The remarkable increases in food production in industrial and developing countries in 1970s and 1980s have come in part at the expense of soil and water resources. There are no major new technologies waiting in the wings to improve the food output. Food scarcity and higher prices may dominate the 1990s.
Improvements are unlikely. Our past success has brought us alarmingly close to the ecological ceiling. There is a growing sense in the scientific community that it will be difficult to restore the rapid rise in agricultural yields we saw between 1950 and 1984. In agriculturally advanced nations there just isn't much more that farmers can do.