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.

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.

Humanity's greatest challenge may soon be just making it to the next harvest.

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

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.

One way or another, the choice will be made by our generation, but it will affect life on earth for all generations to come

The biggest threat to global stability is the potential for food crises in poor countries to cause government collapse.