Measuring Cow Burps in Fight Against Climate Change

While Congress considers taxing auto and industrial pollution, a U.N. report fingers another guilty party — cows.

The U.N. accuses our bovine buddies of producing 18 percent of the world's greenhouse-gas emissions — more than planes, trains and automobiles combined.

"Methane is a greenhouse gas. It leads to climate change, that leads to global warming," explains Frank Mitloehner, an air-quality specialist at the University of California, Davis. "What we do is we study how much methane comes from different animal types, let's say dairy cows or steers."

When cows digest their food, stomach bacteria produce methane, an ozone-forming gas considered 23 times worse than carbon dioxide when it comes to trapping heat in the atmosphere.

"A lot of people think this gas is coming from the rear end," explains Nancy Hirshberg of Stoneyfield Farms in Highgate, Vt. "Ninety-five percent is actually from the front end, from the burps."