
burgeoning population throughout human history.
I did the math on this once, there were around 8.5 city blocks per
person for everyone on the face of the planet, and that included using
the seas as surface area also:


that this is the total surface area of the Earth, not just the land
masses:
"Here's another way of looking at it; the total world population is
around 6,490,115,551 as of this morning:
http://www.census.gov/main/www/popclock.html
The total surface area of the earth is 196,940,400 square miles:
http://pages.prodigy.net/jhonig/bignum/qland2.html
So if we take divide that population by that surface area we end up with
an average of around 33 people per square mile of the Earth's surface.
Now there are a total of 27,878,400 square feet in a mile, so we end up
with one person for around every 844,800 square feet of the Earth's
surface, or to put it another way, around one person for every 8.5 city
blocks, which although they vary wildly in size tend to cover around
100,000 square feet total on average (assuming they are a tad over 300
feet on a side)

Take the oceans out of that equation and you are starting to get near
the point where we have only enough area to support our total population
via farming, particularly when areas unsuitable for farming (mountains,
forests, deserts) are taken into the equation.
When you move out into space in any large numbers, the amount of area
required for food production starts to look pretty daunting,
particularly if you want a varied diet including things like meat and
cheese, although I imagine a lot of things could be made in a synthetic
form.

Pat