"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.
Lester Brown talk on Plan B: Rescuing a Planet Under Stress & a Civilization in Trouble at Environment Canada Policy Research seminar series. French translation. [Note: http://www.ec.gc.ca/seminar/Brown_e.html no longer exists.]