Climate at a Glance: Livestock and Methane 
Bullet-Point Summary:
    American ranchers and meat consumption have virtually no impact on overall greenhouse gas emissions or climate.
    EPA reports cattle and beef account for just 2% of U.S. greenhouse gas emissions.
    EPA reports all livestock account for less than 4% of U.S. greenhouse gas emissions.
    By contrast, crop production accounts for more greenhouse gas emissions than total livestock production.
Short Summary:
https://climateataglance.com/climate-at-a-glance-livestock-and-methane/