Burger King is doing its part to help clean up the environment -- by ridding the air of nasty cow farts. The fast food chain on Tuesday announced it's teamed up with scientists to develop a new cow diet that reduces gas emissions by an average of 33 percent. The cows supposedly not only fart less, but they burp less, too. An ad in which Burger King pats itself on the back reads, "Since we are part of the problem, we are working to be part of the solution." Cows are responsible for 14.5 percent of greenhouse gas emissions, which contribute to global warming, scientists say.