What We Can Learn From Paul Ehrlich

He has been remarkably wrong but he still has much to teach

I want to talk about Paul Ehrlich. Because everybody is talking about Paul Ehrlich.

Last Sunday, as those of you on Twitter will have heard, the American news program 60 Minutes interviewed the biologist Paul Ehrlich for his expert opinions and prognostications about historic declines in a frighteningly large number of the other species we share the planet with. This was provocative, to say the least — because Paul Ehrlich, who is now 90, wrote the 1968 book The Population Bomb, which was a massive best-seller. And as wrong as it was widely read.

“The battle to feed all of humanity is over,” it famously begins. “In the 1970s, the world will undergo famines – hundreds of millions of people will starve to death in spite of any crash programs embarked upon now.” The book goes on like that, laying out the suffering and horrors that must inevitably unfold in the near future thank to soaring human populations. But the inevitable didn’t happen. I won’t go into the details of how Ehrlich was wrong, and the evidence that proves it. If you’re interested, I laid out all that in my second book, Future Babble. Loads of people have been dredging up Ehrlich’s ancient predictions and having a laugh this week. Piling on is ungentlemanly. Worse, it is lazy.

Instead, I want to offer a few thoughts not about Ehrlich but about what we can learn from Ehrlich. To do that, I’ll share some samples from Future Babble and some of my other writing.

But first, experience has taught me that I need to provide a little Demography 101 because so many of the presumptions of Ehrlich’s heyday became so embedded in the culture that even young people today take them to be true. So here are the basic facts.

Background

When the Second World War ended, baby booms in nations helped national populations soar across the developed world. Population growth was even more explosive across the developing world. Experts extended the trend lines and saw trouble coming. In the 1950s and 1960s, overpopulation and the mass starvation it threatened steadily rose in prominence until it was almost universally considered a crisis. When Lyndon Johnson was president, he said the population explosion was second only to nuclear war as a threat to humanity. This atmosphere inspired such gems of 1970s culture as Soylent Green. (Plot spoiler: Soylent Green is people!!!)

But in the 1970s, the Green Revolution delivered agriculture productivity gains that grew until food production far outstripped population increases. In the same decade, large declines in fertility — the rate at which women have babies fell well below what’s needed to merely maintain the present population — made it impossible for the explosive population growth of the early 20th century to continue throughout most of the developed world. This change in fertility subsequently spread to the developing world. It is now the norm, or is becoming the norm, globally. Today, only some portions of Africa and a few backwaters like Afghanistan have high fertility rates (and even in these unfortunate places, fertility has fallen substantially). As a result, the demographic challenge we face in the present and for decades to come is radically different: How do we deal with rapid population aging and population decline? (The latter is far from theoretical. Japan, Italy, Poland, and a host of other countries are already experiencing significant population decline. Remember that demographic trends are a lot like a battleship: It takes ages to get one going but once it has momentum, it takes ages for it turn even a little.)

I should also mention that people often look at the change in fertility rates in the late 1960s and 1970s and say, “aha! That’s feminism and The Pill at work!” With a narrow perspective, that conclusion is plausible. But widen the lens and you see that the post-war baby boom was a brief aberration in a long-term trend of declining fertility rates that goes all the way back to the mid-19th century or earlier. When fertility rates slipped below replacement levels in the 1970s, they were merely resuming a very old trend line they had briefly departed from. Demographers call this long-term, profound shift — from high mortality and high fertility to low mortality and low fertility — the “demographic transition.” Global experience of the past three centuries suggests it is one of the most powerful forces in the modern world.

Forecasts and Worldviews

The Population Bomb wasn’t Paul Ehrlich’s only jeremiad. Far from it. He wrote a string of books. From Future Babble, here is my summary of Ehrlich’s 1974 book.

“In the early 1970s, the leading edge of the age of scarcity arrived,” he wrote in 1974’s The End of Affluence. “With it came a clearer look at the future, revealing more of the nature of the dark age to come.” Of course there would be mass starvation in the 1970s – “or, at the latest, the 1980s.” Shortages “will become more frequent and more severe,” he wrote. “We are facing, within the next three decades, the disintegration of nation-states infected with growthmania.” Only the abandonment of growth-based economics and other radical changes offered any hope of survival. And some countries were doomed no matter what they did. India was among the walking dead, Ehrlich was sure. “A run of miraculously good weather might delay it – perhaps for a decade, maybe even to the end of the century – but the train of events leading to the dissolution of India as a viable nation is already in motion.” Japan is almost certainly “a dying giant.” Same for Brazil. The United Kingdom was only slightly better off. The mere continuation of current trends will ensure that “by the year 2000 the United Kingdom will simply be a small group of impoverished islands, inhabited by some 70 million hungry people, of little or no concern to the other 5–7 billion people of a sick world,” he wrote in an earlier paper. Of course, it could be worse than that: Thermonuclear war or some variety of eco-catastrophe were distinct possibilities. “If I were a gambler, I would take even money that England will not exist in the year 2000, and give 10 to one that the life of the average Briton would be of a distinctly lower quality than it is today.” Not that Americans are in any position to gloat, Ehrlich cautioned. The United States is entering “the most difficult period ever faced by industrialized society.” This dark new age may well see the end of civilization. Ehrlich noted that those in the burgeoning “survivalist” movement were stockpiling supplies in wilderness cabins – “a very intelligent choice for some people” – but he and his wife had decided to stay put. “We enjoy our friends and our work too much to move to a remote spot and start farming and hoarding,” Ehrlich wrote. “If society goes, we will go with it.”

Ehrlich’s writing was all like this. He despised capitalism and consumerism and economic growth. Or to put it more bluntly, he despised modern society. The constant subtext in his writing is that the doom descending on us is righteous. We earned it. It is what we deserve.

The Population Bomb wasn’t simply a forecast that failed. It was an expression of Paul Ehrlich’s passionately felt worldview.

That’s key to understanding why it failed.

If you’re merely trying to foresee and prepare for the future, taking countervailing trends and sources of uncertainty into your analysis, and thinking about what it would take for your expectations to be knocked askew, is obviously important. And you will have no trouble doing it. But if you are passionately committed to a particular worldview — especially if moral judgment is the fire in your belly — you will have nothing but withering contempt for countervailing trends and sources of uncertainty. Prophets never say, “on the other hand...”

Paul Ehrlich always liked to cloak himself in the mantle of science — “as a scientist” was his constant refrain — but his thinking on these public issues has always been profoundly anti-scientific. He doesn't doubt and question and explore with a constant willingness to overturn existing thinking as new truths emerge. He knows the truth. He has always known the truth. The evidence and arguments he marshals do not lead him to his conclusions; his conclusions lead him to marshal evidence and arguments.

Ehrlich doesn’t think like a scientist. He thinks like a prophet. Or worse, a lawyer.

This is why, as a general rule, I want to know what a forecaster’s worldview is. I don’t judge the worldview. I judge the alignment between the forecast and the worldview: The more closely a forecast supports and confirms the forecaster’s worldview, the more reason to think the forecast is less the product of careful, dispassionate analysis than it is an expression of the worldview itself. Conversely, the greater the gap between the forecast and the forecaster’s worldview, the more comfortable I am with it.

Best of all is a forecast the forecaster hates. That’s a forecast I can love.

This isn’t a perfect test, not by a long shot. But it’s a good rule of thumb — the brown M&Ms of forecasting, if you will.

Why He Succeeded

If Paul Ehrlich was so very wrong, why did he get such a huge profile? And not only in 1968, when the accuracy of his forecast couldn’t be judged. Even in the 1980s and 1990s, when it was clear he was wrong, he was showered with awards and sought out by the media. And then there’s that 60 Minutes interview. In 2023! What is it about Paul Ehrlich that keeps people coming back to him for wisdom?

Some of the answer has to be do with worldviews and confirmation bias. But I think the core is more basic.

Ehrlich is a fantastic interview. I know. I interviewed him at length. He’s charming and funny. “Ask me questions and I’ll try to give you honest answers or clever lies,” he kidded at the start of our interview. Ehrlich’s language is clear and compelling. He has a lovely, deep voice. And every word he spokes rolls out with calm, unshakeable confidence.

Imagine Moses with a sense of humour and carefully crafted talking points. Who wouldn’t listen to him?

Here’s my description of Paul Ehrlich on one of his many appearances on The Tonight Show with Johnny Carson.

“This is a little different for us,” says Johnny Carson, the legendary host of The Tonight Show. After an hour kibitzing with the comedian Buddy Hackett about such weighty matters as Hackett’s hair – “You can comb it till your nose drops off and it stays like that,” Hackett observes – Carson will now moderate a debate about the fate of humanity. On one side is the journalist Ben Wattenberg. On the other is a familiar face. “Dr. Paul Ehrlich has been with us a few times before,” Carson says. “He’s a population biologist at Stanford University and his book The Population Bomb has sold nearly a million copies.”

As one might guess from the brown suits, sideburns, and ads for cigarettes – “New Kent Menthol has got it all together!” – this unusual moment in television history took place in August 1970. (As always, Carson sat at his desk. Ehrlich took the chair normally occupied by grinning movie stars, while Wattenberg sat on the couch reserved for sidekicks and second-tier guests.)

Carson asked Ehrlich to get things started by summarizing the basic argument of his book. “The main premise is there are 3.6 billion people in the world today. We’re adding about seventy million a year and that’s too many,” Ehrlich said. “It’s too many because we are getting desperately short of food. Matter of fact, recent indications are that the so-called green revolution is going to be less of a success than we thought it was going to be.” Ehrlich’s deep voice is calm and steady and his words flow smoothly. His left elbow is propped casually on the edge of the chair. He’s young, but with his suit and tie, his relaxed confidence, and “dr. paul ehrlich” flashed on-screen, he is every inch an authority. He knows what he’s talking about. And he knows what’s coming. “The very delicate life support systems of the planet, the things that supply us with all our food, ultimately with all our oxygen, with all our waste disposal, are now severely threatened. I would say that trained ecologists are divided into two schools. There’s the optimistic school, of which I’m a member, that thinks that if we should stop what we’re doing now very rapidly, that there’s some chance that we’ll prevent a breakdown of these systems. There are others who feel that the changes in the weather, that the permanent poisons that we’ve already added to the planet, have already set in train the sequence of events that will lead to disaster. They feel it’s already too late. I think the only practical thing to do is pretend that it’s not too late. So we’re in deep trouble and I’m worried about it.”

Wattenberg gives a decent reply but it’s obvious from the beginning he’s no match. His delivery is hesitant, and his message is diffuse, unfocused. He accepts some of what Ehrlich is saying but suggests it’s “overstated” and should be more balanced, but his alternative vision is as fuzzy as Ehrlich’s is sharp and vivid.

Wattenberg tries gamely to parry Ehrlich’s attacks but Ehrlich is far too quick-witted. When Wattenberg claims, “The new cars have 60 per cent less pollution,” Ehrlich shoots back, “That’s nonsense.”

Wattenberg looks a little stunned. “Well, that’s my data,” he says.

“That’s not your data. That’s the automobile manufacturer’s data for cars that have never run anywhere,” Ehrlich responds.

Wattenberg leans back in his chair. “I can’t debate the scientific data with you.”

Ehrlich smiles gently. “True,” he says. The audience laughs. It’s like watching Mohammed Ali float like a butterfly and sting like a bee. You can’t help but feel sorry for the poor chump in the ring.

Ehrlich delivers all the elements that make a powerful presentation – evident expertise, confidence, clarity, enthusiasm, and charm. He tells a story that is simple and clear and fits the audience’s beliefs and current concerns. (“I consider the Vietnam War and racism to be part of the same mess,” Ehrlich says. “So it’s really one big crisis.”) And Ehrlich is able to move from one element to the other as smoothly as Johnny Carson working his way through the opening monologue.

As I explain in Future Babble, we have a profound psychological aversion to uncertainty. Ehrlich’s message may be dark. But it is certain. And certainty is what the audience craves most.

Compare Paul Ehrlich with Kevin O’Leary. TV’s “Mr. Wonderful” is a money-grubbing, growth-loving, capitalist investor. In that sense, he couldn’t be more different than Paul Ehrlich. But in his style of delivery, he could be Paul Ehrlich’s son. (Although, to be fair to the older man, Ehrlich is far less abrasive and far more charming.)

There are many others like them. Their messages may all be different but they win attention and success by delivering the same goods: entertainment and certainty.

Never Wrong, Ever

When Ehrlich’s appearance on 60 Minutes prompted a torrent of tweets mocking his past predictive failures, Ehrlich responded in kind.

This tweet was itself roundly mocked and criticized. But it’s exactly what Ehrlich has been saying for literally half a century. It’s one reason for his appeal: It’s hard to express perfect certainty if you admit that your past certainties proved to be wrong. Ergo, the Successful Pundit’s Rule: Never admit you were wrong about anything really important, ever. And the Corollary to the Successful Pundit’s Rule: Always admit that you got some inconsequential things wrong because that makes you look like a reasonable person open to being persuaded by the evidence, as opposed to the certainty-peddling dogmatist you are.

From Future Babble:

I asked Ehrlich to summarize his predictive record for me. He responded: “The main things of course that I predicted was that there was going to be continued hunger, that we would not solve the hunger problem in the foreseeable future, and since there are more hungry people now than when I made the prediction, that seems like a valid one. I predicted that if we were to keep putting crap in the atmosphere, we were going to get climate change, although at that time we didn’t know if there would be heating or cooling. . . . I was too pessimistic about the speed with which the Green Revolution would spread. It did reduce the large-scale famines and more or less transform the whole thing into hunger spread around the world rather than famines as concentrated as I would have expected. I shouldn’t say ‘as I would have expected’ [but] ‘as the agricultural scientists I talked to expected’ because it’s not my area of expertise. I totally missed the problems with the destruction of the tropical forests. I did predict that there were going to be novel diseases, and of course we’ve had AIDS since, so that was an accurate prediction.” Notice that the only flat-out mistake Ehrlich acknowledges is missing the destruction of the rain forests, which happens to be a point that supports and strengthens his world view – and is therefore, in cognitive dissonance terms, not a mistake at all. Beyond that, he was, by his account, off a little here and there, but only because the information he got from others was wrong. Basically, he was right across the board.

For the record, Ehrlich’s summary of his predictions, and what happened, is highly tendentious, as I detail in Future Babble.

Again, Ehrlich is far from alone in this. For Future Babble, I interviewed many famous authors who had made predictions in the past that any reasonable person would agree had gone badly wrong. Not one admitted being off about anything that matters. “Oh sure,” they all said in effect, “I got this or that wrong. But generally I was right. Just as I am right. And will always be right.”

Paul Ehrlich, Anti-Environmentalist Asset

One thing that sets Paul Ehrlich apart from run-of-the-mill bloviators is the backlash he has experienced. Typically, old predictions are treated like old newspapers, and, like old newspapers, they are soon forgotten. But as Ehrlich alluded to in that tweet above, conservatives opposed to environmentalism have raked Ehrlich over the coals for half a century.

In fact, it’s a safe bet that a whole bunch of right-wingers were privately thrilled when 60 Minutes brought him back to prime time.

That’s not because right-wingers are feel strongly about predictive accuracy and accountability. It is because mocking and dismissing Paul Ehrlich is a quick and easy way to mock and dismiss any environmental warning.

Of course it makes no sense whatsoever to say, “an environmentalist waving his hands in 1968 was spectacularly wrong therefore environmentalists waving their hands today are spectacularly wrong.” But the conservatives who do this seldom state it so baldly. Instead, they flog Ehrlich’s record and then more or less let the implication unspool itself in the minds of readers.

It’s a damned effective line of attack, as I know from experience. I’ve had right-wingers who read Future Babble cite the parts on Ehrlich — and I’ve watched as people drew the conclusions they intended: Ehrlich was wrong; therefore environmentalists are wrong; therefore stop worrying about climate change.

That is absurd and insidious. And Paul Ehrlich handed that weapon to anti-environmentalists when he chose to barrage the world with hyperbolic, inflammatory rhetoric.

After half a century of right-wingers using Ehrlich this way, you would think environmentalists would have learned the lesson. Many did. But some keep making the same dumb mistake.

The Ehrlich-Simon Bet: A Case Study In How Not To Use Predictions

In the 1970s, Julian Simon was Paul Ehrlich’s chief antagonist. In many ways, Simon was a dogmatic Yin to Ehrlich’s Yang: He was a radical optimist who thought everything was getting better and better, and would continue to improve provided the population kept growing and we didn’t listen to those dumb environmentalists.

To settle who was right, they agreed to a bet. In ten years, would the price of a basket of basic commodities like copper be higher or lower than it was now? Simon said yes. Ehrlich said no.

I love bets of this kind if the questions are well-designed to ensure that the disagreement will really be settled by the outcome. This bet wasn’t well-designed. In fact, it was stupid. The two men disagreed about a whole host of sweeping matters. If the price ended up higher, would Simon actually be proved wrong? Of course not. Nor would Ehrlich be proved wrong if it was lower. It was perfectly predictable — pardon the pun — that whatever happened, one man would claim complete vindication while the other grumbled, “you just got lucky.”

And that’s exactly what happened. Simon “won” and Ehrlich groused that it changed nothing.

Ever since then, cornucopian conservatives have waved The Bet around as definitive proof that they are right about everything. That’s pure confirmation bias. The Bet proved nothing. Meanwhile, Malthusian environmentalists did their best to either forget The Bet or demonstrate that Simon merely got lucky.

A more recent re-appraisal excludes the war years and comes to a very different conclusion.

These long-term appraisals make it abundantly clear that the Simon-Ehrlich bet was incapable of settling anything. So why did these two smart men agree to do it anyway?

Really putting their disagreement to the test would have called for a wide array of bets across multiple timeframes, including some much longer than ten years. That almost certainly would have led to results that were mixed to some degree. And there wouldn’t have been a single moment in which everything was wrapped up.

For people sincerely interested in putting their thinking to the test and learning, that’s no problem. But Simon and Ehrlich were both attention-seeking ideologues. They didn’t want to learn and adjust their views to suit new evidence. They wanted to score points! So they both agreed to roll the dice on a stupid publicity stunt.

I should note that here I am venturing into motive and speculating heavily, which is always fraught. But after long study, that is my best guess as to how The Bet happened even though it was a manifestly silly exercise.

Beware Certainty

I don’t blame Paul Ehrlich for being wrong. Reality is vast and complex. Our ability to comprehend it, let alone predict it, is strictly limited. Being wrong is as inherent to the human condition as breathing and sex.

But I do blame Ehrlich for being certain.

Ehrlich is a scientist. As any scientist knows, nothing is every truly certain. He himself wrote that in The Population Bomb. But he also claimed that he wasn’t over-confident. Indeed, he accepted the possibility he might be wrong and invited the reader to consider what would happen if he were, in fact, wrong.

“Any scientist lives constantly with the possibility that he may be wrong,” he wrote. Recognizing this, it’s critical to ask, “What if my prediction doesn’t pan out? What if I’m wrong? Will the course of action I’ve recommended still be a good one?” Ehrlich thought the answer in his case was obvious. “If I’m right, we’ll save the world,” he wrote. “If I’m wrong, people will still be better fed, better housed, and happier, thanks to our efforts.”

Sounds good, doesn’t it?

But Ehrlich urged a course of action that has been completely forgotten today.

Along with many other scientists, Ehrlich supported “triage,” a policy that called for the withdrawal of food aid for countries that had no hope of avoiding catastrophic famines. One of those countries was India.

If Ehrlich were wrong — as his thought experiment called for — his policy would have cut off food aid which was keeping millions of people alive. And caused the very famines he was predicting.

The logic was obvious and inescapable in 1968. But Ehrlich didn’t see it because he never seriously considered the possibility that he was wrong.

That’s certainty. Certainty is dangerous. Certainty can kill.

This aspect of the story is little-known today, but to me it is the most important. So I’ll close with an article I wrote in 2010 after I interview M.S. Swaminathan, the father of India’s Green Revolution.

I hand the worn and faded book to the old man, and he smiles. He remembers it well.

He is Professor Monkombu Sambasivan Swaminathan. Little-known in this country, Swaminathan, 85, is a legend in Asia. He is the scientist who brought the Green Revolution to India in the 1960s and in doing so he likely saved tens of millions of people from starving to death. Maybe hundreds of millions. He may even have saved India itself.

The book in his hands is Famine 1975! It was a hugely influential best-seller in 1967. "This is Paul and William Paddock," Swaminathan grins. The Paddocks argued that mass global famine was inevitable. It was "foredoomed," as they put it. Efforts to avoid it -- efforts like Swaminathan's -- would fail. "They said Indians, and others, were like sheep going to the slaughterhouse. They'll all die."

The Paddocks were wrong and Swaminathan was right, a fact that was established long ago. But this is not ancient history. The story of how Malthusians like the Paddocks were certain that mass starvation would sweep the world, and destroy nations like India, is an important reminder to beware experts who are sure they know what the future will bring. It's also an important warning for decision-makers: Excessive confidence can be extremely dangerous.

Today, it's often thought that concerns about soaring populations and mass starvation started with Paul Ehrlich's famous 1968 bestseller The Population Bomb. They didn't. All through the 1950s and 1960s, fear rose as rapidly as the number of people. The population crisis made the cover of Time magazine in 1960. In 1967, U.S. President Lyndon Johnson called it the second greatest threat facing the world, after nuclear war.

How could a world of four, five or even six billion people feed itself? By the time Famine 1975! was published in 1967, countless experts had become convinced it could not. "All serious students of the underdeveloped nations agree that famine among the peoples of the underdeveloped nations is inevitable," wrote biologist James Bonner in a review of Famine 1975! published in the prestigious journal Science.

That sense of inevitability was critical. If the catastrophe were merely possible, but not certain, the best response may be to pour resources into stopping it, but, if it is certain to happen anyway, that would be foolish.

Paul and William Paddock understood the logic. They denounced the Green Revolution as an inevitable failure. Instead, they proposed "triage": Rich countries should stop sending food aid to countries that were doomed and instead direct it to those who at least had a chance of averting tragedy. Which countries were doomed? At the top of everyone's list was India.

In The Population Bomb, Paul Ehrlich praised the Paddocks and passionately endorsed "triage." A few years later, the head of the U.S. National Academy of Sciences did the same.

The Paddocks were under no illusions about what "triage" would do. India was on the knife's edge. Whole regions lived "ship-to-mouth" on Western food aid. Cut aid off and "immediate turmoil and possible catastrophe" would result, the Paddocks wrote. In effect, it would cause the very famines they predicted.

They were at least right about that, says Swaminathan, who was in Ottawa to give a lecture at the International Development Research Centre. "It would have been a terrible tragedy," he says. Small wonder that Norman Borlaug "couldn't stand the name Paul Ehrlich," Swaminathan says.

Fortunately, "triage" was never implemented. In 1968, Swaminathan's work caused the country's wheat harvest to soar from 12 to 17 million tons. In 1970, Norman Borlaug, "the father of the Green Revolution," whose work Swaminathan adapted for India, won the Nobel Peace Prize.

When fears of starvation surged again in 1973 and 1974 -- thanks to soaring oil prices and regional crop failures caused by bad weather -- Ehrlich published The End of Affluence. Once again, he declared India doomed. With luck, it might stagger on to the end of the century, Ehrlich wrote, "but the train of events leading to the dissolution of India as a viable nation is already in motion."

In 1975, India did well enough to decline all foreign food aid, and it never looked back. Today, India is an emerging global power.

That is not all there is to the story, however. In the 1980s and 1990s, as food surpluses grew, governments cut funding to agricultural research and rural development. The threat that once seemed so vivid receded in memory. It came to seem inevitable that the Green Revolution would succeed, that there would be no global famine, that the world would have plenty to eat. So why worry about food production? "There was a spirit of complacency," Swaminathan says.

In 2008, soaring food prices caused riots. The phrase "food crisis" returned to headlines for the first time in a generation. Governments scrambled to restore funding, hoping to make up for decades of lost progress.

The problem then and now is overconfidence. As I discuss in my new book, Future Babble, psychologists have amply demonstrated that people tend to be far too confident in their judgments. So, in a world where essentially nothing is certain or inevitable, people often declare themselves "certain" that something is "inevitable," and they make very bad decisions as a result.

The solution is to temper confidence with humility and avoid rewarding overconfident fools. Unfortunately, we struggle with both these points.

In 1994, the United Nations Environment Program made a joint award of its prestigious Sasakawa Prize to two men: Monkombu Sambasivan Swaminathan and Paul Ehrlich. The UN said Swaminathan won for feeding India; Ehrlich won for raising the alarm on population growth. It apparently escaped the judges' notice that Ehrlich had not only made numerous false predictions during the crisis, he had also urged a course of action that would have undermined Swaminathan's work and doomed millions to starvation.

Swaminathan only grins when I mention the award. He is too gentlemanly to be critical. "It puzzled me," he says with a laugh.