# How much could a population of 100 million rise in 30 years? [closed]

How high could a population of 100 million people rise in 30 years, living on a terraformed planet with more or less limitless resources and advanced life-prolonging nanotech?

• I should perhaps note that there is some immigration from earth to Mars, but also vice-versa, so it more or less evens out. Commented Dec 12, 2022 at 13:07
• What is their age distribution?
– Mary
Commented Dec 12, 2022 at 13:18
• These are some questions which could severely limit the high-range of the number of people, can you add them to your question? Are the resources limitless as in "you don't even have to worry about building houses", or there's some efforts needed to expand using these resources? Is your planet at peace during these 30 years? Has fertility improved with nanotech medecine? Are there laws which actively prevent or encourage big families? And yes, age distribution : You can't grow much if your population is mostly kids ^^. Commented Dec 12, 2022 at 13:31
• The population could rise a lot, it could rise a little, it could decrease. For example, during the last few decades, the natural increase of the population of the USA, "living on a (perfectly) terraformed planet with more or less limitless resources and advanced life-prolonging tech", varied between 8 per thousand per year in 1990 to a lowly 0.7 per thousand per year in 2020. (And voting to close because LibreOffice Calc is free, and Google Sheets and Microsoft Excel on the Web are free to use.) Commented Dec 12, 2022 at 13:41
• -1 for not using trivially available world population data to get your first order approximation. VTC:Opinion-Based unless you can explain with adequate detail exactly what "limitless resources and advanced life-prolonging nanotech" means.
– JBH
Commented Dec 12, 2022 at 16:30

# Up to 2-3 billion

Assuming they were really into child birth, and half were female, they could have one baby every 9 months on average, use advanced healing to recover, and repeat. That means 40 generations of 50 million babies, which is 2 billion. When their children were 18 some could join in.

That said, not all women are likely to want to constantly be pregnant, so less births are likely. 2-3 billion is the likely cap.

• That seemed like a lot, so I did a bit 'o research. Women can have 15-30 children in their lifetimes assuming no magic recovery benefits. (I thought about telling my wife about this, then my sense of self preservation kicked in.) Assuming worst-case (all population is 16 years old, 90% women, and, um... "flexible" in terms of conception), that's 90M*30= 2.7B in the first generation. (*Continued*)
– JBH
Commented Dec 12, 2022 at 19:58
• ...However, I think a lifetime average number of 5 is closer to the truth and a female-to-male ratio closer to the world average of basically 50%, so 250M in 30 years with only one generation. Which is closer to the math Justin used 1950-1980.
– JBH
Commented Dec 12, 2022 at 20:00
• They have advanced life preserving tech, so I assume they can mitigate or stop the effects of age. Commented Dec 12, 2022 at 21:31
• Yeah... in that case your estimate could be considered very low.
– JBH
Commented Dec 12, 2022 at 22:21
• My estimate assumes they're basically always pregnant, so it shouldn't be too low. Commented Dec 12, 2022 at 22:33

The highest population rates registred are around 3% to 4%.

These numbers came from natural growth, without migration.

So, 3.5% per year in 30 years increase the population in 180%. The 100 million turn in 280 million.

This scenario looks like countries in first to second step of demographic transition: high fertility rate while child mortality is in the ground.

To force women of the planet give birth in a high rate you will need some despotic ruler, and also make their workforce unecessary.

Btw, since your planet have tons of nanotech to prolong life perhaps they have some kind of artifitial womb and some Star Wars's Kamino clone factory technology, or the baby factories of Brave New World. This would make the growth rate skyrocket to any number of you desire.

• They'd ask women if they wanted to have a lot of children, and pick their colonists out of those who said "Yes."
– Mary
Commented Dec 13, 2022 at 2:03

In 1950, the population of Earth was some 2.5 billion people. 30 years later, in 1980, it was around 4.5 billion. A period of comparatively limitless resources (compared to the population and abundance of resources, there was no lack of resources during this period), and it was during a period of exponentially decreased mortality and lengthening of the human life span.

• So... given a starting number of 100M, (4.5/2.5)*100M = 180 million in 30 years assuming "limitless resources and advanced life-prolonging nanotech" has no relevant impact?
– JBH
Commented Dec 12, 2022 at 19:49
• @ JBH I would posit this as a low ball park figure that has been proven to be doable. It was during this period that global food production was high enough to provide sufficient nutritious calories to the entire population, even though distribution was still a problem. Mineral resources, oil, and other energy resources were coming on line faster than the population could use them. All new manufacturing produced product that was in addition to current manufacturing. That is, new plants added to existing production, they did not replace it. So basically everything was in full expansion mode. Commented Dec 13, 2022 at 1:03
• I should also mention that the graph starts at 1.8% per year in 1950, peaks at 2.09% in 1968, and then declines back to 1.31% in 2000. so the peak growth was in the middle of this 30 year range. The baby boom was NOT due to more females giving birth, it was due to more children and females surviving birth. Followed, of course, by the pill. Commented Dec 13, 2022 at 1:38
• Those are great points! But I was gently reminding you that your post didn't actually answer the OP's question. No population estimate based on the OP's starting point. No percentage. It's just an observation of something that happened on Earth without much context.
– JBH
Commented Dec 13, 2022 at 18:43
• @JBH Truthfully, I am not sure what the OP question is, beyond "How much wood could a woodchuck chuck if a woodchuck could chuck wood?" Does the OP want a reasonable answer, or something that is way out there? Conjecturally, one female could have multiple pregnancies, even ten or more at a time, with 'unlimited resources'. Commented Dec 13, 2022 at 21:18

To prevent osteoporosis and have good enough recovery woman can give birth of 8 childrens every year - 6 month pregnacy and then early birth and child grow with nanotech help.

50 milion womans * 8 kids = 400 milion kids every year. And so on for 10 Years - 4 bilon kids. Why 10 Years? After 10 Years with nanotech help kids will be grow enough to have kids.

• 11 year have 2.4 bilion births, total population 6.5 bilion
• 12 - 4 bilion, TP - 10.5B
• 13 - 5.6 bilion, TP - 16.1B
• 14 - 7.2 bilion, TP - 23.3B
• 15 - 8.8 bilion, TP - 32.1B
• 16 - 10.4 bilion, TP - 42.5B
• 17 - 12 bilion, TP - 54.5B
• 18 - 13.6 bilion, TP - 68.1B
• 19 - 15.2 bilion, TP - 83.3B
• 20 - 16.8 bilon, TP 100.1B
• 21 - 26 bilion, TP 126.1B
• 22 - 42 bilion, TP 168.1B
• 23 - 64.4 bilion, TP 232.5B
• 24 - 93.2 bilion, TP 325.7B
• 25 - 128.4 bilion, TP 454.1B
• 26 - 170 bilion, TP 624.1B
• 27 - 218 bilion, TP 842.1B
• 28 - 272.4 bilion, TP 1113.5B
• 29 - 333.2 bilion, TP 1446.7B
• 30 - 400.4 bilion births, total population 1.8467 trilion peoples.

This is theoretical maximum with extend use nanomachines and drugs, without use of incubators, artifical utreus, oviary extraction and modification.

• 8 kids in one pregnacy/labor - maximum obtainable by use drugs and nanomachines. Commented Dec 12, 2022 at 15:18
• Fertility drugs? Multiple egg pregnancies? Why not a sex ratio of ten females to one male? Start with 90 million females. This assumes unlimited food availability. Four billion people is a LOT of food. And the female could not nurse that many children without supplementing the milk production. That is a lot of formula. Commented Dec 13, 2022 at 1:08
• Resources are limitless. Including artifical milk and robot nurses :) Can start even with all females and sperm bank(limitless resource - sperm). Can remove male embryo too to get numbers doubled, 800m girls per year , 8 bilion in 10 years, around 4 trilions in 30 Years Commented Dec 13, 2022 at 9:32

Depends on the demographics of your people and their motivation.

One factor is age distribution. You want to know what percentage of you population is of child-bearing age. This tends to be 18 at the lower end for cultural reasons, and 40-45 at the upper end for biological reasons. The lower end is unlikely to change much, but the higher one might depending on precisely how this life-prolonging tech works. In a typical rich nation today this might be around 25-30% of the population, but with luck or good planning the proportion of your colonists might be close to 100% - at least until the children start being born, that is.

Gender distribution also matters. In most cases you'd have a somewhat equal distribution of me and women, but the number of working wombs is a bottleneck here. The higher the proportion of your population are women, the more growth you can have (up until you start having difficulty getting enough sperm samples to go around, but you'd have to get lower than 1% men before that is a big problem). It's unlikely you'd get that distribution on your first wave of colonists, but with the limitless resources having artificial insemination and selecting for gender shouldn't be a problem so I'll assume all future generations are 99% women.

I've run a short python simulation under these numbers to see what we'd end up with. I'm assuming one birth per woman per year, partly because you need recovery time and partly because it makes calculations easier. After 30 years you have 650 million adults and 4.761 billion children, for a total of almost five and a half billion people. Hope those limitless resources include robot nannies.

If you instead assume (perhaps more realistically) one child every two years, numbers drop to 350 million adults and 1415250000 children, for a total of 1.77 billion people.

All this is just a theoretical maximum, assuming your colonists had as their highest motivation to maximize their population to the detriment of all other pursuits. If you find a hundred million people willing to to that, and convince their children to do the same, you'd get these numbers. In any other scenario, the numbers will be lower - likely a lot lower.

• "but the higher one might depending on precisely how this life-prolonging tech works." Menopause happens when the eggs run out. Commented Dec 12, 2022 at 15:08
• "I'm assuming one birth per woman per year, partly because you need recovery time". Gah!!!! Children need to be nursed and cared for. 18 months is the MINIMUM practical frequency; 24 months is much better. Commented Dec 12, 2022 at 15:10