I applaud the idea on general principle, but the last paragraph of this article spells that it is probably too late already:

> The latest United Nations Food and Agriculture Organization report on the future of agriculture[0] indicates that most of the predicted growth in demand for meat from China and Brazil has already happened and many Indians are wedded to their largely vegetarian diets for cultural and culinary reasons.

While I think it would be a good idea because we should actually strive to reduce our production of greenhouse gases, the above paragraph indicates that it's unlikely to become economically viable.

[0] http://www.fao.org/docrep/016/ap106e/ap106e.pdf