Humanity has 30 years to find out.
By Charles C Mann (adapted from his book Wizard and Prophet).
Atlantic March 2018
All parents remember the moment when they first held their children—the tiny crumpled face, an entire new person, emerging from the hospital blanket. I extended my hands and took my daughter in my arms. I was so overwhelmed that I could hardly think.
Afterward I wandered outside so that mother and child could rest. It was three in the morning, late February in New England. There was ice on the sidewalk and a cold drizzle in the air. As I stepped from the curb, a thought popped into my head: When my daughter is my age, almost 10 billion people will be walking the Earth. I stopped midstride. I thought, How is that going to work?
In 1970, when I was in high school, about one out of every four people was hungry—“undernourished,” to use the term preferred today by the United Nations. Today the proportion has fallen to roughly one out of 10. In those four-plus decades, the global average life span has, astoundingly, risen by more than 11 years; most of the increase occurred in poor places. Hundreds of millions of people in Asia, Latin America, and Africa have lifted themselves from destitution into something like the middle class. This enrichment has not occurred evenly or equitably: Millions upon millions are not prosperous. Still, nothing like this surge of well-being has ever happened before. No one knows whether the rise can continue, or whether our current affluence can be sustained.
Today the world has about 7.6 billion inhabitants. Most demographers believe that by about 2050, that number will reach 10 billion or a bit less. Around this time, our population will probably begin to level off. As a species, we will be at about “replacement level”: On average, each couple will have just enough children to replace themselves. All the while, economists say, the world’s development should continue, however unevenly. The implication is that when my daughter is my age, a sizable percentage of the world’s 10 billion people will be middle-class.
Affluence is not our greatest achievement but our biggest problem.
Like other parents, I want my children to be comfortable in their adult lives. But in the hospital parking lot, this suddenly seemed unlikely. Ten billion mouths, I thought. Three billion more middle-class appetites. How can they possibly be satisfied? But that is only part of the question. The full question is: How can we provide for everyone without making the planet uninhabitable?
While my children were growing up, I took advantage of journalistic assignments to speak about these questions, from time to time, with experts in Europe, Asia, and the Americas. As the conversations accumulated, the responses seemed to fall into two broad categories, each associated (at least in my mind) with one of two people, both of them Americans who lived in the 20th century. The two people were barely acquainted and had little regard for each other’s work. But they were largely responsible for the creation of the basic intellectual blueprints that institutions around the world use today for understanding our environmental dilemmas. Unfortunately, their blueprints offer radically different answers to the question of survival. The two people were William Vogt and Norman Borlaug.
Vogt, born in 1902, laid out the basic ideas for the modern environmental movement. In particular, he founded what the Hampshire College population researcher Betsy Hartmann has called “apocalyptic environmentalism”—the belief that unless humankind drastically reduces consumption and limits population, it will ravage global ecosystems. In best-selling books and powerful speeches, Vogt argued that affluence is not our greatest achievement but our biggest problem. If we continue taking more than the Earth can give, he said, the unavoidable result will be devastation on a global scale. Cut back! Cut back! was his mantra.
Borlaug, born 12 years after Vogt, has become the emblem of “techno-optimism”—the view that science and technology, properly applied, will let us produce a way out of our predicament. He was the best-known figure in the research that in the 1960s created the Green Revolution, the combination of high-yielding crop varieties and agronomic techniques that increased grain harvests around the world, helping to avert tens of millions of deaths from hunger. To Borlaug, affluence was not the problem but the solution. Only by getting richer and more knowledgeable can humankind create the science that will resolve our environmental dilemmas. Innovate! Innovate! was his cry.
Both men thought of themselves as using new scientific knowledge to face a planetary crisis. But that is where the similarity ends. For Borlaug, human ingenuity was the solution to our problems. One example: By using the advanced methods of the Green Revolution to increase per-acre yields, he argued, farmers would not have to plant as many acres, an idea researchers now call the “Borlaug hypothesis.” Vogt’s views were the opposite: The solution, he said, was to use ecological knowledge to get smaller. Rather than grow more grain to produce more meat, humankind should, as his followers say, “eat lower on the food chain,” to lighten the burden on Earth’s ecosystems. This is where Vogt differed from his predecessor, Robert Malthus, who famously predicted that societies would inevitably run out of food because they would always have too many children. Vogt, shifting the argument, said that we may be able to grow enough food, but at the cost of wrecking the world’s ecosystems.
I think of the adherents of these two perspectives as “Wizards” and “Prophets.” Wizards, following Borlaug’s model, unveil technological fixes; Prophets, looking to Vogt, decry the consequences of our heedlessness.
Borlaug and Vogt traveled in the same orbit for decades, but rarely acknowledged each other. Their first and only meeting, in the mid-1940s, led to disagreement—immediately afterward, Vogt tried to get Borlaug’s work shut down. So far as I know, they never spoke afterward. Each referred to the other’s ideas in public addresses, but never attached a name. Instead, Vogt rebuked the anonymous “deluded” scientists who were actually aggravating our problems. Borlaug branded his opponents “Luddites.
Both men are dead now, but the dispute between their disciples has only become more vehement. Wizards view the Prophets’ emphasis on cutting back as intellectually dishonest, indifferent to the poor, even racist (because most of the world’s hungry are non-Caucasian). Following Vogt, they say, is a path toward regression, narrowness, poverty, and hunger—toward a world where billions live in misery despite the scientific knowledge that could free them. Prophets sneer that the Wizards’ faith in human resourcefulness is unthinking, ignorant, even driven by greed (because refusing to push beyond ecological limits will cut into corporate profits). High-intensity, Borlaug-style industrial farming, Prophets say, may pay off in the short run, but in the long run will make the day of ecological reckoning hit harder. The ruination of soil and water by heedless overuse will lead to environmental collapse, which will in turn create worldwide social convulsion. Wizards reply: That’s exactly the global humanitarian crisis we’re preventing! As the finger-pointing has escalated, conversations about the environment have turned into dueling monologues, each side unwilling to engage with the other. Which might be all right, if we weren’t discussing the fate of our children.
The Roads to Hell
Vogt entered history in 1948, when he published Road to Survival, the first modern we’re-all-going-to-hell book. It contained the foundational argument of today’s environmental movement: carrying capacity. Often called by other names—“ecological limits,” “planetary boundaries”—carrying capacity posits that every ecosystem has a limit to what it can produce. Exceed that limit for too long and the ecosystem will be ruined. As human numbers increase, Road to Survival said, our demands for food will exceed the Earth’s carrying capacity. The results will be catastrophic: erosion, desertification, soil exhaustion, species extinction, and water contamination that will, sooner or later, lead to massive famines. Embraced by writers like Rachel Carson (the author of Silent Spring and one of Vogt’s friends) and Paul Ehrlich (the author of The Population Bomb), Vogt’s arguments about exceeding limits became the wellspring of today’s globe-spanning environmental movement—the only enduring ideology to emerge from the past century.
When Road to Survival appeared, Borlaug was a young plant pathologist working in a faltering program to improve Mexican agriculture. Sponsored by the Rockefeller Foundation, the project focused on helping the nation’s poor corn farmers. Borlaug was in Mexico for a small side project that involved wheat—or rather, black stem rust, a fungus that is wheat’s oldest and worst predator (the Romans made sacrifices to propitiate the god of stem rust). Cold usually killed stem rust in the United States, but it was constantly present in warmer Mexico, and every spring winds drove it across the border to reinfect U.S. wheat fields.
The sole Rockefeller researcher working on wheat, Borlaug was given so little money that he had to sleep in sheds and fields for months on end. But he succeeded by the mid-’50s in breeding wheat that was resistant to many strains of rust. Not only that, he then created wheat that was much shorter than usual—what became known as “semi-dwarf” wheat. In the past, when wheat was heavily fertilized, it had grown so fast that its stalks became spindly and fell over in the wind. The plants, unable to pull themselves erect, had rotted and died. Borlaug’s shorter, stouter wheat could absorb large doses of fertilizer and channel the extra growth into grain rather than roots or stalk. In early tests, farmers sometimes harvested literally 10 times as much grain from their fields. Yields climbed at such a rate that in 1968 a USAID official called the rise the Green Revolution, thus naming the phenomenon that would come to define the 20th century.
The Green Revolution had its most dramatic effects in Asia, where in 1962 the Rockefeller Foundation and the Ford Foundation opened the International Rice Research Institute (irri) in the Philippines. At the time, at least half of Asia lived in hunger and want; farm yields in many places were stagnant or falling. Governments that had only recently thrown off colonialism were battling communist insurgencies, most notably in Vietnam. U.S. leaders believed the appeal of communism lay in its promise of a better future. Washington wanted to demonstrate that development occurred best under capitalism. irri’s hope was that top research teams would transform Asia by rapidly introducing modern rice agriculture—“a Manhattan Project for food,” in the historian Nick Cullather’s phrase.
Were the Prophets disproved? Was carrying capacity a chimera? No. As Vogt had predicted, the enormous jump in productivity led to enormous environmental damage: drained aquifers, fertilizer runoff, aquatic dead zones, and degraded and waterlogged soils. Worse in a human sense, the rapid increase in productivity made rural land more valuable. Suddenly it was worth stealing—and rural elites in many places did just that, throwing poor farmers off their land. The Prophets argued that the Green Revolution would merely postpone the hunger crisis; it was a one-time lucky break, rather than a permanent solution. And our rising numbers and wealth mean that, just as the Prophets said, our harvests will have to jump again—a second Green Revolution, the Wizards add.
Following Borlaug’s lead, irri researchers developed new, high-yielding rice varieties. These swept through Asia in the ’70s and ’80s, nearly tripling rice harvests. More than 80 percent of the rice grown in Asia today originated at irri. Even though the continent’s population has soared, Asian men, women, and children consume an average of 30 percent more calories than they did when irriwas founded. Seoul and Shanghai, Jaipur and Jakarta; shining skyscrapers, pricey hotels, traffic-jammed streets ablaze with neon—all were built atop a foundation of laboratory-bred rice.
The Story of Nitrogen
Almost everybody eats every day, but too few of us give any thought to how that happens. If agricultural history were required in schools, more people would know the name of Justus von Liebig, who in the mid-19th century established that the amount of nitrogen in the soil controls the rate of plant growth. Historians of science have charged Liebig with faking his data and stealing others’ ideas—accurately, so far as I can tell. But he was also a visionary who profoundly changed the human species’ relationship with nature. Smarmy but farsighted, Liebig imagined a new kind of agriculture: farming as a branch of chemistry and physics. Soil was just a base with the physical attributes necessary to hold roots. Pour in nitrogen-containing compounds—factory-made fertilizer—and gigantic harvests would automatically follow. In today’s terms, Liebig was taking the first steps toward chemically regulated industrial agriculture—an early version of Wizardly thought.
But there was no obvious way to manufacture the nitrogenous substances that feed plants. That technology was provided before and during the First World War by two German chemists, Fritz Haber and Carl Bosch. Their subsequent Nobel Prizes were richly deserved: The Haber-Bosch process, as it is called, was arguably the most consequential technological innovation of the 20th century. Today the Haber-Bosch process is responsible for almost all of the world’s synthetic fertilizer. A little more than 1 percent of the world’s industrial energy is devoted to it. “That 1 percent,” the futurist Ramez Naam has noted, “roughly doubles the amount of food the world can grow.” The environmental scientist Vaclav Smil has estimated that nitrogen fertilizer from the Haber-Bosch process accounts for “the prevailing diets of nearly 45% of the world’s population.” More than 3 billion men, women, and children—an incomprehensibly vast cloud of hopes, fears, memories, and dreams—owe their existence to two obscure German chemists.
Hard on the heels of the gains came the losses. About 40 percent of the fertilizer applied in the past 60 years was not absorbed by plants. Instead, it washed away into rivers or seeped into the air in the form of nitrous oxides. Fertilizer flushed into water still fertilizes: It boosts the growth of algae, weeds, and other aquatic organisms. When these die, they fall to the floor of the river, lake, or ocean, where microbes consume their remains. So rapidly do the microbes grow on the manna of dead algae and weeds that their respiration drains oxygen from the lower depths, killing off most other life. Nitrogen from Midwestern farms flows down the Mississippi to the Gulf of Mexico every summer, creating an oxygen desert that in 2016 covered almost 7,000 square miles. The next year a still larger dead zone—23,000 square miles—was mapped in the Bay of Bengal, off the east coast of India.
All the while that Wizards were championing synthetic fertilizer and Prophets were denouncing it, they were united in ignorance: Nobody knew why plants were so dependent on nitrogen. Only after the Second World War did scientists discover that plants need nitrogen chiefly to make a protein called rubisco, a prima donna in the dance of interactions that is photosynthesis.
The Luddites’ Moonshot
For as long as Wizards and Prophets have been arguing about feeding the world, Wizards have charged that Prophet-style agriculture simply cannot produce enough food for tomorrow. In the past 20 years, scores of research teams have appraised the relative contributions of industrial and organic agriculture. These inquiries in turn have been gathered together and assessed, a procedure that is fraught with difficulty: Researchers use different definitions of organic, compare different kinds of farms, and include different costs in their analyses. Nonetheless, every attempt to combine and compare data that I know of has shown that Prophet-style farms yield fewer calories per acre than do Wizard-style farms—sometimes by a little, sometimes by quite a lot. The implications are obvious, Wizards say. If farmers must grow twice as much food to feed the 10 billion, following the ecosystem-conserving rules of Sir Albert Howard ties their hands.
Consider cassava, a big tuber also known as manioc, mogo, and yuca. The 11th-most-important crop in the world in terms of production, it is grown in wide swathes of Africa, Asia, and Latin America. The edible part grows underground; no matter how big the tuber, the plant will never fall over. On a per-acre basis, cassava harvests far outstrip those of wheat and other cereals. The comparison is unfair, because cassava tubers contain more water than wheat kernels. But even when this is taken into account, cassava produces many more calories per acre than wheat. (The potato is a northern equivalent. The average 2016 U.S. potato yield was 43,700 pounds per acre, more than 10 times the equivalent figure for wheat.) “I don’t know why this alternative is not considered,” Botoni said. Although cassava is unfamiliar to many cultures, introducing it “seems easier than breeding entirely new species.”
Am I arguing that farmers around the world should replace their plots of wheat, rice, and maize with fields of cassava, potato, and sweet potato and orchards of bananas, apples, and chestnuts? No. The argument is rather that Prophets have multiple ways to meet tomorrow’s needs. These alternative paths are difficult, but so is the Wizards’ path exemplified in C4 rice. The greatest obstacle for Prophets is something else: labor.
The Right Way to Live
Since the end of the second world war, most national governments have intentionally directed labor away from agriculture (Communist China was long an exception). The goal was to consolidate and mechanize farms, which would increase harvests and reduce costs, especially for labor. Farmworkers, no longer needed, would move to the cities, where they could get better-paying jobs in factories. In the Borlaugian ideal, both the remaining farm owners and the factory workers would earn more, the former by growing more and better crops, the latter by obtaining better-paying jobs in industry. The nation as a whole would benefit: increased exports from industry and agriculture, cheaper food in the cities, a plentiful labor supply.
There were downsides: Cities in developing nations acquired entire slums full of displaced families. And in many areas, including most of the developed world, the countryside was emptied—exactly what Borlaugians intended, as part of the goal of freeing agriculture workers to pursue their dreams. In the United States, the proportion of the workforce employed in agriculture went from 21.5 percent in 1930 to 1.9 percent in 2000; the number of farms fell by almost two-thirds. The average size of the surviving farms increased to compensate for the smaller number. Meanwhile, states around the world established networks of tax incentives, loan plans, training programs, and direct subsidies to help big farmers acquire large-scale farm machinery, stock up on chemicals, and grow certain government-favored crops for export. Because these systems remain in effect, Vogtian farmers are swimming against the tide.
To Vogtians, the best agriculture takes care of the soil first and foremost, a goal that entails smaller patches of multiple crops—difficult to accomplish when concentrating on the mass production of a single crop. Truly extending agriculture that does this would require bringing back at least some of the people whose parents and grandparents left the countryside. Providing these workers with a decent living would drive up costs. Some labor-sparing mechanization is possible, but no small farmer I have spoken with thinks that it would be possible to shrink the labor force to the level seen in big industrial operations. The whole system can grow only with a wall-to-wall rewrite of the legal system that encourages the use of labor. Such large shifts in social arrangements are not easily accomplished.
My daughter is 19 now, a sophomore in college. In 2050, she will be middle-aged. It will be up to her generation to set up the institutions, laws, and customs that will provide for basic human needs in the world of 10 billion. Every generation decides the future, but the choices made by my children’s generation will resonate for as long as demographers can foresee. Wizard or Prophet? The choice will be less about what this generation thinks is feasible than what it thinks is good.
VEGANISM It is lunchtime and a queue is forming for the burgers at Krowarzywa, voted the city’s best in an online poll: students, families, businessmen in suits. This is Warsaw, where (you might think) lunch is usually a slab of meat with a side order of sausage. But at Krowarzywa—which means “cow alive” and contains the word warzywa, meaning vegetables—no animals were harmed in the making of the food. The burgers are made of millet, tofu or chickpeas. The bestselling “vegan pastrami” is made of seitan, a wheat-based meat substitute.
Warsaw has almost 50 vegan restaurants. That does not mean it has all that many vegans. Kassia, a 20-something professional in the queue, says she has no ethical objection to eating meat. She comes to Krowarzywa because she likes the food. Kornel Kisala, the head chef, thinks that most of Krowarzywa’s clientele eat meat, but it does not worry him. “Animals don’t care whether you eat a vegan burger because it is fashionable or because it is tasty.” Altogether, 60% of Poles say they plan to cut back on meat this year. Eating vegetarian and vegan meals now and then is one of the ways some choose to do so.
Interest in vegan food has been booming across the rich world. Celebrity claims of veganism are everywhere: Bill Clinton and Al Gore, Serena and Venus Williams, Lewis Hamilton, Mike Tyson, Beyoncé, take your pick. In America sales of “plant-based” foods—a term for foods that contain no meat, eggs or dairy that reliably says “vegan” to vegans but doesn’t say “weird” to the less committed—rose 20% in the year to June 2018, according to Nielsen, a market-research group. That was ten times the growth in food as a whole that year and two and a half times faster than vegan foods grew in the year before.
McDonald’s is offering McVegan burgers in Scandinavia. The American restaurants in the TGI Fridays chain sell soyabean burgers that ooze blood made of beetroot juice. Tyson Foods, one of the world’s largest meat producers, recently bought 5% of Beyond Meat, the company which makes them. Waitrose, a posh British grocery chain, introduced a range of vegan food in 2017, expanded the selection by 60% in mid-2018 and says sales of vegan and vegetarian foods in July 2018 were 70% above the level in July 2017.
Some people see great things in this. Two years ago Eric Schmidt, a Silicon Valley figure who used to be chairman of Google, called plant-based meat substitutes the world’s most important future technology; he foresaw them improving people’s health, reducing environmental degradation and making food more affordable for the poor in developing countries. The founder of the first vegan society said in 1944 that “in time [people] will view with abhorrence the idea that men once fed on the products of animals’ bodies.” Many since have shared his hope. Perhaps their time is come at last.
If so, it is a slow coming. Meat consumption worldwide has been growing consistently by almost 3% a year since 1960, mostly because people in poor countries buy more meat as they get richer, and the trend has yet to slow. In the early 1970s the average Chinese person ate 14kg (31lb) of meat a year. Now they eat 55kg, which is 150g, or five ounces, a day. But though most growth in consumption has been in the developing world, rich countries are eating more meat, too; their consumption is just not growing as fast as it used to. According to the UN’s Food and Agriculture Organisation (FAO), meat consumption in the richest nations has risen 0.7% a year since 1991.
Polling data is used to claim that the number of vegans in rich countries is both quite high—around 10% in some European countries—and growing. But there is reason to doubt at least the first of these. Some of the best data come from Britain, home of the world’s first vegan society. A poll carried out by that society in 2016 found that 1.05% of people in Britain never ate meat or animal products. This is considerably higher than the result the society got in 2007, which suggests real growth in numbers. But it is a far cry from the 5.3% of the population reported as vegan in a more recent poll. In general, polls seem to find many more people claiming to be vegan than they do people abstaining from all meat, fish and animal products.
In America, Nielsen found in 2017 that 3% of the population called themselves vegans and 6% vegetarians (people who eschew meat, but eat eggs and/or dairy products). This proportion seems more or less stable; the country’s largest polling organisations, Gallup and Harris, both found 3% of the population calling themselves vegan over the period 2012-18. But more detailed research by Faunalytics, a company which has been running large surveys of eating habits for 20 years, puts the numbers at just 0.5% for vegans and 3.4% for vegetarians. Fully a quarter of 25- to 34-year-olds in America claim to be either vegan or vegetarian, whereas studies by Faunalytics find the median age of American vegans to be 42, four years older than the national median. It seems that a fair amount of aspirational self-deception, terminological inexactitude or simple hypocrisy is at play.
The idea that veganism is most widely espoused, if not necessarily adhered to, by the young seems to be true in many countries. In Germany, according to Mintel, a research firm, 15% of 16- to 24-year-olds say that they are vegetarian, compared with 7% of the population at large. In many countries declared vegans lean towards the political left. In America polling by Pew has found that 15% of liberals espouse a meat-free diet, as opposed to 4% of Republicans. American vegans and vegetarians are also poorer than average, and twice as likely to be single. Three-quarters of them are women. This all fits veganism’s association with valuing health, simplicity and low environmental impact—an implicit rejection of the values and coronary arteries of older red-meat-eating men.
Veganism is not a way of life that it is easy to keep up. According to Faunalytics, for every active American vegetarian or vegan there are more than five people who say they have abandoned such a diet. The growth in the number of restaurants catering to veganism and the availability of plant-based products on shelves may reduce this churn and allow more to stick with the programme. As it is, a moving target makes it unsurprising that accurate figures on veganism are hard to come by.
Overall, though, it seems safe to say that the number of people sometimes or regularly choosing to eat vegan food is growing much faster than the growth in people deeply committed to a meat-, egg- and dairy-free life. Patrice Bula, a vice-president at Nestlé, says he thinks that only a quarter of the people buying his company’s vegan meals are committed vegetarians or vegans. People in this larger group are often called “flexitarians”, who shift back and forth between omnivorous and vegetable diets. Almost two Americans in five say they fit this category, says Nielsen. The true vegan efflorescence lies in casual, part-time veganism.
In rich countries, people become flexitarians as a response to three concerns: their own health; the health of the environment; and the welfare of animals. On all three, they have a point; on at least the first two, though, a lot of the benefits can be captured without strict veganism.
The direct evidence that vegan and vegetarian diets are in themselves good for people is mixed. Between 2002 and 2007, 73,000 Seventh Day Adventists, a religious group in America, participated in a study of eating habits. The 27,000 vegans and vegetarians among them had significantly lower mortality rates. A smaller survey of British vegetarians from 2016, though, found no such link.
Aspects of veganism do go with the grain of some health advice. Large studies have shown that people who eat a lot of red meat have higher overall mortality rates (the same does not apply to eating poultry). Eating a lot of processed meat is linked to colorectal cancer. The evidence on this seems clear enough for various authorities to recommend limits to the total ingestion of red meat—the World Cancer Research Fund suggests less than 500g a week—and minimising the intake of processed meats such as bacon and salami.
And the damage to health done by meat is not all captured in the sort of studies that reliably cast doubt on diets heavy in red meat. Lots of factors, both dietary and non-dietary, influence health problems such as obesity, high blood pressure or diabetes, and it is hard to understand exactly what is responsible for what. Comparing diets on a statistical basis, though, allows some striking inferences. In 2016 a study by Marco Springmann and colleagues at the University of Oxford found that, globally, a transition to well-balanced vegan diets might result in 8.1m fewer deaths a year. Universal vegetarianism would avoid 7.3m deaths.
If the associations on which this computer modelling is based are robust, those are impressive figures. But much of the benefit they claim to demonstrate could still be realised if omnivores ate better-balanced diets with less meat. If the world adopted what the study called a healthy global diet, with less sugar than most in the West consume, plenty of fruit and veg and just 43g of red meat a day, the number of deaths avoided would still be 5.1m.
Red meat is typically a quarter to a third protein by weight, so just 43g is nowhere near enough to supply the 50-60g of protein a day that people require (the exact amount depends on a person’s weight, amount of exercise and several other factors). The global healthy diet thus has people relying on quite a lot of plant protein, too. Rich-world diets, though, tend to get all their daily protein requirement from animals, and then some. Americans eat 90g of protein a day, Europeans 85g, and most of it comes from animal products.
Because meat is energy rich, eating more than your protein needs dictate means taking on a lot of calories, which may well be stored as fat. Vegans both eat less protein and get it from less energy-rich and potentially fattening products. In 2017 a French study found that both vegans (62g of protein a day) and vegetarians (67g) were healthier than the meat eaters wolfing down 81g. They were also eating more varied diets, and, perhaps crucially, fewer calories overall; it may have been those choices, rather than veganism per se, that made the difference.
On the environment, too, vegans and vegetarians have a point. Growing their food requires less land than raising meat does. Animals do not turn all the energy in the crops they eat into calories in their muscles. They need some of that energy to stay alive—and while that overhead is good for the animals, from a food-production standpoint it looks like a waste. This waste means you need more land per calorie of food if you are producing beef than if you are producing broccoli. Admittedly, a lot of grazing is on land that would not necessarily be suitable for arable farming. But the FAO’s finding that raising livestock takes about 80% of all agricultural land and produces just 18% of the world’s calories is still telling.
Alon Shepon of the Weizmann Institute and colleagues have looked at this in terms of opportunity costs. Choosing to make a gram of protein by feeding an egg-laying hen, rather than getting the equivalent of a gram of egg protein from plants, has an opportunity cost of 40%. Getting the gram of protein from beef represents an opportunity cost of 96% (see chart 1). They argue that if America stopped paying these opportunity costs and got the protein from plants in the first place, it would be equivalent to increasing the food supply by a third—or eliminating all of the losses due to food waste.
Being so land hungry means cattle farming changes the climate; clearing land for pasture creates greenhouse gases. On top of that, the bugs in ruminant digestive systems produce methane, a fairly powerful greenhouse gas. Once it gets out of the cows—by belching, mainly, not, as is commonly thought, farting—this warms the world. The FAO calculates that cattle generate up to two-thirds of the greenhouse gases from livestock, and are the world’s fifth largest source of methane. If cows were a country, the United Herds of Earth would be the planet’s third largest greenhouse-gas emitter.
Mr Springmann and his colleagues calculated that in 2050 greenhouse emissions from agriculture in a vegan world would be 70% lower than in a world where people ate as they do today; in the “healthy global diet” world they would be 29% lower. The savings are not all owing to cows; but a large part of them are (see chart 2). Raising cattle produces seven times more in terms of emissions per tonne of protein than raising pork or poultry does, 12 times more than soya and 30 times more than wheat. Giving up beef captures many of the benefits of going vegan. Other animals make a lot less difference. Getting your protein from insects—very efficient converters—might be almost indistinguishable from veganism in environmental terms.
Except, that is, to the insects. One of the main things that motivates many vegans and vegetarians is a belief that killing and eating animals is wrong. The vegans also abstain from milk and eggs because there, too, they see a lot of exploitation, death and suffering (the question of honey remains a point of contention). In dairy herds calves are typically taken from their mothers within 24 hours, compared with the nine months to a year they would suckle if left to themselves. Male calves are killed or reared for meat. In industrial egg-production day-old male chicks are killed and simply discarded. Even if one keeps strictly to meat, though, the death toll involved is immense. Over 50bn farm animals are killed for meat every year.
#MooToo
The best known proponent of the case that this matters is Peter Singer, a philosopher at Princeton University. Mr Singer argues that treating the interests of humans as superior to those of other animals is a prejudice, analogous to treating men as superior to women or whites as superior to blacks. It depends on an arbitrary distinction between two groups, one of which has the power to make the distinction stick.
What matters, he says, is not what species an individual belongs to but its capacity for suffering. If an animal suffers as much as a person, then things that it would be impermissible to do to a person—killing and eating him, immobilising him in a cage—are unacceptable if done to the animal, too. “In suffering,” Mr Singer writes, “the animals are our equals.”
This moral point would seem to depend in part on an empirical point; to what extent and in what manner do animals suffer? Animals’ brains contain regions clearly analogous to those correlated with consciousness, perception and emotion in humans. What that reveals about their suffering as compared with a human’s is a subtle question. But they definitely feel pain, and some can both express preferences and, it would appear, hold beliefs about the preferences of others. That would seem to have some moral salience.
But would it be better for animals that suffer not to exist at all? A vegan world would have no need of cows, happy or sad. The genus Bos currently numbers some 1.5bn. Should those lives be valued less than the lives of the wildlife which might repopulate their overgrown pastures when they are gone? When it comes to wild animals, people tend to abhor population collapse; are things that different when it comes to domestic animals?
Mr Singer’s project of seeking legal rights for animals is certainly going to be a tough row to hoe, if not an impossible one. Neither courts nor legislatures seem very interested. Reducing the cruelty that animals suffer, though, is more plausible, both through legislation—battery cages for hens have been banned in the EU since 2013—and through consumer pressure, such as a preference for free-range products, cruelty-free certification, transparent sourcing and the like. This second route, though, is not available to vegans.
Though biology is not destiny, humans, like their relatives the chimpanzees, evolved as omnivores; the evidence is in the teeth and the guts. If people’s diet is otherwise restricted, for example to staple starches, meat does them good. As the increasing consumption of meat worldwide shows, a lot of people in most cultures really do like eating it; the vast majority will do so, at least a bit, when they get the chance. The great exception is India, where, mostly for religious reasons, about 30% of the population has a vegetarian lifestyle.
None of that makes veganism, full- or part-time, and the spread of plant-based foods irrelevant. A mixture of ethical concerns, innovative cuisine like Mr Kisala’s and more convenient vegan shopping at supermarkets could yet see the rich world reach “peak meat” and head down the other side. If so, and in particular if reduced consumption of red meat is part of the process, there will probably be substantial gains in health and happiness. And if the world improves standards in the meat-rearing operations that remain, some of that may even be shared with animals.