According to this article from newscientist.com, 'a kilogram of beef is responsible for more greenhouse gas emissions and other pollution than driving for 3 hours while leaving all the lights on back home.'
According to this article about the same report, 'The calculations based on standard industrial methods of meat production in Japan did not include the impact of managing farm infrastructure and transporting the meat - so the total environmental load is higher than the study suggests.' From the same article: 'Japanese researchers worked out putting a kilogram of beef (2.2lbs) on the dinner table is equivalent to the amount of CO2 emitted by the average car every 155 miles'
SUITE // http://www.veganforum.com/forums/showthread.php?16001-1-kg-meat-pollution-from-a-car-driving-250-km