Ideas Have Consequences
Various bloggers and article writers have done an excellent job of laying out the many mistakes of Stanford professor Paul Ehrlich, whom CBS recently devoted a segment to on “60 Minutes.”
So I won’t bother to repeat their cogent criticisms.
Yesterday I went to the Wall Street Journal to see a letter by my friend and economist colleague Francois Melese in which he took on Ehrlich. It’s an excellent letter. Then I read one of the other letters and felt profoundly sad for the writer, Kenneth Emde of Woodbury, Minnesota.
Emde wrote:
I was a college student when I read Mr. Ehrlich’s “The Population Bomb.” I took it to heart and now have no grandchildren, but 50 years later the population has increased to eight billion without dire consequences. I was gullible and stupid.
The picture above is of Paul Ehrlich.
READER COMMENTS
Richard W Fulmer
Jan 12 2023 at 11:02am
Back in the 1970s while pursuing a degree in Mechanical Engineering, I took a course in Environmental Engineering. It was profoundly depressing. If we didn’t end up buried in our own refuse, air and water pollution would poison us. And if we managed to dodge those bullets, the U.S. was going to run out of oil before 1980.
I briefly toyed with the idea of dropping out of school. Why bother if we weren’t going to survive the decade? Fortunately, I stuck it out, got my degree, got a job and, eventually, a family. Later, I stumbled into Julian Simon’s book, The Ultimate Resource, which convinced me that nearly everything I’d been taught in that class was a lie.
Lying to our kids and telling them that they have no future is a self-fulfilling prophecy. Let’s stop.
Anders Jönsson
Jan 16 2023 at 1:24pm
And yet on almost every metric of the desasters that loomed then, such as actual pollution and managing a growing population, we have improved substantially overall and massively in terms of harm per unit of output. Most of this was incremental profit seeking innovations, such as finding elements to add to aluminum so that we now only need a quarter of materials for soda cans that perform better in other ways. When we pushed cfcs out, it took only a few years because we quickly found ways to replace it and the science was much more direct and clear compared to what we understand of the entire climate. And cultivated land now supports double the population using less acreage… and malnutrition and hunger are on their way out apart from war zones and disaster struck areas. And it is the poor of the world that have made the most astonishing advancements.
How mch of this happened because of the Limits to growth report and related discussions? Not sure. We would have gotten rid of harmful pollution anyway. And found ways to boost agri productivity (and how to suppress it with organic mandates). And protected polar bears and whales. Perhaps the panic is doing more harm than good. But perhaps teenagers need something to panic about. Whether it be tglobal cooling, the end of oil, nuclear annihilation, and now for over three decades, climate change that in some way endangers not only us, but the entire planet. This time, though, many adults are panicking with them. Meanwhile, deserts are shrinking at an astonishing rate and we are richer than ever.
Kevin Corcoran
Jan 12 2023 at 12:47pm
That really is heartbreaking. I wonder if Mr. Ehrlich, himself a father, would flinch or feel even a slight pang of remorse upon hearing this person’s story. I suspect not.
Monte
Jan 12 2023 at 1:28pm
“I was a college student → I was gullible and stupid” is generally a true statement, wouldn’t you agree, Dr. Henderson? Old age and experience help to attenuate the negativity bias we feel when we listen to doomsayers, which the young and impressionable obviously lack.
As a sophomore attending the University of Winnipeg on January 14, 1967, were you daydreaming about being at the Human Be-In in San Francisco’s Golden Gate Park when Tim Leary was speaking to a gathering of 30,000 hippies and offering his sage advice, “Turn on, tune in, and drop out.”, or were you front and center? Or can we assume you were wise beyond your years and more intrigued with the demand and supply of illicit drugs than with experimenting with them? Enquiring minds want to know…
Jon Murphy
Jan 12 2023 at 2:28pm
I cannot speak for David, but in my (admittedly short) experience, I wouldn’t agree. I’ve taught at community college, regional universities, and major universities, and I found my students to be generally skeptical and intelligent.
Of course, there are always that subpopulation within a group that may be gullible. But I wouldn’t say college students generally are.
Monte
Jan 12 2023 at 5:16pm
My statement was more or less tongue-in-cheek. Stupid is, perhaps, too harsh. But on a serious note, I do believe – and statistics will bear me out – that college kids today are certainly more illiterate. And I’m hesitant to back off from gullible (Youth and inexperience, even among college students, is conventional wisdom, my friend.). Case in point: A large percentage of college graduates today believe socialism is superior to the free market, in spite of the fact that history has proven otherwise.
What else can we attribute this to other than gullibility? The failure of economists like Julian Simon, or the success of evolutionary biologists like Paul Ehrlich in winning the hearts and minds or our future generations?
Jim Glass
Jan 13 2023 at 10:19pm
“college kids today are certainly more illiterate”
Well … yes and no. Remember that before World War 2 the high school graduation rate in the USA was on the order of <10%. [NYC data.] And the number of students going on to college was a lot less than that.
Today the percentage of students going to college is about 10x larger. That obviously includes a whole lot more of the “less smart, prepared and motivated” percentage that didn’t even finish high school way back then. Draw a trend line from then to today of the ever increasing numbers trying to get a college education, and you’ll see one reason why educators have been steadily complaining all along that college students just aren’t what they used to be. On average, they’ve always been right. OTOH, that doesn’t mean the top 5% of students today wouldn’t beat the pants off the 5% who went to college at the start point of that trend line.
And remember … Animal House! The superior students of yesteryear. 🙂
Jim Glass
Jan 13 2023 at 11:08pm
It can be attributed to: #1, the strong human bias to believe negative information; plus #2, the strong human drive into tribalism; plus #3, the immense psychic reward derived from the righteous feeling that you are saving the entire world!
Compare to liberal democratic capitalists, trying to improve the world just incrementally, bargaining to do it, often two-steps forward, one-step back, while blindly turning their backs to the grave dangers and injustices facing the entire world!
Add 1 + 2 + 3, get tribal religious crusades to save the world. That the steps needed to save the world justify one’s tribe’s demand to take political power is a nice perk, but not the main motivation (for most). Everyone involved believed they are really good people doing good.
So in my adult life I’ve seen sequentially the marching tribes proclaiming world is doomed by: Ehrlich’s population bomb, “the earth being stripped of resources!”, “running out of oil, the price is going to $1,000/b (2007!)” “burning too much oil, we have to tax it out of use (2017!)” etc.
But much worse, over history we’ve seen the combination 1 + 2 + 3 = Communism, German Fascism (they thought they were good people too!), countless wars, aggressive religions, religious wars, etc. (Many good sources on Putin say he really believes he is fighting the good fight to save the world, or at least the Russian world, today.)
It seems to have been written into our DNA by the forces of pre-industrial age natural selection over 200,000+ years, so I fear we are just going to have to find ways to keep on dealing with it.
Monte
Jan 14 2023 at 1:34am
Ah, yes! Feel-good politics by self-appointed crusaders who unwittingly destroy their world by trying to save it. Even those leaders who understand these are bad policies bend to the will of the people and give them what they want, a golden calf.
I’m afraid you’re right. The pendulum swings eternal.
David Henderson
Jan 12 2023 at 5:20pm
You write:
No. Uninformed? Certainly. Gullible and stupid? Many are; many aren’t.
You write:
I agree with your first part but not your second. The young are more impressionable but that doesn’t mean that a large percent would fall for what Ehrlich peddled.
You write:
Actually I was in grade 12 at the time. I wasn’t daydreaming. I had never heard of the guy. But as for “turning on,” I strongly opposed the use of marijuana and anything stronger when I was 16. I hadn’t thought about legalizing them. I came to favor that when I was 17.
You write:
I didn’t want to experiment with them and, at age 16, I had no views about economics. That’s not quite true: I understand gains from exchange and I understood arbitrage.
By the way, Monte, I’m not sure what any of this has to do with my post.
Monte
Jan 12 2023 at 8:29pm
My apologies, sir. I was just being nosy about your past (but thanks for sharing).
The inquiry about your attitude towards drugs and Leary’s counter-culture shibboleth was, I suppose, a weak segue into your topic that ideas have consequences. I’m sure many who followed Leary’s advice have regrets, just as Emde does having taken Ehrlich’s advice to heart.
Jim Glass
Jan 13 2023 at 9:03pm
“I was a college student → I was gullible and stupid” is generally a true statement, wouldn’t you agree, Dr. Henderson?
“Youth is easily deceived because it is quick to hope.”
– Aristotle
Brad Hobbs
Jan 12 2023 at 5:42pm
This is the man who literally called for the sterilization of Indians as a precursor to granting economic aid. Among the crew, that venerates him, it is not that unusual to be totally unawares of their deeply privileged heartlessness.
vince
Jan 12 2023 at 5:46pm
In defense of Monte’s posts, I read his comments as a version of the cliche, youthful indiscretions. College kids have plenty of that. And it generally doesn’t end but declines and is no longer excused as youthful.
I’m not sure about the connection between Ehrlick and Emde not having grandkids, unless his kids grew up and relied on the book.
David Henderson
Jan 12 2023 at 6:14pm
You write:
I’m not sure either, but I assume that he was saying that believing Ehrlich’s nonsense was what led him not to have kids.
James P. Gerner
Jan 12 2023 at 6:44pm
My contention is that most of this doomsday crap is a mechanism of intended societal control, the latest being you can’t have a gas stove.
Jose Pablo
Jan 12 2023 at 7:29pm
I have 4 kids in college (or about to be). I didn’t read Ehrlich. I wish I had.
Don’t be so sad. Maybe Emde was, after all, well served by such a nonsensical advice. Who knows.
Sometimes we make the right decisions for the wrong reasons
Warren Platts
Jan 13 2023 at 2:42am
Good point Jose. And people still wonder why other people aren’t having more kids. Don’t get me wrong, you’re doing the Lord’s work Jose, and will be blessed in your old age, but unless you’re a multimillionaire that’s long row to hoe!
Dan Griffing
Jan 12 2023 at 8:01pm
“The Population Bomb” was required reading in my 1969 freshman chemical engineering class at Montana State University.
From a factual perspective, none of Paul Ehrlich’s dire “Malthusian” predictions were anywhere close to being accurate, partly because they were based on a the simplistic analysis that apply to non-sentient biological populations.
We have used science to expand our food supply with the “green revolution” and many societies and families have limited their birth rates.
But more importantly we have recognized that our global resources are not limitless and have taken steps to live sustainably.
Many of us are, but with the exception of the political right who are fighting to ignore these important lessons about reality.
Jim Glass
Jan 14 2023 at 2:30am
more importantly we have recognized that our global resources are not limitless and have taken steps to live sustainably.
But capitalism does this for you automatically. Why knock yourself out?
Economic growth comes from increasing productivity: getting more from less. Competition via the profit motive drives greater efficiency, ever less consumption of physical goods, and energy too. (That’s how producers cut costs!) Let’s see some data from when I researched this a bit several years ago.
[] NYC trash collections annually: 2,000 pounds per person late 1940s, under 900 pounds 2010 — as average real income tripled.
[] GDP versus tons of consumption of the 31 most consumed minerals, 1965-2005: GDP per capita: +83%; Mineral consumption per capita, -42%.
[] As GDP grows the non-material portion of it consistently expands: Education, entertainment, medical care, etc. The material portion of GDP has steadily declined: Coal, iron, etc. Circa 1900 US Steel had the biggest production plants in the USA, consuming mountains of coal and iron. Now the plants producing the greatest value make microchips, consuming little bits of sand. Alan Greenspan expanded on this…
And let’s not forget energy. USA from 1979 to 2009…
[] Real GDP per capita: +59%; energy consumption per capita: -14%; cost of energy as % of total GDP: -35%; energy consumption per real dollar of total GDP: -47%.
Many of us are, but with the exception of the political right who are fighting to ignore these important lessons about reality.
Perhaps the political right has been closer to reality than you’ve realized? Economic growth causes less material consumption. Good news! Do you want to save the planet? More world-wide economic growth! More! Only poor countries burn rain forests.
In the meantime relax, enjoy the good news, and have a soft drink. I’m old enough to remember when they came in steel cans and one needed a “church key” to open them. Then tin cans, and a can opener. Then aluminum cans, pop tops. Now light plastic bottles, recycled. Take a look around you and see how this process has long been in action times … everything! And feel good about it.
Warren Platts
Jan 13 2023 at 3:00am
There’s been a lot of gloating regarding Paul Ehrlich, but his basic point — that there must be a limit to population growth — is 100% correct. This is case of the boy who cried wolf. After he was proven wrong so many times, the people started to believe there was no threat. And then the wolves came anyways.
Thus, for the life of me, I cannot understand the reasoning of economists and others who lament that birth rates are below replacement rates in places like China, Europe, and the United States. Honestly, any closed economy (and Planet Earth is a closed economy) that depends on continual population growth is literally a Ponzi scheme that will blow up sooner or later.
Thankfully, the UN is projecting that the world population will shortly peak at 10 or 12 billion and thus there will be no need for coercive measures or cynical policies of allowing famines to run their course.
It seems to me an important area of study for economists is how to run (or not) a national or global economy where population growth is stagnant or negative.
Mark Z
Jan 13 2023 at 1:26pm
“his basic point — that there must be a limit to population growth — is 100% correct.”
That point is literally trivial. I don’t think anyone believes that the earth can fit infinite people.
”And then the wolves came anyways.”
What wolves? Reality has consistently gone in the opposite direction; problems traditionally associated with overpopulation, like hunger, have declined as population has grown. Moreover, the world is soon going to have exact opposite problem of the one Ehrlich has persistently predicted, rapidly aging and shrinking populations.
Jose Pablo
Jan 13 2023 at 2:03pm
How are “shrinking populations” a problem?
David Henderson
Jan 13 2023 at 2:28pm
You asked: How are shrinking populations a problem?
You actually answered your own question, at least in part, with your comment that appeared only 11 minutes later. You pointed correctly to the “gigantic Ponzi scheme” that is Social Security. That’s one of many reasons why we need growing population, especially of young people, either through birth or immigration.
Jose Pablo
Jan 13 2023 at 3:42pm
But David, this problem is not due to “shrinking populations”. It is due to a very bad design of the Social Security.
The reason you point out is akin to say that the problem with Madoff’s Ponzi scheme was that it was running out of new fools.
Warren Platts
Jan 13 2023 at 7:58pm
David, you admit Social Security is a Ponzi scheme, but by artificially adding young workers (from whom rents can be extracted), all you’re doing is kicking the can down the road. And as with all Ponzi schemes, there must be a day of reckoning. By postponing that, the inevitable crash will only be worse.
Let this be said: any economist who claims the number of workers ought to be managed, cannot be described as a free market economist. In a free market, the workers themselves (aka parents, as opposed to technocratic central planners) decide how much labor needs to be provided.
If the rate of reproduction declines below replacement levels, that is above all else a MARKET SIGNAL that the marginal cost of adding another worker is below the marginal expected value of adding another worker.
Subsidizing Labor Supply either directly or through immigration (which is another form of labor subsidization) will have the same effects as subsidizing any other commodity: it will make the situation worse. It will be counter-productive because subsidizing the labor market by artificially adding more workers will only put more downward pressure on wages that will in turn further reduce the incentive to reproduce in a vicious cycle.
Honestly, Ricardo’s theory of wages is far more relevant to the 21st century than is his theory of comparative advantage…
Jim Glass
Jan 14 2023 at 12:13am
Warren Platts wrote:
Nah. Not the way you’ve claimed this before, that somehow “the cost” of children has gone up so much that, as per Ricardo, the resulting “privations” imposed on families cause them to have fewer. That requires one to explain how the average US family could afford to have 7 kids in 1800 but can’t afford even 2 today.
Which suggests life must have been a whole lot better for us all in 1800. When US life expectancy was 34! But, obviously, no…
The reality was known by population economists even in Ehrlich’s day — which makes his entire program such a tragedy of willful ignorance by him and all his esteemed academic followers.
As societies become richer, parents’ need for children declines. In subsistence agricultural societies parents need as many children as they can make — especially considering huge child mortality rates — to work the farm and provide for the parents in their latter years.
But as societies develop trade and financial wealth, parents increasingly move off farms and can provide for their own retirements — and women find they have better things to do with their lives than die in childbirth. The top 2 causes of total deaths in all human history are #1 malaria, and #2 childbirth. So you can see how women might prefer to cut back on it in favor of more time getting educated or having a social life – or, like, anything. (Not to mention the pain that kids can be.)
So societies with advancing economies start having ever fewer children. This is universally so throughout history. Emperor Augustus ordered Rome’s noble families to have more children when they were being outbred by the plebes. (How could the plebes afford to have more kids than the nobles?)
Nah, his theory of wages is all “labor theory of value”, long gone into history. Your aren’t going to find any working economists who agree with you. (Who aren’t old-school Marxists.) Is there a reason for this?
Now, if you want to invoke today’s standard economic analysis by saying the falling economic value of kids to parents now increasingly often is exceeded by the “opportunity cost” to them of having kids — e.g., mom prefers to take the opportunity to keep her youthful looks, have more money to spend on herself, and have more free time in which to spend it, rather than squander all that on a little screeching meemie — then you might have a point.
Jim Glass
Jan 14 2023 at 12:40am
Warren Platts wrote:
Lump of Labor Fallacy
In 1900 the US population was 76 million. Today it is 330 million. What’s happened to wages? As every generation of children has entered the work force to expand it, have wages steadily fallen?
Nah. E.g.: A child grows up, newly enters the labor market, takes say a $25k job — spends the $25k, increasing demand in the market by $25k, creating a new $25k job. Repeat…
Soybeans, cotton, coffee and sugar are commodities. Workers are not commodities. There is a systematic difference.
Warren Platts
Jan 14 2023 at 5:03am
Jim, I can tell from your comment that you’ve never read Ricardo’s chapter 5 (“Of Wages”) of his On the Principles of Political Economy and Taxation because Ricardo’s theory of wages is entirely distinct from his theory of value. Here is the link:
https://www.econlib.org/library/Ricardo/ricP.html?chapter_num=6#book-reader
Jon Murphy
Jan 14 2023 at 7:54am
It’s not “entirely distinct.” The two are related, and his theory of wages falls out of his theory of value (as he discusses).* It is important to understand the framework in which Ricardo is building his model of wages, rather than just a series of “entirely distinct” items. (Really, this goes for any systematic study of any science. Science isn’t picking and choosing; it’s coherent).
Odd that you would choose a theory that has absolutely no evidential support (especially in the 21st Century) as “more relevant” than a theory that has mountains of evidentiary support (especially in the 21st Century). In fact, just the other day you were saying comparative advantage was bad, not because it was wrong, but because it resulted in a pattern you, personally, disliked.
*As a purely scientific and logical manner, one shouldn’t expect an application of a theory to be “entirely distinct” from the theory itself. There can be, of course, be certain factors that matter more for an application than the general theory, but the two shouldn’t be “entirely distinct.” That would imply one or the other (or both) are incorrect.
Jon Murphy
Jan 13 2023 at 3:07pm
Well, from a purely economic perspective, human capital is an extremely valuable resource. It is what allows us to escape the very trap Ehrlich is discussing. With fewer people, there’s less human capital to be devoted to developing and sustaining growth. It’s one of the ironies of his schemes: the very programs he wishes to implement will contribute to the problem he wishes to avoid.
In a related manner, there’s a network effect that goes on in the human world. We learn from each other, we develop and expand, and we make discoveries (accidental or otherwise). This network effect, like any network, is not determined by a single person (node) but rather by the complexity and interconnectedness. The larger the network, the more discoveries can be made. The smaller the network, the fewer.
Humans are, ultimately, social creatures. Other people make our lives better. Shrinking populations are more likely to lead to lower quality of life.
Jose Pablo
Jan 13 2023 at 3:51pm
“network effect”
We are using but a very small part of the “network effect potential” for the planet. I guess very few people from Burundi or Somalia participate in this blog.
Around 1/8 would be my guess (1b people out of 8b).
Helping billions of people to actively participate in this “network effect” seems more sensible that increasing the total number of people, doesn’t it?
“Humans are, ultimately, social creatures”
That’s one of the reasons, I guess, we tend to live in megacities. Tokyo, Delhi or Sao Paulo have a lot to shrink before the number of people living there affects their citizens ability to socialize!
Jon Murphy
Jan 13 2023 at 4:43pm
Why not both? I mean, that is one of the great advantages of free trade: it helps more people connect to the ever-expanding connectivity. I mean, that’s the Hayekian knowledge story: more and more people have more and more knowledge.
Jim Glass
Jan 14 2023 at 1:09am
“Network effects” are well and good, but there’s more than that.
Larger labor force enables greater division of labor, more specialization in more areas, greater productivity.
And there is the “skills-IQ pyramid”. There are very few people say 3+ standard deviations over the norm, but their contributions as discoverers, leaders, innovators etc., can be huge across the whole economy. The larger the population the more of them there will be as a matter of statistics.
Tyler Cowen recently ran an article saying the US’s current attempt to take over the world’s highest-tier computer chip industry will fail because there aren’t enough people in the USA with sufficiently high IQs to do the jobs required, literally.
Jose Pablo
Jan 13 2023 at 2:14pm
“lament that birth rates are below replacement rates”
“no need for coercive measures”
I still don’t understand why politicians (even if advised by the likes of Mr. Ehrlich) think they can “fine tune” the birth rates to get us to the “perfect population” number.
I have way more confident in the wisdom of each couple (or single, don’t want to sound old fashioned patriarchal here) deciding the number of kids they want to have (taking into account the relevant trade-offs involved in having children).
They are unable to get the invasion of a foreign country right, they are unable to manage social security without creating a messy gigantic Ponzi scheme, 50% of violent deaths are never cleared … but they are going to manage the population pyramid right? …
Some professions are impervious to discouragement, I guess
Jim Glass
Jan 13 2023 at 9:40pm
This is false. His actual point was that 4 billion people would be dead by 1989 in “the great die off”. Nothing correct about that!
And the ‘basic point’ you pose on his behalf is as wrong as the commonly heard claim that capitalism is unsustainable — and thus should be replaced with no-growth socialism or some such — because infinite growth is impossible.
Whenever you see anyone refer to the likes of “infinite … perpetual … forever” in economics, someone has gotten something very wrong. (My physicist friends tell me that “infinite” is a sign of something wrong even in physics, which is why they use renormalization to get rid of it.)
You just made the infinite growth argument!
The world’s #1 health problem is obesity, and it is getting worse. Especially in poor countries.
Ehrlich wasn’t just wrong … he was >4 billion x WROOOOONNNGGGG!
Laurel Kornfeld
Jan 13 2023 at 3:17pm
I am a lifelong hippie who for many reasons has never wanted children. I didn’t want them as an 18-year-old college student, and today, at 57, I have no regrets. People who don’t want kids shouldn’t be encouraged to have them, as that only brings more unwanted children into the world.
Jon Murphy
Jan 13 2023 at 3:31pm
And vice versa. People who want kids shouldn’t be misled (or, if Ehrlich has his way, forcibly prevented) about children
Jose Pablo
Jan 13 2023 at 4:01pm
I still find pretty implausible, a couple citing Ehrlich while discussing whether or not to have children.
Looks like a good idea for the script of a tv comedy show, though.
Jon Murphy
Jan 13 2023 at 4:44pm
Sure, but many are influenced by ideas even if they don’t cite them. I know several people in my friend group who say they will not have children because of overpopulation. I doubt they have heard of him, but are yet still influenced by their ideas.
Warren Platts
Jan 14 2023 at 7:48am
I can see from the comments by the economists and other optimists here and elsewhere that the perception is that my (and Ehrlich’s) basic point that there MUST be a limit to population growth at some point is arguing against a straw man: namely that pro-population growth people are advocating for perpetual growth. But the pro-population growth folks say, rightly, that’s baloney; they are not advocating that at all: Of course(!), population growth cannot go on forever because, after all, there is only a finite number of atoms on Planet Earth.
And since Ehrlich proved dreadfully wrong in his early predictions, and now that we have 8 billion people who seem to be doing just fine (as evidenced by the obesity epidemic), then the inevitable peak population will not be reached until sometime in the misty, distant future. Therefore, there is no need now to worry. Thus, since a population larger than 8 billion is desirable, in the meantime, then, we should pursue reasonable policies that promote further population growth.
I think that’s a fair statement of the pro-population growth argument.
My point is that, Ehrlich’s predictions notwithstanding, the day of reckoning is not in the distant, misty future but must happen in a relatively short time on normal human time scales, if not in our own lifetimes.
Consider the following astonishing facts. Out of all 1.5 animal million species, humans themselves have the 2nd most biomass. The only other animal species that outweighs us are cows. Human + livestock biomass exceeds the combined biomass of all wild mammals, birds, reptiles, and amphibians by a factor of 16X. Thus humans and our commensals already dominate the terrestrial ecosystem.
Hence my question to the optimists is this, if 8 or 10 or 12 billion people is below the optimum peak global population, then what do you think **IS** the optimum global population? Please be specific. A plus or minus of 20% is reasonable.
Jon Murphy
Jan 14 2023 at 8:07am
No, it’s quite a strawman, as evidenced by your challenge:
The whole point of optimal levels makes the same mistake:
Ehrlich and other neo-Malthusians make the same mistake of straight-line estimation. It’s a no-growth model (“optimal” only makes sense in a no-growth model).
The point, however, is that growth does indeed happen. Humans are brilliant at finding more ways to do more with less. I’m sure you’re well aware of the bet between him and Julian Simon?
You claim that the day of reckoning is possibly “within our lifetimes.” That’s the same claim Ehrlich has been making for decades now. It’s a lot like the “peak oil” claims. Each time he has been proven wrong, ant not by a marginal of error of 20% but of hundreds. Each time, he has had to push out the “day of reckoning” by decades. I mean, that suggests something crucial is missing from the model.
So, tell me: why is this time different? Why is this model, which has been wrong for centuries, suddenly accurate?
Warren Platts
Jan 14 2023 at 10:31am
Jon, I’m quite sure you managed to squeeze in at least one ecology class in your many years of education; both ‘ecology’ & ‘economics’ derive from the same Greek root word ‘oikos’. Consequently, you’ve heard of the concept of carrying capacity. At that point, yes indeed growth must stop, or else resources will be outstripped, and the population will crash.
Thus, my question could be rephrased as, “What do you think the human carrying capacity of Planet Earth is?” because it sounds like you guys want to go right up to that level before stabilizing.
So let’s do a little thought experiment and extrapolate the human population. For the sake of the argument, we will stipulate the current growth rate of 1% per year. That’s reasonable right? That’s a doubling rate of once every 70 years. Plenty of time for society to adjust!
Now one way of thinking about the future of society is to see how far back we think about the history of our society. And that in turn can be judged by the holidays the society celebrates. Thus we shall consider four holidays:
1. Martin Luther King Day (93 years ago — as of today!)
2. Independence Day (246 years ago)
3. Columbus Day (~500 years ago)
4. Christmas (~2000 years ago)
So we will extrapolate the human population the same number of years into the future, and at each stage try to imagine what that would be like.
MLK Day: 93 years into the future; 1.34 doublings; population = 20 billion; biomass = 0.15 GtC (gigatonnes of carbon) 0.4 GtC counting our livestock at current ratio.
20 billion is probably sustainable. We would probably want to more or less enjoy the same things in life such as the eating of meat, and so our livestock biomass would tend to increase proportionately. However, the combined biomass would now exceed all other terrestrial animal life, including annelid worms & insects. We would probably want to rethink our global warming policies, however, since we’d want to fertilize the air with CO2 and ensure the vast land areas of Siberia & Canada could be farmed.
4th of July: 246 years into the future; 3.5 doublings; population = 90 billion; biomass = 0.7 GtC (which equals current fish biomass)
Given that the Planet’s total terrestrial biomass now is 0.6 GtC, we would probably want to dispense with livestock at this point. But it wouldn’t be that bad because cultured meat technology would be well perfected by then.
Hail Columbia: 500 years into the future; 7 doublings; population = 1 TRILLION; biomass = 7.7 GtC
I have seen people (mainly physicist techno-optimists) actually say that it would be cool if Planet Earth had a trillion human beings on it. Maybe so, but it would seem to require some serious geoengineering at this point. Counting Antarctica, there would be about 1600 square feet for every person on the Planet.
Come to Jesus: 2000 years into the future; 28.6 doublings; population = 3 X 10^18 (10^18 is one quintillion — I had to look that up); biomass = 24 million GtC
At this point, Earth has become Trantor. The population density counting the entire Earth’s surface (including oceans) would be 6,500 PER SQUARE METER (yes, that’s per one single square meter). The entire planet would be honeycombed with a structure 10s of thousands of stories thick. Note that Planet Earth’s current total biomass including plants, bacteria, everything is about 550 GtC.
Thus my question to you, Jon, and the rest of you optimists that ridicule Paul Ehrlich, is exactly where along this timeline (which is extremely short on a human time scale, given that our species is at least a hundred thousand years old) do you think we ought to apply the brakes? When is enough enough? How many is too many?
Jon Murphy
Jan 14 2023 at 11:45am
Apparently, we posted at the same time. I anticipated your thought experiment and explain below why it is incorrect.
Jon Murphy
Jan 14 2023 at 10:42am
Allow me to elaborate on why your summation of the economic critique of the Ehrlich model is a strawman:
Ehrlich isn’t wrong because he missed the peak, even if he missed the peak by over 300%. Any model can do that. The problem is Ehrlich’s model is fundamentally flawed. He not only missed the peak but didn’t even get the direction right.
Ehrlich’s model assumes no technological advancement. He takes a certain number of resources for granted, assumes a certain use rate, develops a “carrying capacity” and goes from there. If Ehrlich’s model is right and he just mistimed the peak, then we’d expect to see real prices generally rising as population rises. We’d expect to see no change in resources consumed per unit of GDP. But we do not see that. In fact, we see just the opposite: real prices and resources consumed per unit of GDP are falling!
Ehrlich didn’t mistime the peak, his whole model isn’t even in the right direction!
I think Ehrlich understands this point on some level. If you check out his tweet justifying his claims, you’ll notice he appeals to everything except results. We tend to see this behavior a lot with planners: they’ll point out how logical their models are, they’ll make appeals to mathematics, they’ll make appeals to peer-review, they’ll make appeals to everything…except results.
Indeed, the whole point that “there is only a finite number of atoms on Planet Earth” is the limiting factor is incorrect. It is indeed mathematically possible to have a finite level of resources and infinite growth: Zeno’s Paradox.
Consider the following simple model:
Define a “quon” as a unit of resources necessarily to maintain a certain standard of living for a single person at time t. Furthermore, only a single quon exists in the entire universe.
At time t, one person exists, consumes a quon, and maintains a certain standard of living. Then, that person discovers a way to maintain the same standard of living with just half a quon.
At time t+1, he consumes a half quon, reproduces, and this new person consumes the other half quon. Then, one of them discovers a way to maintain the same standard of living while consuming only 1/4th a quon. Now the population can grow to 4.
If the quon can continuously be halved, the population can continuously double. A finite resource (1 quon) can support an infinite population.
Now, of course, this model is simple and silly.* I bring it up to show that the fact that there are only so many resources is not the hard upper limit you and Ehrlich consider it to be. The silliness of this model is why I prefer to use the term “indeterminate” rather than “infinite.”
*You may be tempted to respond “the real world doesn’t work that way!” True. Like any model, this is just a simplification to show the flaw in your logic. In the real world, many factors come into play. But the point still holds.
Warren Platts
Jan 14 2023 at 12:04pm
Hmm… It looks like our posts crossed in the mail. However, it is not the case that Ehrlich’s model assumes no technological advancement. The point is technology ultimately doesn’t matter: if the current human population growth rate were to keep going, the numbers very soon get ridiculously huge. Even if we could expand into the Milky Way at the speed of light it wouldn’t take long to consume the entire galaxy.
Consider 7000 years in the future. That’s not a very long period of time. That would be 100 doublings at the current population growth rate. The total human population would be 10^40. Assuming 30 kg per human, our total mass would be 3 X 10^41 kg. The mass of the Milky Way is about 3 X 10^42 kg. Thus it would take about 7,210 to eat up the entire galaxy. The speed of light wouldn’t even allow that.
Bottom line: no imaginable technology can fix a 1% growth rate in a physical system.
Jon Murphy
Jan 14 2023 at 12:12pm
As a factual matter, that is incorrect.
Jon Murphy
Jan 14 2023 at 12:29pm
Here’s the thing:
If you understand Ehrlich’s model as you present it here, not only is that in direct contradiction to what Ehrlich himself says, it’s a model that is utterly useless. Might as well say none of it matters because eventually there is a heat death of the universe.
Warren Platts
Jan 14 2023 at 12:32pm
Because quantum wormholes into the infinite multiverse will be invented in the next 500 years? Is that what you’re saying? Because that’s what it would take, assuming there is in fact an infinite multiverse.
Warren Platts
Jan 14 2023 at 12:47pm
The point of the model is to show that if the human population were to continue to grow at 1% annually, a crisis would be reached in a few short centuries instead of trillion years in the future.
This should not be hard to understand. It’s a matter of physics. And since technology must obey physics, technology cannot allow a 1% population growth rate to continue for more than a few hundred years at most.
Jose Pablo
Jan 15 2023 at 9:11am
I would not devote a lot of time to outline that scenario.
The Gosplan was reportedly bad “designing” the next five years. Let alone the next 2,000!
“People” will find the right way. No need for a masterplan designed by self-appointed (or democratically elected) great minds extrapolating their biases.
Warren Platts
Jan 15 2023 at 12:07pm
Agree 100%. My own take is let the free market decide: let the labor force (aka parents) decide how much labor needs to be provided. And the free labor market seems to be doing just fine.
What dismays me is are these nominal free marketeers suddenly going all technocratic when it comes to below replacement level reproductive rates. Even going so far as to make that an argument for increased immigration. If Americans were reproducing willy-nilly as they were in the 19th century, that would be an argument for more immigration! But if birth rates drop below replacement, that’s a market signal that there are too many workers and thus an argument for putting the brakes on immigration.
Jim Glass
Jan 15 2023 at 1:26pm
The point of the model is to show that if the human population were to continue to grow at 1% annually, a crisis would be reached in a few short centuries instead of trillion years in the future. This should not be hard to understand. It’s a matter of physics.
When I drive my car onto the Interstate it goes from 0 to 60 MPH in eight seconds. If it were to continue to accelerate at that rate it would break the sound barrier in 1 1/2 minutes — and in a mere 2 years 10 months blast past the speed of light, breaking the laws of physics and creating an existential crisis for the universe.
This should not be hard to understand. It’s a matter of arithmetic.
And as relevant to reality as your and Ehlrich’s model of population growth.
Warren Platts
Jan 15 2023 at 2:53pm
lol Jim! Your model is extremely relevant to reality: it clearly demonstrates that if you keep the pedal to the metal, you’re going to run into a crisis in an extremely short time frame. Why is that so hard to understand?
You know, it’s easy to sneer from the sidelines. Why won’t you step up to the plate and tell us what you think the population growth rate ought to be if not zero or negative, and at what population level do you think the brakes should eventually be applied, if it’s more than 12 billion people?
Jim Glass
Jan 16 2023 at 12:06am
Well, given your model of perpetual constant compounding we certainly don’t want the rate to be negative, being that any rate <1.00… will result in the extinction of humanity — just as certainly as any rate >1.00… will result in the crust of the Earth collapsing under the weight of human meat. And as a rate of precisely 1.0 seems very improbable, I guess your model tells us that humanity is doomed.
OTOH, given the reality that birth rates are highly variable over time (and currently plunging world-wide) while the major nutritional problem of the world today for the first time in its history is obesity, I don’t see any reason at all for even imagining there is an “ought to be” rate. By what standards? Why not just let parents decide?
Exactly *who* do you propose to “apply” those brakes? The last person to actually apply these brakes was Mao. (And it’s been a disaster for China.) He had the same reasons you have. Are you a Maoist?
And of course applying the brakes here in the USA isn’t the issue, right? The USA birth rate is already below replacement. If you are worried about >12 billion, the problem area is the rest of the world. Are you for a Maoist World Government?
Hmm … “The 2022 revision of the UN’s World Population Prospects report expected a peak of 10.4 billion in the 2080s, it would then begin to fall.” [Wiki] Not even 12!
OK, so given that world population is projected to fall from the 2080s onward … the state of the growing world obesity problem … and the fact that world income will grow into the 2080s and perpetually beyond … I see no problem at all. No reason to imagine any break-hitting issue at all. ‘Tis a moot point. Next problem, please.
Let’s worry about the world cooking instead.
Warren Platts
Jan 16 2023 at 11:25am
Exactly. That was my point all along.
But then it gets interesting when it comes to immigration, doesn’t it? The people are voting with their wombs on what the population should be, but the sum of all that free choosing can then be undone by the government-set level of immigration.
David Henderson
Jan 15 2023 at 5:30pm
Warren Platts writes, in one of his comments above:
If he means managed by government, which he clearly seems to in context, then I agree. I have the sense that he thinks I disagree. I’m not sure why. Is it because I think that employers should be able to hire immigrants? But wouldn’t government preventing them from doing so amount to government management of the number of workers?
Warren Platts
Jan 15 2023 at 6:30pm
There’s nothing wrong with employers hiring immigrants. We all gotta make a living!
But yes, I guess you’re right David: the government is in charge of the border including who or what gets to cross that border.
Therefore, whatever the level of immigration that’s set by the government, from total closure to leaving the border wide open, it’s all management.
But still, when managing, the government can choose to go with the free market flow, or else choose to buck that trend.
I take it we agree that in a free market, the labor force itself gets to decide the supply of labor.
Thus the question is: When the labor force’s birth rate dips below replacement level, is that a sign of a labor surfeit or a labor dearth?
David Henderson
Jan 15 2023 at 10:27pm
You write:
A labor force can’t “decide.” What’s true is that in a free market, people decide whether to work. They can’t decide for others.
Warren Platts
Jan 16 2023 at 11:17am
OK, I agree my use of “decide” is sloppy in the sense that, strictly speaking, a “real” decision is supposed to be a conscious choice (whatever that means). So let me rephrase:
In a free market, each member of the labor force gets to decide how many future workers she/he will personally supply.
Thus my question still stands. Ricardo would have had a ready answer: he would say that, by definition, if the birth rate is below the replacement rate, that’s because the market wage rate is below the natural wage rate. Consequently, the majority of workers will be unhappy with the current level of compensation. Thus workers are acting rationally when they reduce their rate of reproduction because by reducing the supply of labor, other things being equal, that will cause wages to rise back to at least the natural wage rate (by definition, the wage rate where the population neither declines nor grows).
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