But surely we can grow more food on each acre, can't we?
Forty years ago, the world's average wheat yield was half a ton per acre. Now it is 1.2 tons per acre. French farmers average 3.2. The highest recorded yield on a single farm is 6.4. Those staggering increases sound promising until you study the numbers behind the numbers.
Globally, the tripling of grain production over the past 50 years was accompanied by a 20-fold increase in nitrogen fertilizer use. The last doubling of U.S. food output was accomplished with a sixfold increase in fertilizer use and an even greater rise in pesticide applications. The price of high yields, it turns out, is the use of synthetic chemicals that bring with them devastating environmental effects.
Wherever soluble synthetic fertilizers are used heavily, there is water pollution. Fertilizers don't stay on fields or go only into crops. They run off into streams and leach into groundwater. Nitrate from fertilizer is one of the most common contaminants in drinking water. In U.S. agricultural areas, according to the Environmental Protection Agency, 22 percent of wells contain nitrate levels that exceed federal safety standards. Where large rivers drain farming regions, they carry fertilizer runoff into the sea, spreading "dead zones" that are barren of marine life. Where the Mississippi River empties into the Gulf of Mexico, for example, a dead zone the size of New Jersey continues to grow.
To protect water supplies and fisheries, some European countries are mandating fertilizer cutbacks. In Germany, the city of Munich pays farmers in the watershed that supplies its municipal water to farm organically. It is cheaper for the city to pay farmers to use sustainable organic practices than it is to build a treatment plant to take agricultural chemicals out of its drinking water.
Pesticides not only harm the health of farm workers and poison wildlife and wells; they also undercut their own effectiveness. They often kill off not only the target pest but also its natural enemies, creating pest resurgences. Furthermore, regular applications of any pesticide tend to hit individual pests most sensitive to the poison while letting the least sensitive survive and breed. So pest populations become resistant, forcing chemical farmers to turn to even more lethal poisons. In the past 50 years, more than 500 insect pests, 230 crop diseases, and 220 weeds have become resistant to pesticides and herbicides.
These and other environmental costs are seldom charged directly or immediately to the intensive farming that seems to produce so much food so cheaply. But they are real costs, paid by someone sooner or later. Some will eventually be paid by farmers—as soil degrades, as water becomes unusable, as pest-control mechanisms fail. Some will be paid by you and me. Most will be paid by our children and grandchildren.