Cows are wicked polluters.  They emit methane through  belching and flatulence, which is by one common measurement 25 times more potent as a greenhouse gas than the carbon dioxide emitted by cars.

“Shifting less than one day per week’s worth of calories from red meat to and dairy to chicken, fish, eggs or a vegetable -based diet achieves more greenhouse -gas reduction than buying all locally sourced food.”

Or you can switch to kangaroos for your beef.    Kangaroo farts don’t contain methane.

From “Superfreakonomics” by Steven Levitt and Stephen Dubner

Can you imagine the marketing campaign?