Sustainability through Massive abundance.

Episode 17: Maintaining Populations

In which I use a global biomass census and galactic population models to explore what it takes to sustain 10 billion people in total abundance.

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Are there too many people?
Intro [music]
How has our population affected the world?
Malthus and Predator vs. ET
What’s Earth’s carrying capacity?
How do we reach a sustainable population?
What’s a desirable number of people?
How do we maintain an urban population?
Close [music]

Are there too many people?

Are there too many people in the world?

I asked two young sisters this question and one said, "yes, because people are annoying and stupid!"

The other said, "no, because there's way more ants than people, and we're way less annoying and stupid than ants."

Population control is an emotionally charged subject, because it touches on religion, social welfare, reproductive rights, economics and environmental ethics. It's almost impossible to frame in a value neutral way. And, as you'll discover today, the grown up experts are in no better agreement than the two youngsters that I just quoted.

Today, I'll be examining these questions: How has human population affected the world? How many people can the world sustain? How do we reach a sustainable population? And how do we maintain our urban populations at replacement levels? As always, today, I'll start from the perspective of ecology, focus on design rather than policy, and end with some ideas about building better cities.

Intro [music]

Cities designed like modern Edens, for economic and ecological abundance. I'm Kev Polk, your guide to Edenicity.

Welcome to Episode 17, where I'll discuss the Edenicity of population maintenance.

How has our population affected the world?

Let's start by asking: how has our population affected the world?

Well, I took a look at (see the program notes for the link), and I saw that the global population has increased 380% in the 20th century.

Now as I was looking into how we're affecting global ecology, I came across an article by Bar-On, Phillips and Milo in the National Academy of Sciences, 2018, titled "The Biomass Distribution on Earth."

This is a wonderful study with many surprises. Well worth the read. The article had this to say:

First of all, the total mass of mammals has increased fourfold since humans arrived on the scene. But according to the article, "the present day biomass of wild land mammals is approximately seven fold lower," than it was before humans. In the oceans, it's even worse: the biomass of marine mammals, whales and dolphins is five times lower than it was before humans. Humans account for 36% of the total biomass of mammals, our livestock accounts for 60%. That leaves just 4% for all wild mammals in the world, including dolphins and whales.

So humans have basically crowded out most of the other mammals in the world. According to the article, "in fact, humans and livestock outweigh all vertebrates combined with the exception of fish." Now fish weigh 3 times more than all of the mammals put together, but we've cut the fish biomass in half.

But what about the creepy crawlies? In other words, arthropods. These are the insects, centipedes, millipedes, arachnids, such as spiders and ticks, crustaceans, such as prawns, crabs and lobsters. Well, these are half again as massive as fish in terms of the total mass of all their bodies. It's really unknown what our effect has been on that population because they're so crawly, they're really hard to count!

Now, what about plants? Well, I have really bad news there. We have cut plant biomass in half. And since plants comprise 82% of the total biomass, we've probably cut the total biomass in half.

Now our crops account for 2% of the total plant biomass. But as we saw in Episode 14, we use 35% of the land for agriculture and grazing. Now when you add roadways, parking buildings, lawns and mines we use about half of Earth's land for our exclusive use. This has come at the expense, mainly of plants, which provide nearly all the energy that life uses on this planet.

But you can compare our monocrop lawns to rain forests, which stack many times more biomass vertically in multiple layers over the forest floor, or to temporal boreal forests which have a huge amount of biomass underground, and range lands which have massive root systems. And again, our agriculture has replaced these with annual crops that have relatively shallow and scrawny root systems.

This has implications for climate as well. There's a USDA study from 2017 called global carbon, and the link in the program notes has lots of great tools and information. It's really worth checking out. According to that paper, plant and soil biomass has 2.7 times the carbon in the atmosphere and 255 times our annual carbon emissions from industry. Remember, we've lost half of the plant biomass, so restoring plants and soils may be, by far, our best strategy to sequester carbon and reverse climate change.

Now, our effects on plants, our effects on soils and our effects on climate, have potentially disastrous consequences for human populations. In Episode 14, I described how hungry Rome expanded its empire after it exhausted its soils and how a starving Europe did the same thing, which drove its expansion into the new world (that is to say, the Americas).

Malthus and Predator vs. ET

Thomas Malthus in his 1798 book, An Essay on the Principle of Population, basically said that human population is going to grow until it reaches hard limits, such as soils and other resources, at which point famine, war, plague and pestilence will rapidly bring down our population. And of course, this is a miserable experience for everybody involved.

Now in college I became acquainted with population biology because one semester I ran computer simulations of population growth and decay in galaxies. Yeah, I studied imaginary extraterrestrial populations. Think of it as predator meets E.T., or should I say, Predator eats E.T. across millions of star systems, slugging it out in the driest possible prose, with equations, statistics, and population graphs.

Anyway, this crazy term paper acquainted me with the two main facts of population dynamics: instability and overshoot. The Predator population grows when there's a lot of ETs to eat. But once they gobble up the ETs, there's nothing left to eat and the Predator starve. Their population exceeds its resource base and crashes. That's called an overshoot. Then if there's any ETs left, their population explodes until a few starving Predators start to find them again.

Did you know that well fed Predator are more fertile? Then it's a catastrophe for the ETS!

Depending on relative birth rates and geographic factors, these cycles can stay bounded within certain limits or spiral out of control. That's called an instability.

The Limits to Growth study from 1972 modeled human population growth limited by finite mineral resources, including chemical fertilizer, and also the effects of increasing chemical and nuclear wastes. Just as civilizations throughout history used up their soil, gone into overshoot and crashed, the study showed that the world's global economy and population are at risk of doing the same. In their status quo scenario, which the world has followed in the 48 years since the study was published, the world population goes into overshoot in the early 21st Century and crashes by mid century.

That means that over a 20 year period centered around, say, 2040, most people die in war, famine or runaway epidemics.

Now, I don't know about you, but in me that awakens a very primitive instinct to want to get away, to want to climb my way out of this situation. If you get people panicked enough, we all basically regress to becoming very much like our little rodent-like ancestors from the days of the dinosaurs, just wanting to flee.

So it was quite natural, knowing about Malthus and his gloomy predictions, to want to escape to places beyond the Earth.

Is the final frontier a real escape? Let's look at it. The world's population has doubled in the past 47 years. And the Moon and Mars offer a land area just about equal to the land area of earth, and they are dead places. All those jobs ecosystems do for us for free, things like waste reclamation, nutrient cycles that recycle carbon, oxygen, nitrogen, potassium, phosphorus, calcium, and so forth? We have to figure out how to do these mechanically and pay for the machinery to get it done. See Episode 13 to get a sense of what a monumentally futile task that is. And anyway, without any big changes in growth, we're back to where we are now well before the end of the century, right? Because if we filled up this world now and the doubling time is 47 years, then by 2067, will have filled up the Moon and Mars as well.

Malthus talks about this, the Limits to Growth study talks about this, and I talked about this in my 2007 book Gaiome: Notes on Ecology, Space Travel and Becoming Cosmic Species.

The basic problem is that exponential growth, the type of growth that you have with bank accounts or populations, always overtakes geometric expansion in a finite amount of time. So expansion is no escape from the problems that we're having with population. It gets more expensive the farther out you go. And within a few thousand years, as I detailed in my book, you're filling up solar systems faster than you can reach new ones.

But the main takeaways are down to earth. Okay, let me read you a little bit from that book:

"Long before growth reaches its limits, though, life gets hectic. A competitive economy with obligatory growth cannot avoid suffering. Because the wealth of individuals and regions changes at wildly different rates, a few get much richer, while most, especially agrarians, can't keep up with inflation... A third world peasant, whose ancestors got by for millennia in the local ecology, now may make two dollars a day or less. Well, that amount may have been fine a hundred years ago, today, it is not even enough to open and pay the fees on an interest-earning account. With her government pressing her to grow exotic crops, such as coffee, rather than subsistence food long adapted to the local ecology, her ability to eat becomes vulnerable to price and currency fluctuations on a global level. As a result, despite the worldwide cultivation of almost twice as much grain as needed to feed the human population, more than 11 million children starve to death every year.

"For the many who struggle somewhere between poverty and wealth, the relentless pressure toward ever greater visible prosperity increases competition, toil and hoarding to the point where these traits dominate. As resources and time dwindle, the incentive to try and rig the game in one's own favor become overwhelming. From the poorest sweatshop to the richest multinational, growth begets greed, greed begets corruption, corruption breeds violence."

So for now, let's keep our focus on Earth where we have the aid of our biosphere's vast services and accumulated intelligence (see Episode 13) to help solve our problems. Our first duty is to that biosphere. Only when we have restored it to perfect health will we have anything like the competence to try living elsewhere.

Notice I said "competence," not "right." Remember, this is an urban ecological design show. Our first design competence is learning how to live within our world's carrying capacity.

What’s Earth’s carrying capacity?

What's a carrying capacity? It's how many of a species can live in an area. Since we live in a global economy, it's fair to ask: what's Earth's carrying capacity?

I was looking over the UN environmental program report, One Planet, How Many People? A Review of Earth’s Carrying Capacity, from their Global Environmental Alert Service, published back in June, 2012. And according to that report, the total carrying capacity estimates range from half a billion people to one sextillion people (which is to say a thousand billion billion people) on the high side. However, according to that article, the vast majority of studies say 8 billion people or less.

Coincidentally, we're on track to reach that number by 2023.

But realistically, our current pattern of consumption can only support about a 20th of today's global population, which is to say 400 million people. And I discussed that in detail in Episode 2. So my estimate is actually lower than the lowest UN estimate available, and somewhere in the middle of what the world's carrying capacity was for hunter gatherers (see Episode 14 for details on that).

Now among permaculturists, that is to say ecological landscape and housing designers, we tend to be optimists. One of the best practitioners in the field, the Austrian farmer and author Sepp Holzer, estimates that the world could easily sustain 21 billion people, no problem.

The Edenicity Reference Design, which you can download from the link in the program notes, is based on a world population of 10 billion people, which I think could live on a fair share basis on 1.4% of the land with 98.6% of the land restored to the wild. This would end the mass extinction as detailed in Episode 2. So I'm going to go with 10 billion as our target population. And remember, we're not there yet. It'll be a few years before we reach that, perhaps even not until mid-century.

How do we reach a sustainable population?

Now the question is: how do we reach a sustainable population? Well, from that UN report again, there's basically three ways: having a bigger pie, fewer forks, or better manners.

So the bigger pie would be finding a way to increase the production of resources that we depend on for survival. So this would be through technological innovation, such as the Green Revolution. But unfortunately, as I mentioned, in Episode 14, the Green Revolution has proven to be short term. Now permaculture is what I draw on for Edenicity. And the methods that I use there include aquaponics, and very high intensity gardening, which can be up to 100 times more efficient than large scale agriculture, as I mentioned in Episode 15. So the bigger pie basically increases productivity.

We can also try having fewer forks. And this calls to mind China's notorious one child policy that ended back in 2016. This was a system that used financial punishments for having additional children, as well as mandatory contraception and sterilization. Its unintended consequences included increased numbers of parents having twins, 30 more million males than females in present day China, and reproduction motivated travel (by the way, in 1999, my hairdresser returned from visiting her family in Vietnam, where there was widespread resentment about this practice).

Now a softer way to have fewer forks is to have better access to contraception and better education with more economic opportunity for women.

Finally, we can have better manners. And what they mean by that is consuming less, eating lower on the food chain, and polluting less. And the best way to do that is to drastically reduce our consumption of animal products, which can consume up to 50 times more resources to grow, as discussed in Episode 4.

Now for many decades, multiple studies have noticed that as people move to the cities, they tend to have fewer children. And so this has led to debates between poor rural nations and rich urban nations as to who's to blame for our environmental woes. The problem is that many cities have very high consumption lifestyles which offset the innate efficiencies of everybody being closer together. And in any case, there is that huge birthrate disparity, so these debates have raged for decades.

Now the question is: why do the birth rates decline in urban areas? Well, there can be a cultural effect.

In 2011, National Geographic and other publications broke the story of how Brazil's birth rate dropped precipitously over just a couple generations. And it turned out there was a cultural element: the telenovelas, the small budget TV soap operas that were popular throughout the country. As with many soap operas, the budgets were small, and so the casts were quite small. And this meant that the on-screen families had to be small as well. The characters often addressed it on screen. Women who'd had maybe one or two children would decide to not have anymore and announce "the factory is closed!" Anyway, this seemed to lead a cultural charge which dropped fertility from six children to 1.9 per female on average and 1.9 is below the replacement rate, which is 2.1.

Some of the other effects of urbanization are better access to health care, including contraception, better access to education, more economic opportunity. So those are all factors. And there's a few other negative factors that I'll get to in a couple minutes.

Now, the Edenicity strategy for reaching a desirable population is to be as culturally neutral as possible so that it can be easily embraced by local cultures, and to welcome immigration, because the biggest problem with Edenicity is that nobody lives there yet. So it's a growth strategy.

What’s a desirable number of people?

Now within that framework is permacultural urbanization, meaning that you're going to design cities that sustain people right there, where they live, and also habitat restoration for the areas that are vacated to populate that city. But what's a desirable number of people?

Well, obviously the answer is every living person. Otherwise you're faced with questions like: which large segment into the population doesn't deserve to live? Nobody's qualified to answer that!

At a deeper level, insofar as we can maintain the healthy ecosystems that secure our long term existence, the desirable population is: as many of us as possible! That just leads to a more creative and vibrant world.

But it's not just a numbers game. Not if more people just means more hunger, illness, ignorance, loneliness and violence. No, we want to live in an abundant society, where everyone has their basic needs met, and every person has ever greater power to engage, heal, nurture, explore, discover and create.

It all boils down to this equation for an abundant civilization:

Population × Equity = Achievement.

We want as many people as possible with as much access to the resources they need to be as economically and socially active as they possibly can. So that means things like access to health care, education, economic opportunity.

For example, in 1980, women earned about 10% of undergraduate physical science degrees. By 2000, that fraction had increased to 40%. And in my visits with student groups at UCLA and Caltech, I noticed that the quality of academic discourse was vastly superior to what I had encountered in the early 1980s. It wasn't just greater competition: gender equity had lent a much more professional tone to the discussions.

Today in the business world, the secret's out: social equity is a powerful economic driver. If you Google "Bloomberg diversity," you get 49.6 million results. Here's an excerpt from an article chosen almost at random. It's by Glenn Llopus, published June 21 2016:

"The reality is that diversity and inclusion is no longer just a numbers game. ... It's about bridging the opportunity gaps that will continue to widen if we continue to ignore the message the marketplace is clearly telling us ... as such, American Enterprise must adopt diversity and inclusion as a strategy for growth if they are to compete in the 21st century."

Achievement = Population × Equity, and equity starts with the basics: food, housing, education and health care. These should be designed into a city as public goods, to which everyone has a basic right.

This has been built into the efficient yet still organic physical pattern of Edenicity.

The world's top permaculturist, Geoff Lawton, has said that we need everybody alive on the planet right now to be engaged in fixing the problems that we've caused. Population, in true permacultural fashion, is as much a part of the solution as it is the problem.

Now paradoxically, given the fact that the world is urbanizing very fast, our biggest problem with population may not actually be too many people, but too few.

How do we maintain an urban population?

In a March, 2019 article in Forbes magazine, Neil Howe pointed out that 98 countries are now below the replacement rate of 2.1 children for every woman, including the United States, which has been below replacement levels since 1971, and fallen steadily since 2007 to a level of 1.77 children per woman on average.

Now China, Russia, South Korea, Japan and Singapore and other countries are working hard to promote having children. Russia awards medals and has special holidays for couples. South Korea posts controversial maps of places with fertile women. Singapore has a massive "Do it for your country!" ad campaign.

Now why would there be a decline in the birth rate? Well, we've talked about some of the positive aspects of urbanization that might reduce the birth rate: the increased number of choices that women have in society. But there's also negatives, the main one being financial and economic uncertainty, especially among people of childbearing age.

This is an inevitable and ironic consequence of a winner take all economic system that rewards the haves and punishes the have nots. A growing majority of people finally have the financial security they need to start a family—when it's too late to have one. And then there's a shortage of young workers, let alone family members, to take care of them when they get old.

Is stagnation inevitable in cities? Not with family friendly policy. From Howe's Forbes article "the best way a country can encourage births is to set up a society in which marriage and family is well aligned with other goals shared by most adults. Research suggests that policies that facilitate work/family balance, see the best results over time."

It doesn't take brutal decrees from an elite Vanguard, nor shaming nor cute slogans nor holidays nor maps of fertile women (for goodness' sakes!). That's all frankly ham-fisted. Edenicity is already more child friendly than any of today's cities, as you can see if you download the Reference Design (see the link in the program notes).

All that's needed to maintain a replacement population are some research-driven tweaks at the town and city level to things like universal basic income brackets, access to family leave and daycare, maybe adjusting asset tax levels to give young people a chance and their parents a shot at grandchildren. These are the levers and in this data-rich age, this area of study is a huge opportunity for social scientists.


So in summary, human population has cost the world half of its biomass of energy producing plants, half its biomass of fish, and 86% of its biomass of wild animals—a staggering loss of ecosystem energy and its creative capacity to recover from change. Our population has doubled since the 1972 Limits to Growth study. And it will hit the carrying capacity of the majority of studies within three years.

My own analysis from Episode 2 suggests that, with present day consumption patterns, our population is 20 times too high. But since Cultural Achievement = Population × Social Capital, we want as many healthy, educated people as possible with lives that are as socially and economically active as possible. Ironically, cities, which are the best tools available to achieve this, have experienced sharp drops in birth rates to below replacement rates.

So Edenicity faces the twin challenge of reducing overall land and resource consumption by a factor of 20 while maintaining populations at a replacement rate. This it will accomplish through its physical design, and by adjusting public services, taxes and safety nets to provide just the right level of confidence to young families who want to grow.

I'll have a lot more to say about children in Episode 22. But for now, just imagine what it would be like to grow up without pollution, or noisy traffic, or anxiety about a fast shrinking wilderness.

Going back to the girls' comments at the beginning of this program, so much of what makes people seem stupid and irritating boils down to coping with bad design. This is something I think of every time I get on a freeway. Remember, from Episode 5, that design embodies intention. So let's design cities as sustainable ecosystems where everybody thrives.

Close [music]

If you enjoyed Episode 17, please be sure to subscribe so you don't miss a show. If you haven't already done s, please visit the news link at to download a copy of the Reference Design. And please join me next time, when I'll discuss the Edenicity of governance.

I'm Kev Polk and this has been Edenicity.


Edenicity 17: Maintaining Populations

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