If the world population is increasing how do vegetarians hope to make a difference?

Well, I don't like smoking cigarettes, so I don't do that either. Will I single-handedly put the entire tobacco industry to rest simply by avoiding their products? No, and I feel the same way about meat. I like animals and I take them seriously enough to not eat them. I don't need their flesh to survive, so I would rather take the ethical high-road and do what I feel is right. I don't expect to make a big difference, but the least I can say for myself is that I am not directly or purposefully contributing to the exploitation of animals. :)