Another agricultural trend of growing concern is the increased nutrient content of coastal waters resulting from fertilizer runoff in agricultural regions. Augmented by urban sewage discharge in some situations, this results in huge algal blooms, which, as they die and decay, deplete the oxygen content in the water, leading to the death of the fish.

Today, more than ever, we need political leaders who can see the big picture, who understand the relationship between the economy and its environmental support systems.

Nuclear power, once regarded as petroleum's natural heir, has become less and less attractive as its numerous drawbacks come to light. Coal, the other fossil fuel, is ultimately as exhaustible as oil.

Our early 21st century civilization is in trouble. We need not go beyond the world food economy to see this. Over the last few decades we have created a food production bubble-one based on environmental trends that cannot be sustained, including overpumping aquifers, overplowing land, and overloading the atmosphere with carbon dioxide.

Children whose developing lungs are particularly vulnerable suffer the most from air pollution. For children, breathing the air in cities with the worst pollution, such as Beijing, Calcutta, Mexico City, Shanghai, and Tehran, is equivalent to smoking two packs of cigarettes a day.

Each summer, for example, nitrogen and phosphate washing from farmlands in the Mississippi Valley enter the Gulf of Mexico, creating a massive algal bloom covering some 16,000 square kilometers. As the blooms die off, this area-roughly the size of New Jersey-is so deprived of oxygen that no fish survive.

Farmers...can no longer keep up with rising demand; thus the outlook is for chronic scarcities and rising prices.