"Attention has focused on oil insecurity, and rightly so, but it is not the same as food insecurity. An empty gas tank is one thing, an empty stomach another. And while there are substitutes for oil, there are none for food." –Lester R. Brown, Plan B 4.0: Mobilizing to Save Civilization.
Lecture by Lester Brown at Google headquarters. Topic: Plan B: Rescuing a Planet Under Stress and a Civilization in Trouble. Watch the video.