JOHN RUSSELL/ NETWORK ASPEN

Fortunately that disaster has stayed on the distant horizon. Over the years since the doomsaying began, the world has indeed seen the face of famine--in Ethiopia, in Somalia and now in North Korea. And today nearly one billion people around the planet are malnourished. But these tragedies are the products of war, poverty and political incompetence. They are problems of distribution, not of supply. Even though the world's population surged by 105% between 1955 and 1995, to 5.7 billion people, the global grain harvest grew by an even faster 124% during that span, thanks to a Green Revolution that relied on hybrid seeds and increased use of fertilizers, pesticides and irrigation. The world's farmers have more than met the challenge of producing enough food to satisfy the masses, if only it could be shared more equitably.

For all the forecasts of apocalypse, the rapid proliferation of the human race has slowed down a bit. The annual addition to the global population peaked at 87 million in 1990 and fell to 80 million last year. In percentage terms the growth rate hit a high of 2.2% in 1963 and has since declined to 1.4%. Part of that was the unfortunate result of higher mortality, particularly from aids and other diseases. On the bright side, though, is a dip in the fertility rate caused by the wider use of birth control. The average number of children per woman dropped from 4.2 in 1985 to 2.9 in 1996. Even in many of the poorest countries, women are becoming better educated and gaining power over their reproductive destiny.

But 80 million extra mouths to feed every year is still a lot. Can the farmers keep up indefinitely? Probably not with the strategies they have been using. All the evidence shows that the Green Revolution has been losing momentum for a long time. Growth in world grain production slowed from 3% a year in the 1970s to 1% a year over the last decade. Seafood is not a simple alternative, since supplies of many kinds of ocean fish are depleted, and varieties raised on fish farms must be fed grain or other food.

TOO MUCH OF A GOOD THING
For many years it was easy for farmers to boost their harvests merely by dumping more fertilizer, pesticides and irrigation water on their land. Now, however, they are running up against the law of diminishing returns. Insects are increasingly developing resistance to pesticide. Reliance on chemical fertilizer, rather than on organic nutrients such as manure or compost, makes the soil more compact and thus more likely to dry out and eventually erode. Improper irrigation techniques can result in the evaporation of too much water from fields, leaving behind salts that build up in the soil and ultimately leave the land infertile. That's why vast areas of Pakistan have turned into salt flats. Concludes economist Donald L. Winkelmann of the Consultative Group on International Agricultural Research in Washington: "We have to maintain high yields but through a different route from the Green Revolution. We can't make any more mistakes. Nature can't buffer us much more."

Even if farmers know how to irrigate carefully, they may face stringent limits on water supplies. "Over the past 40 years intensive irrigation has been a principal means of feeding people," says Sandra Postel, who directs the Global Water Policy Project in Amherst, Massachusetts, "but if you look at the future, the water needed for irrigation in Africa and in the Middle East would fill the Nile River 20 times over. That's a lot of water." Egypt already has to import 50% of its grain.