Countdown: Our Last, Best Hope for a Future on Earth?

by Alan Weisman

  “The more family planning, the less abortion. That truth is as simple as the existence of water.” She’s proud that her country was the first in Latin America after Cuba to reach replacement rate. She’s proud that her church supports her work. Some Jehovah’s Witnesses, she says, aren’t having children at all, taking environmental destruction and rising world tensions as signs of the End Times. Contraceptives make it easy to wait to have their families after the eternal resurrection on Earth commences.

  “It’s a religion that makes sense, not one that emotionally jerks you around.”

  ii. The Rivet Poppers

  Five hours south of San José, Gretchen Daily stands in a coffee field just above the Panamanian border, afraid to move, because the pregnant fruit bat hanging from her forefinger has clearly fallen asleep, and Gretchen doesn’t want to wake her. “Hey, guys, how long am I supposed to stand here?” she asks her two Stanford graduate students seated at a nearby white plastic field table.

  Chase Mendenhall and Danny Karp, headlamps trained over the specimens they’re measuring with calipers, grin at each other and don’t answer.

  It’s an hour after dusk. Costa Rican researchers and more Stanford biology students are bringing in the catch from twenty mist nets they set out twice a day: at 4:30 a.m. to trap birds, and at dusk for bats. The gossamer nets, twelve meters long, woven of black polyester thread the thickness of a human hair, are invisible before sunrise and after sunset. The students string them like phantom volleyball nets from bamboo poles between the rows of coffee plants, across flyways that connect silhouetted patches of forest that edge the plantation.

  This is a pretty good haul, Gretchen sees, as she waits for her bat to awaken. Because it seemed stressed by its entanglement with the mist net, after banding, Chase laid it in the “bat ICU”—a cardboard box containing a hot-water bottle—until it calmed. He then hung it on Gretchen’s finger, but rather than flying off, it swung serenely and dozed off. Meanwhile, from soft cotton bags, the students are handing Chase tent-making bats, broad-nosed bats, orange nectar bats, a pale spear-nosed bat, a Sowell’s short-tailed bat, a tiny insectivorous hairy-legged myotis, and a chestnut short-tailed bat. Once again, no Spix’s disk-winged bat—a beautiful, long-eared, reddish-brown and cream-colored creature that clings to the insides of curled-up heliconia leaves—but they know they’re around: they’ve recorded their calls. There are sixty-one native bat species here—nectar feeders, seed eaters, insectivores, and fruit eaters—but except for isolated ribbons, their forest has been turned to coffee plantations.

  This is Coto Brus, a 360-square-mile canton in southern Costa Rica’s Pacific watershed. Until the early 1950s, its jungles were barely touched by humans, other than indigenous Guaymí hunters. Then, several Italian families who’d lost their farms in World War II were offered homestead grants to settle this ostensibly empty land in exchange for declaring loyalty to Costa Rica, which needed settlers to discourage Panama’s expansion interests.

  Within a decade, exploding population was also pushing native Costa Ricans to this remote outpost. Clearing land was the way to stake a claim, and they used the fastest way possible. The dollar and ecological value of precious hardwoods that vanished in smoke during what is remembered as el fosforazo—“the torching”—is incalculable. By the late 1970s, three-fourths of the rainforest was gone. What remained was mostly on slopes too steep to cultivate.

  The Stanford researchers are trying to determine how much biodiversity this fragmented countryside still sustains, and whether that biodiversity somehow contributes to the success of the agriculture. If coffee plants closest to the forest turn out to be the healthiest—meaning free of pests such as la broca, a tiny black African coffee-bean borer that recently turned up in Costa Rica—that would suggest that something from the forest is eating them. In Africa, where coffee originates, la broca’s natural predators are tiny wasps; Brazil tried importing them as a natural pest control, but they didn’t thrive there. The fact that Costa Rican coffee has been spared until recently, Gretchen Daily’s team surmises, may be due to any of several small insectivorous birds—rufous-capped warblers, slaty-and pale-breasted spinetails, or tropical gnat-catchers—that reside in thin bands of remaining forest in the most rugged parts of this green landscape. Or it may be these bats: in the coming weeks, Danny Karp will spend most of his waking hours collecting and preserving bat and bird guano from plastic sheets laid below the mist nets, carefully noting which species hanging in the mesh corresponds to which pile of poop, which he and laboratory techs back at Stanford will then analyze for la broca DNA.

  This is a lot of work. Chase has a study under way to quantify the benefits from single trees still standing in farmers’ fields. By her own description, Gretchen nearly went blind one year here at a microscope, trying to distinguish some six hundred species of local native bees by minute differences in how hairs grow on their heads. Since no one here can keep European honeybees anymore since they turned lethal after crossing with African killer bees, she was searching for possible native pollinators.

  Eventually she found twenty bee species with coffee blossom pollen on their bodies. All live in the forest and don’t like to fly very far from it. When she and her team explained in agricultural extension offices that they were testing whether Costa Rica’s most important commercial crop, coffee, depended on the number of bees available to transfer pollen, they were told that of course it didn’t: modern cultivars are self-pollinating, and don’t need help from insects. Daily, whose thick blond hair and jogger’s frame belie the fact that she’s in her late forties, took this assertion that pollination is irrelevant as the latest government malarkey she’s heard throughout her career in various countries, including her own. Recent research she’d seen suggested that coffee yields were lowest in tropical countries with the least amount of rainforest left. Since wherever coffee grows in the Americas was previously rainforest, she had a hunch that the difference might be due to missing pollinators.

  So they’ve counted the beans harvested from dozens of individual coffee bushes at varying distances from the forest patches. “We’ve found that yields from bushes adjacent to rainforest were 20 percent higher than plants a kilometer away,” she says, as the fruit bat dangling from her index finger finally stirs and flaps back into the night. “For one farm, the difference the rainforest made added up to $60,000 per year.”

  Next came seeing whether birds as well as bees also help agriculture, and now they’ve added bats. Besides continual netting and banding, the bird research has included years of pinpointing the range of local species by using false eyelash glue to attach radio transponders the size of an M&M onto 250 of them—including tiny ones like white-ruffed and blue-crowned manakins, which weigh around a third of an ounce.

  The reason for taking all these pains is that Gretchen Daily and her colleagues at Stanford’s Center for Conservation Biology believe that the future of biodiversity will be determined by what happens in agricultural countrysides across the Earth’s tropics. In a world where 40 percent of the nonfrozen landmass is either cultivated or grazed, there is logic in this idea. However, to many conservationists, suggesting that human-altered ecosystems can support biodiversity is sacrilege.

  “Whenever we publish a paper,” says Daily, “some reviewer calls it dangerous, or ‘highly emotional.’ We’re told that as conservationists, we’re supposed to be concentrating on saving the rarest of the rare.”

  She has no objection to anyone’s efforts to do that. Unfortunately, however, “rarest of the rare” often means functionally extinct—species such as California condors, with so few individuals left they no longer play a role in the ecosystem. In the meantime, every species that still does play a role is clinging ever more precariously to the planet where they make their living. Ensuring that they still can has her attention now, especially since one of those species is her—our—own.

  Besides, she is used to controversy. She springs from a veritable royal academic
lineage of it.

  Gretchen Daily came to her life’s work through a case of mistaken identity. In the mid-1980s, she was a junior at Stanford, still sampling majors and needing a job to make tuition. A posting caught her eye; a professor named Paul Ehrlich was hiring people to check data entries for his research. Gretchen recognized the name—or so she thought. The daughter of a U.S. army doctor, she had grown up partly in Germany, where the federal agency that regulates vaccines and medicines is the Paul-Ehrlich-Institut. She wasn’t aware that its namesake founder, who won a Nobel Prize for developing chemotherapy, had been dead since 1915.

  She took the job, and found that it was a different Paul Ehrlich. This one was a lanky, joking biologist who handed her thousands of records dating back to 1959 of checkerspot butterfly catches he’d made in Colorado, which she was to verify for accuracy. It turned out to be easy work, as Professor Ehrlich had entered everything correctly. But she was intrigued by his meticulous investigation, how data accumulating over time revealed fascinating detail about these beautiful insects and the mountains they inhabited.

  She switched her major to biology and gradually became acquainted with her boss. She soon learned that while butterfly populations were his passion, he was better known—notorious, by some accounts—for his forays into the ecology of human population. After reading Extinction, the latest book he’d written with his wife, Anne, that connection made perfect sense to Gretchen. Its preface, written as a parable, had become as famous within ecology circles as The Population Bomb was to the outside world.

  It imagined a passenger who notices a mechanic popping rivets from the wing of the airplane he’s boarding. The mechanic explains that the airline gets a great price for them. But it’s no problem, he assures the aghast passenger: with thousands of rivets, the plane surely won’t miss a few. In fact, he’s been doing this for a while, and the wing hasn’t fallen off yet.

  The point is that there’s no way to know how many missing rivets is one too many. To the passenger, it’s insane to remove even one. Yet, the Ehrlichs noted, on the spaceship called Earth, humans were popping them with increasing frequency. “An ecologist can no more predict the consequences of the extinction of a given species than an airline passenger can assess the loss of a single rivet.”

  As Gretchen Daily came to understand, one reason why Paul Ehrlich was obsessed with butterflies was that, like birds, they were valuable environmental indicators, because they’re easy to identify and sensitive to changes—especially changes caused by humans. Sooner or later, the changes affecting butterflies would be affecting the humans as well.

  Ehrlich invited her to the Rocky Mountain Biological Lab field station near Crested Butte, Colorado, where he and Anne went every summer. They lived in cabins in a 9,500-foot alpine valley flanked by ridges only briefly free of snow, and rose at dawn to track birds and checkerspots flitting among groves of spruce and quaking aspen, and in meadows filled with sunflowers, bluebonnets, yellow glacier lilies, and purple larkspur. In the evening, Gretchen joined them and Paul’s best friend, a bearded UC-Berkeley engineer and physicist named John Holdren, who was writing a book on energy, and his biologist wife, Cheri, over dinners of trout that Holdren and Anne Ehrlich caught while Paul and Cheri were catching butterflies.

  Gretchen, dazzled by the minds discoursing across the table, contributed pies she made with local apples and cherries and her rapt, shy attention. She was disarmed by these gifted people: Paul, tall and black-haired, so solicitous and adoring of the wife he towered over; John Holdren with his intelligent gaze; Anne and Cheri’s glowing skin that to Gretchen reflected inner brilliance. Cheri was writing a book on environmental toxins; Anne, who never finished her degree when the birth of their daughter intervened, had published so many papers and books that she’d earned two honorary doctorates. They were all so healthy, fun, relaxed, and made so much imaginative sense that Gretchen wanted to become like them.

  In 1969, a year after The Population Bomb appeared, Paul Ehrlich and John Holdren had responded in the journal BioScience to a frequent objection to the book: that modern technology would surely solve the shortages of food, water, energy, and sea harvests that Paul and Anne Ehrlich had predicted if population kept growing.

  Holdren contributed math projecting an alarming tonnage of synthetic fertilizer that would be needed indefinitely to feed ever-expanding human civilization, and its inevitable chemical consequences. He calculated that nuclear plants, then touted as the answer to the future, would run out of uranium long before the world could be powered by atomic energy.

  He also mentioned a fact largely unnoticed in the 1960s: atmospheric CO2 had risen 10 percent since the beginning of the century. Factoring that news with soaring energy demand and waste heat that power plants generate, including the ones in vehicles, he and Ehrlich calculated that in less than a century, the Earth would be looking at drastic, if not catastrophic, climatological changes.

  Over the next two years, Ehrlich and Holdren wrote eighteen articles for the national magazine Saturday Review, discussing the fallout of overpopulation in lay language. They boiled human impact on the environment down to a single expression, multiplying the number of people by their consumption level and by the technology needed to produce whatever they were consuming. The resulting equation, simple enough for anyone to understand, is now a standard in ecology:

  I=PAT

  (impact = population X affluence X technology)

  In 1977, with Anne Ehrlich they published a textbook called Ecoscience. At 1,051 pages, it was a compendium of how the planet’s land, sea, and atmosphere interact. To the Ehrlichs’ biological research, John Holdren added hard numbers and expertise in energy to estimate what it might take for humanity to forge a sustainable relationship with the rest of nature. Ecoscience showed how quickly resource levels were changing, and projected how long it might take civilization to change course. It speculated how fast technology needed to evolve to maintain a decent standard of living if human numbers kept surging.

  It was a hugely comprehensive, successful textbook, but it also became known beyond academia because of its analysis of how runaway population growth might be slowed. As scientists, the authors had researched every theoretical possibility ever broached. Three decades later, some of them would be selectively resurrected when President Barack Obama appointed Holdren as his science advisor.

  Holdren’s attackers disregarded the fact that in the same sentence that discussed adding a human sterilant to drinking water supplies or staple foods, he and the Ehrlichs rejected it as horrifying to the public and to themselves. Another option envisioned 30-year contraceptive capsules to be inserted in women at puberty, removable “with official permission, for a limited number of births.” Acknowledging how chilling this was, the authors reiterated why they were raising such repellent conjectures: Unless current trends in birth rates were reversed, some countries might soon resort to compulsory birth control.

  A year after Ecoscience’s publication, China announced its one-child policy.

  An inserted contraceptive capsule, the Ehrlichs and Holdren allowed, might be acceptable if it could be removed whenever a woman chose, then replaced after childbirth. This would solve what many family planners call the biggest problem of all: the fact, as studies even today show, that around half of all pregnancies are unintended.

  “Unwanted births and the problem of abortion would both be entirely avoided,” they wrote. But, they added, the logistics of keeping the entire female population on a continual steroid dosage rendered this contraceptive prospect prohibitive as well. Nevertheless, in 1983, Norplant, a hormonal-releasing capsule worn up to five years beneath the skin of the upper arm, would appear. Along with several others, it is still used widely.

  Holdren and the Ehrlichs considered legal bases for population laws. As the U.S. Constitution balances individual rights with a society’s compelling interests, they noted, a mandated limitation on family size might be no more unreasonable than requiring men
to serve in the military. But, they correctly guessed, the reaction to this opinion among conservatives who advocate both minimal government intervention in people’s lives and robust national defense would be outrage.

  “Compulsory control of family size,” they concluded, anticipating the outcry, “is an unpalatable idea, but the alternatives may be much more horrifying.”

  So much so, they warned, that conceivably someday people might actually demand such control. Before scarcity and civil order devolved into food riots and water wars, “A far better choice, in our view, is to expand the milder methods of influencing family size preference, while redoubling efforts to ensure that the means of birth control are accessible to every human on Earth within the shortest time possible.”

  John Holdren went on to a chair at Harvard’s Kennedy School of Government and to become president of the American Association for the Advancement of Science. He was elected to the National Academy of Sciences, the National Academy of Engineering, and the American Academy of Arts and Science. He shared in the 1995 Nobel Peace Prize, for which he gave the acceptance lecture. His appointment as Obama’s science advisor occurred early enough, when Obama enjoyed a Senate majority and the opposition had yet to shape its paralyzing strategy, to assure confirmation. During his hearing, in reply to a Republican senator, he stated that he did not believe in forced sterilization or any coercive form of population control.

  He also responded to an issue raised at the end of Ecoscience. He and his coauthors had imagined a superagency they dubbed a “Planetary Regime,” which might one day combine the UN’s environmental and population programs and expand the UN treaty called the Law of the Sea to manage all natural resources. It would be a steward of the global commons, empowered to control pollution of the atmosphere, oceans, and transboundary waters. Such an agency, they added, also “might be given responsibility for determining the optimum population for the world.”