They release methane into the atmosphere which is a greenhouse gas. greenhouse gasses trap heat into the atmosphere, causing the atmosphere to get warmer.
The impact the population of cattle has on the Earth's atmosphere is very miniscule albeit present. Cattle release methane gas which is destructive to the atmosphere, but the current impact is hardly recognizable. With the increasing requirement of food to support a gradually rising population, we will see either now or in the near future the impact the need for cattle has on our atmosphere. I believe that this problem can be controlled and contained with the right technology.
*The highlighted sentence can either be kept in or taken out based on the user's preferance.
