Population Size/​Growth & Reproductive Choice: Highly effective, synergetic & neglected

[RafaelF]

In this post I want to make several points regarding a cause area that is neglected both by the mainstream and by EA. It is neglected by EA even though this cause even though it is:

• highly effective

• cheap to effect change

• synergistic with several other EA focus cause areas, including climate change, bio risks, poverty and animal suffering

• neglected by the mainstream

• big funding gap

The cause area I am talking about is population growth (also known, depending on your perspective, as reproductive choice, family planning, or population size reduction). Without further ado...

Synergistic & Network Effects

Both high population size (status quo) and population growth (positive delta) negatively effect several cause areas commonly viewed as aligned with EA reasoning:

• Climate change

• Poverty, education and economic development

• Bio risks

• Individual suffering

In this section, I want to quickly go into how population growth slowdown or population size reduction could have severe positive effects on the aforementioned cause areas.

Climate change /​ Global warming

Climate change /​ global warming is, as we all know, primarily driven by human activity and consumption. It is a function of (number of consumers) * (consumption level). Both variables are currently quickly rising. In fact, population growth has cancelled out 75% of all improvements in energy and emission efficiency achieved in the last three decades [1]. Project Drawdown has identified population growth reduction or population reduction—anything that brings down human population numbers—as the second-most effective means of reducing global warming. However, likely for political reason, this action point is hidden within Project Drawdown’s greater policy recommendations for “Girls’ education” and “Family planning” [2]. When resolving the arbitrary split between these two categories, family planning/​access to contraceptives and girls’ education/​women empowerment becomes the second-most effective policy action [3]:

On an individual level, having one child less is the most effective action an individual can take, as emissions scale with the number of individuals on the planet [3]:

This is immediately obvious, as no action increases your carbon emissions more than adding one more individual which will emit basically as much as you.

For more information, have a look at [3].

Poverty, Stunted Economic Development & Education

One lesser known fact about population growth is that the causal relationship is very likely—at least in our current times—not one way or potentially even reversed. Previously, it was believed that people have more children when they are poorer; however, at the moment, it seems that more children contribute more strongly to poverty and cultural reasons play a bigger role in the number of children in at least some countries [15]. Some studies have found that in some cultures a better economic situation does not lead to less, but to more children because they are a status symbol; in almost all countries, on average, though, desired fertility is lower than actual fertility [16]. That means that, even in countries where people want to have a high number of children, they still have an unmet need for contraception.

In several countries, population growth leads to more poverty rather than less. The reasons are the following:

• Most countries with high population growth have economies mostly based on unskilled and/​or manual labor with too few education opportunities. This increases competition for unskilled employment opportunities and depresses wages.

• Governments cannot afford to build infrastructure that keeps up with exponential population growth, as their revenue and budgets do not grow accordingly (but, rather, stay quite the same). Poverty depletes government budgets through growing social spending, with is lacking in infrastructure or education. This effect creates a vicious cycle: Population growth increases pressure on government budgets, which leads to less education, which exarcabates poverty and population growth. In general, population growth “eats” all economic development.

• Poverty also strikes at the family and individual level, as effective wages decrease, competition for employment increases, education opportunities are scarce. This arguably leads to suffering and a reduction in personal satisfaction.

• The number of dependents increases, increasing financial strain on families.

• Demographic risks: At one point, there will be a reversal in the demographic pyramid. The earlier that reversal is achieved, the less dire the consequences when it happens.

• Political risks: Some researchers argue that the big migratory movement from Africa and the Middle East to Europe is a consequence of limited opportunities for too many people in source countries.

For some sources on how population growth exarcerbates poverty and destroys government budgets, thus stunting economic development and education, see e.g. [4], [5] and [11].

Bio risks & zoonoses

Population growth and consumption directly lead to habitat loss. Several studies show that encroachment is a main driver in zoonoses like CoViD-19. The Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES) has recently released a report that clearly states that population growth, animal habitat destruction, wet markets and encroachment are increasing the risks for pandemic zoonoses drastically [6].

Individual suffering & Extent of the problem

This is the one point I couldn’t find proper studies for. I argue, however, that women—who are 50% of the global population—suffer greatly when they are forced to bear children against their will. The extent of this is huge. Stealing from Wikipedia, but well cited [7, 8]:

“The global rate of unintended pregnancy was estimated at 44% of all pregnancies between 2010 and 2014, corresponding to approximately 62 unintended pregnancies per 1000 women between the ages of 15–44 years old. While unintended pregnancy rates have been slowly downtrending in most areas of the world, different geographic regions have different estimated unintended pregnancy rates. Rates tend to be higher in low-income regions in Latin America and Africa, estimated at 96 and 89 unintended pregnancies per 1000 women, respectively, and lower in higher income regions such as North American and Europe, estimated at 47 and 41 unintended pregnancies per 1000 women, respectively.”

Additionally, cultural norms prevent (protected) sex for pre-marriage in many high-fertility countries [9]:

“Young, sexually active, never-married women face much greater difficulties in obtaining contraceptives than do married women, in large part because of the stigma attached to sexual activity before marriage. Some 44% of never-married women in need of contraception (most of whom are young) are not using modern methods, compared with 24% of married women in need.”

At present, it is estimated that there are at least 240 million women that want to have access to contraceptives but don’t. The number of women who given a choice would also desire access to contraceptives, would likely be much larger.

Animal suffering

The amount of animal product consumers directly influences the number of animals in farming, most of which is factory farming nowadays. The number of consumers who consume animal products has exploded in the last few decades [17], due to dietary patterns changing away from mostly plant-based diets to diets including more animal products [18].

In other words: The population size pretty much directly determines the amount of animal suffering in farming.

UN Sustainable Development Goals

Almost all UN SDGs are directly affected by human population size [12]. For the sake of brevity I won’t go into details here because for most SDGs this connection is pretty obvious. If you want, though, I can go into details in a response.

Costs to Effect Change & Effectiveness

Preventing unintended pregnancy for a full year is cheap, at about 10 USD per woman [9]. Assuming that a woman wants to stop having kids, and assuming that she has 25 more productive years, and lastly assuming 2.5 ton of CO2 p.a. per person (this is the number for egypt—I would expect per-capita CO2 emissions to rise in the future), 250 USD to eliminate a lifetime of CO2 (180 tonnes at current levels in Egypt). That, it turn, means about 1.38 USD per permanently eliminated/​prevent ton of CO2, which is extremely cheap. It is almost as cheap as Cool Earth’s (very optimistic!) estimates and much cheaper than any technological solutions known to us. Likely, it is even cheaper than 1.38 USD because of the effect of preventing the consumption and emissions of any offspring (and offspring’s offspring, and so forth) of the child that will thus never come into existence. Assuming, furthermore, that the same 10 USD p.a. per user do not only prevent one but two children, cost-effectiveness increases even further. Assuming two children permanently not being born and that offspring’s offspring is also prevented, this intervention would easily be the most effective for climate change known to EA; though harder to prove, I think this might even hold if only one additional child is prevented per woman.

In general, 10 USD per user per year can greatly improve the lives of those who don’t want more children, can set overburdened economies back on track and decrease strain on struggling families. And you get all these network effects from focusing on just a few interventions that target the upstream problem of women’s rights/​opportunities/​education and reproductive rights.

I would like to paint the following picture in your mind: A dependency graph. If you draw a dependency graph for many cause areas, women’s rights/​education/​empowerment and reproductive rights/​familiy planning are at the top and influence many, many other cause areas. Thus, by targeting an upstream cause area, we will have positive effects on many downstream cause areas. This makes it an efficient and effective intervention.

As you can see above, preventing CO2 emissions is already pretty cheap by following a family planning/​planned parenthood approach. If we manage to do a calculation of all positive effects, I am pretty sure family planning/​planned parenthood/​women’s education & rights would come out as one of the most cost-effective “interdisciplinay effects” interventions possible.

Cause Area Neglectedness & Funding Gap

I guess I don’t need to explain this one. The topic is completely neglected in the mainstream. What is sad, in my opinion though, is that it is completely neglected by EA as well. It literally ticks all the EA boxes: Being neglected by the mainstream, being highly effective (as a cause area of its own and due to positive cross-effects on EA focus areas) and being cheap to have signficant effects on several cause areas at once.

The UN Population Fund alone currently has a funding gap of about 250 Million USD. Reliable total funding gap numbers are hard to come by, the most reliable numbers I have found are between 1 billion USD p.a. and 8 billion USD p.a.; many sources such as this one [13] place the funding gap at around 3.6 billion USD annually.

Charities

I will just name a few charities in this area I know and donate to—in no particular order:

• Population Matters

• Population Services International

• Population Media Center

• Marie Stopes

• Deutsche Stiftung Weltbevölkerung

Wrapping it up

This post is only a very superficial overview of why EA should place much greater focus on anything that reduces population growth and/​or size (in an ethical way, of course). Ethical and consent-based ways to reduce population growth and/​or size are cheap, cost-efficient, have signficant positive effects on several other EA focus areas, and are neglected by the mainstream. I personally am very convinced that this cause area and different interventions in it are highly aligned with EA views. With this post I want to raise a bigger discussion and awareness of this cause area in the broader community and give it the recognition it should receive from EAs. I would like to see this cause area researched better by GiveWell and other EA-aligned groups, especially those doing cause prioritization.

References

[1]: Aalok Ranjan Chaurasia: “Population effects of increase in world energy use and CO2 emissions: 1990-2019”
[2]: Jane O’Sullivan for Overpopulation Project: “Drawdown: a review of the Review”
[3]: Population Matters on Climate Change
[4]: Steven W. Sinding: “Population, poverty and economic development”
[5]: Klasen, Stephan; Lawson, David (2007) : The impact of population growthon economic growth and poverty reduction in Uganda
[6]: IPBES Workshop Report on Biodiversity and Pandemics
[7]: Wikipedia: Unintended Pregnancy
[8]: Bearak, Popinchalk, Alkema, Sedgh: “Global, regional, and subregional trends in unintended pregnancy and its outcomes from 1990 to 2014: estimates from a Bayesian hierarchical model”
[9]: Guttmacher Institute/​UNFPA: “Costs and Benefits of Investing in Contraceptive Services in the Developing World”
[10]: Kenneth Gillingham: “Carbon Calculus”
[11]: Mona Khalifa, Julie DaVanzo, David M. Adamson: “Population Growth in Egypt—A Continuing Policy Challenge”, RAND Corporation
[12]: UN Sustainable Devlopment Goals (SDGs)
[13]: “What Would It Cost to Meet Family Planning Needs in Developing Countries?”
[14]: John Bongaarts and John Casterline: “Fertility Transition: Is sub-Saharan Africa Different?”
[15]: Muhoza, Broekhuis, Hooimeijer: “Variations in Desired Family Size and Excess Fertility in East Africa”
[16]: Anne Bakilana and Rifat Hasan: “The complex factors involved in family fertility decisions”, World Bank Blogs
[17]: Our World in Data: Meat and dairy production
[18]: UN Food and Agriculture Organization (UNFAO): “Global and regional food consumption patterns and trends”

[John G. Halstead]

Thanks for writing this. I disagree that EAs should prioritise this cause area and I disagree with the analysis of the cause-specific arguments.

Firstly, I think it is good for happy people to come into existence, but this is ignored here.

On climate change, I generally think Drawdown is not a reliable source. The only place where births per woman are not close to 2 is sub-saharan Africa. Thus, the only place where family planning could reduce emissions is sub-saharan Africa, which is currently a tiny fraction of emissions. Working on low carbon technology by contrast can affect global emissions, and policy change in the US or EU can affect a much larger fraction of emissions.

I’m also strongly sceptical of the cost to prevent a pregnancy provided. $10 seems far too low. This seems similar to the kind of mainstream charity cost to save a life estimate that EAs have criticised for a while

[Ben Millwood🔸]

The only place where births per woman are not close to 2 is sub-saharan Africa. Thus, the only place where family planning could reduce emissions is sub-saharan Africa, which is currently a tiny fraction of emissions.

This is not literally true: family planning can reduce emissions in the developed world if the desired births per woman is even lower than the actual births per woman. But I don’t dispute the substance of the argument: it seems relatively difficult to claim that there’s a big unmet need for contraceptives elsewhere, and that should determine what estimates we use for emissions.

[Larks]

At least in the US women have been having fewer children than they want for many decades:

As a result, the gap between the number of children that women say they want to have (2.7) and the number of children they will probably actually have (1.8) has risen to the highest level in 40 years.

[Daniel_Eth]

Another point—more humans means more people to find solutions. So we have more people polluting the planet, but also more people working on clean energy solutions that will get us off fossil fuels.

[RafaelF]

Do you think that this has a net-positive balance, i.e. do you think that more people generally contribute, on average, more to solutions or more to pollution, CO2 emissions, animal suffering, etc.?

[Daniel_Eth]

I’m honestly not certain—I don’t believe we’ll solve any of these problems by a degrowth approach, so the only way to get a real solution is via innovation and/​or adoption of solutions. More people would help with that, but also would contribute more to the problem in the meantime. I think whether the sign was positive or negative might depend on the specifics (eg, I think if environmentalists have fewer kids because of a fear of overpopulation, that will generally be bad for the environment).

[RafaelF]

As you might have seen, Project Drawdown is not my primary source. I came to my conclusions from various sources, which mostly agree on the general idea: Reducing population size and/​or growth is a very effective means for positive change in several other cause areas. This does not rely on one single source.

Regarding the cost for providing contraceptives, the costs of less than 10 USD p.a. per user are well established. See, for example, this publication by the UN Population Fund (UNFPA):

Average direct costs to provide one year of method use are highest for hormonal methods—implants ($7.75), injectables ($8.61) and pills ($7.26)—with the commodities themselves accounting for most of the cost (Table 3, page 12). Permanent male and female sterilization and the IUD have the lowest annual costs when total method costs are divided by the average number of years users are covered by these methods. Annual average direct costs for male condoms fall between these method groups, at $4.17 per year.

As BenMillwood already mentioned, emissions reduction can be achieved almost anywhere, because in most countries actual fertility is higher than desired fertility. This gap varies from country to country but exists almost anywhere. At a current global birth rate of more than 130 million births annually, out of which more than 40% are unintended, I see big potential.

Which analysis of the beneficial effects on other cause areas do you disagree with, and why? I’d be happy to provide more sources and/​or explanations, but for that I’d need to know which ones exactly you found to be weak.

I’d also like to point out that per-capita CO2 emissions in many countries will be rising in the next few decades and that, according to at least one peer-reviewed paper I cited, most of our efficiency gains that would reduce emissions were undone by population growth.

[Larks]

I think this post is very mistaken.

There are some relatively minor issues. For example, the methodology used in Wynes & Nicholas (from Murtaugh & Schlax) to compare the climate change impacts of less driving with fewer children involves comparing temporary changes in automobile usage with an infinite duration population change, which seems like an obviously unfair comparison. Indeed, there is nothing in this methodology to prevent each individual child from having an infinite impact on climate change… except that the authors arbitrarily prevented this, probably realising it would show their results were absurd:

Some lineages persist indefinitely, in which case a pre-specified time limit terminates the simulation.

Similarly, you suggest that ‘unintended’ pregnancy means women are ‘forced to bear children against their will’. But this is incorrect. Many couples are not planning on conceiving but are nonetheless happy to be blessed with a child! Indeed, the Wikipedia article you quote makes this clear in the sentence immediately preceding your quote:

Terming a pregnancy “unintended” does not indicate whether or not a pregnancy is welcomed

More importantly, when doing cost-benefit analysis, it is important to analyse both the costs and the benefits. Here, you analyse in detail the costs of population growth—but with no mention at all of the benefits. Yet these benefits are very large:

• Population growth means more people will get to experience the joys of living. They will get to learn, play, make meaningful relationships and fall in love. They can play with lego, read books and enjoy the sunset. I think for most people life is good, so this is a huge deal!

• Children benefit existing generations who will enjoy being parents and grandparents. Anecdotally grandchildren seem to be one of the primary joys in most grandparents’ lives, and people generally rank their relationship with their children as one of the most meaningful parts of their life.

• Larger populations allow more specialisation and division of labour, which are key components of economic growth, as well as other economies of scale.

• Larger populations mean more artists and scientists, whose inventions and discoveries can then be enjoyed by everyone at essentially zero marginal cost.

• More prosaically, we need future generations to keep social security and other retirement systems working.

Given that the post has ignored all positives of population growth, it is unsurprising it found that population growth to be negative. Indeed, according to the analysis here—which treats people as entirely a burden, with no benefits whatsoever, whether to themselves or others—encouraging the deaths of existing people, by spreading the pandemic for example, could also appear a very positive policy!

[RafaelF]

Fair points that I ignored the benefits of larger populations—you are completely right. I didn’t do this, though, for the sake of brevity and because that is not something people need to be convinced of, generally.

If you claim, however, that there are large benefits to larger populations, then why bother with access to contraceptives in the first place—if people feel blessed with more children? Also, does that mean that societies should become arbitrarily large? It would almost follow from the points you raised.

Also, if you think that generally the benefits of children outweigh their costs, it should be common policy to have as many as parents want. This, however, cannot work on a finite planet with finite resources if parents would want, for example, to have at least 4 kids.

My personal view on this is that, as long as human population is below maximum carrying capacity (whatever that capacity may be—there are big arguments about it as you’re probably aware), an additional human probably has a “net-positive” effect on total happiness/​suffering. Once, however, the total population surpasses a certain point (which may be way above long-term carrying capacity—because initially, negative effects will still be buffered by resource surplus). Once however you surpass that point, additional lives will have a net-negative effect on total happiness/​suffering.

Take, for example, the following thought experiment. You have a population of 20 and a good which they need. The good has a recovery rate of 100 per year and a current total amount of 1000. Every individual in the population (of currently 20) consumes 5 units per year. They can survive also at 4 units a year; when they only get 3 units or less for each of them, they would suffer. You could add more consumers to this system for a long time because of the total stack of 1000, which will initially only be depleted slowly. At one point, consumption needs to drop to 4 units per individual p.a.. Individuals would prefer to consume 5 units but they cannot, and they do not suffer terribly from suffering 4 (but their utility is already less than at 5). If you now add more individuals to the system such that every individual can only consume 3 units, people will suffer one way or the other—through suboptimal resource access or armed conflict.

What I am trying to say is: Until a certain point, more individuals means more total happiness for all individuals. This, however, likely drops at one point until more individuals mean less total happiness and more total suffering.

Leaving the thought experiment aside, are humans currently having a net-positive impact on other lives? Worldwide average meat consumption per capita is currently at 43 kg p.a., with up to 100 kg annually per capita in the US. That means that the average human causes intense suffering to dozens of sentient animals through his or her lifetime—lives completely lived in captivity in factory farms with incredibly stressful slaughter conditions. Is this a net-positive impact on total happiness/​suffering? It seems to me a rather anthropocentric/​speciesist view that does not take into account total suffering caused by millions of individuals.

Needing future generations for social security is, by the way, the equivalent of a pyramid scheme if following the current approach. Gains in productivity eliminate a need for increasing future generation sizes. Do check out per-capita GDP productivity growth—you will see that automation solves much of this problem.

Lastly, I want to point out that I would never support death of people currently alive—and I don’t know why you would raise it. My post was clearly only about the gap of unmet contraceptive need. This is, obviously, ethically a completely different matter.

Edit: As I showed by citing several works related to the example of the Egyptian economy, a bigger population size does not actually translate into better division of labor, more scientists, and so on. It only does so if the state can grow its infrastructure and education opportunities alongside with the population. If the state can’t, then you actually have a relatively lower proportion of highly trained/​skilled workforce. This phenomenon is actually well studied in several developing countries which, currently, seek to slow down their population growth because the population grows much faster than the (relatively poor) states can ensure healthy economic development and opportunities for individuals.

[EdoArad]

Thanks for writing this post!

You might be interested in the works of Charity Entrepreneurship on Family Planning (link to a blogpost about why that matters, where they also list a potential positive impact from reducing population growth). Here are some more explicit models about the relation of reducing population growth (via family planning) on animal welfare and CO2 emissions.
Also, their list of top charity ideas and an in-depth report on their top charity idea, which they will hopefully incubate at the upcoming program.

[RafaelF]

Thanks for those links—pretty interesting!
I especially liked the “ROI analysis”: “Through research into the most cost-effective development policies, the Copenhagen Consensus recommended expanding access to contraception universally as the third-best policy with a return to investment estimated at $120 per dollar spent [10]. [...] Family planning may have large benefits and ripple effects on various sectors, and is a large problem at scale.”

[Ben Millwood🔸]

I agree with Halstead that this post seems to ignore the upsides of creating more humans. If you, like me, subscribe to a totalist population ethics, then each additional person who enjoys life, lives richly, loves, expresses themselves creatively, etc. -- all of these things make for a better world. (That said, I think that improving the lives of existing people is currently a better way to achieve that than creating more—but I wouldn’t say that creating more is wrong).

Moreover, I think this post misses the instrumental value of people, too. To understand the all-inclusive impact of an additional person on the environment, you surely have to also consider the chance that they become a climate researcher or activist, or a politician, or a worker in a related technical field; or even more indirectly, that they contribute to the social and economic environment that supports people who do those things. For sure, that social and economic environment supports climate damage as well, but deciding how these factors weigh up means (it seems to me) deciding whether human social and technological progress is good or bad for climate change, and that seems like a really tricky question, never mind all the other things it’s good or bad for.

[RafaelF]

It is indeed a very tricky question. Of course, there is a chance that each newly born child becomes a climate researcher, politician, social worker etc. - but what are the odds? And do they outweigh, as you mentioned, all the “bad” (for lack of a better work that encompasses suffering and future issues) points?

My personal view on this, as I mentioned in my reply to Larks is that, until a certain point (namely the point where there is neither conflict about scarce resources within human society nor intense suffering caused by human society to other sentient beings) each additional individual probably has a net-positive happiness/​suffering balance sheet. Once the population has reached a certain size, however, this may tip. Total carbon emissions are a direct function of (number of emitters) * (emission levels). Total factory farmed animal suffering is a direct function of (number of consumers) * (amount of factory-farmed meat consumed). The average consumer nowadays consumes more than 40 kg of meat p.a. - that means that several sentient beings spent almost all their lives in intense suffering because of one average consumer. Is that a net-positive balance sheet?

Either way, my main point is about voluntary pregnancy avoidance and not about forced population reduction through whatever coercive means. If providing access to family planning counselling, women’s education and empowerment means, and to contraceptives is so cheap—and at the same time links free choice with significant net-positive effects on several EA-aligned cause areas—what reasons would support not helping close that unmet need?

[alex lawsen]

I’m cautiously optimistic about Family Planning as a neartermist cause area, so thank you for raising it, however I strongly disagree with the substance of the argument above, that the problem family planning is solving is population growth, particularly when it comes to climate change. Honestly, I find the idea of reducing population in poorer countries in order to prevent climate change pretty objectionable.

However, there is a resonable amount of evidence that family planning reduces infant and maternal mortality, and if I remember correctly also at least some evidence that it reduces gender inequality (which certainly seems like a reasonable prior). As an illustration of why I find the population growth argument objectionable, if your primary goal is reducing populations, then family planning programmes reducing mortality makes them worse, which seems obviously wrong.

The Life You Can Save recommends one of the charities you mentioned, Population Services International, they therefore seem like a good bet.

[RafaelF]

Reducing population size in richer countries has an even bigger net-positive effect on several issues, especially that of climate change. Per-capita emissions in developed countries are simply much bigger. Obviously, thus, I completely support population size and/​or growth reduction in developed countries as well.

The difference between developed and developing countries, however, is the dimension of the unmet demand for contraception. Developed countries are usually able to provide those who want to prevent further pregnancy with affordable and effective means, whereas in developing countries there is a big unmet need. As stated in the opening post, more than 40% of pregnancies globally are unintended. Why should EA, given the significant positive effects on users themselves, not support closing an unmet demand?

Reducing mortality is obviously a positive outcome of these programs. The point of family planning programs, women’s education, giving access to contraceptives etc. is increasing the quality of live and reducing suffering of individuals already in existence while, at the same time, eliminating negative effects of unintended pregnancies. Thus, reducing mortality is in line with the first goal.

[[e-mail]]

Thanks for the post. I found it very well written. I would further argue on the points on women’s’ rights. Access to contraception for teenagers, for example, would not only delay first pregnancy and thus risk of fistula, but also enable girls to stay in education longer—which usually leads to them choosing to have fewer children. The impacts on each of the millenium development goals are not to be understated either.

I found this article an excellent supplement. https://​​www.charityentrepreneurship.com/​​blog/​​category/​​family-planning-research

[Trev Prew]

There has been plenty of discussion above relating to family planning, birth rates and global population, but no mention of death rates. Longer life spans means a higher population. So does this mean euthanasia and right to die policies should be considered as a means to reduce population levels too?

[Trev Prew]

I agree that a lower global population would solve many environmental problems but is fraught with issues.

In low income countries with minimal welfare provisions, children are seen as an alternative to a pension. Sons and daughters will look after you when you are old, so having many will be added security. Therefore female education and contraception provision should go hand in hand with increase in wealth and welfare.

Lowering population will lower GDP which is a principal measure of Governments success or failure. Countries with falling populations currently solve this by immigration which defeats the goal of a lower population. If governments concentrated on alternative measures of success, such as happiness measures per person this may help.

Other people telling couples how many children to have is an infringement of basic freedoms and morally wrong. So a programme of contraception education within local communities based on freedom of choice is essential.

Who decides what is the “correct” global population level? I see the “correct” level of population as a balance between life style ie consumption level and number of people. If everyone in the world adopted a western high consumption level then a low population would be obvious, but if everyone lived sustainable simple life styles a higher level of global population would be unproblematic. Proposing lower population levels could be viewed as culturally biased, ie rich westerners wishing to protect their high consumption life styles at the expense of other equally valid cultures. Dangerous ground to be avoided.

China adopted a one child per family policy which has been abandoned, so this is not the way to go. It lead to a sex bias of more sons than daughters and much resentment and suffering at the state intervention required to enforce it.

So to summarise, make contraception and the knowledge to use it correctly freely available, but do no more. Let people decide what is best for their lives, after all they are the true experts in this field.

[Noah Scales]

Who decides what is the “correct” global population level? I see the “correct” level of population as a balance between life style ie consumption level and number of people. If everyone in the world adopted a western high consumption level then a low population would be obvious, but if everyone lived sustainable simple life styles a higher level of global population would be unproblematic. Proposing lower population levels could be viewed as culturally biased, ie rich westerners wishing to protect their high consumption life styles at the expense of other equally valid cultures. Dangerous ground to be avoided.

I think this raises some questions about the responsibility of developed countries to developing countries. A risk analysis of climate change impacts shows that it is plausible that developing countries suffer worse, even suffer their destruction, and that the global poor will suffer the most.

On a per capita basis, carbon consumption of individual lifestyles could be globally leveled. The result though would be an opportunity for developing countries to seek more carbon release to the atmosphere as part of their economic growth. For example, they might 3x their per capita GHG production, while we have to produce 30x less than we do now.

At the moment, populations in developing countries will suffer the burden of our historical carbon production. As that burden grows, their people will leave, if they can. From what I know of the popularity of refugees of various types in Europe, and in the US, developed countries will not welcome any sizable flow of migrants from any country. Sizable, meaning in the tens of millions.

This is the dangerous ground you mentioned. I think avoiding that dangerous ground requires that western countries curb their birth rates, drastically reduce their GHG production by a variety of means, and prepare to welcome a large influx of climate refugees. They also have to do what they can to proactively increase the consumption patterns of those in developing countries whose country is expected to survive climate changes.