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Conditions of life are forcing a fundamental shift in the nature of agriculture. A generation ago, some advances — largely in plant breeding — produced a quantum leap in food production, especially in the developing world, averting worldwide famine. We feed ourselves largely on those earlier gains, which we call the Green Revolution. Now we are in need of another such leap, but we lack the technology to effect it. This is the dilemma that frames all the efforts and debates this book will follow.
A forecast of famine is nothing new. Since the time of Thomas Malthus, who gave his name to the whole enterprise of considering doom, supposedly ironclad calculations have demonstrated the onset of worldwide famine — and many times, they have ultimately proved incorrect. The most famous of these in modem times came from the respected biologist Paul Ehrlich, who in 1969 forecast a starving Japan and China invading Russia in a food war within a decade. Driving his conclusion was the seemingly inexorable collision course of two graph lines: it seemed certain that humanity would outbreed any possible gains in agricultural production. Ehrlich's scenario did not foresee a remarkable blip in one of those lines — the Green Revolution.
Ehrlich didn't know about Norman Borlaug's work, by then already twenty-five years old. Backed by the Rockefeller Foundation, Borlaug had been working in Mexico to breed high-yielding strains of wheat resistant to fungus and rust diseases. The experiment worked so well that wheat heads became top-heavy with fat kernels and toppled over, a problem called "lodging." More breeding, this time with a dwarf Japanese variety to prevent lodging. More breeding, to improve nitrogen use. More tweaking of fertilizers, and so on and so on with this wheat, with parallel work in rice and corn. ("Corn" is the Old English word for grain in general, now applied in the United States to what is more properly called maize. I use the terms "corn" and "maize" interchangeably.) Wheat, rice, and maize are the big three, the trio of grasses that were domesticated in separate parts of the world — rice in south China, wheat in the Middle East and Southwest Asia, maize in central Mexico — and now provide more than half the energy humans consume, in the dense, storable package of carbohydrates that is grain. The net result of the work Borlaug inspired was an average annual increase in harvests of 2.1 percent a year between 1950 and 1990, the compounding growth curve that led to a tripling of harvests during that period. The collision Ehrlich had predicted was avoided.
Asia, the predicted "basket case," became a bread basket that now mostly feeds itself, as does much of Latin America. Periodic pockets of famine remain, but by and large, the world is less hungry than it was a generation ago. When Ehrlich wrote The Population Bomb, 56 percent of the world's population lived in nations that provided less than 2,200 calories of food per day per person, a subsistence diet. In its 1992-94 report, the UN's Food and Agricultural Organization estimated that number had dropped to 10 percent. Indeed, a revolution. Hungry people still exist in the world, but proportionately fewer than a generation ago. So why not ride the happy results of this into the future and call the problem solved?
A fitting person to answer this might be Timothy Reeves, director general of CIMMYT, which is the acronym in Spanish for the International Center for the Improvement of Wheat and Maize. CIMMYT evolved like modern wheat from Borlaug's work and, together with the IRRI, the International Rice Research Institute based in the Philippines, institutionalized the Green Revolution. Borlaug himself still maintains an apartment and offices at CIMMYT's headquarters just outside Mexico City.
Reeves, an Australian, articulate, confident and direct, sits in his campus-like office building amid the experimental fields of wheat and looks across the brown haze toward Mexico City a half hour away. He's just back in Mexico after visiting state-of-the-art farmers in Nebraska and Australia.
"The thing that really alarms me is I feel most people have underestimated the task," he says. The task he refers to has a simple number attached to it: population growth will double demand for food as soon as the year 2020, by some estimates.
"There's an additional one of those Mexico cities being added every twelve weeks, he says. "If you tell farmers in Australia or Nebraska that they have to double production in twenty years, they're stopped in their tracks, because . . . all they know is it's going to take new technology, but they can't think about what it would be . . . That gives you some idea of what has to be done in developing countries, if the cutting edge has no idea of what needs to be done."
From the beginning, the Green Revolution has had its critics, especially those who have suggested that its heavy reliance on high inputs of water, capital, and chemical fertilizers and pesticides are simply not sustainable. Reeves himself voices the critics' chief concern: "In feeding ourselves, are we starving our descendants?"
The sense of discomfort with the Green Revolution is no longer limited to its critics. There is consensus that the techniques that have brought us this far will not be able to sustain us in the future. Production is leveling off. Since 1989-90, world grain harvests have risen on average only .5 percent a year, a quarter of the rate of the Green Revolution boom years. Changed political circumstances, particularly the collapse of the Soviet Union and the resulting economic chaos in one of the world's most important grain-producing regions, offer partial explanations, but there are signs that, politics aside, Green Revolution techniques are approaching the limits of what they can produce.
If that's true, not only will supply be constricted but the demand side of the equation will also be thrown into flux. From the beginning, agriculture has been the primary engine of human population growth; the dense package of storable carbohydrates that grains provide allows mobility, cities, hierarchy, technology, medicine, longevity. We count on more agriculture to provide food for ever-growing numbers of people, the solution to the population problem. We forget that the relationship is circular, dynamic, and not at all simple.
Overall, a veneer of good news shines on the population front, what demographers sometimes call a "reproductive revolution," a mirror image of the Green Revolution that has given the planet some respite from the population bomb. What they mean is that, for a variety of reasons like birth control and increased prosperity, fertility worldwide has dropped to an overall annual growth rate of 1.5 percent now, compared to 2 percent in the 1960s. Indeed, in much of the developed world, especially Europe, population growth has stabilized.
This overarching trend, however, masks some problems embedded in the numbers. First, as with much that happens in the world, the trend is geographically lopsided. Large parts of the developing world, precisely the areas least able to grow their own food, still have high birth rates. Even with Green Revolution gains, regions of Africa have more than offset increased crop yields with increased population. Food production per person actually decreased in thirty-one of forty-six African countries in the decade beginning in 1985.
Probably these statistics mask an even greater food crisis, in that an undeniable effect of the Green Revolution has been to displace rural people through mechanization and larger-scale, capital-intensive farms. This occurred in both the developed and less developed world, but in the latter the people displaced were often subsistence farmers. Their produce often doesn't show up in yield statistics, but it used to feed people. Displaced to the cities, this class of people no longer feed themselves.
Meanwhile, there is a well-established correlation between an increase in income and declining birth rates, to the point that development accounts for much of the reproductive revolution. But there is also a correlation between increased income and consumption of meat, which in turn greatly ratchets up the demand on grain. (it takes about seven grams of grain to make a gram of beef) Forecasters expect demand for grain for human food to increase by 47 percent in the developing world by the year 2020. At the same time, demand for grain for livestock is forecast to jump 101 percent during the same period.
Finally, the current low birth rate is only one factor determining population growth. Another factor is the bulge of people of reproductive age who were themselves the result of the earlier boom. A lower birth rate applied to a higher base still yields a lot of new mouths. UN projections say there will be 8 billion humans by 2025. This is what drives the sense of urgency among agronomists and agricultural economists.
According to projections by the International Food Policy Research Institute, there will be 150 million malnourished children under the age of six among us in the year 2020. That is a decline from the present percentage, but one out of four children on the planet would still be malnourished, with the heaviest concentration in South Asia and Africa. These projections are based on an agriculture that continues along the curves carved by the Green Revolution, an assumption perhaps more responsible for the uneasiness among experts than the raw numbers of people.
Begin by considering the United States, which represents the cutting edge of agricultural productivity. Average grain yields in 1960 were 45 percent higher than in 1950. During the decade 1960-70, the increase was 43 percent, then 20 percent during the next decade, and 10 percent during the next.
During the same period, the United States and the rest of the world increased harvests by boosting yield per acre, and also by bringing more land under production. At present there is no more uncultivated land to be converted to crops. In some areas, the supply of arable land is decreasing, especially in the United States, where urbanization continues to chew up farms. In the 1970s, the United States brought into cultivation about 50 million hectares (a hectare is 2.5 acres) of land considered "highly erodable" and was forced to retire it a decade later, after it was found to be losing more than thirty tons of topsoil per year per hectare to erosion. The land was seeded back to grass. Furthermore, much of the yield increase came about by increasing irrigation, yet supplies of fresh water are rapidly being exhausted. Much of the United States' prime grain lands overlay the Ogallala Aquifer that lies under parts of Nebraska, Oklahoma, Texas, New Mexico, Kansas, South Dakota, and Colorado. This fossil water aquifer has been pumped to depletion in some irrigated areas, and will be entirely depleted at current rates in a few decades.
Much of the gain in yields came through increased use of fertilizer, yet fertilizer application rates have reached their maximum in the developed world, the point of diminishing returns. Any more fertilizer simply couldn't be absorbed by the crops and therefore would not bring a corresponding increase in yields. Farmers know this and are already starting to cut back.
Gain also came through improved crop varieties, yet this strategy, too, has an upper limit. Increasing yield is really a matter of coaxing plants through selection to adopt a strategy that favors seed over all other plant parts: roots, leaves, and stems. Agronomists measure the improvement with something called the harvest index, the weight of grain a plant produces compared to the weight of everything else. At the beginning of this century, grain crops typically had harvest indices of .25, a quarter of a plant's total bulk. The Green Revolution's plant breeders brought the index to about .50. There is some more yield to be gained this way, researchers think, but they also believe the maximum index possible is about .60. Beyond that, in a manner of speaking, there is no blood in the turnip.
|The Seed: The Case for a Second Green Revolution||3|
|An Island in Africa: Global Methods, Local Choices [Ethiopia]||22|
|How Things Fall Apart: When Politics Pushes People Against Nature's Limits [Zimbabwe]||40|
|To Work in Peace: Visionaries in Violent Times [Uganda]||60|
|From Basket Case to Bread Basket: When Biotechnology Has a Brain Trust [India]||79|
|The Critical Mass: The Fate of Farming in an Industrializing World [Nanjing, China]||95|
|Genetic Revolution: Bioengineering on the Loose [Shanghai, China]||111|
|Forging a Magic Bullet: Technology Based in Biodiversity [Chile and Brazil]||128|
|In Wildness Is the Preservation of the World: Sustaining Traditional Farming and Genetic Resources [Mexico]||149|
|Roots: Restoring Rural Wisdom [Peru]||173|
|The Genie in the Genome: Bioengineering in Context||191|
|A Common Ground: Food, Cities, and the Integrity of Rural Life||208|