Limiting food choice to cut carbon emissions?

I don't recollect anybody actually saying this, other than on the ultra green, vegan fringes, but it seems to be exercising the mind of one of Sainsbury's directors as reported by First4Farming.

"Managing needs versus demand seems like a form of communism, he said. It's something the world we are living in isn't ready for."

The thing is, if climate change does tick past any of the theoretical tipping points some time in the future, we all may have no option but to eat only what is available locally (if amongst the lucky ones). However, in the meantime, the idea of a 'meat tax' might just have our erstwhile chancellor licking his lips in anticipation of yet another way to fill the coffers!