by Alan Weisman
It is a temperate-zone analog of what Gretchen Daily and Paul Ehrlich’s students find in tropical Costa Rica. In each, a corollary is that the higher the diversity of plants, the fewer plant-eating pests—apparently because in a diverse, more natural landscape, a wider variety of other insects, bats, and birds show up to prey on them.
The reason to preserve the flight of songbirds between the hemispheres each year is not just for our pleasure at the sound of their voices and sight of their plumage. The reason they migrate at all is to bear their offspring where there is an immense food supply. As they eat the insects out of all the fields and trees, they provide our most important pest control. If we lose those birds, we don’t know what will happen.
The northern California March night turns chilly, and the party moves indoors. Gretchen’s children sit at the piano, picking out melodies for Paul and Anne. Confronted with deepening ecological data and pernicious politics of denial, they are the ones that Ehrlich worries for.
“I don’t say there’s no hope. When I think there’s just a 10 percent chance that we’ll avoid a collapse of civilization, I keep working for Luke and Carmen to make it 11 percent.”
“Enough already,” says Anne.
“I give it less than 50 percent,” says Gretchen. “But higher than 10.”
Everyone hugs. Paul is so proud of his former protégée, who has applied principles of population ecology to the challenge of running the world, from governments to businesses to NGOs on whose boards she serves, tasked with speaking for voiceless nature in a future that either will or won’t hold us all. Apart from stemming consumption, the most intractable puzzle that Paul Ehrlich has encountered is why health decisions about Mother Nature—the mother that gives us life and breath—are made by politicians, not by scientists who know how critical her condition is.
“It’s the immoral equivalent of insurance company accountants making decisions about our personal health.”
Even a president astute enough to appoint his friend John Holdren as his scientific counselor seemingly has failed to consult him; granted another term, perhaps that will change. But meanwhile, Gretchen Daily and her Natural Capitalists, with their expanding worldwide web of scientists, moneymakers, policy shakers, and software communicants, and their deepening data on the cost-effectiveness gained by not squandering nature’s principal, may yet get the plutocracy’s attention. Ehrlich is endlessly grateful to her for trying.
In 1995, the head of the Laboratory of Populations at Rockefeller University, mathematician and biologist Joel E. Cohen, published a book titled How Many People Can the Earth Support? His exhaustive inquiry offered no single numerical answer to that question, except to say that none exists, because it begs so many other questions. Questions such as: At what level of material well-being, and with what degree of distribution among the world’s people? With what technology, in what physical environments, and with what kind of governments? With what risk, robustness, or stability—that is, support people for how long? And with what values?
For the ecologists of the world, who are also sons, daughters, and parents, and whose closest friends are humans like themselves, the answers to all of these are informed in their minds by mounds of data and observation, but truly answered in their hearts. There comes a time when what we do and how many of us do it must be fairly considered, measured, and guided, and that time appears to be this century.
In what has become a parable of our age, traced to an American mathematician and meteorologist, chaos theorist Edward Lorenz, we gather that the beating of a butterfly’s wings in Brazil might touch off a tornado in Texas. In 1945, a butterfly spotted at a Vermont summer camp touched the imagination of a thirteen-year-old boy named Paul Ehrlich. One thing led to another, leading him to the University of Kansas to learn from a sage as impassioned with bees as he was with Lepidoptera. There he met his first and only wife, an artist, biological illustrator, and clear-eyed writer who could draw flawless butterflies and who helped him articulate that the population dynamics of the frailest insects pertain to our own. It was a short step from there to understanding that we are ultimately as fragile as they are. Poison their nectar, usurp their fields, exhaust their sustenance, or disrupt their climate, and they fail—as do we.
Eventually, their communion would reopen a discussion first broached in the eighteenth century by a much-maligned, but never really refuted, economist and cleric named Thomas Robert Malthus. His argument had been all but crushed by the heavy machinery of growth that for the next two hundred years redefined the world. Then, at the point where growth accelerated toward its greatest expression, a book the Ehrlichs wrote reached millions, but brought the same disparagement upon themselves. Legions of pundits and self-styled economic sages tried to drown their message. But it keeps bobbing to the surface.
It isn’t very complex, although an infinite, awesome ecology underlies it:
Keep everything in reasonable balance—chemistry, variety, and numbers—and there is hope for our children, and for the spawn of all the birds and butterflies, to continue, together.
Author’s Epilogue
If the human race maintains its current trajectory, by the year 2100 there will be more than 10 billion of us. With slight perturbations to that pace, we may be several billion more.
Let’s suppose, however—theoretically, social objections aside—that the entire world adopted a one-child policy tomorrow. By the end of this century, we would be back to 1.6 billion, our population in 1900.
That sounds incredible, but it’s true if you think about it: If we stopped reproducing completely, in little more than a hundred years our population would be zero. So holding to just one offspring per family for a few generations would exponentially bring us down to size.
That would reduce our numbers by three-quarters, freeing billions of acres for other species, on whose existence a functioning ecosystem—including our place in it—depends. But the thought of a one-child edict is appalling, even to most Chinese, who’ve tried it. No one wants to be told what to do about something so private and natural.
Nevertheless, many today do choose to limit their procreation, in their own self-interest. In 2008, during a speaking tour in the U.S. state with the highest fertility, Utah, I posed a question about this to audiences that were largely Mormon. Like early Israelites, early Mormons had multiple wives, and for the same reason: It was a strategy to have many children so the tribe would grow quickly. But by the end of the nineteenth century, Mormons had been forced by the U.S. government to abandon polygamy. Still, they kept having a lot of children, and soon a crisis developed, as many Mormon women began dying in childbirth. In order to keep the birth rate up with only one wife per family, women were getting pregnant too quickly after their last delivery.
In a family-centered culture such as the Mormons, motherless families are not only tragic, but a structural threat to the community. Fortunately, Mormons also emphasize education, and by the early 1900s, a growing generation of Mormon doctors realized they needed to counsel women to space pregnancies, lest the Mormon way of life be threatened.
“So it occurs to me,” I said, “that a culture that already chose once to manage pregnancies for the sake of the mother and your society might best understand the need to do so in order to save Mother Nature. Besides, as people who venerate latter-day saints, you may have an advantage over those of us who are still tied to liturgies thousands of years old. You were flexible enough to form a new Christian church in modern times. Flexibility is exactly what we’ll need to respond to the environmental crises we all now face.”
In the discussion that followed, there was wide agreement that it was in their interest to do so. Many complained about the traffic-clogged hundred-mile strip city that now ran from north of Ogden to south of Provo and clawed ever higher up scenic mountains, where pollution billowed high enough to obscure ski slopes. And the water situation in their desert state, part of the depleting Colorado River Basin, frightened everybody.<
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“There is not a single problem on Earth that wouldn’t be easier if there were fewer people,” said a woman in Salt Lake City, and surprisingly, no one objected.
That made me wonder: Was there something in the histories or holy books of the rest of the world’s cultures and religions that might embrace the idea of, so to speak, refraining from embracing as much during the next two or three generations, limiting our progeny to bring us back into balance with the rest of nature—at which point, having reached an optimum number, we could resume averaging two children per family?
But as I began journeying to many different lands to probe that question, another one, universal to our entire species, also arose:
Do we have the will and foresight to make decisions for the sake of descendants we will never know?
Once, humans would begin great cathedrals, understanding that they wouldn’t be completed for 250 years. The last of these are the unfinished Cathedral of Saint John the Divine in New York, begun in 1892, and Barcelona’s Basílica de la Sagrada Familia that Antoni Gaudí began in 1882, whose latest projected completion is 2026—both novel exceptions to the rule that our societies don’t plan much for posterity anymore. Touching appeals to preserve nature for the sake of our grandchildren, featuring kids cuddling threatened koalas, are regrettably ineffective. Our immediate needs ultimately take precedence over theirs.
So the question becomes: Might we benefit right now if everyone agreed to bring population down in the twenty-first century, much as the world’s nations came together during the last century to sign a protocol to save our flickering ozone layer?
In a coffee shop in London’s Liverpool Station, I posed that to twenty-one-year-old Asma Abdur Rahman.
“You mean would it benefit me to only have one child?”
“One or two.” Reaching optimum population would be more gradual if some couples chose to have two, but that option makes the possibility far more realistic. Even Paul Ehrlich assures women friends like Gretchen Daily, and his own daughter, that “two will do.”
She sipped her tea, her expression thoughtful beneath her red and gold hijab. Born in the UK to Bangladeshi immigrants, Asma was one of four children; her father was one of seven, and her mother one of nine. She was also an Oxford graduate getting her master’s at the London School of Economics in environmental policy. Recently she’d made a presentation in class, arguing that population couldn’t be addressed in isolation. “If we don’t bring down consumption in tandem with population, it could be futile, because a wealthy few can use as much resources as the many.”
There is also a risk that families with fewer children become more affluent and consume more. No one she knew of at the London School of Economics had a solution for overconsumption. Neither did I. So back to the idea of lowering the number of consumers.
She typified, she said, educated second-generation Muslim Britons who will never have families as big as their grandparents’. But neither will her cousins in Bangladesh. Since earning the dubious honor of being the world’s most densely populated large country, it has committed to family planning. There are now more girls than boys in Bangladesh’s primary and secondary schools. The total fertility rate, 6.9 children per woman when it separated from Pakistan in 1971, is now 2.25: nearly replacement. A 2011 Vienna Institute of Demography study that modeled different educational scenarios concluded that if every country ambitiously invested in schooling girls, by 2050 there could be a billion fewer people than if nothing changes.
“But women’s education should be promoted for itself, not for bringing down population,” said Asma. “Although,” she added, “that’s a natural side effect.”
No argument here, and I suspect that a study that modeled a world where women have full equal rights would be even more revealing. Tapping wasted female brainpower would be a priceless resource exploitation with no downside. It would also help alleviate feared labor shortages as populations shrink. But I reminded her of my question: Would contributing to that shrinkage benefit her?
“I agree: It’s not the environment that needs to be managed, it’s us. Imagine how pleasant England would be with half the people. But I don’t think I’d be happy having just one. I’ve been shaped so much by having siblings.”
As had I, the second of two children in my own family and the grateful beneficiary of an older sister’s love and guidance. In China, I raised the same question at Guangzhou University. At 13 million, Guangzhou, two hours north of Hong Kong, is now China’s third biggest city—if taken just by itself. It is actually part of the world’s largest metropolitan industrial complex: 40 million people in the Pearl River Delta, where five other now-contiguous cities top 3 million. Their astonishing growth is due to immigration from poorer parts of China for the promise of work in factories.
I was speaking to four hundred college students who, relieved of shackles that restricted an entire prior generation during the Cultural Revolution, were bursting with opportunities to learn and get interesting jobs and make money. The sky was their limit—figuratively, but also literally, and they knew it. Outside, it was possible to gaze directly at the sun, a pallid disk shrouded by the chronic murk of industrial Guangzhou. These Chinese youth knew that the future was theirs, one way or another. Environmental havoc was the bogeyman standing between them and their dreams, and they were keenly interested in how to avert it.
At one point, a thought struck me. “Is every one of them an only child?” I asked my translator.
“Of course,” she replied. “We all are.”
“You’re one of the most animated and intelligent groups of students I’ve ever met,” I told them. “You don’t seem psychologically warped. Don’t you miss having brothers and sisters?”
They acknowledged that they did, but they understood why reproductive restraint was necessary, and they’d adjusted. “Our cousins and closest friends have become our siblings,” the student moderator explained to me.
“We’ve kind of reinvented the family,” said another young woman.
Again, I was reminded how adaptable Homo sapiens are, and how much our flexibility explains how we’ve survived up until now. And maybe portends how we’ll be able to keep surviving.
Our current unprecedented numbers came about quite simply: After remaining nearly constant for roughly two hundred thousand years, during the last 0.1 percent of human history, each year fewer people have died than have been born. That happens only two ways: more births, or fewer deaths—and the two are inextricable. Over the past two centuries, we have become brilliant at beating back diseases or preemptively protecting ourselves from them. We repair damaged bodies. Through much of the world, we’ve doubled average human lifespans from under forty years to nearly eighty.
Had we not done that and let nature take its usual course, it would periodically roar through our population with pandemics, just as it burns through forests to thin overgrowth, and there would be far fewer of us alive. Most of the 2.3 billion of us over forty would not be around. Almost half of all children would have died before age five, and at least one-fifth of all women would have died of pregnancy or childbirth complications before giving birth to all the ones they did.
How our ancestors bore that pain is unimaginable, and we’re not going back, at least not voluntarily. Overuse of our miraculous antibiotics, especially in livestock feed, has rendered many of them useless; like the escalating arms race between coevolving insects and plants, emerging resistant strains of bacteria are now firing back at us. Nevertheless, our medical technology is a benefit we’ve earned by evolving the intelligence to create it—and it also means that there are more people on the planet, because we hang around longer, consuming more food and more everything else. Since all but a few sociopaths oppose raising death rates, if we are ever to lower population, there is only once choice: lowering birth rates.
Is that what most of us would choose? In Utah, as people lamented the relentless urbanity filling their valleys and mountainsides, I ag
ain heard them express something I hear wherever I travel. No matter where people are from, or whatever age or politics or faith, everyone remembers a place where they used to go to escape the clamor and congestion of their lives. A place not too far away, where they could hike, or picnic, or ride a dirt bike. Where they could watch birds—or if they like to hunt, kill birds. Where they could hug trees, or cut them for firewood, or just fall asleep beneath one. But now, that favorite place is gone, vanished beneath strip malls or industrial parks or condominia.
Everyone remembers a world that was better. Less crowded. Lovelier. Where they felt freer.
So did I, as I returned to my birthplace, Minneapolis, to meet the University of Minnesota’s Jon Foley, compiler of the vast planetary database of what we humans grow. First, though, I headed north of the Twin Cities to the Cedar Creek Ecosystem Science Reserve, the prairie grassland research station where for three-and-a-half decades evolutionary biologist David Tilman has documented, among other things, how we weaken the web of life whenever we extract another species.
Logically, most of the world’s settlements occurred near good farmland, much of which unfortunately has disappeared in the past half-century under pavement. Each time I go back home, I am unprepared for how much farther urbanity has advanced. For forty-five miles, I found that State Highway 65 was now lined with ministorages, real estate offices, copy shops, gas stations, discount tire outlets, pet hospitals, Domino’s Pizza, tanning salons, mobile home parks, used car and truck sales, credit unions, Hollywood Video, Auto Zone, Chili’s, Office Max, and sales lots hawking faux colonial, vinyl-sided prefab homes. On Minnesota Public Radio, two economists discussed how many new housing starts the state needed to again have a healthy market.
Like flood victims clinging to life preservers, amid all the cloned commerce were scattered vestiges of my boyhood: farm stands selling sweet corn, and live bait shops. After an hour, I turned onto County Road 24, now known as 237th Street Northeast. It led to Tilman’s field research station, a compound of green wooden buildings in a field of black-eyed Susans and purple bee balm.
