Jeremy Rifkin is concerned about our future.

Scientists tell us that within the lifetime of today's children, the wild will disappear from the face of the earth.

Our species now consumes nearly 40 percent of the net primary production on Earth -- the amount of solar energy converted to plant organic matter through photosynthesis -- even though we make up only one-half of 1 percent of the animal biomass of the planet.

This last statistic is kind of meaningless, as our agricultural efforts have dramatically increased those production levels relative to their "natural" state.

The Risks of Too Much City