The good news, if the Guttmacher Institute and UNFPA are correct, is that we’re three-quarters of the way there. According to their figures, as of mid-2012, 75 percent of the sexually active women in the developing world who aren’t trying to get pregnant over the next two years (meaning they’re either spacing pregnancies or avoiding them altogether) are already using contraceptives. They calculate that 218 million unintended pregnancies are thus prevented annually, averting 138 million abortions, 25 million miscarriages, and 118,000 mothers dead of complications from childbirth or backroom abortions.
Subtracting the avoided abortions and miscarriages, family planning in developing countries prevents 55 million unintended births. Since we currently add 80 million people annually—a million more of us every 4½ days—without contraception reaching those women, our ranks would expand by a million more hungry humans every 2½ days. That’s seven more Beijings a year, instead of the four we’re currently adding.
Such big numbers are awfully hard to grasp. “That’s because we evolved in small groups,” says Malcolm Potts. “Until modern times, none of us ever saw more than maybe a thousand people. So most people’s minds go blank after a hundred thousand. Darwin said that we can understand some parts of nature and the universe, but we can’t comprehend them. A billion seconds equal 31.7 years. In the next twelve years, we’re going to add another billion people. So at the rate they’re arriving, we couldn’t even count them.”
Suppose, in the interest of avoiding another billion in the next dozen years, that the quarter-billion1 women who currently don’t or can’t plan their childbearing were able to, and did so. According to Guttmacher and UNFPA estimates, such women annually have 80 million unintended pregnancies. Half—40 million—get abortions, and more than half of those are the unsafe, frightening kind. Another 10 million miscarry. Thirty million have babies, 6 million of whom die before their first birthday.
If all the contraceptive needs in the developing world were met, not all those 30 million unplanned births would be avoided: contraceptives are sometimes forgotten, and sometimes fail. Some women stop using them, fearing side effects, and get pregnant before finding an alternative. Some mistakenly believe that breast-feeding provides total protection. But at minimum there would be 21 million fewer births. Subtract one Beijing per year.
The number of abortions would also drop, from 40 million to around 14 million. For anyone who opposes abortion, that is a powerful pair of numbers. They mean that right now, half the poor women of the world who get pregnant when they can’t afford to do something dangerous, and emotionally and physically painful—and often, by their own or someone else’s reckoning, sinful. They do this whether or not it’s legal, and regardless of what their (invariably male) religious authority permits. Access to contraception for them would prevent an additional 26 million abortions per year worldwide, on top of the 138 million abortions already averted by available birth control—numbers far exceeding any total achieved by pro-life movements. As an added humanitarian bonus, since more than half the abortions that poor women get—22 million—are unsafe, that number would drop to 7 million or less, and some 50,000 women’s lives would be saved.
There are barriers to this happening, such as getting birth control to unmarried women where premarital sex is stigmatized, or to married women who traditionally don’t get to decide when they’re ready to give birth. Some of them will contrive to get an IUD or long-lasting injections without a husband’s knowledge, and some single women will find ways to meet their needs—if those ways are locally available.
Whether they are depends on a surprisingly small amount of money to cover the contraceptive needs of every woman on Earth.
Currently, $4 billion each year is spent on contraceptive care in the developing world. UNFPA and Guttmacher estimate that about double that amount, $8.1 billion per year, could fully meet the needs for modern contraception in the developing world.
Between 2001 and 2011, the United States frequently spent more than that per month in Iraq and Afghanistan.
Nearly a billion of the current amount comes from countries such as the UK, the Netherlands, and Germany. The United States is the biggest donor, but since 1984 the amount depends on who happens to be president. Although the United States helped to create the United Nations Population Fund, UNFPA, in 1969 under Richard Nixon, by 1973 the Helms Amendment prohibited using foreign aid to pay for abortion as a method of family planning. In 1984, the Reagan administration proclaimed by executive order what is still known as the Mexico City Policy (or the “Global Gag Rule”) requiring foreign NGOs to pledge not to “perform or promote [emphasis added] abortion as a method of family planning”—meaning that the option of abortion couldn’t even be mentioned—as a condition for receiving U.S. funding, no matter whose money actually funded the abortion counseling or services.
This policy was rescinded by President Clinton, reinstated by President George W. Bush, and rescinded again by President Obama. Bush II also pulled all U.S. funding from UNFPA, claiming that UNFPA’s activities in China violated the Kemp-Kasten Amendment, which prohibits funding any program that supports coercive abortion or involuntary sterilization. In 2009, Obama reinstated it with a $50 million contribution, a number chopped steadily by Congress in succeeding years.
Most U.S. donations for population programs, however, are not sluiced through the United Nations but go directly through USAID, the world’s biggest supporter of family planning and reproductive health. The rest of the funding comes from private foundations, local governments, and from consumers buying pills and condoms over the counter.
In 2009, 98 percent of UNFPA’s foundation funding came from four American foundations—and 81 percent of that was from just one: the Bill and Melinda Gates Foundation.2 That the fate of the world’s women depends so much on American largesse underscores the fragility of global family planning—especially in the polarized new millennium, as a brutal partisan divide over not just abortion but even contraception has ignited what one side touts as a return to moral values, and the other calls a war on women.
By any name, it would have shocked Republican presidents Eisenhower, Nixon, and even George Bush Senior, who all supported population control.
During the years of Bush the younger, money that would have otherwise gone to international family planning was directed into HIV-AIDS programs. Worldwide, those programs today receive ten times more funding than family planning, a fact that greatly worries Malcolm Potts.
“HIV accounts for 5 percent of the global burden of disease, and it’s taking 20 percent of the money going from rich to poor countries for international health,” says Potts, who was one of the first doctors to bring attention to the threat of AIDS. As frightening as it is, the population crisis scares him more. “In the first five months of this year,” Potts and Martha Campbell wrote in 2011, “world population grew by enough to equal all the AIDS deaths since the epidemic began 30 years ago.”
Most conversations about population growth, Potts says, use the UN’s medium estimate of 9.2 billion people, which was where population was supposed to level off by 2050.
“Now, in a dramatic shift, they say it will exceed 10 billion by 2100. But the UN’s high and low estimates for 2100 are equally possible, depending on how serious the world gets about family planning. The difference between them is just half a child per woman. Half a child less, you get a far more sustainable figure of 6.2 billion. Half a child more, you get 15.8 billion. That last possibility would be utter disaster. So what we do in the next ten to fifteen years will make all the difference in the world.”
Paul Ehrlich, in an old blue sweater and a floppy canvas hat, armed with a pair of trekking poles, punches his way across the Jasper Ridge meadow that he has studied for more than half a century. It is a brilliant, sunny March afternoon, with a breeze masking the growl of Silicon Valley below. At eighty, Ehrlich still has a stride that makes friends quicken their pace to keep up. “Coming up here makes life worthwhile,” he says, gazing happily around the golden grassland, even though the Bay checkerspot butterfly populations he first came to observe in 1959 disappeared here by 1998.
Jasper Ridge, which rises alongside the San Andreas Fault, was part of the original farm that became the Stanford University campus. Ehrlich often says that his one substantial contribution as an ecologist was saving this uplift from the development that devoured surrounding farms and woodlands. For a decade, the maneuvers to create this two-square-mile experimental biological reserve occupied nearly a quarter of his time, as Stanford’s finance division considered it ideal for a large, profitable subdivision.
The ridge today looks much as it did then—even better, because the invention of catalytic converters cleared away much of the smog. The lichen-draped valley oaks that Ehrlich sees are just starting to leaf out. The ridge’s dry western slope is covered with spiny chaparral; growing on its wetter, north side are smooth-barked red madrones and Douglas firs; and following the streambeds are redwoods—this is the southern extreme of their range. The golden grasses are mainly invasives like wild oats that came on ships and in imported mission bricks: smog-borne, human-generated nitrogen has favored the growth of these invasive annuals. Part of the current research is to determine what it would it take to restore the perennial grasses that covered California before Europeans arrived—one of some fifty research projects under way here at any given time.
Paul Ehrlich on Jasper Ridge
A downy woodpecker roller coasters between two evergreen oak glades as Ehrlich passes through. During the 1970s, a student project discovered that Jasper Ridge, situated on the Pacific flyway, had the highest density of breeding land birds anywhere in the United States. More than a hundred fifty migratory and resident bird species are found here, as well as bobcat, red and gray fox, weasels, raccoons, mule deer, and mountain lions. A research center here archives fifty years of student projects; a habitat map of two tarantula species by one of Ehrlich’s undergrads, Stewart Brand, who would later publish The Whole Earth Catalog, is still used.
Years before The Population Bomb appeared, Paul Ehrlich had already gained renown among ecologists for the paper he coauthored with Peter Raven, the future director of Missouri Botanical Gardens. It was the first to describe coevolution: how two interacting species, such as butterflies and the plants their larvae eat, each influence the other’s development. Although coevolution is often understood as an ever-escalating biological arms race—in which plants evolve chemicals to repel insects, which in turn evolve immunities—their career-making collaboration came from observing that two distinct species of checkerspots, the Bay and the Chalcedon, were feeding on two different related species of flowers.
Across the meadow, Ehrlich can see an undergraduate biology class examining the saffron-colored sticky monkey-flower, the food that coevolved with the Chalcedon checkerspot. Because it typically grows along edges of trails and roads, it’s a good species for classes to study without stumbling into one of Jasper Ridge’s most abundant botanical species, poison oak, whose little red emerging leaves are everywhere.
It’s too early by a couple of weeks for the Chalcedon checkerspot, a mostly black and white butterfly that resembles the now departed Bay, except with far fewer red spots. What extirpated the latter, Ehrlich now knows, were weather extremes characteristic of a changing climate. The Bay checkerspot’s cycle depends on its caterpillar entering hibernation before the spring rains end and its host plant dries out. Beginning in the 1990s, years of unusually heavy spring rains that slowed the caterpillars’ feeding began alternating with unusually dry years that deprived them of food—either way resulting in mass caterpillar starvation.
Mass starvation was what Ehrlich began to fear back in 1966, after he, Anne, and their daughter, Lisa, found themselves on a mobbed Delhi street, their taxi marooned in an ocean of humanity. This was before the Green Revolution; as a population biologist, Ehrlich knew the mathematics of doubling times, and when he and Anne compared the human race’s spiraling numbers with crop data, they concluded that by the 1970s, famines would kill hundreds of millions of people—unless, as they wrote in the prologue to The Population Bomb, dramatic programs to increase food production stretched the Earth’s carrying capacity.
“But these programs,” they said, “will only provide a stay of execution, unless they are accompanied by determined and successful efforts at population control.”
Even as their book was published, Norman Borlaug’s miracle hybrids were coming to first harvest in India and Pakistan, and the famines the Ehrlichs predicted for the 1970s were averted. In subsequent decades, pro-growth economists made Paul Ehrlich and his forebear Thomas Robert Malthus their favorite punching bags, never missing a chance to ridicule them. Except, among scientists, no one was laughing. Ehrlich is today one of the world’s most esteemed ecologists, winner of the Crafoord Prize of the Royal Swedish Academy of Sciences, given in disciplines where there is no Nobel Prize, as well as a MacArthur Fellowship, a Heinz Prize (with Anne), and the Distinguished Scientist Award of the American Institute of Biological Sciences. He is a member of the National Academy of Sciences and a Fellow of the British Royal Society, among many others.
Neither was Norman Borlaug among his detractors, issuing the identical warning in his Nobel acceptance speech that Green Revolution crops were only buying the world time, unless population controls were implemented. Yet Ehrlich’s name has continually incited derision outside of scientific circles, especially after a famous wager with economist Julian Simon of the Cato Institute, a free market think tank.
Simon, the cornucopian author of The Ultimate Resource 2 who argued that human ingenuity ensured that resources would never run out, frequently challenged environmental scientists to prove otherwise. In 1980, he bet Ehrlich and Berkeley physicists John Holdren and John Harte $1,000 that the price of five commodity metals of their choosing wouldn’t rise due to scarcity over the coming decade. They selected chromium, copper, nickel, tin, and tungsten—and ten years later lost the bet, having failed to anticipate a global recession during the 1980s that suppressed demand for industrial metals.
The outcome became a publicity windfall for free marketeers, and is still widely cited as proof that Ehrlich, Malthus, and the authors of The Limits to Growth, the 1972 report to the Club of Rome, were and always will be wrong.
Yet in the new millennium, several economists—and The Economist of London—have noted that Ehrlich’s mistake was only one of timing: the following decade, he and his friends would have won. Ehrlich also would have won a second bet he proposed to Simon: that fifteen environmental indicators—including global temperature, CO2 concentration, croplands, forests, and human sperm count—would worsen over a decade. Simon declined to wager.
A few years later, in 1994, Simon would write: “We now have in our hands—in our libraries, really—the technology to feed, clothe, and supply energy to an ever-growing population for the next 7 billion years.” With world population then growing by 1.4 percent annually, the Ehrlichs checked his math and responded that this was unlikely, because at current growth rates, within six thousand years the mass of human population would equal the mass of the universe.
Ehrlich’s vindication is no surprise to him, although there is no joy in being right about matters so disturbing. The unlikely agriculture miracle that he and Anne hoped for in The Population Bomb, which unexpectedly arrived with the Green Revolution, also postponed the timing of what increasingly now looks inevitable. With crop ecologists expecting grain harvests to drop 10 percent for each 1°C rise in average temperatures, and with the world now headed beyond 2°C at present rates of emissions, population will be up, food production down, and dikes may have to protect much of the world’s rice production. Even at a 0.8°C increase, China barely missed losing its winter wheat crop in 2011. Thanks to last-minute March rains, the harvest was saved; few dared imagine the chaos had shaky Egypt, the world’s largest wheat importer, been forced to bid against China for grain.
And no one can predict what North America’s massive 2012 drought portends for future crop disasters. With most of the world’s meals dependent on a few critical monocultures of rice, wheat, and corn—once three rare weeds, until we made them the most abundant plants on Earth—humanity may be just one disease away from a catastrophe that could shake civilization’s foundations. In the past century in North America alone, it happened to elms and chestnut trees. The chance of an epidemic like Ebola wiping us out is far less likely than pathogens blown around the world collapsing our food supply.
The week before Rio+20—the June 2012 UN conference held twenty years after the original Earth Summit—the world’s 105 science academies, led by the Royal Society of Britain, warned that failure to act on population growth and overconsumption would have “catastrophic implications for human wellbeing.” It was no shock to Paul Ehrlich that Rio+20, billed as the United Nations Conference on Sustainable Development, ignored the question of population, for much the same reasons that the Earth Summit did. As in 1992, the Vatican courted support from human rights and feminist groups, contending that population programs unfairly blame poor women for the world’s environmental ills. But as he drives his pickup back into Palo Alto, down six-lane El Camino Real, which formerly passed through orchards, not miles of commerce, Paul Ehrlich has no doubt that the most overpopulated country on Earth is his own.
“There is no condom for consumption,” he says, sorrowing at the unabashed displays of Silicon Valley purchasing power. How to curb human acquisitiveness is more vexing a mystery than finding a unified theory of physics. In the last fifty years, world population more than doubled, but world economic growth increased sevenfold. With luck and contraception, world population might stabilize, but consumption grows on, almost exponentially, as the more people have, the more they want.
“Yet to separate consumption from population,” says Ehrlich, “is like saying the length of a rectangle contributes more to its area than its width.” The United States is the world’s highest per-capita consumer, and its 315 million people are headed to an estimated 439 million or more by 2050. And a new factor has intensified the Impact in the I=PAT formula that he and John Holdren wrote in the 1970s: Population, Affluence, and Technology are further exacerbated by Time.
“The next 2 billion people we add will do a lot more damage than the last 2 billion,” says Ehrlich. Those of us already alive have already plucked the lowest-hanging resources. Like wringing oil from rocks, from now on acquiring things we use will be much harder, involving much more energy and leaving much bigger messes in our wake.
The day after the 2008 U.S. presidential election, Paul and Anne Ehrlich wrote a letter entreating Barack Obama to “put births on a par with deaths.” During the past century, they wrote, humans had made great progress raising life expectancy. “But given the frightening potential consequences of the explosion in human numbers that has followed reductions of the death rate, it is essential to pay equivalent attention to reducing high birthrates as well.”
The goal, they wrote the president-elect, “must be to halt population increase as soon as humanely possible, and then reduce human numbers until births and deaths balance, at a population size that can be maintained with desired lifestyles without irreparable damage to our natural life-support systems.”
They didn’t mention the 2 billion figure they’d previously suggested. They proposed a global discussion over the next several decades “to reach a consensus on those lifestyles and thus on the appropriate maximum population size—which we already know must be smaller than the present 6.7 billion. Fortunately,” they added, “the target can be tentative, since (if we’re lucky) it may well be a half-century or more before a worldwide decline can begin, so there will be decades to consider and evaluate the best level at which to stabilize our numbers.”
Their letter also called on Obama to “immediately drop the Reagan administration’s ‘Mexico City policy’ for killing women worldwide by suppressing access to legal abortion”—which, to their satisfaction, he did within days of his inauguration. By then, Obama had also chosen Ehrlich’s best friend, John Holdren, as his science advisor. The following year, the president signed a bill to make health care and health insurance available to all, and a year later announced that as of 2013, health insurance in America must cover birth control for women with no co-pay. As a result, millions of women who paid up to $50 a month for birth control suddenly found themselves not having to decide between dinner and Depo-Provera.
In a country where nearly half of all pregnancies are unintended, there was finally some reason to feel hopeful. Like most who supported Obama’s candidacy, Paul Ehrlich has had his disappointments with the president, starting with his first-term inattention to climate change. Ehrlich well understands, however, what few Americans who expected Obama to be the new Franklin D. Roosevelt ever stopped to consider:
With more than 300 million Americans, Obama had nearly triple the number of citizens to employ, feed, educate, and medicate as FDR had.
He stops to pick up Anne, and drives across campus to the potluck dinner Gretchen Daily is having for her graduate students. Her Costa Rica team is there, as well as young women who have been doing fieldwork in Hawaii and Colombia, several of the Jasper Ridge staff, and some out-of-town visitors. Paul, a head taller than Anne, leads her solicitously through the airy house into the backyard throng, proudly asking everyone if they’ve met his first wife.
It’s an old joke they’ve all heard, but it’s always sweet to see how much Paul adores her. Anne, the associate director of Stanford’s Center for Conservation Biology, still publishes prolifically with her husband, and is the acknowledged custodian of their prose. They fill plates with wild salmon and grilled vegetables, and settle into lawn chairs and rapt discussion with Gretchen’s young children, Luke and Carmen, both blond as their mother. Gretchen emerges, arms laden with salad bowls. Her laser scientist husband is in Europe; they intersected briefly as she returned from Minneapolis, where she met with partners in her Natural Capital Project. “I was blown away!” she announces, her wide smile suggesting that this was a good thing.
One of those partners, she explains, is the director of the University of Minnesota’s Institute on the Environment, a former astrophysicist named Jon Foley, who started applying higher math to this planet and its atmosphere. “He’s compiled this fantastic data set on food production worldwide that goes down to the county level for the entire globe. It vastly exceeds the UN Food and Agriculture Organization’s own database.”
It is also a key source for the free InVEST program they’ve designed to help decision makers see how conservation can enhance businesses and protect their communities. To make the program broad and powerful enough to benefit users anywhere on Earth requires phenomenal amounts of information. A few years earlier, Foley had realized that while NASA’s global satellite images show what is a forest and what is a field, they don’t reveal who owns that land, what they’re growing, and how they grow it. If they knew that for everywhere and merged it with the satellites’ big picture, he reasoned, they could really understand what was happening on the planet.
He was told that such a huge international project would require thousands of researchers, ten to twenty years, and millions of dollars. But Foley reckoned that every country has a ministry of agriculture with guys with clipboards running around in trucks, asking farmers, “What are you growing this season? How much fertilizer are you using? Who are you selling it to?”
“Bullshit,” he told detractors. “It will take about ten smart undergraduates who can speak different languages and a lot of persistence—and maybe tens of thousands of dollars, but not millions.” So he cast around for students who read Portuguese, Spanish, Chinese, Russian, Arabic, Swahili, Tagalog, and other languages, who were happy to work for $10 an hour at something more interesting than flipping hamburgers. In two years, using interlibrary loans and writing agriculture ministries all over the world, they’d amassed the world’s biggest collection of census data on agriculture, covering every country on Earth.
“The only ones we had trouble with were some whose governments fell apart,” he told Gretchen. “And we don’t have very good information from North Korea.”
But for everywhere else, they had rich data from 1960 to 2010: the fifty-year period that encompassed the entire Green Revolution to the present, which tracked the amount of land, water, fertilizer, and chemicals used to grow 175 different crops. Suddenly they were getting calls from Google, the Gates Foundation, the World Bank, even from hedge fund managers, saying this was a gold mine of data. “Which they make available in the public domain,” says Gretchen, “giving it away as fast as they can.”
Imbuing graphic landscape overlays with Foley’s golden data and housing it on Google with its massive distribution power makes InVest one of the most potent environmental planning tools in existence. Behind its dazzle, however, lurks the scientists’ foreboding for their species and their planet: trepidation that hangs over every inspiring encounter with brilliant colleagues and students, and with their families and children, making every new publication and every international prize bittersweet.
They are asking, and trying to answer, the most serious question in history: How can we humans go on?
In 2008, Jonathan Foley and twenty-eight colleagues from three continents who had gathered at a conference in Sweden acknowledged that they all felt like they were staring over a cliff: Push the planet a little farther in any of several ways, and the world would change dramatically from anything known to humanity before. No one was sure exactly how much farther, or even if it could be known. But they agreed it would be important to try.
The paper they published in the journal Nature—versions also appeared in Ecology and Society and in Scientific American—identified nine planetary boundaries, beyond which the world would enter a phase shift that could prove cataclysmic for humanity. They acknowledged that, while based on the best science available, these were “rough, first estimates only, surrounded by large uncertainties and knowledge gaps” that will require major scientific advancements to fill. The nine boundaries were climate change, biodiversity loss, disruption of global nitrogen and phosphorus cycles, ozone depletion, ocean acidification, freshwater use, changes in land use, chemical pollution, and atmospheric particulates.
Behind each of these was the same unspoken cause: cumulative human presence, for which they did not hazard a boundary. A decision to limit one’s own species is so emotionally loaded that the very idea is as troubling to scientists as it is to any human. Attempting to do so might have unavoidably distracted from this imaginative study that so starkly lay open the state of the planet.
Two of the categories, atmospheric particulates and chemical pollution, they decided had not yet been studied enough to determine Earth’s capacity to absorb them. For three categories, however, the boundaries they proposed had already been surpassed.
One was climate change, for which they concluded that atmospheric CO2 concentrations should not exceed 350 parts per million. At the time of publication, 2009, levels had risen to 387 ppm.3
The second was the amount of nitrogen siphoned from the atmosphere for human use, chiefly through the Haber-Bosch process. The boundary they arrived at was 35 million tons per year, versus the current 121 million. (Phosphorus was still within its proposed boundary of 11 million tons flowing into the oceans, although the current 8.5 to 9.5 million tons of phosphates were already contributing to dead zones at the world’s great river deltas. Another worry about phosphorus, however, is that this essential mineral nutrient is scarce in the planet’s soils, and deposits in Pacific guano atolls and Florida limestone formations are nearly spent. Only one plentiful source remains, in Morocco and neighboring Western Sahara, a barely functioning state whose future stability has agronomists everywhere concerned.)
The third was biodiversity loss. Before the Industrial Revolution, the fossil record suggests, 0.1 to 1 species per million went extinct annually. The acceptable limit they proposed was 10. The actual current loss is at least 100 missing species per million, a figure widely feared to rise tenfold this century. Nothing remotely similar has happened since an asteroid did away with the dinosaurs.
Assigning actual numbers to how much damage to nature is allowable for humans to still thrive was bold but potentially meaningless. How does one quantify biodiversity? By counting species, or counting what they do? Foley found himself posing unanswerable questions like: Is it more important to lose a bacterium or a dodo bird? Or: Do we really need five hundred kinds of hummingbirds? Or do we need five hundred kinds of bacteria that eat the forest litter and turn it into organic matter and free nutrients?
In a world where total animal biomass is mostly insects, and where most species are microbial, our perceptions are skewed by having much more data on things we can see, such as birds and mammals, than on bacteria or nematodes. To pinpoint exactly which ones we can’t live without turns out to be impossible, in the grand experiment called life on Earth, because there is no control group. We will not know for certain until they’re gone, when it will be too late to call them back.
What we do know is that life does far better when there is a greater assortment of it. The world’s longest-running experiment in biodiversity, directed since 1977 by Foley’s University of Minnesota colleague David Tilman, is thirty-two miles north of their campus. On hundreds of experimental plots, prairie grasses grow in various combinations or separated into monocultures. Some receive extra blasts of carbon dioxide, or extra warmth from heat lamps, or varying levels of nitrogen, to test the impacts of all these variables. Most apparent is that primary production—the ability of plants to turn atmospheric carbon into more biomass—is highest where biodiversity is highest. The more kinds of plants, the more efficiently they use different resources in the soil.
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.