Visitors to Monsanto headquarters in St. Louis in 2003 stopped on their tour to admire a potted YieldgardPlus corn plant, a variety that can fend off both the corn borer and the corn rootworm. According to Eric Sachs, Monsanto’s director of Scientific Affairs, “These are the only two corn pests that need pesticide applications.” Each is a billion dollar pest for American corn farmers. “Both problems were solved by Monsanto,” said Sachs.

Asked why he considered YieldgardPlus such a breakthrough, Sachs explained that traditional methods—even crop rotation—no longer hold the pests in check: “What has emerged over the past five years is that the insects have developed ways to get around crop rotation. Instead of laying their eggs in a cornfield, they lay their eggs in a soybean field, which is the rotation crop. So the larvae hatch in a cornfield. The second way is to lay eggs that overwinter more than one year. They don’t hatch in the soybean field, they hatch in the cornfield after the rotation.” Eventually, he agreed, the insects will become resistant to the Bt toxin produced by YieldgardPlus. “We’re already working on the second generation plant, producing a second Bt protein that targets the same insect. It makes it much more difficult for the insect to become resistant. It needs to have two rare mutations at the same time.”

YieldgardPlus, like earlier versions of Bt corn, will benefit farmers and make money for the company—not trivial accomplishments. But it isn’t likely to improve the image of genetically modified foods—or of Monsanto.

A very different variety of corn, casually mentioned by Monsanto vice president Rob Horsch, however, inspired the St. Louis Post-Dispatch to print an editorial, “Genetically Modified Crops Feed the World,” in which the new corn is called a boon to the world and an example of the technology’s greatest promise. Horsch calls it Golden Corn. It has pale kernels with brilliant orange embryos, half moons at the kernel’s heart. “It’s a white corn with a golden embryo,” he explained. “It’s really quite beautiful.” Like Golden Rice, it has been modified to produce more beta carotene, the precursor to vitamin A. White corn was chosen as the starting material because it is preferred in Africa, where vitamin A deficiency is a problem and corn is a staple crop. “It has an embryo-specific promoter,” Horsch said. “But there’s enough packed in the embryo that the whole kernel has higher beta carotene than yellow maize.”

According to Horsch, Monsanto has said it will donate the rights to Golden Corn to the African Agricultural Technology Foundation (AATF), a nongovernmental organization developed with funding from the Rockefeller Foundation. “Farmers will be able to use the seed without paying Monsanto,” the St. Louis Post-Dispatch explained.

Initially thought of as a patent bank, the AATF was designed, according to its brochure, “to resolve many of the barriers that have prevented smallholder farmers in Africa from gaining access to existing agricultural technologies that could help relieve food insecurity and alleviate poverty.” It describes itself as “the neutral intermediary, a ‘responsible’ party between owners of proprietary technologies and those that need them.”

Florence Wambugu was a member of AATF’s Design Advisory Committee, along with representatives from seven African countries. USAID was represented, as were its counterparts in Denmark and the U.K. Gerard Barry represented Monsanto on the committee; he left the company late in 2003 to become head of the Golden Rice project at IRRI in the Philippines.

Yet while Monsanto, Dow AgroSciences, Pioneer Hi-Bred, and Aventis CropScience helped set up the foundation, Horsch points out that “the AATF board of directors doesn’t include any of the companies.” The companies donate licenses for patented genes or technologies; AATF owns any product that results. “For Golden Corn,” said Horsch, “we’ve donated the basic set of genes to enhance beta carotene.” Associates at Ohio State University and at CIMMYT, the international maize and wheat research center in Mexico, will use the genes to transform corn plants, analyze the results, breed the trait into popular varieties, and see them through the regulatory process.

Horsch enthusiastically identified this coalition of public and private entities as “we.” “We want to combine beta carotene with the high protein maize already developed,” he said of the future. “The problem with the high protein trait is that you can’t see it, you can’t taste it.” But combined with the high beta-carotene trait, the protein trait becomes visible: the plants with orange embryos will also be high in proteins.

Golden Corn is just one example of a new trend in plant breeding, called biofortification. The idea was popularized by economist Howarth Bouis of the International Food Policy Research Institute, one of the 16 Future Harvest Centers under the World Bank’s Consultative Group on International Agricultural Research. “The idea is to breed plants for higher nutrition content,” said John Beard, a nutritionist at Penn State University. In May 2003 Beard had attended a meeting in Cali, Colombia, of some 70 plant breeders, nutritionists, economists, and community activists. Beard reported: “Ten years ago Bouis had the idea that supplement and fortification programs, from an economics aspect, need constant investment to get a response. He wondered, Is there some way to frontload the system? To make a big investment at first, and then tail off? Why not breed staple crops for higher nutrition?” Each of the international plant breeding centers allied with the Food Policy Research Institute was asked to start screening their varieties for micronutrients, not simply for hardiness or high yield. Said Beard, “You want to shift a whole population to a different plane of nutrition. You won’t see benefits right away because the content of the micronutrient is usually quite small; hence, the improvements will occur in small increments over a long time.”

Karel Schubert at the Donald Danforth Plant Science Center, for example, is working with nutritionists at Tufts University and the University of Florida to fortify rice with folate. Folate (or vitamin B9) and iron are the most important micronutrients whose deficiency leads to anemia, impaired cognitive development, and neural tube defects such as spina bifida, Schubert explained. “In Asia there are 100,000 cases of neural tube defects a year. In China it’s called ‘the disease of the winter marriage,’ because the mother is deficient in folate prior to conception. It’s also the most important birth defect in the U.S.” Spinach is a prime source of folate. Legumes and some fruits are high in it, but all cereals, including rice, said Schubert, are “seriously low in folate.” So are root and tuber crops, like potatoes. However, unlike the beta-carotene pathway, how plants make folate is not yet well understood. Schubert and his colleagues are studying the folate pathway in the common laboratory plant Arabidopsis; they have much to learn before any folate-rich crops will be ready to market.

Plant breeders are increasingly paired with nutritionists in such biofortification projects because simply raising the amount of folate or other nutrients in a plant isn’t enough to enrich it: the nutrient must also be in the right form. A bioavailability study is needed to measure how easily the human body can take up the nutrient and make use of it. Penn State’s John Beard, along with Jere Haas at Cornell University, became involved in the biofortification of crops after plant breeders at IRRI discovered an iron-rich variety of rice.

The rice, called IR68144, had been developed using conventional breeding techniques to grow well in poor soils and cold temperatures. When Bouis first announced his biofortification challenge, IRRI plant geneticist Glenn Gregario began screening the 80,000 varieties of rice in the IRRI germplasm banks. He grew 2,000 different varieties, harvesting the grain and analyzing it for iron content, before he discovered IR68144 in 1998. Because it wasn’t altered by molecular techniques, IR68144 was not subject to any safety testing. It was grown in quantity immediately and used in feeding trials. It advanced through cell culture tests and a pilot study of 27 people to a full feeding trial involving 300 nuns in a convent in Manila. If not for the typhoons that twice destroyed the harvest, proof of the rice’s nutritional advantage (if any) would have been available in 2000.

As it was, by 2003 Beard and his collaborators at Cornell University had analyzed 10 different parameters of nutrient status on each of 1,080 blood samples from the 300 nuns. They measured levels of vitamin A, iron, folate, vitamin B12, and zinc. The blood tests were combined with direct dietary analyses. “We weighed everything the sisters consumed three times randomly every two weeks throughout the course of the nine-month feeding trial,” Beard explained. “Their meals were analyzed for micronutrient content by using the Philippine Food Tables, which tells us that so many grams of this food contains so much iron, zinc, etc. Then, based on the amount of vitamin C, coffee, and tea consumed with the meal, we can calculate the bioavailability of the rice. Then we ask, What happens when we switch the forms of rice in the diet? Does the iron status change?”

According to an IRRI publication, “The trial of IR68144 is being widely regarded as an attempt to prove the concept that staple foods enriched with micronutrients directly benefit human nutrition.” Said Gregario, “If this new variety is successful, then micronutrient deficiency may be a part of history—like smallpox or polio. But that’s still just a dream.”

Golden Rice is also still just a dream—although Monsanto’s Horsch confidently predicts that it will eventually reach the people it was designed to help. For Golden Rice inventor Ingo Potrykus, bioavailability studies are critical. He agrees that to get governments in developing countries and international humanitarian groups to back Golden Rice as a means of easing vitamin A deficiency, IRRI must prove that the beta carotene in the rice is usable and will make a difference. Until such tests are done, the developers of Golden Rice remain open to attacks from critics who believe they are making “false promises” by claiming that it will help alleviate vitamin A deficiency.

Golden Rice, said Greenpeace, is “fool’s gold.” Michael Pollan, in a New York Times Magazine article, cited a figure that appears to have come from Greenpeace’s propaganda: “An 11-year-old would have to eat 15 pounds of cooked golden rice a day—quite a bowlful—to satisfy his minimum daily requirement of vitamin A.” Yet this figure is merely a conjecture. Robert Russell, a nutritionist at Tufts University and a specialist in vitamin A nutrition, has calculated a figure of 200 grams per day—7 ounces—or two out of the three to four bowls full that an

adult on a rice-based diet ordinarily eats. Which figure is right? It will take a bioavailability trial to learn. But as long as Golden Rice is confined to the greenhouse, the protocol established for the iron-rich IR68144 cannot be followed: enough rice cannot be grown under glass to feed 300 nuns for nine months.

Lecturing at Yale University in April 2003, Potrykus was asked if Golden Rice, like Borlaug’s wheat and the other Green Revolution crops, would not simply contribute more to the problem of malnutrition by encouraging poor farmers to move from nutritious vegetable-based multicropping systems to a rice monoculture. “It was not without reason that production moved from high nutritious low-yield crops to low nutritious high-yield crops,” answered Potrykus. “You can either die from hunger or from malnutrition. I don’t know what is worse. The solution I am offering is to make high production crops like rice or wheat more nutritious.”

Asked why he invented Golden Rice, he answered, “I have been asked this before, and I have thought about it. I’m a refugee myself, from a part of Germany generously given to Russia after the war.” For Potrykus, a year shy of 70, “the war” is World War II. “I lost my father in the last days of the war,” he continued. “He was a medical doctor. My mother had to raise four children without anything. She managed to allow us all higher education. But we have experienced hunger. Between the ages of 12 and 14, much of my brother’s and my attention was given to where to find something to eat. You could say we reaped what we did not sow.”

After earning a college degree in biology, Potrykus taught high school. He married and had children. He considers himself first “an old-fashioned field biologist, a naturalist. From my mother I have this strong interest in nature,” he said. A project he has been working on for many years is to videotape all the birds of North America. “I was teaching in high school when the director of the Max Planck Institute for Plant Breeding, Josef Straub, offered me the possibility of a Ph.D. I was exposed to a lot of breeding practices. I did the Ph.D. while still teaching half time, and then I went back to teaching full time. I came into this idea already when I was teaching high school. I was running courses then on the topic, ‘More Food for More People.’ This looks

strange now, because it was the early sixties and the peak of the Green Revolution.”

He was still teaching More Food for More People 20 years later at the university level. “In my student evaluations I heard again and again the complaint that I am talking about transgenic plants and they don’t want to hear about it. I felt I had to produce a case that demonstrates to my students that they are wrong, that you can use the technology for a good purpose.”

Does the world really need more food? Since 1798, when Malthus published his Essay on the Principle of Population, catastrophists have predicted imminent famine. Nearly 200 years later Paul Ehrlich, like Malthus, reduced the problem to its simplest form: too many people, not enough food. In his 1968 book The Population Bomb, Ehrlich concludes, “The battle to feed all humanity is over.” “At this late date,” he says, “nothing can prevent a substantial increase in the world death rate.” Ehrlich was writing on the eve of the Green Revolution—the largest expansion in agricultural productivity in the history of human civilization. His prediction, like Malthus’s, did not come true.

And yet the earth is finite.

In the course of just one century, the twentieth, the human population doubled twice: from 1.5 billion to 3 billion to 6 billion. It continues to expand by 80 million people a year. It doesn’t take a catastrophist to see that humanity is pushing against some planetary limits. The demands of agriculture and industry, human habitation, and transportation are driving to extinction more species per year than at any time since the Cretaceous. In 1998 Dan Simberloff, an ecologist at the University of Tennessee, was quoted in the Washington Post: “The speed at which species are being lost is much faster than any we’ve seen in the past—including those [extinctions] related to meteor collisions.”

There’s little doubt that the trends of the twentieth century cannot continue. In his 1995 book How Many People Can the Earth Support?, Joel Cohen lays out the problem of the earth’s “carrying capacity” in all its complexity. There is no single answer, no simple answer to his title’s question. The number of people Earth can accommodate depends on how they live and how well they manage the planet’s physical, chemical, and biological environments. The choices available to us—and the

choices we make—depend on science and technology, on the one hand, and on politics, preferences, and moral judgments, on the other.

There is no single, simple path to a sustainable future, either. To meet people’s needs without further harm to the environment requires changes of many kinds. Cohen puts them into three categories: we must “put fewer forks on the table” (decrease population growth and reduce consumption), “make a bigger pie” (grow more food), and “teach better manners” (change how people interact with each other for everyone’s benefit).

The rate of population growth is declining—more rapidly than the experts predicted even a decade ago, when the population was expected to double yet again before stabilizing. Some of the underlying trends are positive, such as improvements in education and economic development, particularly for women. But some are negative. They are the familiar scourges of too many people: disease, famine, war. As Garrett Hardin, author of the famous essay “The Tragedy of the Commons,” points out, no one dies of overpopulation.

Experts now estimate that the number of people will stop growing by the middle of the twenty-first century. Before then, however, some 3 billion more people will be living on Earth than are alive now. This number is nearly 10 times the population of the United States today. Many—probably most—of these people will live in countries that are, even now, unable to provide their people with enough food for good health.

Putting fewer forks on the table doesn’t just mean decreasing the population growth rate. It is also about how much we eat, what we eat, and what we waste. An adult needs between 2,000 and 2,200 calories per day—more for men and less for women, more for those who do heavy manual labor and less for those who sit at desks. In Feeding the World, Vaclav Smil estimates that the total food available per person in 1990, according to data from the FAO, was about 2,700 calories per day. Averaged worldwide, each person ate about 2,000 calories per day. The rest—about 700 calories per person per day—was lost during harvesting, processing, and distribution, or simply discarded.

These figures say that we already produce enough food to feed the world. What they conceal is the appalling gap between the richest and

poorest nations. The amount of food each person in a rich country eats every day is at the high end of the range, about 2,200 calories each day—and sometimes even higher, up to 2,700 calories. In the poorest countries, people eat an average of 1,500 to 1,700 calories per day.

The amount of food available to people in rich and poor countries is also very unequal. According to FAO statistics, the per person food availability in the United States between 1992 and 1994 was about 3,600 calories per day, some 40 percent more than was eaten. (Available, in this case, assumes a person can afford to buy it, yet even in the United States millions of people use food stamps or go hungry.) In less developed countries, only 10 to 15 percent more food was available than was eaten. Moreover, the people in affluent countries consume between two and four times as much milk and meat as the world’s average citizen. Converting plant foodstuffs, like grass and grain, to milk and meat is inefficient. Of the usable energy in animal feed, only 33 percent ends up as food energy in milk, 20 percent in pork, and 6 percent in beef.

But getting everyone to adopt a vegetarian lifestyle is not a likely solution, even if every grain and vegetable is biofortified. As Dennis Avery of the Hudson Institute points out, “No country or culture in history has voluntarily accepted a diet based solely on the relatively low-quality protein found in vegetable sources. Meat and milk consumption is rising by millions of tons per year in China and India right now as their incomes rise.” Even among America’s 12 million vegetarians, only 4 percent never eat any animal products, according to a survey commissioned by the Vegetarian Times in 1992. Fifty percent agreed with the statement, “In order to satisfy my appetite, a main meal must include meat.” Nonetheless, Smil argues, cutting down the amount of food rich nations waste, reducing their meat consumption to a healthier 25 percent of total calories, and breeding animals that are more efficient in converting feed to food would go a long way toward feeding the world of the future.

Yet even if food is shared out fairly among all peoples—with no waste—we will soon need more: in 50 years, there might be another 3

billion people who need to eat. To “make a bigger pie,” in Cohen’s words, we have two choices. We can cultivate more land, knowing that land put under the plow is land taken away from black bears and monarch butterflies, Bengal tigers and tropical birds. Or we can produce more food from the land that is already being farmed.

The huge increases of the Green Revolution came from improvements in the yield of each plant, which made each farmed acre give more food. But in the last decade, yields of the major grains have not increased significantly. Agronomist Ken Cassman has argued that some crops are reaching their yield limits, the maximum amount of grain that they can produce under the very best of weather and fertilization conditions. Where will additional yield gains come from?

When Ingo Potrykus in Switzerland was lecturing his high-school students on the subject of More Food for More People, no one could begin to answer this question. What has changed since then is our knowledge of plant biology. Today we know the sequence of the entire genome of the tiny model plant Arabidopsis thaliana, as well as the genome sequences of two rice varieties. Work on sequencing the corn genome is underway, and a start has been made on the genomes of wheat, soybeans, and many other crops. Knowing the genome sequences makes it vastly easier to identify, analyze, change, and reintroduce genes that affect critical processes in plants. Comparing genomes, we’ve identified the similarities among genes and we’ve understood that what is learned in one plant can often be applied to another. All of these advances have quickened the pace of discovery and broadened our knowledge of photosynthesis, of how plants use nitrogen, and of how they cope with excess salt, toxic chemicals, and lack of water. Together with the ability to move genes between plants and into plants from other sources, this knowledge lets us begin tackling the barriers that limit agricultural productivity.

The first of these barriers is nitrogen use. Plants, together with the bacteria that live in and with them, convert carbon and nitrogen in the air into sugars and amino acids. These sugars and amino acids are the basic building blocks of the starches and proteins of which plants are made—and which feed both humans and their domestic animals. The amount of nitrogen that can be provided by bacteria or derived from

composted animal and plant materials is much less than plants can use. Once people discovered how to fix nitrogen from the air, converting it into fertilizers, it was possible to overcome this limit on the nitrogen supply. Crop yields rose as fertilizer plants were built all over the world.

But beyond a certain point, adding more fertilizer no longer helps. Plants use only about half of the nitrogen applied as fertilizer, even under the best conditions. Much of the rest runs off with the rain into streams, rivers, lakes, and oceans. There it becomes a major pollutant. It acts as a fertilizer for small organisms, particularly algae, whose populations explode. Algae produce oxygen by day and consume it at night, depleting the oxygen available to other animals. When algae die, their decay also uses up oxygen in the water. The end result of an algal bloom is the suffocation of fish and other animals that live deeper down.

One way to solve the problem of nitrogen pollution is to increase the plants’ ability to use nitrogen, turning more fertilizer into plant proteins and leaving less to run off the land. By increasing the crop’s yield, such an improvement could also benefit farmers who do not use chemical fertilizers, either because they cannot easily afford them or because they are limited by the Organic Rule.

Whether it comes to the plant by means of nitrogen-fixing bacteria, from animal manure or plant compost, or from chemical fertilizer, plants first convert nitrogen to ammonia (NH₃). Then a plant enzyme called glutamine synthetase attaches the nitrogen atom in the ammonia to glutamic acid, an amino acid. Once attached to glutamic acid in the plant, the nitrogen can be moved by other enzymes into a variety of small molecules, including all of the other amino acids. These, in turn, are converted to proteins and other nitrogen-containing compounds. When researchers introduced a bean glutamine synthetase gene into wheat, providing more glutamine synthetase, the wheat plants developed faster, flowered earlier, and produced heavier seeds containing more protein.

Another important nitrogen enzyme is glutamate dehydrogenase. When nitrogen is abundant, glutamate dehydrogenase seems to help the plant redistribute it and make better use of its supply. The enzyme

removes the nitrogen from amino acids, leaving keto-acids and NH₃ that are then available to make other needed compounds. Again, preliminary experiments show that plants containing an extra, highly expressed glutamate dehydrogenase gene grow bigger, yielding more biomass than plants that don’t carry the extra gene. While these observations are still far from the wheat field, they suggest that changing the expression of a relatively small number of genes might produce substantial gains in crop yields.

Yields don’t depend just on nitrogen. They also depend on how efficiently the crop plant makes use of carbon. Plants take carbon from the carbon dioxide (CO₂) in the air and convert it into a sugar molecule, which consists of carbon and the hydrogen and oxygen from water (H₂O). The energy for this reaction comes from photosynthesis. The plant absorbs light and uses it to increase the energy level of electrons. The excited electrons then trickle down through a chain of proteins. There, the energy is extracted and used to drive the reduction of CO₂ by the enzyme RuBP carboxylase, commonly called Rubisco—the most abundant protein on Earth. The net result of this reaction is that the carbon atom is incorporated into a sugar molecule.

Plants differ in their ability to capture CO₂ and in how efficiently they convert it into sugars. The basic photosynthetic process, called “fixing” carbon, captures the carbon in a sugar-like molecule that has three carbon atoms. Plants that can carry out only this basic reaction are called C₃ plants. But some plants, designated C₄ plants, have an additional pathway that makes a four-carbon sugar. In C₃ plants, photosynthesis is always coupled to photorespiration, which is carried out by the same enzyme, Rubisco, and drives the reaction in reverse. That is, photorespiration consumes oxygen and releases CO₂, but it doesn’t capture the energy this reaction produces—that energy is wasted. As much as half of the carbon drawn from the air in the first place is released again through photorespiration, using up energy in the process.

Although C₄ plants use a bit more energy to fix carbon in the first place, overall they can be two or even three times as efficient as C₃ plants. C₄ plants have an additional enzyme, called PEP carboxylase, that fixes carbon into a four-carbon sugar. PEP carboxylase, unlike

Rubisco, is not bothered by oxygen. In simple terms, the C₄ photosynthetic pathway serves as a CO₂ pump. It concentrates CO₂ near the Rubisco enzyme, suppressing the oxygen-driven photorespiration in favor of carbon fixation. A majority of land plants, including rice, wheat, oats, and rye, are the less-efficient C₃ plants. Among major crops, only corn is a C₄ plant. Although many plant breeders have tried, they have not been able to transfer the C₄ traits to C₃ crop plants using conventional breeding techniques.

In 1999 Maurice Ku of Washington State University, together with a group of Japanese scientists at the National Institute of Agrobiological Resources in Tsukuba and at the BioScience Center of Nagoya University, reported that he had successfully transferred the PEP carboxylase gene from maize to rice. The researchers also tested a second maize gene, one that encodes pyruvate orthophosphate dikinase, an enzyme that provides one of the compounds that the PEP carboxylase uses in fixing carbon. The rice plants carrying either maize gene showed higher rates of photosynthesis. Oxygen didn’t interfere with photosynthesis in the rice plants carrying the maize PEP carboxylase gene—this oxygen-insensitivity of carbon fixation is the hallmark of the C₄ plant. The gene was expressed at a high level. Indeed, as much as 12 percent of the protein in these plants was PEP carboxylase. The researchers reported that the yields of the rice plants that expressed the added corn PEP carboxylase were 10 to 20 percent higher that those of the parental plants. The rice plants expressing the other maize gene gave yields as much as 35 percent higher.

These results, while they await confirmation and are a long way from being applied to agriculture, make plant breeders optimistic. Molecular techniques might be able to break through limits that have long stymied their best efforts. Indeed, they make it possible to alter the fundamental biochemical reactions that set the upper limit on the yields of crop plants today.

Another limit on yield is water. Lack of water—drought—and too much salt (which has the same effect) reduce crop yields around the world. Both dehydrate plants: water from the inside of the plant’s cells moves out by a process called osmosis. This loss of water triggers severe stress reactions. Photosynthesis shuts down. In extreme cases the

plant dies. Salty soil can come from irrigating too heavily for too long. Much of the irrigation water simply evaporates, leaving behind whatever salts were dissolved in it. Soil salinization affects more than 700 million acres of otherwise arable land. If plants could better withstand salt stress, yields could increase even on marginal land.

Some plants have evolved to live comfortably under very salty conditions. These plants, called halophytes, have several mechanisms that prevent or limit the damage done by water loss and too much salt. Some plants pump out sodium, the most damaging component of salt. Others accumulate it inside of vacuoles, central compartments in their cells. Still others fill up their cells with compounds called osmoprotectants that keep the water inside. Sometimes these compounds are sugars or amino acids, but plants—and marine algae—use other compounds as well. A number of studies have shown that introducing genes that code for enzymes that produce osmoprotectants increases plants’ ability to withstand salt stress.

So far, most of these studies have used genes that come from organisms other than plants, particularly bacteria. Plant genes have yet to be explored for this purpose. But both genes that encode salt pumps and those that code for enzymes that cause osmoprotectants to be made are being identified and studied. Other genes are being investigated as well, such as the regulatory genes that control the plant’s overall response to salt.

Still another major factor that limits crop yields is the quality of the soil. Not all soils are hospitable to plants. One major problem in acid soils, for instance, is aluminum. Aluminum is the third most abundant element on Earth. When soil is alkaline or neutral, aluminum is in a form that doesn’t harm growing plants. When the soil’s acidity increases, the aluminum is converted to a soluble form that is toxic to plants. Soil acidification is exacerbated by some farming practices and by acid rain. It affects an estimated 40 percent of arable land worldwide. In the tropics, aluminum toxicity cuts yields by as much as 80 percent on about half of the arable land. Even at quite low concentrations, aluminum ions inhibit root growth, which in turn affects plant growth and yield.

Plants have developed several mechanisms for aluminum toler-

ance. Some plants exclude it. Others secrete organic acids, such as citric acid, oxalic acid, and malic acid, that bind tightly to the aluminum and prevent the plant from absorbing it. It is the growing root tips that secrete the acids, forming a protective shield. In 1997 a research group led by Luis Herrera-Estrella at the National Polytechnic Institute in Irapuato, Mexico, reported that the ability of a papaya plant to tolerate aluminum could be enhanced by introducing a bacterial gene coding for citrate synthase, the enzyme that produces citric acid. The plants produced and secreted more citric acid, allowing them to grow in soils that had been toxic to them previously. These experiments establish the principle of using genes to enhance the aluminum tolerance of plants, but the first experiments might not provide the final answers. As more is learned about how plants tolerate aluminum, more genes will be identified.

Limits on nitrogen and carbon use, salt and aluminum toxicity—these are among the major problems that must be overcome if farmers’ yields are to double or perhaps even triple to meet the demands of a human population 8 or 9 billion in number and demanding more and better food. It seems unlikely that the future holds another simple breakthrough, like the synergy between dwarfing genes and fertilizer that made the Green Revolution possible. But a breakthrough that enhances either the use of nitrogen or the efficiency of photosynthesis, or both simultaneously, could push yields up dramatically. More likely, the advances will be incremental. Small improvements of many different kinds will be made in many different crops. But it depends. And what it depends on has rather less to do with the science than with people.

In 2002 Zambia’s president rejected a shipment of donated corn from the United States, ostensibly because genetically modified food had not been proven safe to eat. According to the Los Angeles Times, “Many Zambians in rural areas have resorted to eating leaves, twigs, and even poisonous berries and nuts to cope with the worst food crisis in a decade hitting southern Africa.” Zambian president Levy Mwanawasa had declared a food emergency in the nation three

months earlier. Yet he refused the American maize, saying, “We would rather starve than get something toxic.”

His choice was bewildering. The health consequences of starvation are undeniably terminal—and there is no evidence that genetically modified corn is toxic. As the Los Angeles Times reported, “The United States, United Nations, and humanitarian aid groups insist that the U.S.-donated corn is safe and identical to grain eaten daily by people in the United States, Canada, and other countries.”

Mwanawasa’s logic is indeed incomprehensible—unless one views it from an economic standpoint. The European Union has urged African governments who want to trade in Europe to treat genetically modified crops as a serious biological threat. If the Zambian government were to lose its “GM-free” status, it would lose access to European markets, where its exports include organic baby corn and carrots. And indeed, President Mwanawasa was quoted as saying that he does not want the introduction of genetically modified foods to hurt his export trade with Europe. The government of Zimbabwe, also facing famine in 2002, agreed to accept U.S.-donated corn only if it was first ground into cornmeal “so that the food aid cannot be planted,” the BBC reported. “Zimbabwe and some of its neighbors are worried that GM seeds could contaminate locally grown crops, threatening lucrative exports to Europe, which insists that food must be GM-free.”

“All across Britain and most of the rest of Europe,” the New York Times reported in February 2003, “shoppers would be hard pressed to find any genetically modified, or GM, products on grocery store shelves, and that is precisely how most people want it.” At the Happy Apple greengrocer in the small English town of Totnes, “the roasted vegetable pasty is labeled, clearly and proudly, as GM-free,” the Times reported. When asked her opinion on GM foods, one shopper replied, “It’s a kind of corruption, not the right thing to do, you know?”

The private and personal choices of European shoppers like this one are setting the public policy of African nations. Zambia’s decision to refuse American corn was greeted with disbelief around the world. But a thoughtful look reveals it to be a logical, if unintended, consequence of the expression of a preference on the part of Europeans for foods that have not been modified by molecular techniques. African

and other less developed nations are caught in a terrible bind. With almost three million people at risk of starvation, they are faced with a choice between immediate suffering and closing the door on future economic prosperity.

The heart of economic development is the ability to grow more crops than growers and their families need to survive. The Rockefeller Foundation’s Gordon Conway and Gary Toenniessen note that two-thirds of sub-Saharan Africa’s more than 600 million people live on small farms. The food they produce, combined with what they can afford to buy, is insufficient. The result is that 194 million Africans, mostly children, are undernourished. “Africa does not produce enough food to feed itself even with equitable distribution,” they wrote in 2003. “Food aid to Africa—currently running at 3.23 million tons annually—helps prevent starvation but can create dependency.”

The first step, they say, is to achieve food security, which simply means reliable access to enough food to lead a healthy, active life. “Most African farmers have land assets adequate to provide food security and to rise above subsistence.” But to do so, “they need to intensify production with genetic and agro-ecological technologies that require only small amounts of additional labor and capital.” In a July 2003 New York Times Op-Ed piece on the same subject, Norman Borlaug argues: “Biotechnology absolutely should be part of African agricultural reform; African leaders would be making a grievous error if they turn their backs on it.” He strongly urged African leaders not to follow the lead of Europe, where biotechnology has been “demonized,” but to use it for the benefit of their farmers and their people.

How can Africa consider adopting molecular technology if by doing so its farmers are locked out of European markets? How can Africa afford not to adopt approaches that are biology-based, low-cost, and beneficial on both small and large scales? How did we—the industrialized nations that developed these molecular techniques for plant breeding—contribute to this extraordinary and deeply distressing state of affairs?

Calestous Juma, director of the Science, Technology and Globalization Project at Harvard University’s Kennedy School of Government, compares it to the persecution of coffee. “In the 1500s,” he explains, “Catholic bishops tried to have coffee banned from the Chris-

tian world for competing with wine and representing new cultural as well as religious values.” Juma continues, “In public smear campaigns similar to those currently directed at biotech products, coffee was rumored to cause impotence and other ills and was either outlawed or its use restricted by leaders in Mecca, Cairo, Istanbul, England, Germany, and Sweden. In a spirited 1674 effort to defend the consumption of wine, French doctors argued that when one drinks coffee: ‘The body becomes a mere shadow of its former self; it goes into a decline, and dwindles away. The heart and guts are so weakened that the drinker suffers delusions, and the body receives such a shock that it is as though it were bewitched.’”

In coffeehouses throughout Europe, and increasingly in America, similar campaigns are being waged now against genetically modified foods—using equally exaggerated claims of potential harm. Juma writes: “Debates over biotechnology are part of a long history of social discourse over new products. Claims about the promise of new technology are at times greeted with skepticism, vilification, or outright opposition—often dominated by slander, innuendo, and misinformation. Even some of the most ubiquitous products endured centuries of persecution.”

It is sobering, for example, to recollect that vaccinations against smallpox—a disease that kills 30 percent of the people it infects and disfigures the rest—were vilified in editorials and cartoons, publicly protested, and strongly resisted. Fortunately, national governments and the United Nations persisted in vaccinating people—sometimes even with a bit of coercion—and smallpox is gone.

The problem today, suggests Stanford University’s Henry Miller, a former FDA official, is compounded by governments that increasingly depend on public opinion in formulating policy involving scientific issues. Noting that in 2003 the British government organized focus groups “to find out what ordinary people really think [about GM foods] once they’ve heard all the arguments,” Miller says: “Getting policy recommendations on an obscure and complex technical question from groups of citizen nonexperts (who are recruited through newspaper ads) is similar to going from your cardiologist’s office to a café, explaining to the waitress the therapeutic options for your chest

pain, and asking her whether you should have the angioplasty or just take medication.”

Even when they’ve “heard all the arguments,” intelligent and inquiring minds not trained in the subject can still be confused. In June 2003, for instance, a Zambian newspaper reported that “Maize is not directly consumed in America.” The writer, Simon Mwanza, was one of seven African journalists who had toured the United States to learn about biotechology, for which he used the abbreviation BT. His tour had included stops at Monsanto and Pioneer Hi-Bred, several universities, the Center for Science in the Public Interest, the Pew Initiative on Food and Biotechnology, the National Corn Growers’ Association, USAID, and the Washington office of a senator from Iowa. None, apparently, had invited him to try cornflakes, corn chips, or corn-on-the-cob. Or perhaps the problem was one of translation, and the fact that “corn” was the American name for “maize” was not made plain. At the University of Maryland he learned that “most of the maize produced in the USA was for animal feed,” he wrote, and that “the US also uses maize to produce ethanol.” Later, visiting the National Corn Growers Association, he wrote, “The journalists’ eyes popped out when they were shown a wide range of products made from maize—thanks to BT.” The Association representatives gave the visiting journalists “t-shirts made from corn to make their BT point abundantly clear.” Mwanza’s conclusion about biotechnology? “While BT appears a promising solution to agriculture, it is difficult to forget what Dr. Scott Angle of Maryland University said: ‘We don’t know what we don’t know.’”

Most people have not devoted even two weeks, as Mwanza and his colleagues did, to understanding the technology behind genetically modified foods. Still, they have strong opinions. A 2003 survey in America found that 58 percent of the people asked were “unwilling to eat genetically modified (GM) food.” That majority response seems to send a clear signal to food producers and seed companies. That is, until you ask the next question: “What food are Americans willing to eat?” A 1993 survey of New Jersey residents found that 41 percent of the respondents would not eat food produced through “traditional hybridization techniques.” A full 20 percent said it was “morally wrong to produce plants this way.” Yet since 1970, more than 96 percent of the

corn grown in America has been hybrid corn. Sweet corn, cornflakes, corn muffins and chips, the corn fed to our beef cows, chickens, and pigs is all hybrid corn, as is the source of the corn sweeteners and corn starch found in mayonnaise, peanut butter, chewing gum, soft drinks, beer, wine, frozen fish, processed meats, all dehydrated foods, all powdered foods, and all granulated foods.

It is perhaps not surprising that the Organic Rule, so heavily influenced by public opinion, forbids the use of irradiation, antibiotics, and molecular genetic modifications in producing “organic” food. But in the end, says Miller, “The goal of policy formulation should be to get the right answers.” “Although it may be useful, as well as politic, for governments to consult broadly on high-profile public policy issues,” he adds, “after the consultations and deliberations have been completed, government leaders are supposed to lead.”

Getting the right answers on genetically modified foods matters—profoundly. The science is complex, and advancing daily. As we continue to learn more about how plants grow, and as we become more skillful in transferring useful genes into plant cells, we find ourselves with an opportunity to get it right—not just for the economic benefit of large companies, but for the benefit of ordinary people everywhere in the world.

Getting it “right” will have many local meanings. It will mean virus-resistant tomatoes in Italy, herbicide-resistant wheat in Washington, and insect-resistant Bt corn in Iowa. It will mean aluminumtolerant crops in the tropics and virus-resistant sweet potatoes in Africa. Some of these crops will be produced by companies because they can return a profit, every company’s prerequisite for survival. But others might never make money. These will come only when governments everywhere recognize—and invest much more heavily in—agriculture both as a public good and an environmental necessity. As well, these will come only when regulators and regulations become more responsive to evolving knowledge than to public perceptions and anxieties. Only then will public sector scientists be able to invest their time and knowledge in raising yields in an ecologically sound way.

And yet, in the deepest sense, getting it “right” is the same for all nations: having enough to eat while preserving and protecting the en-

vironment. Every civilization rests on food. Over many thousands of years, humans have devoted a great deal of intellect, energy, and effort to changing wild plants into food plants. These changes—all of them—involved changes in the plants’ genes. We have a long history of tinkering with nature. It is no exaggeration to say that our tinkering, our modification of plant genes—and those of domesticated animals—to meet our nutritional needs, has shaped our world.

At the same time, agriculture in its very essence is ecologically destructive, whether it is performed at the subsistence level for a single family or on an industrial scale. The challenge now, as our population pushes against the planet’s limits, is to lessen the destructive effects of agriculture on the earth even as we coax it to produce more food.

“To assert that GM techniques are a threat to biodiversity is to state the exact opposite of the truth,” writes Peter Raven, director of the Missouri Botanical Garden. “They and other methods and techniques must be used, and used aggressively, to help build sustainable and productive, low-input agricultural systems in many different agricultural zones around the world.”

At the International Botanical Congress in 1999, Raven announced: “We are predicting the extinction of about two-thirds of all bird, mammal, butterfly, and plant species by the end of the next century, based on current trends.” In a 2003 essay he elaborates, “These organisms are simply beautiful, enriching our lives in many ways and inspiring us every day. By any moral or ethical standard, we simply do not have the right to destroy them, and yet we are doing it savagely, relentlessly, and at a rapidly increasing rate, every day. Many believe, and I agree with them, that we simply do not have the right to destroy what is such a high proportion of the species on Earth. They are, as far as we know, our only living companions in the universe.”

And the greatest danger to other species is our own need for food. “Nothing has driven more species to extinction or caused more instability in the world’s ecological systems than the development of an agriculture sufficient to feed 6.3 billion people,” Raven says. “The less focused and productive this agriculture is, the more destructive its effects will be.”

Using our growing knowledge of plants and plant genes, and our

increasing skill at modifying them with molecular techniques, we can make agriculture more focused and more productive—if we are careful. The thoughtful choice of genetic modifications can help us become better stewards of the earth. The key words here are careful and thoughtful. Whether the technology will be helpful or harmful, in the long run, depends on how it is used, on the choices people make. The better we understand what this technology is—how it has come to be and what it involves—the wiser will be the decisions we make as a civilization about how it will be used in the future.