Cows

The EPA has seriously underestimated the emissions of the powerful greenhouse gas, methane, particularly from oil and gas activity (five times) and from cattle and livestock operations (two times), according to a new report published in the PNAS.
Dec 6, 2013   The New York Times
So you think cars are to blame for L.A.'s air pollution problems? That might be bull excrement, literally, reports David Biello.
May 11, 2012   Scientific American