Last week, the City of Ghent in Belgium started eating vegetarian one day a week. Public officials and politicians will start, with school children following in September. It's their way of acknowledging the impact of livestock on the environment.
Not only is there reason to believe that livestock contribute to greenhouse gases, but meat is resource-intensive to produce. A lot of land and money goes into producing meat in a world with diminishing space. Is meat really the best way to feed our growing population?
I honestly believe it will take environmental catastrophe for people to stop eating other species. I have very little regard for the human conscience when it comes to empathy outside themselves. Only when humans start to freak out about their own survival will they stop eating meat. In the meantime, they will always justify it in some manner whether it be "logic" or "God."