Can We Raise Grain Yields Fast Enough?

Article excerpt

Many countries have tripled or even quadrupled the amount of grain they produce per hectare of land. But now these gains are slowing, while global demand continues to soar. We need a new strategy for food security.

After a half-century of global surpluses of wheat, rice, corn, and other grains, it is easy to be complacent about the food prospect for the twenty-first century. We have come to take for granted the supply of grain that provides half of humanity's food energy when consumed directly and a good portion of the remainder when consumed indirectly in the form of livestock products.

But this complacency can be dangerous. Each year, as population continues to expand, the world's farmers must stretch their production capacity to feed an additional 80 million people. Beyond that, they must now satisfy the needs generated by record rises in affluence. As people make more money, they consume more beef, pork, poultry, milk, eggs, beer, and other grain-intensive products. A kilogram of pork, for example, may require four kilograms of grain to produce, so as people are able to afford more pork their demand for grain increases. And Third World incomes are now rising at record rates. In Asia, where more than half the world's people live, incomes are rising faster than they have on any continent at any time in history. This combination of more people and more consumption per person is putting heavy pressure on the land.

The world's farmers responded heroically to past increases in demand, nearly tripling the grain harvest from 630 million tons in 1950 to 1.8 billion tons in 1990. Most of this expansion came not from plowing a lot more land, but from more than doubling the amount of grain produced on existing farmland. Between 1950 and 1990, the yield per hectare grew at 2.1 percent per year. Augmented by whatever new land could be added to grain production, including that from expanded irrigation in arid regions, this boosted total grain production by an average of nearly 3 percent a year throughout that four-decade run - well ahead of population growth.

Although there were disastrous shortages from time to time during this period - in China, Ethiopia, and Somalia, for example - and although some 800 million people are still hungry and malnourished, overall supply has not been a major issue. In the United States, the government paid farmers not to plant part of their land. The steady growth in the harvest, and resultant decline in grain prices, created a psychology of surpluses - a psychology that has made it easy for policymakers both to put off the difficult task of stabilizing human population and to take their farmers' capacities to meet future challenges for granted.

The world's total demand for food is likely to nearly double its present level by 2030, and there is little new land available to plow. The key to food security in the years ahead, then, is whether farmers can continue to rapidly raise the productivity of their land, as they have done in the past. However, assessments of the potential for raising land productivity vary widely. In a recent World Bank report, researchers indicated that they expect grain yields to increase at 1.5 to 1.7 percent per year, or "at rates comparable to those in recent years. ..." With this rosy outlook, the Bank projects a surplus capacity in world agriculture as a whole, accompanied by declining food prices. This Worldwatch Institute analysis comes to a very different conclusion.

The World Bank economists base their projections on simple extrapolation, arguing that "historically, yields have grown along a linear path from 1960 to 1990, and they are projected to continue along the path of past growth." Although extrapolating past yield trends worked well enough in previous decades, it won't work in a world where the yields simply are not continuing to climb rapidly. In contrast to the robust increases of 2.1 percent per year between 1950 and 1990, the rise between 1990 and 1995 averaged only 1 percent a year. …