I think their argument is like this: Imagine there are 10 units of methane in the atmosphere and every year 1 unit breaks down into CO2. If cows add 1 unit per

I think their argument is like this: Imagine there are 10 units of methane in the atmosphere and every year 1 unit breaks down into CO2. If cows add 1 unit per year and the source of that unit is ultimately CO2, then the cows aren't actually making things worse than they are now.