An Edible History of Humanity (25 page)

In a preindustrial society, it makes sense to have as many children as possible. Many of them will not survive, due to disease
or malnutrition. But once those that do survive are old enough to work in the fields, they can produce more food than they
consume, so the household will benefit overall (provided that availability of labor is the main constraint on agricultural
production). Having lots of children also provides security in old age, when parents expect to be looked after by their offspring.
In such preindustrial societies, both birth rates and death rates are very high, and the population grows slowly. This was
the situation for most of human history.

The advent of new farming techniques, crops, and tools that boost food output then move the society into a second phase in
which the population grows quickly. This is what happened in western Europe starting in the eighteenth century, following
the introduction of maize and potatoes from the New World and the spread of new farming practices. In this phase, the birth
rate remains high but the death rate falls, resulting in a population boom. At the same time, greater agricultural productivity
means that a smaller proportion of the population is needed in farming, opening the way to urbanization and industrialization.

This in turn seems to cause people to reassess their attitude to having children: Wealth, it seems, is a powerful contraceptive.
The decline in infant mortality means parents in rural areas do not need to have so many children in order to be sure of having
enough people to work in the fields, or to look after them in old age. In urban areas, meanwhile, parents may take the view
that it makes sense to have a smaller number of children, given the cost of housing, clothing, and educating them. This is
sometimes characterized as a switch from emphasizing child “quantity” to child “quality.” In addition, as female literacy
improves and women enter the workforce, they may delay marriage and change their attitude toward childbearing. And governments
in industrializing countries generally introduce reforms banning child labor and making education compulsory, which means
that children are a drain on household resources until they reach working age. The result is that the birth rate falls, and
the population stabilizes. This pattern can be clearly seen in Western nations, which were the first to industrialize. In
some European countries the fertility rate (the average number of births per woman) has now fallen below the replacement rate.
Most developing countries, meanwhile, are now in the midst of their demographic transition.

Of course, the reality is more complicated than this simple model suggests, due to other factors such as the effects of migration,
the impact of HIV/AIDS in Africa, and China’s one-child policy, introduced in 1980. But having initially sustained a population
boom, the green revolution is now tipping many countries, and consequently the world as a whole, into demographic transition.
According to forecasts published by the United Nations in 2007, the world population is expected to reach eight billion around
2025, and to peak at 9.2 billion in 2075, after which it will decline.

Research carried out in the village of Manupur, in the Indian Punjab, illustrates how the demographic transition has manifested
itself on the ground. In 1970, men in the village all said that they wanted as many sons as possible. But when researchers
returned to the village in 1982, following the introduction of green-revolution crops, fewer than 20 percent of men said that
they wanted three or more sons, and contraceptives were being widely used. “These rapid changes in family size preference
and contraceptive practice are indications that the demographic transition will continue, if not accelerate, in rural areas
experiencing the green revolution,” the researchers concluded. Similarly, Bangladeshi women had an average of seven children
in 1981. Following the widespread adoption of green-revolution technologies in the 1980s and the rapid expansion of the country’s
textiles industry in the 1990s, however, that figure has fallen to an average of two or three.

The world will face new challenges as its population shrinks—not least the difficulty of looking after an infirm and aging
population, which is already a concern in developed countries where the fertility rate has fallen. But the peak of world population
may now be in sight. Once the population starts to decline, worries about population growth outstripping food supply may start
to seem rather old-fashioned. A flood of bestselling books will no doubt warn of the dangers of the coming population implosion.
But the ghost of Malthus will finally have been laid to rest.

New technologies often have unforeseen consequences, and the technologies of the green revolution are no exception. High-yield
seed varieties, which require artificial fertilizers, other agricultural chemicals, and large amounts of water, have caused
environmental problems in many parts of the world. Nitrogen-laden runoff from agricultural land has created “dead zones” in
some coastal areas, stimulating the growth of algae and weeds and reducing the amount of oxygen in the water and thereby affecting
fish and shellfish populations. In some cases high-yield varieties proved to be less resistant than traditional varieties
to pests or diseases. This necessitated a greater use of pesticides, overuse of which can contaminate the soil and harm beneficial
insects and other wildlife, reducing biodiversity. Pesticides can also cause health problems for farm workers. According to
the World Health Organization, pesticides cause around one million cases of acute unintentional poisoning a year and are also
involved in around two million suicide attempts, leading to some 220,000 deaths a year. (The availability of pesticides has
made pesticide poisoning the most widespread method of suicide in the developing world.) A further worry is the depletion
of water supplies. In the Punjab, the cradle of India’s green revolution, for example, the proliferation of millions of tube
wells caused the water table to fall by more than fifteen feet between 1993 and 2003 alone, and many farmers now have insufficient
water to irrigate their crops.

Much can be done to mitigate these problems, however. More frugal and precise application of fertilizer can reduce runoff
without affecting yields. Fertilizer intensity has in fact been declining in recent years in some developed countries. In
the United States, maize yields have increased from 42 kilograms per kilogram of fertilizer in 1980 to 57 kilograms in 2000.
Similar improvements have been achieved with wheat in Britain and rice in Japan. But in many developing countries fertilizer
is heavily subsidized by governments, discouraging more efficient use. More can also be done to reduce the unnecessary use
of pesticides and minimize harmful side effects. During the rollout of the green revolution, farmers were instructed that
the use of pesticides was a necessary component of “modern” agriculture, which resulted in overuse. Some farmers were told
to apply pesticides according to a calendar, whether or not such applications were necessary. The use of pesticides is now
flat or declining, and biological pest-control techniques are being promoted in conjunction with chemicals, making the best
use of both traditional and modern practices. This hybrid approach, called “integrated pest management,” can reduce the use
of pesticides by 50 percent for vegetable crops. In some cases it can eliminate the need for pesticides altogether in rice
production, according to the United Nations’ Food and Agricultural Organization.

Similarly, there is plenty of scope for improvements in water use. Far more attention is now being paid to aquifer management,
for example, and to the deployment of rainwater harvesting and storage systems, and of more water-efficient irrigation systems
such as drip-irrigation technology (which also reduces nitrogen runoff). Clearly defined water rights that can be traded by
farmers can also encourage more sensible use of water, by encouraging farmers to concentrate on the most appropriate crops.
It seems odd to grow water-intensive crops such as potatoes in Israel, oranges in Egypt, cotton in Australia, and rice in
California, for example, when all of these crops could be grown more cheaply and efficiently elsewhere. And in the Punjab,
the provision of free electricity to farmers, along with subsidies for growing rice, a water-intensive crop, encouraged farmers
to leave their water pumps running continuously. In recent years, growing concern about the scarcity of water for agriculture—it
has even been called the “oil of the twenty-first century”—has prompted policymakers to pay greater attention to the development
of sensible water policies.

The environmental problems associated with high-yield farming must also be weighed against its unseen environmental benefits,
in the form of damage to ecosystems that would otherwise have been done in order to increase food production. High-yield varieties
have enabled food production to multiply with only a marginal increase in land use. Asia’s cereal production doubled between
1970 and 1995, for example, but the total area cultivated with cereals increased by just 4 percent. Globally, the figures
are even more striking. Norman Borlaug has pointed out that world output of cereal grains tripled between 1950 and 2000, but
the area used for cereal cultivation increased by only 10 percent. Without green-revolution technologies, he contends, there
would either have been mass starvation, or enormous amounts of virgin land (such as forests) would have had to have been taken
under cultivation.

Many critics of the green revolution advocate a return to traditional, or organic, agricultural techniques that do not rely
on chemical fertilizers and pesticides. This would reduce both the direct environmental impact of agriculture (in the form
of nitrogen runoff and pesticide use) and its indirect impact (since the production of chemical fertilizer is an energy-intensive
process that consumes natural gas and contribtues to climate change). But farming without the use of chemical fertilizers
produces lower yields, so more land is then needed to provide the same amount of food. Studies have found that organic production
of wheat, maize, and potatoes, for example, requires two or three times as much land as conventional production. Global agriculture
in 1900, using almost no chemical fertilizer, supported about 1.6 billion people on an area of about 850 million hectares
(2.1 billion acres), according to the University of Manitoba’s Vaclav Smil, an expert on the nitrogen cycle. Farming using
fertilizer-free (that is, organic) methods on today’s 1,500 million hectares (3.7 billion acres) would support only 3.2 billion
people on mostly vegetarian diets, he estimates, or half of today’s global population.

That said, the use of fertilizer in the developed world could be reduced while still providing enough food to provide adequate
nutrition, despite the fall in yields. That is because rich countries produce more food than they need, in part because paying
subsidies to farmers encourages overproduction. The excess allows for unnecessarily protein-rich diets (resulting in rising
levels of obesity in rich countries) and large exportable surpluses. So there is scope to switch some food production to less
chemically intensive methods, such as organic farming. The situation in the developing world is very different, however. In
rich countries, chemical fertilizer supplies only about 45 percent of the nitrogen applied to fields. But in poorer countries
it supplies as much as 80 percent. It is the use of fertilizer that makes the difference between inadequate and adequate nutrition,
and in many developing countries the supply of dietary protein remains inadequate even so.

By the late 1990s, 75 percent of all nitrogen being applied to crops in China was coming from chemical fertilizers. Since
90 percent of the protein consumed by Chinese is homegrown, this means that two thirds of the nitrogen in China’s food comes
from the Haber-Bosch process. Traditional methods, such as planting nitrogen-fixing legumes or using animal manure, simply
cannot supply as much nitrogen per hectare. In many other populous developing countries, the level of food production now
exceeds the level that could be produced by traditional, fertilizer-free methods. There may be scope to reduce the amount
of fertilizer used by more precise application, but it is difficult to see how it can be eliminated altogether without reducing
food output.

There are no easy answers. Both conventional and organic farming have environmental costs and benefits. During the twentieth
century mankind became dependent on artificial nitrogen, and turning back the clock is not an option. Chemically intensive
agriculture has undesirable environmental side effects, and more effort is undoubtedly needed to mitigate them. But the consequences
to humanity of abandoning the green revolution would surely be far worse.

Between January 2007 and April 2008, after several years of stable prices, wheat prices abruptly doubled, rice prices tripled,
and maize prices increased 50 percent. For the first time since the early 1970s, food riots erupted in several countries simultaneously.
In Haiti the prime minister was forced to resign by crowds of protesters chanting “We’re hungry!” Two dozen people died in
food riots in Cameroon. The president of Egypt mobilized the army and told soldiers to start baking bread. In the Philippines,
a new law was introduced making the hoarding of rice punishable by life imprisonment. After years in which farmers and development
specialists had lamented the low prices of staple foods, the era of cheap food seemed to have abruptly come to an end. In
many respects the origins of this food crisis can be traced back to the consequences of the green revolution.

One consequence was that governments and aid agencies lost interest in agriculture as a means of promoting development. According
to the World Bank, the proportion of “official development assistance” spent on agriculture fell from 18 percent in 1979 to
3.5 percent in 2004. There were several reasons for this shift, according to the World Bank’s 2008 World Development Report.
To some extent it seemed that the food problem had been solved. There were food gluts in North America and Europe, and low
international prices for staple foods, the result of both green-revolution technologies and subsidies to farmers in the developed
world. As a result, donors lost their enthusiasm for funding agricultural projects in the developing world. Waning investment
by governments in agricultural research, starting in the 1990s, meant that growth in yields slowed.