Comment by adrianN

Methane accounts for less than 20% of all GHG emissions (in CO2 equivalent units), and cows are only responsible for a part of that. Reducing the number of cattle is important, but killing all cattle would only buy us a few years before we have to completely decarbonize the global economy. In industrialized economies, agriculture's relative impact is even lower, since we emit so many GHGs from other sources.