Yeah, my friend and I are pretty much unapologetic carnivores -- we half-kid sometimes about buying a 4H cow. But, I've noticed that ever since we started getting fresh veggies, I haven't minded eating the green stuff nearly as much.
I'm skeptical about these food practices being able to feed everyone though. While, personally, I'd like to see dairy farms in California with pasture-fed free-range etc. etc. cattle, that would probably make milk too expensive for poorer families to afford.
I think a lot of tribal meat eaters ate pretty sustainably because their population numbers held pretty steady, didn't explode. So just hunting wasn't enough to require the wild herds to also grow exponentially for survival. Let's face it, the issue is not meat, it's growth of the human population. But nobody wants to advocate eliminating humans (and definitely I don't), so we have to make the hard choices sometimes. I'd say the bigger issue isn't carbon footprint, it's water supply.
A way of implementing this, nudging it towards more politically correctness, is birth control. At one extreme is China's One Child policy, which probably led to some economic benefits (yes, and created other social problems).
Here's a thought: which reduces carbon emissions more, population control, or having a few people in a population do more environmental friendly stuff? (not suggesting one or the either, it actually needs some data.... sneaks away before getting stoned...)
There's a cash bonus paid to women who opt for sterilization after two children, coupled with preferred admission into the best state schools for the children of sterilized women and increasing tax penalties for each child beyond the second.
we have plenty of water, it's just that most of it is dirty, or at least, salty, which makes it unsuitable for irrigation. Dirty water plus energy equals clean water. If the political barriers to fission are overcome, we'd have a whole lot more energy.
I also think that lowering our carbon and environmental footprint by eating less meat is the right thing to do.