It's worth noting that rain forest is also cleared for palm and soy. I have yet to see a concise study comparing CO2 and general environmental impact of large soy plantations and meat farms. And I totally support getting rif of industrial style meat farms and production.
Of course, if most of that soy is going to feed cattle, then maybe it should be counted towards cattle's impact - especially when that soy could feed many more humans than the cattle that eats it does.
