Lester Brown notes that if the environmental trends of recent decades continue, the global economy will soon begin to unravel. The food sector, he believes, is the most vulnerable. Record-high temperatures and falling water tables are already taking the edge off grain harvests in some countries, including China, the world's largest grain producer.

The wake-up call will come, Brown believes, when 1.3 billion Chinese consumers with an $80 billion trade surplus start competing with Americans for U.S. grain, driving up food prices. Rising food prices could create political instability in low-income countries, disrupting global economic progress.

At that point, it will be clear that business as usual-Plan A-is not working. In Plan B, Brown outlines a World War II-type mobilization to stabilize climate by restructuring the global energy economy and to stabilize population by investing heavily in health care, family planning, and the education of girls in developing countries.