while what he's saying is fundamentally correct, you simply can't scale this at a reasonable level. he's essentially undoing the reason that malthus was wrong, and projecting a system that requires massive depopulation in order to work. people that have done the math on this conclude it can only sustain about 200 million people.

you're using a fraction of the resources because you're growing a fraction of the food.

and, regarding the carbon production of meat...

there's lots of reasons to not eat meat. i won't eat cows, either, although i continue to eat pork and eggs (and cheese). but, part of what he's trying to address here is that oil-based pesticides used to produce fruit and vegetables are actually worse in terms of carbon production, which is a fact you can look up. the nitrates are just vicious carbon emitters.

so, if you think you're reducing carbon by abstaining from meat, you're just wrong. it's the entire system that needs to be rejigged, not any specific food item.

i'm critical of permaculture because you can't scale it, so what's the right answer?

the only way we can grow enough food for everybody is to recycle the carbon by containing the process, which means producing all agriculture in greenhouses. the soil is wrecked. the future is in hydroponics, in a controlled setting.