The growing global human population is and will be a massive challenge, in particular because of the strain it puts on natural ressources, which might in turn increase tensions between groups and potentially start conflicts when access to them is restricted. Humanity already has massively disrupted nutrient cycles, one of the consequences being global warming, and it is fair to suppose that a bigger population will further disrupt them. Interplanetary travel aimed at relocalising people away from the Earth is currently not expected to happen in the next century.

What are some ethical ways to significantly curb the human population growth in order to make a societal collapse less likely?

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    I doubt interplanetary travel will ever be feasible, but asides from that, it would open an even more difficult issue: how do you convince a sizable portion of humanity to get frozen for a few decades or centuries and leave mother earth for some other place, probably never to come back, and impose that choice on all their descendants? Migration across countries is already hard enough..
    – ggll
    Commented Oct 8, 2016 at 8:46
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    @ggll with current technology people can travel to Mars in six to eight months
    – THelper
    Commented Oct 8, 2016 at 16:47
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    @THelper I was referring to exoplanets that are already similar enough to Earth. Mars is kinda cold, dead, and too far from the sun. As for terraforming, I would have to ask how big a research and economic effort would it take - if possible at all - and what could we do on Earth if we invested the same resources here.
    – ggll
    Commented Oct 9, 2016 at 14:07
  • @THelper An astronaut has not landing on mars. No buying private citizens will be traveling there in 6-8 months.
    – paparazzo
    Commented Sep 22, 2018 at 23:51

9 Answers 9


It may sound contradictory, but according to scientist and statistician Hans Rosling, the main criterion to limit population growth is a reduction of the child mortality rate (see also his Ted Talk on the topic and the stats below).

Child mortality vs Population Growth Child mortality rate vs Country population growth rate (including migration) in 2011,
Each bubble is a country, bubble color indicates continent, bubble size relates to number of babies per woman

In the next decades most population growth is expected to be in developing countries where child mortality is high. This is especially the case in the sub-Saharan countries, where children are an insurance that there is someone to take care of you when you are old. Population growth rates in developed countries are much lower. In some countries like Germany, Russia and Japan it is even zero or negative (not counting recent immigration, see also wikipedia)

Lower child mortality can be achieved by better living conditions and better health services. This in turn can be achieved by better education and higher income. Also women who are better educated tend to marry later and get children at a higher age.

As Móż has also mentioned in his comment, another big influence on population growth can be government policy and incentives. China for example still has one of the lowest population growth rates in Asia (although I do not consider their former 1-child policy ethical).

More information about population growth can be found on the website of Hans Rosling's Gapminder.org organisation. The site also has a great interactive graphical statistics tool that shows the relationship between child mortality, babies born per woman, education, income, health services and many other factors, plus their changes since 1960.

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    I feel that this confuses correlation and causation; just because two numbers are correlated doesn't mean one causes the other. I suspect that better economic conditions in general are the cause for both the reduced child mortality and lower population growth. Commented Nov 18, 2016 at 10:54
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    @Carpetsmoker The problem is that we know that things like economic conditions, health, education and child mortality are related, but we do not know how this works exactly. So it's very difficult to determine what is cause and effect. Although I may have reversed the order in which I introduce it in my post, I do mean that we need economic improvements to reduce population growth.
    – THelper
    Commented Nov 18, 2016 at 11:05

Education, education, education. Also healthcare, and access to contraception.

I don't have any references available, I'm afraid, but repeatedly we have seen that when standards of education are improved in a community - especially education of women - birth rates go down.

When child mortality goes down, so does fertility, but that has little effect on population. However, when healthcare provision for the elderly improves, people feel less need to have many children as insurance.

And access to contraception - both physically and in terms of cultures making it acceptable to use - is obvious.

This all takes time. I don't think there's an ethical quick fix.

  • I accepted your answer, but I would love to see that supported by some references. Also, would anyone consider a form of legislative cap on number of children per couple to be ethical?
    – stragu
    Commented Oct 10, 2016 at 21:29
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    Iran is a useful case study as they have been through cycles of different government incentives over the last 50-odd years, leading to crazy population changes. en.wikipedia.org/wiki/Family_planning_in_Iran has an outline. It's less authoritarian than the Chinese approach so might be more acceptable to white countries (and less brutal that the policies applied to brown countries by white ones, so more acceptable to the brown ones). Ethics of population control is a tricky question since it directly involves balancing individual freedom with group freedom and species survival.
    – Móż
    Commented Oct 10, 2016 at 21:30
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    @stragu So would I! But I'm answering from memory as a time-strapped layperson, I'm afraid. If anybody can suggest appropriate references I'll be very glad to edit them in.
    – Flyto
    Commented Oct 10, 2016 at 21:33
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    Hans Rosling has given several interesting lectures on the topic. I can recommend this Ted talk where he shows that low child mortality has led to (more or less) stable population sizes in many countries. If you have more time I can recommend this 1-hour documentary about Hans Rosling's work
    – THelper
    Commented Oct 16, 2016 at 14:25

Increase broadcast coverage of television soap operas

From the abstract of a research paper titled "Soap Operas and Fertility: Evidence from Brazil" (pdf):

We estimate the effect of television on fertility in Brazil, where soap operas portray small families. We exploit differences in the timing of entry into different markets of Globo, the main novela producer. Women living in areas covered by Globo have significantly lower fertility. The effect is strongest for women of lower socioeconomic status and in the central and late phases of fertility, consistent with stopping behavior. The result does not appear to be driven by selection in Globo entry. We provide evidence that novelas, and not just television, affected individual choices, based on children's naming patterns and novela content.

A CNN article referencing the paper notes that:

Despite a religious culture that condemns modern family planning methods, birth rates in Brazil have decreased from 6.3 children per woman in 1963 to 2.3 in 2000. This drop is of a similar scale to that seen in China, where the government has played an extensive and controversial role in controlling population numbers.

So while spurious correlation is certainly a possibility, the fact that the decline in Brazil's fertility rate matches that of a country with an official policy effort devoted to reducing fertility rates, means that something significant is happening.

  • haha great, an upvote for the unexpected input, and for the relevant comment :)
    – stragu
    Commented Sep 11, 2018 at 5:57

It has already been stated that population growth decreases in countries that experience an increase in prosperity. It seems clear to me that this goes hand-in-hand with access to education for all members of the population. To encourage a decrease in number of births per woman in the developing countries, it would seem that the primary goal would be to keep girls out of early marriages, keeping them in the classroom instead. Easier said than done... I am by no means an expert in these issues, but from what I have read and heard it seems that girls are married off early for many reasons: one less mouth to feed; fulfill expectations; cement ties across families, etc. Unmarried women may also be regarded with suspicion or even hostility in many cultures.

Some of these aspects will probably lose influence with increasing internet access, simply because that broadens horizons. But the "rich" countries should carry on in their efforts to support education, help in family planning, etc. What we should also be doing is to practice true fair trade with developing countries...


Let me challenge the framing of the question: Your premise -- that population size per se strains natural resources -- is wrong.

What strains natural resources is overconsumption, i.e. consumption of natural resources that exceeds the world's biocapacity. Not the most populous but the richest countries in the world consume most natural resources.

enter image description here

Image source

The world has a biocapacity of 1.63 global hectares (gha) per person. Australia, for example, has an ecological footprint of 9.31 gha per person; the United States have an ecological footprint of 8.22 gha per person, and the United Kingdom has an ecological footprint of 7.94 gha per person. By contrast, Eritrea has 0.49, Rwanda has 0.87, and Ethiopia has 1.02, staying well below biocapacity despite their alleged "overpopulation".

Data Source

"Overpopulation" is an ideological red herring. The way in which our politico-economic systems (in the affluent "global north") produce wealth by exploiting natural resources is the actual issue. At their current ecological footprints, North America, Australia and Europe, rather than Africa and Asia, would actually have to drastically reduce their population size.


Fight to poverty. In fact this is the main goal of the UN agency for sustainable development. People living in poor countries use to have more children because they need somebody to take care of them when they'll be old and they rely on their family and cluster to help eachother. It's too easy to thingk that they don't do contraception because of their ignorance. Health care programmes and campaign helps but don't stop the problem how to fight poverty then? fair trade comes first! stop land grabbing stop pollution in developing countries


Even though I agree with most of the previous answers that education and economic equality would be the most efficient mechanics in the long-run, I feel like they do not directly answer your question as it seemed you wanted to have an instrumental answer in the style of IF-THEN.

Given the fact that a multidimensional problem such as over-population deserves a multi-dimensional answer, I feel hesitant to state my claim, but I wanted to share it anyway. I heard this thought on the podcast "Tangentially Speaking" by Christopher Ryan, namely "Increasing economic incentives for families with small amounts of children". As we have these types of stimuli already at present, I do not see why we could not do so in terms of population reduction. That addresses the element of ethical concern. Instead of getting money for children, you get money if you do not have any. Or tax breaks, alternatively.

Adopting a stance of systemic thinking again, however, we should consider the social and socio-economic incentives, that are present in several countries with high birth rates and population increases, such as heightened social standing, assumed higher levels of masculinity, secured future and retirement, and tribal social structures.

In my personal view, as with most frictions between environmental and social/economic interests, it boils down to habits and the innate human difficulty in breaking them...


This is obviously a difficult question. In fact it’s probably more difficult than you state because you do not indicate either a time frame or a target population number, both of which are necessary to frame a response. So a more complete question should be to ask.... How can we ethically get to X population by Y date. But then you have basked additional questions, “How few?” And “By when?”

So to be controversial and throw out some of my own thoughts (unsubstantiated due to time and space concerns) and to limit it to just the USA. For now I have to leave all “Whys?” aside. If you are curious google “Al Bartlett.” Here goes my modified but more complete question.

“How do we ethically get the USA population down to 150 million, as soon as possible? “

USA population is already declining except the decline is being off-set by immigration resulting in a net population increase. The reason for immigration is to support the idea we require an ever growing economy. That nothing can grow forever should be prima ca is obvious, yet we take it as gospel.

Step 2 is to realize we need to shrink, degrow, the economy. That will sting no doubt but is necessary. It can be partially off set by Artificial Intelligence IF we shift our taxation from employee base to production base.

Step 3 is to drastically limit immigration until we get below the target number.

Step 4 is to remove tax incentives for families, child deductions.

STEP 1 Is a massive public education program that describes the problem and the dangers should we not deal with it. Not unlike the anti-smoking and anti-alcohol campaigns. We need to start treating the public like mature adults and telling the truth.

Obviously I am leaving out great swaths of explanation, of necessity.


Although there are other ways nowadays, most births result from people having old-fashioned heterosexual intercourse. So a good way to decrease births is by stimulating people having less of that. This could be done in the following ways.

  • Like LShaver says in his answer, a good way is to provide for other engaging (nightly) entertainment like television, video-games, social media etc.

  • Make with image-editing software pornactrices and pornactors so attractive that real men and women look pale, ugly and unattractive in comparison.

  • Promote alternative (non-cis/non-heterosexual) gender identities and sexual orientations. Most/a lot resulting intercourse probably cannot lead to offspring.

  • Interacting with other humans in general and intercourse specifically can be joyous. However both can also be a source of potential deadly diseases, for example: AIDS, syphilis, corona. Spread this message!

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