Per bill nye, cow flatulence accounts for 20% of the greenhouse gas emissions by warming capacity. 12billion pounds of methane per year. Methane is 23x more warming than CO2. Also, if cows were fed garlic regularly, it woyld cut their emissions by more than half.
Also, sub 4oz of tofu per week in place of 4oz of beef and you'll save 20,000 gallons of water.