Preserving biodiversity in rich habitats is good. But global warming and other new threats may call for a new strategy
Former CIA director, R. James Woolsey, says America's oil dependence is a grave threat
The world's most outspoken climatologist argues that today's carbon dioxide levels are already dangerously too high. What can we do if he is right?
Cultivating crops in downtown skyscrapers might save bushels of energy and provide city dwellers with distinctively fresh food
- From the Editor