So commenter "David F" on the Rolling Stone site posts
I don’t suppose anyone has seen the study that shows bovine flatulence is a larger cause of global warming than any man-made pollution.
...as suggested in this article:
There are 1.4 billion cows worldwide, each producing 500 litres of methane a day and accounting for 14% of all emissions of the gas.
And why are there 1.4 billion cows in the world?
Could it be because we raise them for food and clothing?