What is a belief? A belief is that which we consider to be the truth. That which we consider true constitutes a belief in something. That which we do not believe, we consider to be false. We hence believe that the proposition “the grass is purple” to be true, because the world of our experience, where the grass is always green, tells us otherwise. Connected to the belief that the ‘grass is green’ are three words, ‘is’ which roughly translates as ‘to be’, ‘green which corresponds to a colour in the world of human sensory input identifiable by association with the third word ‘grass’, which indicates a common species of plant life present on our planet. The same may be said of propositions such as: “the sky is blue,” we say that it is true, because we all assent to it; and if our language is different, we translate and infer; we may ask: “well, what colour is the sky (in your language)?” They may reply: “It is x.” Then we say: “well that is your word for blue.” Meaning always implies an equation. If one thing means something, this process is equivalent to something being equal to something else. I was once told, somewhat disingenuously I think, that we determine what a thing is in relation to those things that it isn’t; this isn’t at all how we do it. What we do is we equate the thing in itself simultaneously to our visual impression of it, and also to a sound that we make with our mouths. Hence we can recognise an image of an apple, and associate with a real apple, because it looks the same as one (or at least similar to it), and we associate this with a sound, because we’ve heard other people do the same thing, we then use this sound (or the written word) to indicate that we mean an ‘apple’ when talking about one.
Pretty much every activity humans undertake has an emissions footprint of some description, and animal agriculture is no different. However, when the suggestion arises that since animal agriculture is responsible for quite a large proportion of manmade greenhouse gas emissions and that we can eliminate these emissions immediately through simply getting rid of it, there are major issues that the vegan activist community has failed to address, and which could spell disaster if such a system were to be implemented. What they've as yet failed to establish is what the current system of agriculture is to be replaced with, the timescales involved and whether or not this new paradigm will actually emit less methane and CO2; additionally, they've failed to answer the most important question in all this: whether or not vegan agriculture can actually feed the population. In addition to this, I suspect that animal agriculture isn't the progenitor of the rising levels of atmospheric methane, which started in the 19th century, since this rise followed the Industrial Revolution and the burning of fossil fuels, not the Agricultural Revolution of the 17th century.