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.

Our numbers expand, but Earth's natural systems do not.

We are witnessing the beginning of one of the great tragedies of history. The United States, in a misguided effort to reduce its oil insecurity by converting grain into fuel for cars, is generating global food insecurity on a scale never seen before.

We can build an economy that does not destroy its natural support systems, a global community where the basic needs of all the Earth's people are satisfied, and a world that will allow us to think of ourselves as civilized. This is entirely doable.

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.

If an economy is to sustain progress, it must satisfy the basic principles of ecology. If it does not, it will decline and eventually collapse. There is no middle ground

Population growth is exceeding farmers' ability to keep up...Our oldest enemy, hunger, is again at the door.