River Reporter: It’s long been known that cows create a lot of methane; from 50 to more than 100 gallons per day according to some studies. And it’s also long been known to some that methane is a much more powerful greenhouse gas than carbon dioxide in terms of global warming. Other farm animals also produce large amounts of methane. So the question is: should cows and other farm animals be taxed because of the green house gases they emit? It was a question put forward by the U.S. Environmental …