Hypothectical population

Norgoth

Quite a weird one, but I know nothing of population growth and I need to work out an aproximate for an rpg settin some friends and I are working on.

So, if there were no disease or external causes of death (I.e only death from age and age related illness), and infinte space and resources, how many people would we have after 120 years, if we start with 4billion people 70% adults and a 50/50 gender split?

Not after an exact number, just a kinda rough estimate.

UltimaGecko

One of the major factors you're forgetting is birthrate, which has an immense impact on population growth. Even with a deathrate of zero you can't figure out population growth without a birthrate (it could be negative or also zero).


This site has a basic equation you can use if you want (with fairly simple math). And a few predictions:

(regarding fertility rates) A value of 2.06 will produce a stable population of about 11.5 billion.
A value 5% below that (1.96) will cause the population to drop back to close to its present value (6.1 billion) while
a value of only 5% above (2.17) would produce a population of over 20 billion and still rising.

The several agencies that try to predict future population seem to be moving closer to a consensus that:

the world population will continue to grow until after the middle of this century
reaching a peak of some 9 billion (up from today's 6.6 billion) and then
perhaps declining in the waning years of this century.

Think about the social aspects of the society you've created. So your society has eliminated most diseases and has evaded wars and famine. This implies a developed (or strictly controlled) society. A well-developed civilization with high technology would likely see lower birthrates (particularly an egaltarian society - one of the reasons birthrates used to be high was a lack of contraceptive use and the fact than wives were relegated to becoming housewives).

There are some theoretical perspectives that predict that human population will reach equilibrium (or begin to decline) at around 8 or 9 billion people. Industrialized countries tend to develop negative growth rates (much of Europe) simply because of low birthrates. People end up living longer, but they don't have children so you end up with fewer people overall.

Djeet

16.5 billion

A quick estimate using this simple population calculator, and the World fact book estimate for growth rate of 1.188% (est. 2008).

FYI, the world pop growth rate has been decreasing from a peak of 2.2% since the late 60's.

Teslan26

Djeet wrote: »

16.5 billion

A quick estimate using this simple population calculator, and the World fact book estimate for growth rate of 1.188% (est. 2008).

FYI, the world pop growth rate has been decreasing from a peak of 2.2% since the late 60's.

There is no food cap huh?