Densely-quartered urban dwellers eating like sparsely-populated pastoralists is not sustainable. A theory behind the sanctification of cows in India is because a cow kept for its meat feeds far fewer people than one kept for its milk. The same would apply to some of the climate effects, such as the feed crops, although I don't know if it would change the cow-emitted methane.

Was looking for this kind of comment in the thread. I think our cities are the main causes of many problems we are creating in our environment.

Are you a climate change denier? Are you unaware of the changes that have happened in the last ten thousand years?

What is the time span requirements for 'sustainable'?

Everything on Earth will be toast in ~5 billion years.

Not sure what your point is, but agriculture needs to change dramatically in the next couple of decades.

Human civilization/all life that wants to keep existing also needs to change dramatically in the next five billion years but I think that is to be expected.

The problem is scale and cumulative effects.