Many years ago a scientist (I had my suspicions he might have been a mad scientist), who has since passed away, hired me to help him identify stocks that would decline in price in the event of a global cooling. I have forgotten a lot of the details of why he expected a global cooling instead of a warming, but I do remember him telling me that cows and cockroaches emitted significant quantities of greenhouse gas emissions through, well, farting.
This all comes to mind because Drudge is linking to a story about the EPA considering a tax on the owners of farting cows (and they all fart):
I keep telling you; all this global warming cult stuff is just an excuse to take more money from you.
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IMO, this is simply a way to tag all cows and make sure no large amount of raw milk makes it into the population.