The metric of “green house gas” emissions is too crude or blunt to be of any practical use as a regulatory device or for discerning the state of environmental quality. But if it is going to be used then we need to look at all of the implications.
“Eating lettuce is over three times worse in greenhouse gas emissions than eating bacon,” said Paul Fischbeck, professor of social and decisions sciences and engineering and public policy. “Lots of common vegetables require more resources per calorie than you would think. Eggplant, celery and cucumbers look particularly bad when compared to pork or chicken.” click here and here