By Sara Place, GreenBiz.
Let’s clear the air on something up front. All those "cow farts" you’ve heard about? It’s actually cow burps. Having spent much of my life around cows and conducting research measuring methane emissions from cattle (I’m sure most readers are jealous), I can confirm the vast majority of methane emissions emanating from cattle come out the front end. Also, despite the sensory experience "gassy cows" may evoke, methane itself is an odorless gas.
Methane emissions from cattle get attention because methane is 28 times (PDF) more potent at trapping heat in the atmosphere than carbon dioxide over a 100-year time frame. Additionally, methane from cattle represents nearly half (PDF) of the carbon footprint of U.S. beef when emissions over the entire life cycle, from feed production to the consumer, are considered. However, methane also can be viewed as the necessary tradeoff for the upcycling services that cattle provide.