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Comment by giantg2 | Hacker News Reader

"Their system dynamics model published by the Club of Rome identified impending ‘limits to growth’ (LtG) that meant industrial civilization was on track to collapse sometime within the 21st century, due to overexploitation of planetary resources."

I'm sorry, but - No shit!

Of course there are growth and population limits, and we are close to them. Everyone talks about global warming, but few talk about population and consumption as the main driver for that. We like the narrative that we have the technology to face climate issues and future resource scarcity because it means we're not doomed.

We will either need unpalatable or forced lifestyle/societal changes or we will inevitably face these unwanted changes when consumption outpaces resources.

Oh and China is now suggesting 3 kids per couple will be to tolerated...

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I recommend reading about the Simon-Ehrlich wager of 1980[1] and also about Thomas Malthus[2]. Many very smart people have speculated many times in the past that major population-reduction strategies must be undertaken, and these doomsday predictions in terms of resource consumption have...almost always been wrong. In Paul Ehrlich's case, in 1968 he predicted that "millions of people will starve to death" in the 1970s due to population growth, and mass sterilization was needed to stop it.

The reason why people keep outpacing our own resource constraints decade after decade is that humans, unlike bacteria or any other species you can model population growth after, can modify our own environment, along with the degree of our own resource usage.

Which is all to say, that this statement has been proven demonstrably false more often in the past than it has been proven true: "We will either need unpalatable or forced lifestyle/societal changes or we will inevitably face these unwanted changes when consumption outpaces resources."

[1]https://en.wikipedia.org/wiki/Simon%E2%80%93Ehrlich_wager [2]https://en.wikipedia.org/wiki/Thomas_Robert_Malthus

Yes, in essence all these dire forecasts are little more than fancy versions of Malthus's predictions, which assume that natural and other resources cannot be improved or increased as necessary by human ingenuity to support and promote societal well-being. Given how large the universe is, I'd bet there's a good chance that scientists, engineers, and enterprising people will find ways to make all these dire predictions wrong. Your comment should be at the top of the page, IMHO. (EDIT: I posted a comment referencing it; it's now at the top of the page.)

My issue with this idea is that that it doesn't take into account time.

For example, theoretically there could be a way to harness the energy of the Sun with a Dyson Sphere, but there's a minimum amount of time that will take:

- Our neurons fire at "X" speed, and there's a minimum "Y" amount of things we need to think of before we can build one.

- Light travels at 299,792 km/s, but there's a minimum "Z" amount of things to be seen, or computed and/or moved before one can be built.

- We can harness "N" amount of energy per unit time right now, but there's a minimum "M" amount of total energy that will need to be invested into building one.

I think we can all agree a Dyson Sphere won't appear around the sun tomorrow, or next year. There's a theoretical minimum amount of time, dictated by the laws of physics, for one to be built: and this will be the minimum amount of time it takes to make one even if we achieve maximum efficiency.

This applies to all human development, so IMO the question really isn't "can we figure out how to build X" but rather "how long would it take to build X". Things like fracking do sound like low-hanging fruit compared to the things we'd have to invent in the future to keep the status-quo. I'm sure theoretically we could invent a lot of things, but as we run out of the low-hanging fruit, can we invent them in time?

Malthus’ predictions were proven incorrect. The predictions of climate models — less rainfall, increased temperatures, less arable land — have proven correct. Not to mention that observable behavior matches those same models. If anything, the models have understated the direness of the situation: both the Arctic and Antarctica are warming far faster than even the most pessimistic models predicted.

You are claiming that because one man was wrong that all men are wrong. That is dangerously absurd.

No I'm not claiming that. I'm claiming that there's something to learn from the history of similar claims and examining why the assumptions in them ended up not being true, to help possibly mitigate similar assumptions today.

I'm but you can be completely right about having been wrong in the past, but growth is an exponential phenomenon in a world with a fixed amount of resources.

You're just saying "it's worked before, it should work again" as an argument. This is complete garbage.

But population growth rate isn't fixed and currently going down. Half of the the world's countries are below the replacement fertility rate, and would be in exponential population decay if it wasn't for increasing life expectancy.

China is a great example of this if you want to look into their demographic information

"There's a consistent track record of being wrong, we should learn from it" is not garbage, it's the bare minimum for engaging with the topic intellectually and honestly.

In that case, we have destroyed about 50% of the earth's natural biomass and we are near the point of depletion of the earth fish stock.

That means that an order-of-magnitude increase in consumption, which would trivially happen is all of the earth's existing population were to have first-world consumption standards, would completely wipe away a sustainable society.

As far as I know, order-of-magnitude reductions in consumption of basic resources while keeping living standards is not something we are anywhere remotely close to achieving.

Then please allow the late Hans Rosling to put you at ease :) https://www.ted.com/talks/hans_rosling_global_population_gro...

Rosling is right if his population numbers are right. 10% higher and things go very badly.

You mention fixed resources as if we're getting close to the limits of those resources. The premise here is that we are currently capable of fully exploiting the resources of the earth, which is provably false.

A good example of this is the technology cycle of the oil industry. In the 20th century, the primary extraction method for oil was tapping shallow, high pressure oil reservoirs. Oil riggers would drill down less than 1000 feet and oil would come gushing out. As the shallow pockets ran out, the oil industry lamented because they approached a perceived resource constraint. Shortly thereafter, it was found that there was an order of magnitude more proven oil reserves deeper down.

I think society is at a similar nexus today. We're at an inflection point between the end of a lot of steep growth curves (oil and gas production, population growth, [possibly] economic development in the West) and the beginning of a lot of new ones (replacing oil with sustainable energy sources, material science, bioengineering, nanotechnology, space exploration). In all of those realms, it's painfully clear that we're a far ways away from the extent of available resources.

Let's consider artificial energy consumption by humans today. In total, humanity consumed ~500 PWh in 2019 [1]. Power flux of the earth is 173 PW; annualized, earth's energy flux is ~15 million PWh. That means that we consume 0.003% of the energy that is incident the earth. Clearly we're not getting close to the fixed resources of the earth.

In this view, global warming and resource consumption are still existential concerns, but we are working against perceived limits rather than today's physical limits. Humans are really good at making technology that increases the exploitable resources at our disposal. I'm relatively confident that we'll build technology to save us from extinction, but perhaps not from societal collapse.

[1] I summed the consumption from 2019 in the spreadsheet available here: https://ourworldindata.org/explorers/energy?country=USA~GBR~...

Oil extraction and the extraction of rare metals mined for solar panels are still limited by the basic laws of thermodynamics. In that context, oil extraction is become ever more inefficient and there is nothing we can do about it.

And in the context of resource extraction, it comes at the cost of a reduction in biomass and biodiversity. It is a laughable claim that we are anywhere remotely close to working towards, let alone reverse, the damage we've done to the biosphere.

The problem with this argument is that it puts us in a very tenuous position: humans need to get over every resource squeeze. Any critical limit that we don't find a technological workaround for in time becomes an extinction threat. In other words: you need to be right every time, I only need to be right once.

Economic growth doesn't consume an exponential amount of resources, it works by increasing productivity, which uses fewer resources.

Human population is definitely not growing exponentially either.

> Economic growth doesn't consume an exponential amount of resources

Right now it does. GDP growth and resource use have been demonstrated to be pretty tightly coupled, so if economic growth is exponential so is resource use, afaik. It's worth noting that energy is also a resource; it is really hard to de-couple productivity from energy usage.

Check out this article, and Figure 1 specifically: https://www.eea.europa.eu/publications/growth-without-econom...

US per capita energy use and total water use peaked around 1980: https://twitter.com/Noahpinion/status/1407626765799878660

Total non-renewable energy use seems set to peak soon. Even ignoring tech improvements, economic growth comes from services, which means trading imaginary things between each other.

The USA has also exported large amounts of its industry to other countries, hence it's important to look at global figures.

Malthus wrote in 1798. maybe he was a little off.

turn it around. there is a clearly a level of population and resource consumption where starvation sets in and consumption drops.

you may personally believe that there is a lot of road left, but you seem to be asserting that it just never ends.

Are the technologies used to "beat" these predictions sustainable? There's no evidence that our current population level is even sustainable.

"Which is all to say, that this statement has been proven demonstrably false more often in the past than it has been proven true"

This is a very complex system, and like the saying goes for another well-known complex system "past performance is not a guarantee of future performance".

Global warming and the heat domes killing crops will be a problem.

All organisms can modify their own environment. Humans are not special. Malthus may have been wrong about the 19th century, but what is a couple hundred years? Life on Earth has been evolving for a much longer period of time.

I wouldn't discredit Malthus too soon.

Over population is not an issue for two reasons.

1 - Birth rates are falling. We’re getting pretty damned close to the peak of human population. There are some very easy steps we can do to expedite this, such as helping reduce infant mortality rate among the global poor, a move that is known to reduce fertility rates too.

2 - Consumption is wildly uneven among the world’s population. Focusing on population implies that those areas with high fertility rates are the issue, when in fact the primary limiting factor is and will remain the high consumption rate of the world’s richest nations.

Population momentum means population will peak at 11.2 billion people near the end of the century [1] before it declines. Total fertility rate drop isn't happening fast enough (need to get closer to 1 vs 2.1 replacement rate), and we've already locked in the expansion to 11.2 billion. 3 billion people can't afford to get enough nutrition [2]. That number will increase before it decreases.

Consider we're already on the path to exceed our carbon budget [3], and billions of people are trying to climb out of poverty (which requires fossil fuels, resources, and food production, which we are already managing....poorly and unsustainably). Many countries still offer funds to people to have children and have pro-natalist policies (to goose economic policy and pay for elderly entitlements and stave off the economic contraction). We're not just headed off the cliff; we're pushing our foot on the gas.

TLDR Those who consume the most will need to consume less, and even then there is likely not enough to go around for first world standards for all.

[1] https://ourworldindata.org/future-population-growth

[2] https://ourworldindata.org/diet-affordability

[3] https://www.carbonbrief.org/analysis-how-much-carbon-budget-...

Yes, there is work to be done. But I really really dislike the overpopulation and “tough decisions” narrative because:

1) It places the onus and blame on the people that are currently not the problem.

2) It implies that we must force people to have fewer kids, when evidence shows that women universally want to have fewer kids given the choice. We don’t need to coerce them, we need to help them.

Physical systems don't really care how distasteful ideas are. I don't mean to be rude, at all, but facts are life isn't fair. Climate systems don't sit around arguing over the equitability of development rights based on who emitted carbon when.

Rich countries burned fossil fuels for 100+ years to develop. Does anyone think those countries are going to revert to much lower standards (somewhere between European and developing country standards) to give that same advantage to developing countries? Absolutely not.

EDIT: I want to be very clear before my edit window expires; I do not believe anyone should be forced not to have kids (although I would be onboard paying folks who choose not to have kids a direct transfer payment, just as it's not taboo to pay people to have kids and many governments do it). But I also believe no one should have one or many kids if their socioeconomic circumstances don't allow for it. We should absolutely strive to empower and educate women, as you mention this causes a natural decline in fertility rates [1].

[1] https://ourworldindata.org/fertility-rate#empowerment-of-wom...

> I don't mean to be rude, at all, but facts are life isn't fair. Climate systems don't sit around arguing over the equitability of development rights based on who emitted carbon when.

I’ll put it simpler: you are completely wrong about what needs to be done and by whom.

Accidentally or not, you are repeating the narrative of eugenicists who are obsessed with over population in the global south, rather than the actual facts on the ground. We need to focus on de-carbonizing our industry, rather than the reproduction rate of those who currently consume the fewest resources per capita.

I argue helping people live better lives through education, robust family planning options and availability, and direct cash payments is not eugenics, but feel free to call me whatever you'd like. I'm comfortable with my position based on a foundation of empathy and pragmatism. I believe all human beings should be treated with dignity and respect.

I’m not calling you a eugenicist, I am worried you’re accidentally repeating their points. We absolutely can and should do what we can to help the global south, but focusing on over population as a source of our ills is a eugenicist talking point.

The problem is, and always has been our dependence on fossil fuels to increase our standard of living. Solve that, and the difference between 7-10billion humans is moot

This is probably not a popular opinion here, but I'm actually quite optimistic on our transition from fossil fuels to renewables. Things have been progressing nicely and I expect that progress to dramatically accelerate over the next 15 years.

I’m actually feeling pretty optimistic too. The fact that my house is currently a net exporter of green energy is certainly helping my mood in this area.

Just want to say I appreciate the discussion you two are having. Excellent points from the both of you. And it's nice to see a civilized discussion for once.

> … "it's nice to see a civilized discussion for once."

I've seen far more of that here than just about anywhere else on the Web where news is discussed. I appreciate it greatly, and the world needs more of it for sure.

"But I also believe no one should have one or many kids if their economic circumstances don't allow for it."

In EU area you can have as many children you like and the social safety nets will generally carry you trough caring for your child.

I suggest you use some other means of argumentation than wealth of parents, as that is a non-issue here (mostly).

Europe is also well below its replacement rate at ~1.5 children per woman.

"It places the onus and blame on the people that are currently not the problem."

This isn't necessarily true. There are many families in developed countries that have more than 2 kids. If you limit families to 2 kids then you could see the fertility rate drop lower (ideally fertility and immigration growth together would be under the replacement rate in developed countries).

"It implies that we must force people to have fewer kids, when evidence shows that women universally want to have fewer kids given the choice. We don’t need to coerce them, we need to help them."

This is generally true, but ignores outliers and the association with other factors. You generally only see the decline in fertility rate in areas that have lower infant mortality, which is also usually associated with a more modern lifestyle and economic conditions. You still have a subset of women in developed countries having a ton of kids for other reasons, like they want a big family, or religious things like the Hassidic community.

Whats wrong with some people having many kids, if the average still remains low?

If the average is low enough, then nothing. If the goal is to reduce consumption in high consumption developed countries, then you need it to drop low enough that the total population growth is at or below replacement (like birth rate + immigration).

While its possible that climate change may slow or reverse this trend, the number of people globally experiencing malnutrition has actually been falling over time.

https://ourworldindata.org/grapher/share-undernourished-regi...

All data indicates that climate change will diminish crop yields [1] and ocean life harvests [2] [3] [4]. If there is data to the contrary, I am open to consuming it to update my mental model.

> Researchers combined a global dataset of field warming experiments conducted at 48 sites to estimate decreased yields of 7.1 percent for maize, 5.6 percent for rice, 10.6 percent for soybean and 2.9 percent for wheat. Their estimates were 95 percent probable for the first three staples and 89 percent for wheat.

> In response, “technological and adaptive measures, such as northern expansion of the croplands, will thus have to increase yield by 1.8–2.0 percent per year to meet the conservative estimates of a 70 percent increase in food demand,” the researchers wrote.

> However, that required rate is higher than the historical yield increases in the late 20th century, “which is both challenging and alarming, considering the stagnating yield increases widely observed for the past decade,” they concluded.

[1] https://allianceforscience.cornell.edu/blog/2020/11/global-c...

[2] https://www.nytimes.com/2019/11/29/climate/climate-change-oc... (Warming Waters, Moving Fish: How Climate Change Is Reshaping Iceland)

[3] https://www.nytimes.com/2019/02/28/climate/fish-climate-chan... (The World Is Losing Fish to Eat as Oceans Warm, Study Finds)

> If current population trends continue at the same rate, the world will need to double its food production by 2050. To compensate, world leaders are consistently looking toward fisheries to be a critical source of protein for millions of people.

> In 2016, 171 million tons of fish were taken from the sea, and that number is expected to rise to 201 million over the next 10 years.

(my note: I have serious doubts this is sustainable)

[4] https://www.nationalgeographic.com/environment/article/clima... (Climate change is depleting our essential fisheries)

Regarding carbon, while it is possible we’ve already exceeded our budget on the pessimistic end, on the optimistic end (that we have 15 years), the current growth of PV alone is enough to for me expect it will turn out… well, ‘fine’ isn’t the right word but “not catastrophic” at the least.

Phosphorus, biodiversity, stuff like that? Still a concern.

> 3 billion people can't afford to get enough nutrition

Depending on the country, 1/3rd to 1/2 of all produced food goes to waste - and a lot of that is due to customers expecting that every supermarket has to have their particular brand of generic, short shelf-life goods (e.g. yogurt, salads and other vegetables, baked goods) on stock 24/7 and similar absurdities. And any suggestion to curb that shit, either by limiting the amount of different brands available in stores or to limit the time slots in which customers can expect fresh goods, gets quickly shot down by outrage mobs fearing the advent of socialism (which is associated with empty shelves).

As for the "can't afford" part: we need to get global wealth disparity under control, and especially us Europeans and Americans have to stop killing African textile and food industry by "donating" our excesses.

> Many countries still offer funds to people to have children and have pro-natalist policies

Anti-natalist politics are by definition always walking on the cliff of eugenics. Any attempt of restricting who is allowed to reproduce or how much will always lead into selection questions - China for example now suffers from a vast lack of women, as parents aborted or murdered female newborns, and I don't want to get started with the horrors that the Nazi regime committed.

The best and especially humane solution to curb overpopulation is to reduce poverty and increase healthcare - it has been shown that once people from a population get lifted in wealth so they don't need to have ten kids to have three survive to adulthood and one to take over their care in old age, child birth rate automatically drops!

"The best and especially humane solution to curb overpopulation is to reduce poverty and increase healthcare - it has been shown that once people from a population get lifted in wealth so they don't need to have ten kids to have three survive to adulthood and one to take over their care in old age, child birth rate automatically drops!"

... and per capita consumption of resources increase, usually creating a large net increase in resource consumption based in the modern lifestyle.

> "… and per capita consumption of resources increase, usually creating a large net increase in resource consumption based in the modern lifestyle."

Exactly why such a complex issue cannot be solved with one or two simple solutions as so many seem to think. We need to reduce consumption and abuse of limited resources and normalize such behavior in the minds of human society as a whole. Especially among those most actively doing said abusing and (wasteful) consuming. We also need to be more open to the idea of change, because change is coming whether we like it or not. There's a terrifyingly large portion of humans in decision-making positions on this planet who are fighting tooth-and-nail to maintain an unsustainable "growth oriented" status-quo.

"There's a terrifyingly large portion of humans in decision-making positions on this planet who are fighting tooth-and-nail to maintain an unsustainable "growth oriented" status-quo."

That's because our economies would collapse. Most of the population don't want the restrictions that would be necessary. So how do we change societal and individual views to give up the freedoms and resources that we have been enjoying?

The nutrition problem is a social problem, not a technical problem.

This only holds true if you are ok with areas with high birth rates and low consumption remaining poor and refusing to let them migrate to the rest of the world, which seems a hugely unlikely scenario in practice.

It seems most likely that either these areas will develop economically and thus consumption will rise, or their skyrocketing populations and lack of development will cause rising internal tensions/crises and pressure to emigrate to the higher-consumption parts of the world. Most likely some of both.

"Adding 2.5 billion poor people to the planet in 80 years won't be a problem because we'll ensure they stay impoverished and in their home countries" isn't really as palatable a solution to overpopulation as you make it sound.

Your point is true if and only if we cannot decouple standards of living and carbon emissions. Then again if that’s true then we are doomed; restricting the world’s poor from breeding or consuming would not be enough to save this planet, the global rich currently produces more than enough CO2 to damn us all.

The only way to save our species is to find a way to decouple standards of living from carbon production. Anything else is insufficient and can only delay the inevitable at best.

"Your point is true if and only if we cannot decouple standards of living and carbon emissions."

There are other concerns like food production, soil erosion, fish stocks, loss of biodiversity, etc. Its not just about CO2.

You assume that our current population is sustainable. Is it? We aren't living sustainable lives. Sure, this varies by country, but I believe this is globally true.

We are expected to peak well beyond our current level. Estimates are about 10-11 billion - a 25%+ increase.

A major problem with your infant mortality comment and consumption comment is that reducing infant mortality is also associated with modern lifestyles and an increase in consumption. Consumption patterns change as the mortality and fertility rates drop and economic opportunities increase. Our economies are built on consumerism and spending. We see this trend in developing nations today (you have to compare for various demographics, not just the country level).

It’s not sustainable, and that has absolutely nothing to do with population count and everything to do with how we’ve structured our society. We could eliminate everyone but America and it still wouldn’t be sustainable, it would just take longer to tip over into disastrous global warming.

It is literally impossible to make a society sustainable via birth rate alone, which is why I object to the argument vigorously. The only solution is to find a way to make our society and technology sustainable, rather than just hoping that birth control will fix it.

"It is literally impossible to make a society sustainable via birth rate alone, which is why I object to the argument vigorously."

And who is making that argument? This isn't what I'm saying at all.

"The only solution is to find a way to make our society and technology sustainable, rather than just hoping that birth control will fix it."

I'm asking is our current global population level sustainable? It sounds like that's a no. There is at least point-in-time population limits to what our "sustainable" system can handle based on advances in technology and societal restrictions. I use quotes here because we do not have a sustainable system, and the number of people who can be sustainably supported is at least billions lower than we are at today given today's technology.

It has to be a combinations of available sustainable tech/lifestyle and having a population that doesn't exceed the limits of sustainability.

> I'm asking is our current global population level sustainable? It sounds like that's a no.

At the current levels, it is not. If we shifted over to renewables then it would be.

I find focusing on the population extremely weird, given that the vast majority of emissions are coming from a relatively small portion of rich nations. We could eliminate the entire global south and still tip this planet into disastrous global warming purely based on the emissions of small, rich countries in the north.

Put more blatantly, I find that a lot of the discussion about overpopulation is an attempt to put the blame of global warming and our sustainability problems on those who emit the least per capita. There is very little merit to discussions about controlling population size while rich nations continue to depend on fossil fuels to maintain their standards of living.

"If we shifted over to renewables then it would be."

How would that help soil erosion, food production/waste? How would that help with other resource use like metals, timber, fish stocks, etc? There is a lot more to sustainability than just CO2. Even looking just at that, where can we get that much lithium, copper, concrete/asphalt substitute, silicon for solar, etc? There are restrictions to the resources we use and process.

"Put more blatantly, I find that a lot of the discussion about overpopulation is an attempt to put the blame of global warming and our sustainability problems on those who emit the least per capita."

Where was that said? That's not what I'm saying. You still seem to be focused solely on fossil fuels here ("emit"). As nations develop, they will also adopt a more modern and higher consumption lifestyle. This is a global trend that also applies to developed nations continuing to get richer and indulge in having an even better life (eg parents always want more for their kids than they had for themselves, substantial numbers of people want the newest iPhone, look at house size over time, etc).

I do agree with your overall point. That said, while an impoverished family with a dozen children isn't consuming much today, inevitably, they're going to consume a lot more as their nation gets wealthier, which is what's happening in Asia. As you alluded to, the solution is to develop these countries more quickly, so they'll no longer be incentives to have more children.

But the birth rate isn't really the point. It's a proxy for consumption. As the nation gets wealthier, the per capita consumption goes up and generally creates a net increase in consumption.

The point is that developing countries will increase their per capita consumption regardless. If birth rate decreases with level of consumption/gdp, you want to accelerate into it, thereby limiting the peak total consumption.

For example, it would be better if Nigeria hit a European standard of living and stabilizes population sooner at say 400 million people. The alternative is they grow per capita consumption more slowly and hit an EU standard and stabilize later at 1 billion people.

"The point is that developing countries will increase their per capita consumption regardless. If birth rate decreases with level of consumption/gdp, you want to accelerate into it, thereby limiting the peak total consumption."

Generally the accelerations coincide with one another. The only reason the population is increasing now is because some developments are being taken advantage of like food supply and medical care.

It depends if sooner is better. Many times it's easier to implement new technologies from scratch rather than revamp old infrastructure. If we rush implementation, then it can just be a waste of resources (look at sewage treatment in many parts of Africa that modeled it after the US).

I wonder once birthrates stabalise globally whether we will be back into a Malthusian economic cycle since we invest in sales and growth.

> Of course there are growth and population limits, and we are close to them.

No science agrees with this. All the models suggest there is a huge amount of land and resources available for a massive rise in population, but population models suggest humans will tap out at about 9 billion due to declining fertility just about everywhere except Nigeria.

Because there is no alignment between resource production and population growth rates local effects continue to impose the greatest limitations just like with other animals. For example humans are really good at finding food. An efficient international network to distribute food further solves that problem, but if a population in a given locale exceeds the capacity of that local to distribute food people will starve despite food availability and human capabilities.

If, as an economic aside, wolves hunt all the rabbits in a given location wolves will starve even if there are other food options and wolves can travel hundreds of miles. That is because a population density in a single location is invariably tied to the food capabilities of that location and changes take additional effort at expenses otherwise not necessary. When those wolves starve in the given locale that has no bearing on the world total wolf population, which is likely regular and stable. Humans have the same limitations due to population densities.

A lot higher than 9 billion

https://www.un.org/en/global-issues/population

"No science agrees with this"

Sources?

Using your wolves example, people can move to locations that are more developed and have the infrastructure for more food distribution. The main problem is that most people are so far removed from their food sources that they don't really think about whether there will be enough for their kids. You could have people starving to death, or something wolves dont have - global conflict.

According to your article 9 billion is still a safe estimate:

The world population is projected to reach 8.5 billion in 2030, and to increase further to 9.7 billion in 2050 and 11.2 billion by 2100. As with any type of projection, there is a degree of uncertainty surrounding these latest population projections. These figures are based on the medium projection variant, which assumes a decline of fertility for countries where large families are still prevalent, as well as a slight increase of fertility in several countries with fewer than two children per woman on average. Survival prospects are also projected to improve in all countries.

Do you have any sources to support your claim?

The quote you give says this is the medium estimate. We would have to know the low and high to know if your estimate is "safe".

I would have to look up source just the same as you. It just comes from various things I have read over the years.

Can you show that source. I don't see one.

> "Using your wolves example, people can move to locations that are more developed and have the infrastructure for more food distribution."

This assumes that people can move to such locations. We live in a society where most "developed" nations will on one day happily accept and try to help refugees from terrible situations, and on another day will shoot those same refugees at the border and call them "invaders".

And then there's the simple issue of many such people in dire need of leaving their current home simply being unable to at all. Undertaking the travel necessary to attempt to reach a "more developed" nation would be a death sentence in and of itself for some (for varying reasons).

> Oh and China is now suggesting 3 kids per couple will be to tolerated.

To rephrase it a bit. China is now suggesting 27h for optimal Earth rotation.

It's never going to happen. Their population is going downhill fast.

Yeah, largely as a result of their one-child policy, the cost of raising a child in China has gone through the roof. People poured everything into getting the very best for their child (and grandparents did the same).

My definite impression is that most new couples in China are worrying about how they'll afford one child, not debating whether or not to have a third.

This also seems to support the idea that as fertility tolerates drop, per capita resource consumption rises to meet a more modern lifestyle.

It might not be feasible for China to get to 3 kids per couple, but it points out there's a natural tension between governments that want population growth for economic reasons and a need to reduce population growth (if there aren't major technological breakthroughs that reduce the pressure of overpopulations).

> few talk about population and consumption as the main driver for that.

This seems like the elephant in the room to me. It's almost never discussed, at least in the US, but as you say, it's the driver for global warming, ecological devastation, and resource constraints of all kinds. Us humans love to talk about our ability to adapt to new environments, but our lack of willingness to plan long-term is highlighting that our adaptability is not universal.

Edit: in before 'but what about the economic growth?': that's the point. Growth is not sustainable, at least when growth is related to resource utilization.

Technological improvement is growth. That isn't intrinsically tied to increasing resource utilisation.

It isn't entirely separate either. Often increases in efficiency direct increases in consumption. This observation was made by the English economist William Stanley Jevons and is known as Jevons paradox[1]. More recently, the economists Daniel Khazzoom, Leonard Brookes, and others have analyzed this relationship[2].

[1] https://en.wikipedia.org/wiki/Jevons_paradox

[2] http://www.iaee.org/en/publications/ejarticle.aspx?id=1091

It is a political non starter. US population growth is driven by immigration, not birth rates.

Focusing on population reduction in other countries is politically toxic. It is too conceptually close to eugenics, genocide, and racial conflict. That said, the idea of reducing population growth still underpins efforts to improve the standard of living the third world, it just isn't branded as such.

> Of course there are growth and population limits, and we are close to them.

This has been true for nearly all of human history. The thing about technology is that it changes what the limits are.

Yes, and we don't know if the current population level is even sustainable. Just look at problems cause by our current technologies like fossil fuel based... everything (oil, gas, plastics, synthetic fertilizers, etc).

Changing limits does not eliminate them entirely, however. There are still limits, and those limits can still be exceeded.

An exponential growth phenomenon is still limit by the basic laws of thermodynamics.

> Oh and China is now suggesting 3 kids per couple will be to tolerated...

This phrasing, specifically "tolerated," implies a misunderstanding of the motivation behind the change in policy.

The CCP is not "tolerating" up to three children per family; it is doing its usual ham-handed best to encourage it. China has blasted right through stage 3 (thanks to one-child) into stage 4 of the Demographic Transition Model, and is staring down the precipice of stage 5, where the likes of Japan already find themselves.

If you're not familiar with the DTM: https://populationeducation.org/what-demographic-transition-...

"Oh and China is now suggesting 3 kids per couple will be to tolerated..."

China came up with the same problem that all developed economies have come up against - low birthrate, and the all the economic baggage that comes with it.

I find it unlikely the party could pump up birth rate just by dictate though.

The problem is thinking of it as a problem. You can't have a sustainable system that requires birthrate (really a proxy for output and consumption) that increases infinitely.

It is absolutely a problem if population shrinks too fast. There is a threshold where the young literally can't feed care for the elderly.

And we are nowhere near shrinking too fast, especially since industrialization and automation provide the ability for a couple people to provide food/care for many.

Depends on what you mean by we. This is a real concern in countries like Japan, China, and Korea. Less on the food side, and more on care and services side.

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