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

by Alan Weisman

  “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 di
d 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.