Grazed and confused? : Ruminating on cattle, grazing systems, methane, nitrous oxide, the soil carbon sequestration question - and what it all means for greenhouse gas emissions

In the context of planetary boundaries on the one hand and the need for human development (in its widest sense) on the other, what role – if any – do farmed animals play in a sustainable food system? If they do have a role, which systems and species are to be preferred, in which contexts, at what scale and at what level of overall production and consumption? How could the required changes happen?