RE: Thinking out loud. . .

G'day,

> John, you've got a free hand to paint whatever you want
> (and I'm trying to think of a reasonable top end for that)
> because there simply isn't enough hard information on
> which to base a proper estimate.

Do you mean population modelling now with projections forward, or
information in the timeline to guide the projections? 
 
> Beth, I've no more evidence than that, but my gut
> reaction is that your figures for off-world populations
> are too low. If the powers have got themselves into a
> "population race" and started fooling around with birth
> labs then you want to consider maximums rather than
> growth rates.

The population growth rates I used set pretty quickly to levels close on
double that humans comfortably naturally maintain (though they would
equal
what you'd get everyone had big "farming" families and no infant
mortality).
One of the critical factors is how quickly the effective resource base
rises
to high levels. Am willing to change these factors, if people actually
have
a feeling for how advanced (quick/good) terraforming and "reproduction
science" are in the GZGverse, and about what time (late 2000s, early
2100s,
mid 2100s) they got that way.

> Extrapolations from current populations are all well
> and good, but have you factored in all the other bumps
> in the history? We don't know how destructive the Wars
> of the Americas were, or what loss of civilian life
> was entailed by the breakup of the EC.

I've made some allowance for this and I've added noise (which is a first
proxy for environment and political interactions). If anything its all
on
the high side as I haven't allowed for epidemic disease, restricted
movement
bottlenecks, natural disasters, major climate change working against
terraforming etc etc. I could factor all those in, even add in cohort
structure, sex ratio fluctuation, economic pressures, the effect of the
welfare system used, sublethal effects of altered environments on
reproductive biology and psychology. That would take a while though
(need
spare time to modify my code to include economics... eeek!) and
ultimately
most people would disagree anyway if they hard a long hard look at the
assumptions. You have to make some grand assumptions about how easy
migration is, how fast terraforming will occur, how habitable planets
will
be without help, how well humans will respond to "lots of free space and
the
need to fill it" if you want even halfway decent offworld populations by
the
2180s. As Noam as mentioned before its a lot easier (with a lot "safer"
assumptions) to get the numbers we all feel fit the GZGverse if it were
a
wee bit further into the future.

Cheers

Beth