The top statements were pure unsubstantiated garbage. Agriculture puts out HGHGs in numerous ways. From bad practices, to mechanization and diesel transportation, plus the ridiculous added sugars, and pressure from extreme gross overpopulation, with the really bad slash and burn emissions. Only 3% of methane is from livestock. Much is coming from the stupid fracking boom, and huge spikes with the Arctic blowholes. More is coming out of the oceans as they warm, and 'drunk forest' and tundras in spring temperatures warmer than the threshold for turnover.
It is only a matter of a decade or so, and people will be eating people, plus any animal they can catch along with stealing all edibles and valuables, in their wandering gangs that eventually run out of food, too. Remote vegetarians may last until temperatures ruin crops before 2050.
I no longer eat as much meat, and no red meat. I also look for added sugars. Gout gets your attention!! The agricultural and food corporations are as bad as the fossil fuel ones, in that profits count more than health or the future of humanity and the planet's biosphere.
I really don't like many vegetarians' better than thou attitude, when they face a different set of health worries, and use it to excuse gross over-breeding like in India. India has a global dimming zone seven times its land size, from fossil fuels and a billion dung cook fires, and the dung and trees are about gone. Soot from them has been shown to be accelerating glacier melting in Greenland. They have disrupted their own needed monsoon regularity, and are near running out of pure ground water while their 'Sacred' Ganges River is full of diseases and human excrement. Half of India's soil is at zero organics and depleted, like China, with only fossil fuel fertilizers making it so the malnourished crop is usable. The soil only holds it in place, not giving it nutrition like it naturally should.
Sure, everyone turning vegan theoretically would make it so about 40% of already deteriorated low soil grazing land can be temporarily used for other foods. I think everyone should do as I do for milk. 1/2 cup almonds with 1 cup water in refrigerator overnight then low then high with 28 ozs cold water in the blender on solar power. Through a sieve into a glass quart bottle, and the leftover can be added to recipes or composted, or even fed to birds.
Tastes just like the dairy kind, but good for you instead of bad.
What does California do?? They let the almond growers have enough less water to ruin them, while giving the unsustainable city people water to flush and waste. 
It is really stupid to use aquifers for agriculture, because they are a very long term loss. In fact it is stupid to use any resources including soils and aquifers, faster than their replenishment rate. People have been depleting and polluting 100 and more times as fast as natural recharge rates, natural regeneration rates, and absorption rates since the early part of last century, getting worse with population growth.
Essentially lowering the long term population possible to sustain, and accelerating to the negative like a reflection of the growth curve. It only gives humanity a few more years if they all go vegan, and before that the entire population is malnourished and losing immunity, along with being pissed off in the crowds.
