The popular media continue to lead Americans to believe that global environmental changes are heading us to disaster. As recently as February 28, 1997, CNN News announced the United States has been declared the world's worst polluter. This related to the release of carbon dioxide into the atmosphere, thus speeding the rate and magnitude of a global warming. Beneath all of this rhetoric, the evidence is that the rising levels of atmospheric carbon dioxide are very favorable for the most essential of human activities, and our most important renewable resource, namely the production of food.
Not many people think of it in this way, but food, climate, and the rising levels of atmospheric carbon dioxide are uniquely interrelated. Food production is a critical and an essential renewable resource. Without food, the human race would not survive. The production of this renewable resource, upon which all life depends, is possible only through photosynthesis, the most important of biochemical processes. An essential raw material, almost always in short supply, is the low level of atmospheric carbon dioxide. For example, an acre of corn crop must process over 40,000 tons of air to produce the record yield of more than 130 bushels per acre recorded in the United States for 1995.
Globally, some 25 crops stand between people and starvation. The largest single food group is the cereal grains, of which corn is a leading member. They provide approximately 60% of the calories and 50% of the protein consumed by the human race. The legumes provide about 20% of the world's protein. The balance of calories, protein, and essential vitamins and minerals is obtained from tuber and root crops and various fruits, nuts, and vegetables. Food animals, deriving their food either directly or indirectly from plants, provide 20% of the protein with 5% coming from fish.
The most determinant factor in agricultural (food) production is weather or the climate. For agriculture, climate must be managed both as a resource to be used wisely on the one hand and a hazard to be dealt with on the other. Food production is very much a function of climate, which in itself is unpredictable. In fact, the principal characteristic of climate is variability. Predictive climate changes derived from computer simulations are far from accurate and may be deceptive even with the most advanced modeling. Volcanoes, cloud cover, regional characteristics, and changing of atmospheric components currently cannot (and may never) be successfully factored into an accurate climate model.
From the perspective of food security, the stability of agricultural production is as important, if not more so, than the magnitude of output. Climate variability has a greater impact on agricultural productivity -- both its magnitude and stability -- than does climate change. Extremes in weather, rather than averages, affect agriculture. Both crops and livestock are sensitive to weather over relatively short periods of time. Annual averages of temperature and rainfall do not convey short-term deficiencies, which affect both the volume and stability of food output. History reveals that for food production, warming is better than cooling. In fact, "the silver lining in the growing cloud of atmospheric [CO.sub.2] that may warm the planet is more raw material for photosynthesis," as the Council for Agricultural Technology reported in 1994.
Of all the natural climate hazards, drought is what farmers fear most. The lack of water is the single greatest impediment to plant growth and global food production. This is illustrated by the fact that today, irrigated cropland -- about 17% of the world's total -- produces one-third of the agricultural output. For the United States, the 12% of the cultivated farm land that is irrigated accounts for 37% of crop production. U.S. agriculture consumes, mostly through irrigation, 80% to 85% of the nation's fresh water …