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.

It takes 1,000 tons of water to produce 1 ton of grain. As water becomes scarce and countries are forced to divert irrigation water to cities and industry, they will import more grain. As they do so, water scarcity will be transmitted across national borders via the grain trade. Aquifer depletion is a largely invisible threat, but that does not make it any less real.

The 20th century was the time when the world turned to use of fossil fuels and the 21st century will be the century of the renewables.

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.

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

Yet, most of the readily accessible reserves of oil formed over hundreds of millions of years will be consumed within a single generation, spanning the years from 1960 to 1995.

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.