A sustainable economy represents nothing less than a higher social order one as concerned with future generations as with our own, and more focused on the health of the planet and the poor than on material acquisitions and military might. While it is a fundamentally new endeavor, with many uncertainties, it is far less risky than continuing with business as usual.

In this era of tightening world food supplies, the ability to grow food is fast becoming a new form of geopolitical leverage, and countries are scrambling to secure their own parochial interests at the expense of the common good.

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.

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.

In the Middle East, where populations are growing fast, the world is seeing the first collision between population growth and water supply at the regional level. For the first time in history, grain production is dropping in a geographic region with nothing in sight to arrest the decline. Each day now brings 10,000 more people to feed and less irrigation water with which to feed them.

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

We know what we have to do. And we know how to do it. If we fail to convert our self-destructing economy into one that is environmentally sustainable, future generations will be overwhelmed by environmental degradation and social disintegration. Simply stated, if our generation does not turn things around, our children may not have the option of doing so.