No need to ignore GWP-100 or GWP-20 or accept losing topsoil. We can reduce the carbon footprint from beef production and from other food production and work on sustainable and healthy diets for all.
We probably have to do all of them at the same time, in fact.
But I don't know how we best fight climate change. My point was just that eating less beef translates into a clear and significant reduction of pressure on the climate. What you do with that fact is up to you.