Methane is a short-lived potent greenhouse gas. In regards to the effect on global warming there is no cushy cute 'circle of life its all natural dude ' effect, methane release heats the world.
Even ignoring methane gas releases the production of red meat causes higher emissions of co2 than comparable plant-based proteins. These emissions originate from feed crop production, synthetic and organic fertilizer application, manure storage, land-use changes like deforestation for pastures, on-farm energy use, and meat processing and transport. As you see most of these are 'running costs', and reducing global meat consumption would reduce emissions.
Even ignoring methane gas releases the production of red meat causes higher emissions of co2 than comparable plant-based proteins. These emissions originate from feed crop production, synthetic and organic fertilizer application, manure storage, land-use changes like deforestation for pastures, on-farm energy use, and meat processing and transport. As you see most of these are 'running costs', and reducing global meat consumption would reduce emissions.