I'm a vegetarian not because I don't like to eat meat, or because I think it's intrinsically wrong to do so (and I probably would eat meat under particular conditions), but because as a person who considers themselves fairly 'aware' of what's going on in our world, I don't think it's ethical to do so. While I at times think the more orthodox vegans can be obnoxious in the way only 'fundamentalists' can be, the call for self-control implied in the major changes in lifestyle necessitated by a transformed and transforming world highlights most people's bottom-line unwillingness to do more than pay environmental lip-service. Our culture of self-indulgence (where a sense of entitlement seems to be the ugly step-sibling of the American dream),
Here's the University of Chicago report by Eshel and Martin (2006), Diet, Energy, and Global Warming where much of the data comes from.
Meat Production 'Beefs Up Emissions' September 7th, The Guardian