From Isla Earth Radio:
Economist Nathan Fiala of the University of California at Irvine has a beef...about beef. Specifically, he's concerned about the impact producing beef has on warming the atmosphere. How much impact? All-told, producing a pound of beef generates the equivalent of 14.8 pounds of carbon dioxide: more than 36 times the amount emitted by producing asparagus! Producing one pound of beef protein, experts say, requires more than 10 pounds of plant protein. Combine everything that's needed to grow a cow and you've got one heifer-sized carbon footprint.

Audio link available at: http://www.islaearth.org/show.php?_a=vs&_sid=1311663600.