Guardian: For decades, environmental arguments against eating meat have been largely the preserve of vegetarian websites and magazines. Just two years ago it seemed inconceivable that significant numbers of western Europeans would be ready to down their steak knives and graze on vegetation for the sake of the planet. The rapidity with which this situation has changed is astonishing. The breakthrough came in 2006 when the UN Food and Agriculture Organisation (FAO) published a study, Livestock’s …