Paul R. Ehrlich, RIP
The "Population Bomb" guy notoriously lost a bet to Julian Simon. But Simon refused Ehrlich's smarter second bet.
At my age, 67, so many people I know a lot about are dropping dead that I can’t get to them all. (My apologies to people who wanted my thoughts on the deaths of Robert Duvall and Robert Redford.)
Paul R. Ehrlich, who died at 93 with two great-grandchildren, one-fourth of the number necessary for Zero Population Grown (an organization he helped found in 1968), was a Stanford entomologist who became famous for his 1968 book The Population Bomb about how billions would starve to death real soon now. (His self-confidence led him into putting dates on his forecasts.)
Besides his ego, Ehrlich had a fine radio-announcer voice and was a frequent guest of Johnny Carson, appearing about 20 times on the Tonight Show.
By the way, Johnny had a lot more scientist guests, such as Ehrlich and Carl Sagan, than recent talk show hosts. If you are a podcaster, you owe it to yourself to read the short chapter in Lucifer’s Hammer by Larry Niven and Jerry Pournelle that’s told from inside Carson’s skull as he figures out on the fly how to make interesting to the vast but sleepy American viewing public the two amateur astronomer nerds he’s booked on the Tonight Show who have discovered a comet that appears to be headed directly for the Earth with apocalyptic potential.
Also … sorry about wasting your time a year ago on asteroid YR4 that had a 1.3% chance of hitting Earth in 2032, but then went off of on an orbit that’s no worry (for awhile). I’m a pretty laidback fellow, but I have to admit that I got slightly worried about that asteroid whose chance of whomping the Earth kept increasing in early 2025 to almost 2%, before vanishing.
So, I’m not going to be quite as harsh as everybody else is being about Ehrlich’s catastrophe-mongering.
Ehrlich was hardly the first to worry about overpopulation. For example, in 1950 the science fiction writer Robert Heinlein wrote a terrific juvenile novel called Farmer in the Sky about how Earth would get so overpopulated that people would migrate to a moon of Jupiter to farm. (Farmer in the Sky would appear to be the main inspiration for the Nolan brothers’ 2014 film Interstellar.)
Heinlein posited only a few new inventions, such as a super efficient “torch ship” that could exploit Einstein’s E=Mc-squared law for space travel and a “heat trap” or artificial greenhouse effect that would melt the ice caps of Ganymede and release oxygen into the atmosphere. Thus, most of colonists’ daily life is like that of sod-busting pioneers on the Kansas prairie a few generations before Heinlein. Granted, it was a story about boring old farming, but it’s farming in outer space! So it was neat and keen to Heinlein’s adolescent fans in 1950.
Toward the end of the book, on a Boy Scout camping trip, the youthful narrator Bill’s scoutmasters have a memorable argument over the future:
… Mr. Seymour, the boss agronomist, said, “I’m not so much worried about where life came from as where it is going--here.”
“How?” I wanted to know. “In what way?”
“What are we going to make of this planet? We can make it anything we want. Mars and Venus--they had native cultures. We dare not change them much and we’ll never populate them very heavily. These Jovian moons are another matter; it’s up to us. They say man is endlessly adaptable. I say on the contrary that man doesn’t adapt himself as much as he adapts his environment. Certainly we are doing so here. But how?”
“I thought that was pretty well worked out,” I said. “We set up these new centers, more people come in and we spread out, same as at Leda.”
“Ah, but where does it stop? We have three ships making regular trips now. Shortly there will be a ship in every three weeks, then it will be every week, then every day. Unless we are almighty careful there will be food rationing here, same as on Earth. Bill, do you know how fast the population is increasing, back Earthside?”
I admitted that I didn’t
“More than one hundred thousand more persons each day than there were the day before. Figure that up.”
I did. “That would be, uh, maybe fifteen, twenty shiploads a day. Still, I imagine they could build ships to carry them.”
“Yes, but where would we put them? Each day, more than twice as many people landing as there are now on this whole globe. And not just on Monday, but on Tuesday, and Wednesday, and Thursday--and the week and the month and the year after that, just to keep Earth’s population stable. I tell you, it won’t work. The day will come when we will have to stop immigration entirely.”
He looked around aggressively, like a man who expects to be contradicted.
He wasn’t disappointed. Somebody said, “Oh, Seymour, come off it! Do you think you own this place just because you got here first? You snuck in while the rules were lax.”
“You can’t argue with mathematics,” Seymour insisted. “Ganymede has got to be made self-sufficient as soon as possible--and then we’ve got to slam the door!”
Paul [the most brilliant of the the scoutmasters] was shaking his head. “It won’t be necessary.”
“Huh?” said Seymour. “Why not? Answer me that. You represent the Commission: what fancy answer has the Commission got?”
“None,” Paul told him. “And your figures are right but your conclusions are wrong. Oh, Ganymede has to be made self-sufficient, true enough, but your bogeyman about a dozen or more shiploads of immigrants a day you can forget.”
“Why, if I may be so bold?”
Paul looked around the tent and grinned apologetically. “Can you stand a short dissertation on population dynamics? I’m afraid I don’t have Jock’s advantage; this is a subject I am supposed to know something about.”
Somebody said, “Stand back. Give him air.”
“Okay,” Paul went on, “you brought it on yourselves. A lot of people have had the idea that colonization is carried on with the end purpose of relieving the pressure of people and hunger back on Earth. Nothing could be further from the truth.”
I said. “Huh?”
“Bear with me. Not only is it physically impossible for a little planet to absorb the increase of a big planet, as Seymour pointed out, but there is another reason why we’ll never get any such flood of people as a hundred thousand people a day--a psychological reason. There are never as many people willing to emigrate (even if you didn’t pick them over) as there are new people born. Most people simply will not leave home. Most of them won’t even leave their native villages, much less go to a far planet.”
Mr. Villa nodded. “I go along with you on that The willing emigrant is an odd breed of cat. He’s scarce.”
“Right,” Paul agreed. “But let’s suppose for a moment that a hundred thousand people were willing to emigrate every day and Ganymede and the other colonies could take them. Would that relieve the situation back home--I mean “back Earthside’? The answer is, ‘No, it wouldn’t’.”
He appeared to have finished.
I finally said, “Excuse my blank look, Paul, but why wouldn’t it?”
“Studied any bionomics, Bill?”
“Some.”
In Heinlein books, the main character teens have an IQ around 150.
“Mathematical population bionomics?”
“Well-no.” “
But you do know that in the greatest wars the Earth ever had there were always more people after the war than before, no matter how many were killed. Life is not merely persistent, as Jock puts it; life is explosive. The basic theorem of population mathematics to which there has never been found an exception is that population increases always, not merely up to extent of the food supply, but beyond it, to the minimum diet that will sustain life--the ragged edge of starvation.
In the early 1750s, Ben Franklin pointed out in Observations Concerning the Increase of Mankind the traditional English alternative to Malthusian population growth: late marriage.
And on his triumphant first trip to France in 1776, the widower Ben may have been introduced to French 18th Century developments for avoiding the Malthusian trap.
But Americans in 1950 tended to be more focused on rapid population growth in Italy, China, and Egypt.
In other words, if we bled off a hundred thousand people a day, the Earth’s population would then grow until the increase was around two hundred thousand a day, or the bionomical maximum for Earth’s new ecological dynamic.”
Nobody said anything for a moment; there wasn’t anything to say.
Presently Sergei spoke up with, “You paint a grim picture, boss. What’s the answer?”
Paul said, “There isn’t any!”
Sergei said, “I didn’t mean it that way. I mean, what is the outcome?”
When Paul did answer it was just one word, one monosyllable, spoken so softly that it would not have been heard if there had not been dead silence. What he said was:
Paywall here.
